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Physician-scientist studies how technology can improve communication about fertility issues
by Diane Duke Williams•July 26
has been named director of the Division of Reproductive Endocrinology & Infertility in the Department of Obstetrics & Gynecology at Washington University School of Medicine in St
Kenan Omurtag, MD, an accomplished fertility specialist, educator and mentor, has been named director of the Division of Reproductive Endocrinology & Infertility in the Department of Obstetrics & Gynecology at Washington University School of Medicine in St Louis
“Kenan has extensive clinical expertise, is an excellent mentor and has played an important role in our curriculum development,” said Dineo Khabele, MD, the Mitchell and Elaine Yanow Professor and head of the Department of Obstetrics & Gynecology
innovative ideas and vision he brings to the division make him ideal for his new role
an associate professor of obstetrics & gynecology
maintains an active clinical practice focused on in vitro fertilization
and medical and surgical treatment of endometriosis and uterine fibroids
His research efforts have focused on how technology
can be used to disseminate information about fertility issues
as well as to improve communication between patients and fertility clinics’ staffs
Omurtag also is one of the first to describe experiences of and novel approaches to fertility preservation among transgender and nonbinary adults and adolescents
He has published and lectured extensively nationally and internationally on these topics
He also serves as medical director of the Washington University Fertility & Reproductive Medicine Center and as co-director of its Integrative Care & Fertility Preservation Program
and there are no guarantees for patients,” Omurtag said
“The next decade of innovation in fertility care will focus on improving the patient experience and improving access to these services
I am honored to take on the role of division director.”
earned his bachelor’s and medical degrees in a six-year program at the University of Missouri—Kansas City School of Medicine
He completed a residency in obstetrics & gynecology at Emory University School of Medicine/Grady Hospital and a fellowship in reproductive endocrinology and infertility at Washington University School of Medicine
He joined Washington University in 2013 as an assistant professor of obstetrics & gynecology and was named an associate professor in 2018
he served as a laborist at Missouri Baptist Hospital/BJC HealthCare and as a health-care policy fellow at Partners Healthcare in Boston
williamsdia@wustl.edu
Could help determine which patients are likely to benefit from new Alzheimer’s drugs
GLP-1 medications tied to decreased risk of dementia
At WashU Medicine, we transform lives and shape the future of healthcare through pioneering research, world-class education, and unparalleled patient care. As one of the nation's largest academic clinical practices, we bring the full power of WashU Medicine to every patient, advancing treatment and training the medical leaders of tomorrow at Barnes-Jewish and St. Louis Children's hospitals
and more than 130 clinics across Missouri and Illinois
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we are driven to challenge convention and elevate care for all
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Children born to mothers infected by Zika virus (ZIKV) during pregnancy are at increased risk of adverse neurodevelopmental outcomes including microcephaly
collectively known as Congenital Zika Virus Syndrome
To study the impact of ZIKV on infant brain development
we collected resting-state electroencephalography (EEG) recordings from 28 normocephalic ZIKV-exposed children and 16 socio-demographically similar but unexposed children at 23–27 months of age
We assessed group differences in frequency band power and brain synchrony
as well as the relationship between these metrics and age
Bonferroni corrected) in Inter-Site Phase Coherence was observed: median Pearson correlation coefficients were 0.15 in unexposed children and 0.07 in ZIKV-exposed children
Results showed that functional brain networks in the unexposed group were developing rapidly
in part by strengthening distal high-frequency and weakening proximal lower frequency connectivity
presumably reflecting normal synaptic growth
These maturation patterns were attenuated in the ZIKV-exposed group
suggesting that ZIKV exposure may contribute to neurodevelopmental vulnerabilities that can be detected and quantified by resting-state EEG
These findings underscore the importance of developing functional methods to assess neural synchrony in normocephalic individuals who were prenatally exposed to the Zika virus
While structural imaging is invaluable for revealing physical abnormalities in the brain
it may not capture the subtle functional disruptions that can occur
This study aimed to address the current knowledge gap by investigating EEG-based functional connectivity in ZIKV-exposed normocephalic
nonepileptic children (ZEC) compared to demographically matched children unexposed to ZIKV (UC)
By focusing on inter-site phase clustering (ISPC)
we sought to elucidate potential alterations in brain network organization associated with prenatal ZIKV exposure in the absence of microcephaly or epilepsy
particularly in brain areas likely to be affected by the virus
together with an analysis pipeline based on the identification of changes in ISPC with age
The average duration of EEG recordings in the analysis group was 12.8 min
Relative band power and its age-dependence
(A) Relative frequency band power (FBP) as a function of frequency for each electrodes site
The UC (solid green line) and ZEC (dashed purple) averages are shown
(B) Topographic illustration of the correlation of FBP with age for specific frequency ranges for the UC (top row) and ZEC (bottom)
Distribution of developmental change in synchrony
the correlation of ISPC with age in the UC (purple) and ZEC (green)
respectively) are shown by the dashed vertical lines; (B) Scatter plot of rN and rZ
with each dot corresponding to an electrode pair and specific frequency
and the diagonal dashed line showing rN = rZ
These correspond to ISPC in the infant gamma frequency range
phase clustering between the left inferior frontal scalp area and the right frontopolar (FP2-F7 at 28–38 Hz) and right parietal areas (P4-F7 at 28–30 Hz)
The correlation strength between inter-site phase clustering (ISPC) and age in UC and ZEC are grouped into rows depending on their effect size in UC
(A) Rapidly increasing; (B) moderately increasing; (C) stagnating; (D) moderately decreasing; (E) rapidly decreasing
Columns 2–5 show randomly selected examples of electrode pairs
separated into UC (purple circles) and ZEC (green triangles) groups
The distribution of the developmental change in synchrony in frequency bands
UC (solid purple) and ZEC (green dashed) for the frequency bands indicated above each subplot
The vertical lines indicate the medians of the corresponding distributions
Distributions whose medians differ significantly are indicated using an asterisk located between the vertical lines showing the medians (*p < 0.05
Topographic illustration of the developmental changes in connectivity
The frequency band for each pair of columns is shown at the top
UC (left) and ZEC (right) connectivity development are shown as lines
Each row corresponds to a different development speed
(A–D) Rapidly developing; (E–H) moderately developing; (I–L) stagnating; (M–P) moderately weakening; (Q–T) rapidly weakening
A line’s colour indicates the sign of the change (blue/red for increase/decrease in ISPC with age) and the line’s thickness is proportional to the magnitude of the change
as indicated in the figure legend at top right
central and frontal areas both inter- and intra-hemispherically
Similar patterns of rapid normal development of pervasive high frequency networks were observed also in higher frequency bands (not included in this figure)
Graph theoretic characterisation of networks and their dependence on frequency
The characteristic path length (A–D) and the clustering coefficient (F–I)
based on all pairs of channels at all frequency bands
in UC (purple solid) and ZEC (green dashed)
The values for individual UC (circles) and ZEC (triangles) and their best fit lines are shown
The rightmost column shows the correlation of the path length (E) and of the clustering coefficient (J) with age
as a function of the frequency of the connection
The shaded regions around each curve indicate the sample standard deviation
Dependence of connectivity development on frequency and cortical distance. Distances based on the MNI locations of primary neuronal populations in adult cortex associated with each electrode, for the UC (A) and ZEC (B). See Table 2 for selected electrode pairs and their values of ISPC at the numbered zones 1–10
This suggests a potential association between altered ISPC and the observed visual dysfunction
offers a theoretical framework to explore how aberrant neural network organization might underlie these visual impairments
Further investigation into this relationship is warranted to elucidate the pathophysiological mechanisms underlying ZIKV-associated visual dysfunction
This could have contributed to later neurodevelopmental gain and reiterates the importance of directing at-risk children to appropriate early intervention programs
Through the analysis of resting-state measurements performed with a portable EEG system
we have uncovered evidence that prenatal ZIKV exposure disrupts the development of large-scale neural network synchrony
The extent to which this is transient and recoverable remains unknown
the functional implications for the disrupted large-scale neural network development now or in the future remain unknown
Our findings shed light on the disruption of normal changes in signal amplitude and shifts from proximal to largely distal functional connectivity
as well as network trends toward small-world properties in young children
These could form the basis for developing practical methods of EEG scanning to assess neurodevelopment
particularly valuable for nonverbal populations
for the purpose of early and targeted provision of therapeutic resources
This approach could be especially beneficial for addressing global child health disparities
particularly in resource-limited settings where children may be disproportionately vulnerable to teratogenic exposures
this study suggests that it is feasible to use cost-effective portable EEG with integrated advanced analysis to study and manage the spectrum of ZIKV’s neurodevelopmental effects
The study was approved by the Institutional Review Boards of St
West Indies (IRB#16061) and Stanford University
and granted research clearance by the Grenada Ministry of Health
Mothers provided written informed consent for themselves and on behalf of their participating children and all methods were carried out in accordance with relevant guidelines and regulations
Caregivers assisted by holding or comforting the children during EEG recordings
caregivers spoke to them softly or read to them while the EEG cap was being applied and during the recording session
The data contained resting-state EEG recordings from 73 children
of whom N = 50 were ZEC (23 female) and N = 23 were UC (11 female)
We next determined the clustering coefficient (CC) and characteristic path length (PL)
which are commonly used in network analysis
CC measures how well connected the neighbours of a typical node are to one another
and high values of CC are associated with functional segregation
PL is the mean shortest path over all pairs of nodes
where the distance was calculated from the inverse of ISPC values
PL quantifies the capacity for information transfer across the network
and low values of PL are associated with greater functional integration
We investigated potential developmental trends in FBP
by determining the Pearson correlation of the relevant quantity with age
where the correlation was denoted rN and rZ for UC and ZEC
the Wilcoxon Signed-Rank test was used for paired values
the set of ISPC values in UC for a specific connection versus the set of values in ZEC for the same connection
and the Kolmogorov–Smirnov (KS) test when the groups were unpaired
the interaction between Zika status and age was assessed with ANCOVA
resulting in N(N − 1)/2 = 171 unordered channel pairs
a total of 171 × 40 = 6840 distinct ISPC values were analysed
The significance threshold was adjusted by dividing the conventional p-value of 0.05 by 6840
yielding p = 0.00000731 as a criterion for statistical significance to control the family-wise error rate across all comparisons
The above calculations were implemented via custom code in MATLAB and using the functions signrank
All data needed to evaluate the conclusions in the paper are present in the paper and/or the Supplementary Materials. All EEG data and analysis scripts are available at https://doi.org/10.5281/zenodo.13311078
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Geisel School of Medicine at Dartmouth and Dartmouth College
Windward Islands Research and Education Foundation
State University of New York Downstate Health Sciences University
National Health Service Clinical Scientist Training
Oxford Maternal and Perinatal Health Institute
Nuffield Department of Women’s and Reproductive Health
ADL (for serological analyses to establish ZIKV status) Investigation: AO
SAB is an employee of Bio-Signal Group Inc
owns stock options in BSG and is a coinventor on US patent US9408575B2
AO was previously an employee of BSG and is a coinventor on US patent US9408575B2
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Volume 11 - 2017 | https://doi.org/10.3389/fnhum.2017.00359
We studied the capability of a Hybrid functional neuroimaging technique to quantify human mental workload (MWL)
We have used electroencephalography (EEG) and functional near-infrared spectroscopy (fNIRS) as imaging modalities with 17 healthy subjects performing the letter n-back task
a standard experimental paradigm related to working memory (WM)
The level of MWL was parametrically changed by variation of n from 0 to 3
Nineteen EEG channels were covering the whole-head and 19 fNIRS channels were located on the forehead to cover the most dominant brain region involved in WM
Grand block averaging of recorded signals revealed specific behaviors of oxygenated-hemoglobin level during changes in the level of MWL
A machine learning approach has been utilized for detection of the level of MWL
and EEG+fNIRS signals as the biomarkers of MWL and fed them to a linear support vector machine (SVM) as train and test sets
These features were selected based on their sensitivity to the changes in the level of MWL according to the literature
We introduced a new category of features within fNIRS and EEG+fNIRS systems
the performance level of each feature category was systematically assessed
We also assessed the effect of number of features and window size in classification performance
SVM classifier used in order to discriminate between different combinations of cognitive states from binary- and multi-class states
In addition to the cross-validated performance level of the classifier other metrics such as sensitivity
and predictive values were calculated for a comprehensive assessment of the classification system
The Hybrid (EEG+fNIRS) system had an accuracy that was significantly higher than that of either EEG or fNIRS
Our results suggest that EEG+fNIRS features combined with a classifier are capable of robustly discriminating among various levels of MWL
Results suggest that EEG+fNIRS should be preferred to only EEG or fNIRS
in developing passive BCIs and other applications which need to monitor users' MWL
MWL is a construct that arises from the interaction of the properties of a task, the environment in which it is performed, and the characteristics of the human operator performing it (Longo, 2016)
Task properties include the difficulty and monotony of the task and the types of resources that it engages
The environment may contain various degrees of distraction and noise
The subject characteristics involve training and expertise as well as changing levels of fatigue
the MWL can be systematically adjusted by tuning a subset of these variables while controlling for the rest
which is a gold-standard for measuring cerebral hemodynamics
In addition to the advantages of pooling different types of signals
EEG+fNIRS offers new types of features
ultimately based on neurovascular coupling (NVC)
the cascade of processes by which neural activity modulates local blood flow and oxygenation
and NVC related features are not resolvable by a uni-modal signal sensitive to only neural activity (e.g.
we built on this work to explore the unique properties of EEG+fNIRS for MWL detection
the third aim of this study was to rigorously compare the performance of uni-modal and Hybrid systems
1 female) with a mean age of 26.2 and standard deviation of 7.7 years from University of Houston students or employees participated in the experiment
The experimental procedures involving human subjects described in this paper were approved by the Institutional Review Board of the University of Houston
The participants gave written informed consent prior to the experiments and were compensated for their effort by being given a gift card from a major retailer
During the performance of the verbal n-back task
target letters should be detected by the operator by means of pressing Space button on the keyboard
All subjects were right-handed and used their dominant hand for performing the experiment
This will reduce the variability of brain signals based on the motor function through all subjects
None of the subjects had ever taken part in an n-back study
subject should find the target letter and interact with the user-interface
Schematic illustration of the letter n-back task for n ϵ {0
The program for implementation of this task was written using Presentation software (Neurobehavioral Systems
All the information about the appearance time of each letter
and also whether the presented letter was a target or not was recorded by this software and stored as a text file for later processing
The objective performance of the subjects within each session was computed from this information
Subjects who had too low accuracy (<90% in the 0- or <80% in the 1-back) were deemed insufficiently focused on the task
Performance level was measured by computing the accuracy defined as the fraction of correct responses
We considered a missed target as an incorrect response
Experimental design for the letter n-back task
NIRScout is a dual wavelength continuous wave system
The EEG signal was band-pass filtered (0.5–80 Hz)
and a 60 Hz notch filter was used to reduce the power line noise
and data transmission to the acquisition platform
(b) Coronal view of the subject showing the close view of the placement fNIRS optodes and EEG electrodes
(c) Topographical view of fNIRS sources (Si
Each pair of source and detector separated by 3 cm creates a channel (CHi)
The figure indicates the temporal variations in the fNIRS signals and the EEG frequency bands
First and second rows are HbO and HbR of fNIRS channel 17
Third row is the EEG time-frequency map for channel O2
Topographic view of EEG electrodes showing neighborhood pattern for Laplacian spatial filtering
Inward arrows to each node indicate the corresponding neighbors used for spatial filtering
Sample preprocessed EEG+fNIRS data for one of the subjects
Vertical dashes separate different n-back task and rest blocks
(a) Concentration changes of oxy-hemoglobin (red curve) and deoxy-hemoglobin (blue) for channel 17
(b) EEG Time-frequency map of the channel O2
In our experiment design we have 40 rest blocks and 10 blocks from each n-back task type
and 2 features were extracted when we changed the size of the window from 5 to 25 s
and 1 features were extracted when we changed the size of the window from 5 to 25 s
Four different epoch styles based on length of windows
The task and rest blocks are divided into (A) 5
We extracted from each window three main categories of features for all 19 EEG electrodes and 19 fNIRS channels: EEG (uni-modal)
We chose 8 EEG channel pairs between right and left hemispheres (F8-F7
fNIRS features were based on HbO and HbR amplitude (HbO/R Amp.), slope of HbO and HbR (HbO/R slope), standard deviation of HbO and HbR (HbO/R Std.), skewness of HbO and HbR (HbO/R Skew.), and kurtosis of HbO and HbR (HbO/R Kurt.). The statistics of HbO and HbR are commonly used as features in fNIRS studies of MWL and BMIs (Naseer and Hong, 2015; Naseer et al., 2016a,b)
Our inspection of the fNIRS data revealed patterns of correlation between HbO and HbR that were time and area dependent
we also included the zero-lagged correlation between HbO and HbR (HbO-HbR Corr.) as an additional feature
Hybrid features were based on EEG and fNIRS features in addition to specifically Hybrid quantities that depend simultaneously on both systems
We chose to focus on a straightforward quantity
which can be easily calculated within the time windows of interest: the zero-lagged correlation between the Hb (HbO or HbR) amplitude and the EEG frequency band power (in eight separate bands described above)
These neurovascular features based on HbO and HbR were denoted NVO (oxygenated neurovascular coupling) and NVR (deoxygenated neurovascular coupling)
To calculate NVO/R for the left hemisphere
the correlation between each fNIRS channel (CH1 to CH9) and each frequency band of F7 EEG channel was calculated (band-passed filter within the specific frequency range)
the correlation between each fNIRS channel (CH11–CH19) and each frequency band of F8 EEG channel was calculated
which is located at the center we used the average of F7 and F8 channels to find NVO and NVR
This resulted in 152 (19 × 8) NVO and 152 NVR features from each window
Each set of features extracted from one subject's data were dc-shifted and scaled in order to have a mean value of zero and standard deviation of one
We pooled all the k confusion matrices of the k-fold cross validation to calculate Sens.A
For all the calculations described in this paper we used Matlab v.8.6.0.267246 (R2015b) (The MathWorks
The top R2 ranked features for three representative subjects for the binary rest v 3-back classification
Behavioral performance of the subjects during task conditions of increasing difficulty
showing response accuracy (red) and response time (black)
Error bars indicate the standard deviation of inter-subject variability
Asterisks indicate statistical significance derived from a two-way ANOVA comparison of each two response accuracy (red) or response time (black) (*p < 0.05
These patterns are not observed in the case of the 0-back task since it is related to perception only and is less involved with WM system
We also examined the time course of selected features that were extracted from the signals
Grand block average of normalized HbO (red) and HbR (blue) during (a) 0-back
The thick curves show the average over all channels and subjects
The shaded area indicates the standard deviation of inter-subject variability
Grand block average of HbO (f) and HbR (g) for rest (dashed curves) and task (solid)
Increasing thickness of solid curves corresponds to increasing task difficulty from 0- to 3-back
The figure shows that the theta and alpha bands of EEG are positive during 0- and 1-back
although they become negative for 2- and 3-back tasks
The positive peak of HbO increases from 0- to 2-back and has a slightly lower peak for 3-back compared to 2-back
The figure also shows that the Hybrid features (such as NVO in the delta range) generally resemble the corresponding uni-modal features (such as HbO and PSD in the delta range) however they were dominated by neither
suggesting that the Hybrid feature contained additional information
Grand block average of normalized features from 5 s windows: (a) PSD (delta
Shaded areas indicate the standard deviation of inter-subject variability
Table 1 shows the top 10 highest ranked features (based on R2) for three subjects obtained during the 3-back v rest training set
The features are characterized by the description (e.g.
as described in Section Methods) and the particular frequency band
The frequency band is applicable only to the EEG and neurovascular features
The table also indicates the order of the feature according to the magnitude of its eigenvalue [ordered from the most energetic (1) to the least (19)]
the channel label is given instead of the PC order
the highest ranked feature for subject one was the third most energetic PC from the EEG frequency band power in the theta range (4–8 Hz)
the highest ranked feature was the second most energetic PC from the neurovascular feature based on the correlation between HbR and the EEG frequency band power in the high beta range (28–32 Hz)
The table illustrates that the types of features in the top ranked group may vary among subjects and that high discriminating ability of a feature does not imply high energy in the sense of the PCA
Figure 10 shows the classification accuracies of various subsystems as well as the Hybrid system for the 3-back v rest using 5 s windows
The error bars represent the standard deviation of inter-subject variability
the leftmost bar is the accuracy of a system based only the PSD features
On its immediate right is the accuracy of the subsystem based only on PLV features
and similarly for PAC and other feature types
The rightmost bar in the EEG group shows the accuracy of the full EEG system which includes all feature types based on EEG signals
Clearly the PSD is the primary contributor to the discriminating ability of the EEG
the accuracy appears to be slightly enhanced by including the other types of features
Among the fNIRS systems (red) the leftmost bar indicates that Hb amplitudes together with the HbO-HbR correlation is the primary contributor to the accuracy of detection
the other feature types such as slope and higher order statistics significantly enhance the accuracy of the fNIRS system
The overall accuracy of the fNIRS system is lower than the overall accuracy of the EEG system
The accuracy based only on the neurovascular features is indicated by the leftmost bar in the Hybrid group (green)
The middle bar in the Hybrid group represents the pooling of all features from the EEG and fNIRS systems
Finally the inclusion of the neurovascular features in the Hybrid system (rightmost green bar) appears to slightly enhance the accuracy
Accuracy of types of features in classifying rest v 3-back with 5 s feature windows
The error bars indicate the standard deviation of inter-subject variability
The union of neurovascular features is abbreviated as NV
Features are extracted from different systems: EEG (gray bars)
The calculations are for the 3-back v rest using 5 s windows and they qualitatively agree with the results (not shown) of binary classifications of other pairs of classes and window sizes
The shaded areas indicate the standard deviation of inter-subject variability
(a) Accuracy and (b) cumulative sum of R2 for EEG (black)
and Hybrid (green) systems as a function of system size
Mean and standard deviation over subjects are indicated by the solid curves and shaded areas
The classification task was rest v 3-back and feature window size was 5 s
Binary classification accuracy for all subjects included in the study (S1 to S14) for 10-fold cross validation
Multi-class classification accuracy for all subjects included in the study (S1 to S14) for 10-fold cross validation
the differences of accuracy among the subjects were not significant and there were no interactions between system type and subject
while the differences in accuracy between the Hybrid and the uni-modal system was significant with a p < 0.001
Table 4 lists the sensitivity (Sens.)
and negative predictive value (NPV) for each individual class within a classification case
For example for the case of {Rest v 3back}
each one of rest and 3-back classes would have a Sens.
this table summarizes all these metrics for EEG
and Hybrid systems in order to make it easier to compare between their capabilities
and negative predictive value (NPV) are listed in percentage (%) for all classification cases (binary and multi-class) and all systems (EEG
The foregoing results corresponded to 5 s windows but qualitatively agreed with patterns we observed with other window sizes as well. We also assessed the effect of window length on classification accuracy for EEG, fNIRS, and Hybrid systems. Figure 12 shows the results of this assessment
We examined four different lengths for the windows (5
Change of window length has the same effect on all three types of systems
By increasing the length from 5 to 20 the accuracy increases and declines thereafter
Accuracy of the rest v 3-back classification as a function of window size for EEG (gray)
The functional activity of the human brain can be observed with various imaging techniques including fMRI
Each of these modalities has its advantages and disadvantages
The advantage of using Hybrid EEG+fNIRS system can be divided into two main categories: First
each of these modalities is measuring the changes in a specific brain physiology
EEG results directly from the electrical activity of cortical and subcortical neurons with a sub-millisecond temporal resolution
fNIRS yields local measures of changes in HbO and HbR concentration and is
an indicator of metabolic/hemodynamic changes associated with neural activity
the physics of measurement behind EEG and fNIRS are quite different
makes EEG signal prone to blink and muscle artifacts
Hence using a multimodal recording system we are able to assess brain behavior from different physiological perspectives in addition to compensating for some weaknesses of one modality by the other one
Our results suggest that EEG+fNIRS combined with a classifier are capable of robustly discriminating among various levels of MWL
the Hybrid system had an accuracy higher than either EEG or fNIRS alone for every subject
The pooling of EEG and fNIRS features and the inclusion of neurovascular features resulted in a synergistic enhancement
rather than in a diluting effect (which would have given a performance intermediate between the two modalities)
In mission-critical contexts such as aviation or surgery
even small improvements in MWL detection can translate into significant gains in safety and efficiency
Our experiments were designed to use WM load (adjusted through the value of n in the n-back task) as a correlate of MWL in general
EEG and fNIRS can be integrated without excessive cost
The combination of all these considerations suggests that EEG+fNIRS should be preferred to only EEG or fNIRS
he loses his concentration on the task and as a result performance as well as the oxygenated hemoglobin changes decline
the subject averaged accuracy of the Hybrid system in binary discrimination was lowest (87.2%) for 1-back v rest and highest (96.6%) for 3-back v 0-back
The corresponding lowest and highest results for uni-modal systems were fNIRS (71.6%) and EEG (92.0%)
We calculated the overall average of accuracy one time for all of the binary cases and one time for all of the muli-class cases
These numbers convey that the accuracy of each one of EEG
and Hybrid systems are higher for the binary cases
The multi-class accuracies were generally lower; however
note that the chance level accuracy for multi-class classification is less than binary classification (33% for 3-back v 2-back v 1-back
Selecting an optimal subset from the full set of features is crucial for achieving high accuracy and avoiding over-fitting. In some applications, e.g., those involving on-board real-time analysis, it may also be important to keep the system size small and avoid computational delays. Figure 11b shows the cumulative sum of R2 v number of features for three systems which qualitatively agrees with Figure 11a
suggesting that R2 ranking is an effective method of feature selection
We have not used an explicit artifact rejection step in our analysis
it is well known that PCA can segregate non-cerebral artifacts (typically of higher amplitude than contributions of cortical origin) into distinct PCs
Our feature selection based on R2 then assigns a lower rank to such PCs and they are excluded from a truncated system
One of the main considerations in developing an online system is computational speed. It is instructive to review the computational loads of particular feature types in conjunction with how effectively they discriminate among rest and task states. For example, Figure 10 shows that PAC is the least discriminating EEG feature
This may be important in designing a compact and efficient detector
as PAC is also the most computationally time-consuming feature
the most effective EEG feature (PSD) was also the fastest to compute
the central processing unit (CPU) time required for computing PSD
The CPU times required for other features were as follows: HbO/R Amp
EEG and fNIRS use different physical processes for detection and the underlying physiology which they detect are different
or subject variability leading to a weak signal would selective affect only one modality rather than both
The Hybrid advantage may be associated primarily with the complementary nature of the individual modalities
They extracted EEG frequency band power and fNIRS Hb amplitude features from 5 s windows and employed them in linear discriminant analysis classifiers
They report maximum accuracies of 89.6% (EEG)
Their results differed from ours in that in some subjects all their systems had very low accuracies and their Hybrid accuracies were not always higher than those of both uni-modal systems
the fact that EEG generally had the higher uni-modal accuracy and that Hybrid could attain the highest observed accuracy were consistent with our findings
The differences from our results could be attributed to the relatively lower number of sensors and fewer types of features they employed
We defined the band-pass filter cutoff frequency (0.5–80 Hz) based on these criteria
Although in the feature extraction section
we did not consider gamma frequency range features and have considered this as the future work
we implicitly used the assumption that an increase in the level of task difficulty will result in a higher MWL
This can be also considered in future studies
it is possible that during the course of an experiment the subjects' performance and MWL change through training effects
Studying the performance and neural correlates of MWL for subsets of our data could reveal differences in the beginning and at the end of the study
This would also require an additional investigation of statistical validity
The statistical significance of the results of our study was demonstrated through a two-way ANOVA that showed significant differences in the accuracy of the Hybrid v uni-modal systems
we have not investigated whether a smaller group of subjects would still yield a significant result
We have investigated the capabilities of various subsets of the types of features that were available
It would also be illuminating to investigate the classification accuracy of subsets of the full array of our sensors
Such information can help design more compact headsets and is the subject of an ongoing study
The headset we used is lightweight and no discomfort was reported by any of the subjects
wearing it may nevertheless affect performance
and this could be revealed in a parallel set of experiments which we have not done
The primary goal of our study was to apply machine learning techniques in discriminating levels of MWL
We used multiple statistical techniques to ensure that the statistical significance of the values of accuracy that we obtained for such discrimination
Our observations regarding the range of changes of Hb are therefore only qualitative and observational
serving to ensure that our results are consistent with expectations
will lead to more effective passive BMIs and other applications in neuroergonomics
This work is based partly on support by the National Science Foundation I/UCRC for Cyber-Physical Systems for the Hospital Operating Room under Grant no
We would also like to thank the Department of Biomedical Engineering and the Cullen College of Engineering at University of Houston for its financial support (Award no
AO participated in the development of the wireless portable EEG device (microEEG)
He holds a financial interest in Bio-Signal Group which is the maker of microEEG
The other authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest
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Keywords: functional near-infrared spectroscopy (fNIRS)
Garbey M and Omurtag A (2017) Measuring Mental Workload with EEG+fNIRS
Received: 09 January 2017; Accepted: 23 June 2017; Published: 14 July 2017
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*Correspondence: Haleh Aghajani, aGFnaGFqYW5pQHVoLmVkdQ==
†Present Address: Ahmet Omurtag Nottingham Trent University
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This paper investigates the neural mechanisms underlying the early phase of motor learning in laparoscopic surgery training
brain-derived neurotrophic factor (BDNF) concentrations and subjective cognitive load recorded from n = 31 novice participants during laparoscopy training
Functional connectivity was quantified using inter-site phase clustering (ISPC) and subjective cognitive load was assessed using NASA-TLX scores
The study identified frequency-dependent connectivity patterns correlated with motor learning and BDNF expression
Gains in performance were associated with beta connectivity
particularly within prefrontal cortex and between visual and frontal areas
and were predicted by delta connectivity during the initial rest episode (r = 0.83)
The study also found correlations between connectivity and BDNF
with distinct topographic patterns emphasizing left temporal and visuo-frontal links
By highlighting the shifts in functional connectivity during early motor learning associated with learning
and linking them to brain plasticity mediated by BDNF
the multimodal findings could inform the development of more effective training methods and tailored interventions involving practice and feedback
The skill acquired rapidly during the early phase of laparoscopic training lays the foundation for later consolidation
hence insights into its neural correlates are potentially useful for designing more targeted forms of practice and feedback
NASA-TLX scores were used to elucidate the cognitive demands imposed by the learning task
The results demonstrated simultaneous improvement in speed and accuracy as well as reduction in cognitive load
and patterns of frequency-dependent connectivity were correlated with the extent of motor learning as well as BDNF expression
We also showed that graph-theoretic properties of the functional networks during rest as well as task performance could be used to discriminate between high- and low-learners
could offer a comprehensive understanding of the complex processes underlying the initial phases of motor learning
EEG was recorded throughout the experiment from 19 channels positioned at the standard 10–20 sites and performance and self-reported cognitive load were measured
Experiments and behavioural and subjective indicators of learning
(A) Photograph of Ring Transfer and Threading boards and a task performing participant
(C) Completion times of initial (x-axis) and repeat (y-axis) performances of the Ring transfer (blue circles) and Threading (red squares) tasks
(D) Change in (repeated minus initial) Error Rate v change in Completion Time for the Ring Transfer task
(E) NASA-TLX Effort score for the initial (x-axis) and repeated (y-axis) tasks
(F) Change in NASA-TLX Effort score v change in Completion Time
Results from the two subjects who reached the 15 min max allowed time in the ring task are indicated by a black plus sign
Connectivity was quantified by ISPC to show the extent of clustering in the polar space of the phase angle differences between pairs of narrowly band-limited signals34
There were a total of 5472 distinct ISPC values as each ISPC was associated with a 1 Hz wide frequency band (in the range 1–32 Hz) as well as a specific pair of electrodes (with 171 undirected pairs of 19 electrodes)
the effect of task performance (Task (black curves) relative to Rest (green)) was to lower ISPC in the alpha and lower frequency ranges
while strengthening beta frequency links across all cortical distances
We also examined the topographic locations of the strongest connections during Rest and Task performance. Figure 2F
G represent ISPC values by a line connecting a pair of sites
These links show the connections with the highest values of ISPC (only top 30 were selected to avoid clutter in the figure)
Symmetric inter-hemispheric frontal connectivity (F7-F8)
as well as longitudinal inter-hemispheric connections (e.g
theta and alpha frequencies were salient in both the initial rest (F) and the task (G)
In addition intra-prefrontal connections (e.g
Subject averaged functional connectivity during Rest and Task episodes
The top row shows the ISPC averaged across connections linking (A) short
and (E) long cortical distances as a function of the connection frequency
for the Rest (green curves) and Task (black solid) and T1R (black dotted) episodes
The range of cortical distance for each of these groups is indicated above each subplot
Also shown are ISPC for selected frequencies during initial Rest (F) and initial Task (G) episodes with the frequencies indicated above each column
The task-evoked change (Task minus Rest) in ISPC is shown in the bottom row (H) where increase and decrease are indicated by red and blue lines
The top 30 connections with the largest differences are shown
Each column is for a selected frequency (shown at the top) while the connections whose correlation coefficients are within the distinct ranges have been segregated into separate rows for better visibility
The ISPC for each participant in this figure was calculated by averaging the ISPCs corresponding to the red lines in the 3 Hz topographic subplot C
The association between functional connectivity and performance improvement
quantified by the Pearson correlation between ISPC and Rescaled Speed Increment
ISPC was calculated during initial rest (A–D) and initial task performance (E–H)
Histograms of correlation coefficients for the frequencies are displayed for rest (A) and task (E)
with 95% confidence intervals indicated by grey shaded regions
Topographic illustrations are provided for the connections during rest (B) and during task (F) that were strongly anticorrelated (r < – 0.4) with RSI; and during rest (C) and task (G) that were strongly positively correlated (r > 0.4) with RSI
Also shown are scatter plots of ISPC v RSI
where ISPC was calculated as the average of connectivity (D) at 3 Hz during rest and (H) at 24 Hz during task
The association between functional connectivity and BDNF
Topographic illustrations are provided for the connections during rest (B) and during task (F) that were strongly anticorrelated (r<–0.4) with BDNF; and during rest (C) and task (G) that were strongly positively correlated (r > 0.4) with BDNF
Also shown are scatter plots of ISPC v BDNF
where ISPC was calculated as the average of connectivity (D) at 7 Hz during rest and (H) at 16 Hz during task
By using ISPC as the weights of edges between nodes represented by electrodes
we constructed weighted undirected graphs whose properties provided descriptions of the overall connectivity profile and its association with motor learning
For these graphs we calculated the characteristic path length (λ) and clustering coefficient (CC)
The reciprocal of λ quantifies network integration or the efficiency of information transfer across the network
while CC measures network segregation resulting from the extent to which nodes tend to cluster together
Graph theoretic quantities and their association with motor learning quantified by RSI
Characteristic Path Length (A) and Clustering Coefficient (C) and the correlation between the Rescaled Speed Increment and Characteristic Path Length (B) and Clustering Coefficient (D) shown as functions of frequency
for Rest (green curves) and Task (black) episodes
The final Rest or Task episodes are indicated by dotted lines
This study presents several novel findings
it demonstrates and quantifies within-session learning in laparoscopic surgery training using the Rescaled Speed Increment
which is independent of the participants’ baseline performance
providing a robust metric to assess skill acquisition during training sessions
we utilised narrow-band inter-site phase clustering
rather than connectivity measures in the traditional wider frequency bands
to quantify the functional connectivity between different brain regions in the participants
the study has shown that shifts in brain’s functional connectivity in specific combinations of frequency and topography were linked to performance enhancements as well as blood BDNF concentrations
the down-regulation of prefrontal and frontal connectivity was revealed to be a significant promoter of fast motor learning
suggesting that cognitive load was not close to levelling off
consistent with the longer time-course of the automation process
It is also worth noting that if the phase clustering had been driven primarily by volume conduction
ISPC would have shown a steady decline with increasing cortical distance
rather than the observed non-monotonic dependence
The performance of bimanual visuomotor training tasks was expected to strengthen the high-frequency inter-hemispheric connections over the motor regions, as well as the connections linking the occipital (visual) and frontal areas. This hypothesised outcome was indeed observed, as depicted by the red lines in Fig. 2H
We used histograms of correlation coefficients as a guide in discovering connectivity related to learning (Fig. 3)
since a histogram will deviate from the null distribution only if there is a pervasive pattern of correlations with the same sign outweighing those of the opposite sign; strong individual correlations potentially due to chance are not sufficient to skew the histogram (Figures S2-S5)
Investigating the extent to which changes in connectivity correlate with learning (Figure S7) showed that high learners had significantly greater task-evoked declines in delta band connectivity (Figure S7B)
Thus our findings about the predictive role of resting and task-evoked changes in delta connectivity for fast motor learning warrants further study
However by closely examining the correlations between ISPC with RSI
we have found that inter-subject differences in these networks during the pre-task rest episode were in fact predictive of better learning (Figure S2E and H
Thus the networks during rest which correlate with RSI share some commonalities with the task activated ones; notably
participants with greater alpha desynchronisation of the DMN and high-beta synchronisation of occipital-frontal networks were shown to be better future fast learners
and occipitofrontal areas are promising candidates as neural markers for the extent of fast learning in laparoscopy training
beta connectivity between left temporal and frontal and central areas were lower during the repeat task and second task relative to initial task performance (Figure S4)
However we did not find any correlations between BDNF and RSI (Table S3)
which suggests that BDNF may be primarily a facilitator of slow learning
although strongly affected by task performance
Furthermore we found that network integration and segregation depended strongly on the frequency of the underlying functional connections
the task-related shifts in integration were similar to the shifts in segregation
This implied that task performance affected connectivity at different cortical distances in similar ways
since λ is influenced primarily by long distance and CC by short distance connections
while summarising the experiments we focus on the methodology specifically relevant to the results in the present paper
A total of 38 healthy adult volunteers without prior experience in laparoscopic surgery participated in a trial to perform predetermined basic laparoscopic tasks on a laparoscopic simulator
One participant could not enroll due to their hairstyle
which made it impossible to fit the cap and record EEG data
Technical problems prohibited the recording of data for four participants
Two participants were excluded from the analysis due to issues with the time stamps routine
Hence the final sample consisted of 31 participants (17 females
14 males) with a mean age of 21.61 ± 2.12 years
All participants provided written informed consent prior to the study and received gift vouchers for their participation
The study was approved by the Ethical Committee of the College of Science and Technology at the Nottingham Trent University and all methods were performed in accordance with the relevant guidelines and regulations
Informed consent was obtained from all subjects and/or their legal guardian(s) for publication of identifying information/images in an online open-access publication
The experiment was conducted in a training laboratory equipped with a Laparoscopic Surgery (LS) trainer box by Inovus Surgical Solutions (The Pyxus laparoscopic box trainer by Inovus Medical—43 cm × 33 cm × 31 cm) and a 21-inch monitor
including the time spent to set up the system and devices and perform the tasks
participants received instructions about the session via a training video
followed by a hands-on introduction to help them become competent before commencing the training
The LS trainer box was equipped with a centrally mounted camera and a light source
with the entry ports of the instruments separated by 13.5 cm
The training bases (14 cm × 10 cm) were placed in the LS trainer box and centred in the camera’s field of view
Laparoscopic video was projected onto the monitor
which was in the direct view of the participant
To perform the primary tasks participants stood in front of the LS trainer box during the performance of Laparoscopic and secondary tasks (Fig. 1A)
The laparoscopic tasks completion time was recorded
and relocating rings from one rod to another using both surgical instruments
Participants used their left-hand to transfer rings from rod A to B
then passed each ring from B to C using the left-hand and right-hand
and finally moved the rings from C to D using the right-hand only
The Threading task consisted of passing a piece of string through holes labelled 1–7 on a Threading base
Participants could use both surgical tools and both hands
To simulate potential distractions or disruptions (e.g.
auditory alarms) that may arise in a realistic setting
an auditory task was added to the experiment
Participants had to respond to a series of beeps as quickly as possible by pressing down on a foot pedal
This was done by using the overall error rate calculated as the average of the rates of two types of error: (i) dropping a ring on the stack board and (ii) dropping it outside the board
The raw EEG data underwent a series of pre-processing steps to remove non-brain signals and preserve the brain signal for further analysis
Segments of data containing high-frequency
likely originating from gross body movements during EEG recording
were identified and deleted using a 1 s wide sliding window
electrodes exhibiting kurtosis values exceeding 5 were considered invalid channels and removed from the data
The signals were then band-pass filtered between 0.16 Hz and 40 Hz to reduce slow drifts and high-frequency artifacts
and subsequently down sampled to 200 Hz to optimise computational and storage requirements
To segregate components such as eye blinks and movements
Independent Component Analysis (ICA) decomposition using the Extended-Infomax algorithm was applied to the filtered EEG data
The ADJUST method was then used to automatically detect and remove independent components associated with artifacts
and topographic maps of the independent components were visually inspected to further refine the artifact removal process
We next determined the clustering coefficient (CC) and characteristic path length (λ)
λ is the mean shortest path over all pairs of nodes
It quantifies the capacity for information transfer across the network
and low values of λ are associated with greater functional integration
We investigated potential association of ISPC
CC and λ with motor learning by determining the Pearson correlation of the relevant quantity
The data and computer programs underlying the study are publicly accessible at https://doi.org/10.5281/zenodo.12810004
Researchers interested in accessing underlying samples for further analysis will be able to contact the corresponding author to discuss the process for obtaining an MTA
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Noninvasive cortical stimulation enhances motor skill acquisition over multiple days through an effect on consolidation
BDNF as a possible modulator of EEG oscillatory response at the parietal cortex during visuo-tactile integration processes using a rubber hand
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High density optical neuroimaging predicts surgeons’s subjective experience and skill levels
and brain activity in laparoscopic surgery training
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Emergence of reproducible spatiotemporal activity during motor learning
An estimation of the absolute number of axons indicates that human cortical areas are sparsely connected
keeping timing: evolutionary preservation of brain rhythms
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Different slopes for different folks: alpha and delta span style=font-variant:small-caps;EEG/span power predict subsequent video game learning rate and improvements in cognitive control tasks
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This research was made possible in part by support from the Foundation for Neurofeedback and Neuromodulation Research (602–2023) provided to A.O
All authors reviewed and edited the manuscript
The authors declare no competing interests
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DOI: https://doi.org/10.1038/s41598-025-89261-0
Alzheimer's disease (AD) is neurodegenerative dementia that causes neurovascular dysfunction and cognitive impairment. Currently, 50 million people live with dementia worldwide, and there are nearly 10 million new cases every year. There is a need for relatively less costly and more objective methods of screening and early diagnosis.
Functional near-infrared spectroscopy (fNIRS) systems are a promising solution for the early Detection of AD. For a practical clinically relevant system, a smaller number of optimally placed channels are clearly preferable. In this study, we investigated the number and locations of the best-performing fNIRS channels measuring prefrontal cortex activations. Twenty-one subjects diagnosed with AD and eighteen healthy controls were recruited for the study.
These scores suggest that fNIRS is a viable technology for conveniently detecting and monitoring AD as well as investigating underlying mechanisms of disease progression.
Volume 16 - 2022 | https://doi.org/10.3389/fnhum.2022.1061668
Introduction: Alzheimer's disease (AD) is neurodegenerative dementia that causes neurovascular dysfunction and cognitive impairment
50 million people live with dementia worldwide
and there are nearly 10 million new cases every year
There is a need for relatively less costly and more objective methods of screening and early diagnosis
Methods: Functional near-infrared spectroscopy (fNIRS) systems are a promising solution for the early Detection of AD
For a practical clinically relevant system
a smaller number of optimally placed channels are clearly preferable
we investigated the number and locations of the best-performing fNIRS channels measuring prefrontal cortex activations
Twenty-one subjects diagnosed with AD and eighteen healthy controls were recruited for the study
Results: We have shown that resting-state fNIRS recordings from a small number of prefrontal locations provide a promising methodology for detecting AD and monitoring its progression
A high-density continuous-wave fNIRS system was first used to verify the relatively lower hemodynamic activity in the prefrontal cortical areas observed in patients with AD
By using the episode averaged standard deviation of the oxyhemoglobin concentration changes as features that were fed into a Support Vector Machine; we then showed that the accuracy of subsets of optical channels in predicting the presence and severity of AD was significantly above chance
The results suggest that AD can be detected with a 0.76 sensitivity score and a 0.68 specificity score while the severity of AD could be detected with a 0.75 sensitivity score and a 0.72 specificity score with ≤5 channels
Discussion: These scores suggest that fNIRS is a viable technology for conveniently detecting and monitoring AD as well as investigating underlying mechanisms of disease progression
Alzheimer's disease (AD) is the most common cause of dementia in the elderly which impacts 50 million people worldwide (Bonilauri et al., 2020)
Functional abnormalities in AD likely start long before its clinical symptoms
which primarily affect executive and visuospatial abilities
Practical fNIRS systems are a promising solution for the early detection of AD because they can make quick and affordable measurements without requiring expert operators
methods based on functional measurements do not rely on patients' ability to respond to questions or follow test instructions
Medication and other therapies administered from early stages can retard disease progression and improve patients' quality of life
the diagnosis of AD relies heavily on clinical examination and tests administered by expert clinicians
there is a need for relatively less costly and more objective methods of screening and early diagnosis
Resting-state recordings were collected from 21 patients and 18 healthy controls
who also completed standard neuropsychological tests
We found reductions in oxygenated hemoglobin in patients with AD consistent with previous studies
we assigned univariate priority scores to the optical channels based on their extent of association with the disease state of the participants
Then we used subsets of channels selected from the highest priority channels to predict the participants' disease state from the measured signal
we used Boston Naming Test and Verbal Memory Total scores as proxies for AD severity
The results suggest that AD can be detected with a 0.76 sensitivity score and a 0.68 specificity score while the severity of AD could be detected with a 0.75 sensitivity score and a 0.72 specificity score
These were obtained with ≤5 channels on the forehead
Our results provide evidence that fNIRS is a viable technology for accurately and conveniently detecting and monitoring AD as well as investigating the underlying mechanisms of disease progression
Among the patients diagnosed with clinical AD
had Clinical Dementia Rating Scale (CDR) scores of 1 or 2
used acetylcholinesterase inhibitors and memantine
and were capable of leading their daily lives independently were included in the study
Exclusion criteria were a history of alcohol/substance abuse
mental illnesses including schizophrenia and delirium
Patients were examined during routine therapy
where the medical treatment was not modified during the study period
and no psychiatric or neurological disorder history was included in the study
The Research Ethics Board of Medipol University approved this study (10840098-604.01.01-E.1925)
and it was performed in agreement with the Declaration of Helsinki
All participants signed informed consent and could withdraw from the study at any time
and Neuropsychiatric Inventory were also used for neuropsychological evaluation
The included subjects and their companions were informed briefly about the whole procedure
They were given an informed consent form to read carefully and sign
It was made sure that they understood that they could stop and leave the research at any time they wished with a guarantee of not facing any kind of consequences
After the researchers decided the given information was understood and informed consent was obtained
the subjects were asked to sit on a chair and the fNIRS device was set on the head and optodes were calibrated while the subject was asked to sit silently and in a relaxed position
sound or any other distracting stimuli were turned off
When the subject confirmed that they were ready for the experiment
Following the 30 s of the beginning session to check the optodes were working properly as set before the test
the 5-min recording of the resting state was started without any warning
the recording signal was briefly checked again and was saved in the following 15 s and the subject was informed that the test was finished
Optical imaging data were collected using a high-density fNIRS device (NIRSIT
Korea) with 24-light sources at 780 and 850 nm and 32 detectors
The channels overlap with parts of the dorsolateral and ventrolateral prefrontal and the upper part of the orbitofrontal and medial PFC
Subject averaged prefrontal cortex activations (color bar units on the right in mM) interpolated from channels with 3.35 cm separations
Open gray circles indicate the location of the fNIRS channels
We repeated the calculations in this study by using only deoxyhemoglobin or by including both oxy- and deoxyhemoglobin concentration changes
these did not improve classifier performance relative to using oxyhemoglobin alone
deoxyhemoglobin alone resulted in slightly lower accuracies overall
Since this is a proof-of-concept investigation
we have limited this study to oxyhemoglobin concentration changes only
we use the term activation to refer to the standard deviation of the oxyhemoglobin changes
We studied the ability of the PFC activations to discriminate between patients and healthy controls and between different subgroups of patient participants
we generated features for a machine learning approach by averaging the activation in each channel across the entire recording session of a participant
a feature matrix contained rows consisting of individual subjects and columns consisting of channels
and its entries were the session-averaged PFC activations
The matrix contained a maximum of 48 columns (channels)
Because each subject's data occurred in only one row of the feature matrix
the training and test partitions never contained data from the same subject
The corresponding binary label vector indicated (1) whether the participant was a patient or healthy control or
(2) whether the patient participant obtained a high or low score on a neuropsychological test
where the high–low cut-off was taken as the median of all patients
we assessed multiple filter-type algorithms for rank ordering our features before feeding them into a classifier: filters based on (1) Pearson correlation between a feature and label vector; (2) p-values obtained from chi-squared tests; and (3) searching for sets of features maximally associated with the labels and minimally associated with each other
The chi-squared method was selected due to its robustness and the resulting classifier accuracies
the features were first prioritized by using chi-squared tests that determined whether each feature was independent of the label vector by calculating a p-value
The priority score of a feature was calculated as the natural logarithm of the reciprocal of its p-value
The prioritized features were then used to predict the labels of a subset of the participants using a Support Vector Machine or Linear Discriminant Analysis trained on the remaining subset of the participants
The results from the Support Vector Machine classifier were overall more accurate hence we only report them in this article
The performance of the prediction was characterized using its sensitivity and specificity defined in the following way
sensitivity was calculated as the ability to correctly identify a patient
and specificity was calculated as the ability to correctly identify a healthy control
considering a positive prediction as the prediction that the subject is a patient
the sensitivity of the method was defined as the number of true positives divided by the sum of true positives and false negatives
The specificity was the number of true negatives divided by the sum of true negatives and false positives
the sensitivity was calculated as the ability to correctly identify a high-scoring patient
and specificity was calculated as the ability to correctly identify a low-scoring patient
Each feature was standardized by centering and scaling with the mean and standard deviation of the corresponding column of the feature matrix
The linear kernel was selected for Support Vector Machine and its scale was computed by Matlab using a heuristic procedure
We used a fixed random number seed for the reproducibility of the results
Optimization of the box constraint and kernel scale parameters was tried to discriminate patients from normal volunteers
both based on Matlab's grid search algorithms in the range [0.001
This significantly increased computing times without a noticeable improvement in performance; thus
we report only results based on Support Vector Machine without hyperparameter optimization
and signrank were used in the above calculations
The demographical and neuropsychological test scores of the patient group with Alzheimer's disease (AD)
Hemodynamic feature priority scores calculated for purposes of feature selection
(A) Univariate feature priority scores ranked in descending order calculated using chi-squared tests
(B) The distribution of scores over the prefrontal cortex
The accuracy (A) sensitivity and (B) specificity of discriminating patients (N = 21) from normal subjects (N = 18) using the Support Vector Machine and a limited number (x-axis) of the top-ranked hemodynamic features
The accuracy is found from 5-fold cross-validation repeated 20 times with different randomly selected partitions
The black boxes indicate the accuracy and the green boxes indicate the corresponding null distribution calculated by randomly permuting the labels
Statistical significance calculated from the Kolmogorov–Smirnov test is indicated using an asterisk (*p < 0.05
The central mark in a box indicates the median
and the bottom and top edges of the box are the 25th and 75th percentiles
while the whiskers extend to the most extreme data points not considered outliers
Discrimination of high-scoring patients (N = 8) from low-scoring patients (N = 7) in the Boston Naming Test
using the Support Vector Machine and a limited number (x-axis in D and E) of the top-ranked hemodynamic features
(A) Hemodynamic feature priority scores calculated using chi-squared tests
(B) Topographic distribution of feature scores
(C) Histogram of Boston Naming Test scores of patients
The vertical dotted red line shows the location of the median score used to distinguish high-scoring patients from low-scoring patients
(D) Sensitivity of discriminating high-scoring patients
(E) Specificity (*p < 0.05
Discrimination of high-scoring patients (N = 8) from low-scoring patients (N = 9) in the Verbal Memory Total Score Recall/15
using the Support Vector Machine and a limited number of the top-ranked hemodynamic features
The dotted red line shows the median score used to distinguish high-scoring patients from low-scoring patients
The sensitivity and specificity of discriminating patients with AD from healthy controls
specificity 0.72) could be achieved with only five features
The sensitivity and specificity of discriminating high-scoring patients from low-scoring patients in the Boston Naming Test
this is the first study in peer-reviewed literature to use machine learning to quantify the AD-related sensitivity and specificity of the resting-state fNIRS signals from the PFC
Resting-state whole-head fNIRS data from patients with AD dementia and amnesic MCI and healthy controls were used to show that the temporal variability of functional connectivity maps was able to distinguish aMCI [area under the curve (AUC 82.5%)] or AD (AUC 86.4%) from the healthy controls (Niu et al., 2019). Further descriptions of related studies can be found in recent extensive reviews (e.g., Bonilauri et al., 2020)
Such close scores in different groups may have reduced the accuracy of discrimination
patients with scores close to the median could not be removed from this calculation since this would have reduced the already small size of the data set
we could have used other classification schemes [e.g.
artificial neural network (ANN)] to predict the continuous range of scores
ANNs require a greater number of training examples than we had in our patient population
By definition, sensitivity is reduced by the occurrence of a higher number of false negatives in the patient group, while specificity is reduced by a higher number of false positives in the healthy control group. Thus, the generally higher sensitivity observed in Figures 3, 4 indicated that PFC hemodynamics was a more robust marker among the patients than it was among healthy controls
This could be due to the greater variability of the signals in the healthy group
The chance distribution of accuracy is shown by the green boxes in Figures 3, 4 and indicates the median and range of values obtained by repeating the 5-fold cross-validation 10 times
with different partitions into training/test sets and randomly reshuffled labels
yielded values that are represented by the green boxes
the chance accuracies in the Figures fluctuate around 50%
they remained close to 50% only if there were a sufficient number of patient responses in each of the high-/low-scoring groups (as was the case with the Boston Naming Test and Verbal Memory Total Score Recall); we used this as a criterion for excluding the other types of tests from this study
Figures 3A,B, 4D,E suggest that the accuracy initially increased with an increasing number of optical channels (features) and then remained near a maximum or slightly declined
The initial increase in accuracy was clearly due to the fact that additional features brought new information useful for discrimination
may have been due to new features adding little or no useful information but instead introducing noise into the system that obscured the differences between groups
fNIRS appears to be a good choice for our study with a reasonable trade-off
The limitations of our study and possible mitigations are as follows:
1. Only two types of tests were available with a sufficient number of patient responses. A greater number of types of neuropsychological test scores (e.g., Viola et al., 2013) would improve the validity of our findings
2. We only collected PFC data, however, the measurement from additional areas may increase accuracy as there are differences between patients and healthy controls in parietal activation (Li R. et al., 2018)
This will become more viable as better-designed headsets and optodes that can conveniently record through hair become available
3. We only used resting-state measurements, however, data collected during cognitive or memory task performance may increase accuracy as there are clear task-evoked differences between patients and healthy controls (Arai et al., 2006; Yeung et al., 2016)
These limitations offer opportunities for further study
Our results suggest that with further improvements in instrumentation and possibly in conjunction with concurrent EEG and neuropsychological tests
a small number of fNIRS channels located in the PFC can be a valuable screening tool for diagnosing and monitoring AD
The original contributions presented in this study are included in the article/supplementary material
further inquiries can be directed to the corresponding author
The studies involving human participants were reviewed and approved by the Research Ethics Board of the Medipol University (10840098-604.01.01-E.1925)
The patients/participants provided their written informed consent to participate in this study
and writing—review and editing: HK and AO
All authors contributed to the article and approved the submitted version
Canberk Cengiz for supporting data collection
The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest
All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations
Any product that may be evaluated in this article
or claim that may be made by its manufacturer
is not guaranteed or endorsed by the publisher
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Received: 04 October 2022; Accepted: 01 November 2022; Published: 28 November 2022
Copyright © 2022 Keles, Karakulak, Hanoglu and Omurtag. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY)
provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited
*Correspondence: Hasan Onur Keles, aG9rZWxlc0BhbmthcmEuZWR1LnRy
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hood during May 1997 commencement ceremonies
As a student at Missouri University of Science and Technology
Youngblood dreamed of breaking down barriers for African Americans
“I’ve always seen myself as being out in front
a leader,” she said in a 1997 interview with Missouri S&T Magazine
“I’ve always seen myself as breaking down walls to let more people through.”
In 1992, she became the first African American woman to graduate from the mining engineering program at Missouri S&T
she became the first African American woman to earn a Ph.D
Dr. Youngblood, of Moon Township, Pennsylvania, died recently at age 46. She was an associate professor of engineering at Robert Morris University in Pittsburgh
According to the Fall 1997 issue of Missouri S&T Magazine
Illinois in low-income housing with her mother
she enrolled at Missouri S&T on a partial scholarship
she received her bachelor of science degree in mining engineering
becoming the first African American woman in the university’s history to earn a degree from that program
She later earned a master’s degree in engineering management from Missouri S&T and in 1997
in engineering management and becoming the first African American woman to receive a Ph.D
She credited her dissertation advisor, Dr. Yildirim “Bill” Omurtag, former chair of engineering management at Missouri S&T and founding dean of the School of Engineering
Mathematics and Science at Robert Morris University
for supporting her during her doctoral studies
advisor and friend,” she said in the 1997 interview
“He can see a raw piece of coal and know that the end product will be a diamond.”
Visitation for Dr. Youngblood will be held from 6-8 p.m. Sunday, March 29, at Gateway Area Bible Fellowship Apostolic Church, 85 Water Street, Cahokia, Illinois. Funeral Services will be held at noon Monday, March 30, at the church, with interment services immediately following at Holy Cross Cemetery in Fairview Heights, Illinois. Arrangements are under the direction of L. King Funeral Chapels of Belleville
On March 25, 2015. Posted in Alumni, Featured, People
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Bulgaria’s Minister of Tourism Miroslav Borshosh and Zurab Pololikashvili
Secretary-General of the World Tourism Organization (UN Tourism)
have officially signed the agreement for Bulgaria to host the 9th Global Conference on Wine Tourism,.
The Mini Bulgaria Park is an unusual place for a tourist tour
spiritual culture and natural landmarks of Bulgaria meet
Gorna Oryahovitsa often remains undeservedly hidden from the eyes of tourists
even though it is only about 10 km away from Bulgaria's old capital
which lies at the foot of the Balkans on the banks of the.
english@bnr.bg
People who can no longer communicate through speech or eye movement can use the power of thought to indicate "yes" or "no" thanks to a brainwave reader developed by Nottingham Trent University (NTU)
an expert in intelligent engineering systems
wanted to support charities which help people with advanced motor neuron disease (MND) and Completely Locked-in Syndrome after his brother-in-law
The research has led to the development of a brainwave reader which is made affordable by using off-the-shelf parts and a novel artificial intelligence (AI) algorithm developed by the research team
The technology centers on interpreting people's brain signals when they are invited to envisage contrasting imaginary situations to indicate "yes" or "no" answers
patients can be asked to imagine the joy of kicking a football to indicate "yes," but
be asked to imagine being trapped in a room with an elephant to mean "no."
which produce different analog signals in the brain
are detected over five seconds by three electroencephalogram (EEG) sensors attached to the patient's head
These analog signals are then magnified and converted to digital signals before being interpreted by the AI and relayed to a display screen to show the answer
"This technology can allow people who are in the late stages of MND to communicate critical information when they are unable to even blink," said Professor Al-Habaibeh
"It could be used for a variety of purposes
such as to communicate what a patient's wishes may be
"Our aim is to make this technology affordable for organizations such as charities so that it can be used more widely by families or hospices
"By allowing better communication in the later stages of MND, it will also allow medical professionals to treat patients better and take key decisions which are in line with the patient's wishes
we are confident that this approach could allow a patient to control a cursor on a computer screen
potentially with just four imaginations for up
"It may also be possible for this technology to be applied to mental health outputs
The research found that the technology takes around ten attempts to learn an individual's brain signal pattern
and that the individual success rate is around 90% if the patient is able to focus without any distraction
The cost of hardware for each reader is estimated at about £300
and the research is being published under a creative commons license to allow organizations to use it freely without copyright
Research on the technology has previously been published by the Neuroscience Informatics journal and a working prototype has now been created as the culmination of the project
Researcher Sharmila Majumdar, a Ph.D. candidate who worked on the project, said, "This technology has the potential to help dying people communicate when they are in an incredibly vulnerable state
"We are proud to have carried out this research to support those with MND and for it to be published freely in the interests of helping others."
"Existing medical EEG devices tend to be expensive
so I think the capability to decipher people's thoughts using only a few sensors will continue to increase in value and find more applications."
A brainwave reader developed using affordable off-the-shelf parts and a novel AI algorithm enables individuals with advanced motor neuron disease to communicate through thought
patients can indicate "yes" or "no," with signals detected by EEG sensors and interpreted by AI
achieves a 90% success rate after ten attempts and is freely available under a creative commons license
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Approximately 5% of emergency department (ED) patients with altered mental status (AMS) have non-convulsive seizures (NCS)
Patients with NCS should be diagnosed with EEG as soon as possible to initiate antiepileptic treatment
Since ED physicians encounter such patients first in the ED
they should be familiar with general EEG principles as well as the EEG patterns of NCS/NCSE
We evaluated the utility of a brief training module in enhancing the ED physicians’ ability to identify seizures on EEG
This was a randomized controlled trial conducted in three academic institutions
A slide presentation was developed describing the basic principles of EEG including EEG recording techniques
followed by characteristics of normal and abnormal patterns
the goal of which was to familiarize the participants with EEG seizure patterns
We enrolled board-certified emergency medicine physicians into the trial
Subjects were randomized to control or intervention groups
Participants allocated to the intervention group received a self-learning training module and were asked to take a quiz of EEG snapshots after reviewing the presentation
while the control group took the quiz without the training
A total of 30 emergency physicians were enrolled (10 per site
Participants were 52% male with median years of practice of 9.5 years (3
The percentage of correct answers in the intervention group (65%
63% and 75%) was significantly different (p = 0.002) from that of control group (50%
A brief self-learning training module improved the ability of emergency physicians in identifying EEG seizure patterns
This results in delayed initiation of appropriate treatment and worse neurological outcomes
it is imperative to diagnose NCS/NCSE early and accurately with electroencephalogram (EEG) and start treatment as soon as possible
Once the EEG is being acquired at the bedside
the non-expert physician (ED physician) needs to recognize electrographic seizures that require rapid management
especially when access to a trained epileptologist is not possible or delayed
The objective of this study was to test the utility of a brief training module (a self-learning PowerPoint presentation) to improve the ability of the ED physician to identify electrographic seizures on EEG
This study is a pilot study with a small number of subjects
which will help determine if the EEG training can be expanded and implemented readily
This pilot randomized controlled trial was conducted at the departments of emergency medicine of three academic medical centers
All three institutions are academic urban teaching hospitals with emergency medicine residencies
Institutional review boards approved the study in each institution
Informed consent was obtained from all participants prior to enrollment
The trial enrolled board-certified emergency medicine faculty
Physicians with previous EEG training were excluded
Subjects were recruited via email through faculty directories in each institution
The first 10 volunteers in each institution (10 subjects per site
30 subjects in total) were randomized to control or intervention groups using a random number generating software
Participants were randomized to the intervention group or the control group
Physicians allocated to the intervention group received a self-learning PowerPoint presentation (training module) and were asked to take a quiz after reviewing the PowerPoint presentation
The control group was asked to take the quiz without reviewing the training slides
Two months after the initial date of their initial quiz
the quiz was re-administered without any training slides for either group to test their retention
A slide presentation describing the basic principles of EEG including EEG recording techniques
and views followed by characteristics of normal and abnormal patterns was developed with assistance of epileptologists and experts in educational research
The goal of the presentation was to familiarize the participants with EEG presentations of seizure
EEG snapshot showing a right temporal focal electrographic seizure
EEG snapshot showing focal slowing over the left temporal region
The primary outcome was the percentage of correct answers to the quiz (corresponding to correct interpretation of each EEG snapshot) initially and after 2 months (test of retention)
Method of determination of outcomes: Overall scores and percentages of correct answers were calculated by administering the quiz to all participants
The total number of correct answers for each participant was counted and divided by 40 (maximum score) to calculate the correct score percentage for each subject
Data are reported as medians and quartiles for continuous variables and percentages with quartiles for proportions
The outcome (percentages of correct answers) was calculated and compared between the two groups using Mann-Whitney U test
We planned a sub-group analysis to compare the responses to seizure versus no seizure questions only between the groups
to specifically examine the performance of physicians to identify seizures on EEG
A total of 30 emergency physicians were enrolled (10 per site, 30 in total, 15 controls and 15 interventions). Participants were 63% male with median years of practice of 9 years (quartiles 3, 14). Groups were similar in regards to years of practice and gender (Table 1)
Comparison of percentages of correct answers between control and intervention groups using Box-Whisker plot
In the subgroup analysis evaluating the question of seizure versus no seizure
the results were similar to the overall analysis
There was a significant difference between the percentages of correct answers identifying seizures between the intervention group (63%
this difference was not significant at the time of the follow-up quiz between the intervention group (55%
while the final confirmatory study and report is provided by the radiologist later
physicians administer sedatives and anticonvulsants to patients with suspected NCS based on clinical suspicion
Training ED physicians to recognize EEG seizures will help them identify and treat NCS appropriately
This will also reduce the risk of administration of anticonvulsants in patients who are not suffering from NCS
Our study evaluated the efficacy of a PowerPoint EEG training module created by a collaboration of an epileptologist
and experts in education research to improve recognition of electrographic seizures by ED physicians at the bedside
The purpose of this brief training module was to provide very basic practical clinically relevant knowledge to the physicians
focusing on identifying normal versus abnormal EEG
It was important to include normal patterns besides seizures in the module
as some of these could be misinterpreted as abnormal patterns by an untrained individual
the ED physicians clearly benefited from the training module
as they performed significantly better than the group who were not provided the module
Follow-up assessment in 2 months showed that this group of ED physicians retained that knowledge over time
the assessment tool scores increased from a mean of 12.00 ± 1.9 before the educational module to 19.7 ± 2.0 (p < 0.001)
no guidelines exist regarding the use of quantitative EEGs and trends
There are several limitations in this study
No sample size analysis was performed as this was a pilot trial
12 months) to evaluate retention of study material
The participants only interpreted a one-page snapshot of the EEG
which is not representative of the bedside EEG that is recorded for an average of 30 min
and can provide much better visualization of patterns and rhythms
Our study was a pilot study that provides preliminary data
The study module needs further refining and testing
before it can be applied to clinical practice
Determining patient impacts of risks and benefits of treatment of ED patients with NCS is not within the scope of this pilot study
our pilot study may justify conducting a larger study to evaluate the safety and efficacy of such a training module in real-time management of patients suspected of NCS
This pilot study demonstrates that providing a brief EEG training module can help emergency department (non-neurology) physicians improve the identification of seizures on bedside EEG
Altered mental status: evaluation and etiology in the ED
Prevalence of non-convulsive seizures and other EEG abnormalities in ED patients with altered mental status
Assessment of acute morbidity and mortality in nonconvulsive status epilepticus
Current practice in administration and clinical criteria of emergent EEG
Diagnostic accuracy of a novel emergency electroencephalography device (microEEG) in identifying non-convulsive seizures and other EEG abnormalities in the emergency department patients with altered mental status
Research electronic data capture (REDCap) – a metadata-driven methodology and workflow process for providing translational research informatics support
Assessment of emergency physician-performed ultrasound in evaluating nonspecific abdominal pain
The effectiveness of a simple novel approach on electroencephalograph instruction for anesthesiology residents
Evaluating the long-term retention of a multidisciplinary electroencephalography instructional model
The effectiveness of an interdisciplinary approach to EEG instruction for residents(r)
Virtual training simulator – designer of EEG signals for tutoring students and doctors to methods of quantitative EEG analysis (qEEG)
Non-expert use of quantitative EEG displays for seizure identification in the adult neuro-intensive care unit
Trend figures assist with untrained emergency electroencephalogram interpretation
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The authors would like to thank Paulina Sergot
Texas) for their assistance in developing the training module and PowerPoint presentation
There are no funding sources used for this study
The datasets used and analyzed during the current study are available from the corresponding author on reasonable request
University of California at Davis Health System
GC contributed to the study concept and design
created the PowerPoint training module and EEG quiz
and revised and submitted the final manuscript
KY contributed to the study concept and design
collected and managed the data using REDCap electronic data capture tools
and revised and approved the final manuscript
DN contributed to the study concept and design and revised and approved the final manuscript
AO contributed to the study concept and design
revised and approved the PowerPoint training module
SZ contributed to the study concept and design
All authors read and approved the final manuscript
This study was approved by the institutional review boards of the three participating academic teaching hospitals
Each subject (emergency medicine physician) signed a consent form to participate in the study
Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/)
provided you give appropriate credit to the original author(s) and the source
provide a link to the Creative Commons license
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DOI: https://doi.org/10.1186/s12245-019-0228-9
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Laparoscopic surgery can be exhausting and frustrating
and the cognitive load experienced by surgeons may have a major impact on patient safety as well as healthcare economics
As cognitive load decreases with increasing proficiency
its robust assessment through physiological data can help to develop more effective training and certification procedures in this area
We measured data from 31 novices during laparoscopic exercises to extract features based on cardiac and ocular variables
These were compared with traditional behavioural and subjective measures in a dual-task setting
We found significant correlations between the features and the traditional measures
and completion time were well predicted by the physiology features
Reaction times to randomly timed auditory stimuli were correlated with the mean of the heart rate (\(r = - 0.29\)) and heart rate variability (\(r = 0.4\))
Completion times were correlated with the physiologically predicted values with a correlation coefficient of 0.84
We found that the multi-modal set of physiology features was a better predictor than any individual feature and artificial neural networks performed better than linear regression
The physiological correlates studied in this paper
could help develop standardised and more easily regulated frameworks for training and certification
These considerations suggest that performance based metrics alone may not suffice to reveal the trainees' actual state of readiness
These traditional measures face some limitations
as they may influence or interrupt what they are trying to monitor
there is limited research on the extent of the agreement among these distinct measures of effort and no studies to our knowledge in the context of LS training
varying levels of effort were generated by differences in subject aptitude and task difficulty
as well as by learning and time on task effects
We believe physiological responses which track their effects are more direct than behavioural and verbal ones
a better understanding of the physiological expression of skill is of potential value for improving training and assessment in LS
Experience and performance metrics grouped by type of experimental episode (three boxes on the left of each subplot) and by task type, namely Ring Transfer, Ring Transfer Repeated, Threading and Threading Repeated (four boxes on the right). (a) NASA-TLX Average score. (b) NASA-TLX Effort score. (c) Reaction time. (d) Non-response rate. (e) Task completion time. (f) The rates of errors during the Ring Transfer task. (*p < 0.05).
Values of the individual predictor features and targets. Linear fits to the data are shown. The Pearson correlation, \(r\), and the p-value of linear regression (black line) are shown. The quadratic fit (thick grey curve) and its p-value \(p_{2}\) are shown only if \(p_{2} < 0.05\).
Predictions of the artificial neural network plotted against the actual values (x-axis) for selected cases. (a) NASA-TLX Average score with \(R_{CV} = 0.60\). (b) Completion Time with \(R_{CV} = 0.84\). The 45-degree diagonal line corresponds to perfect prediction.
Heart rate (a) and heart rate variability (b) extracted from NIRS signals for the experimental episodes, and smoothed by a 10 s moving window. The black curves represent subject average and the shaded regions are the standard deviation of subject variability. For the task episodes, 40 s segments at the beginning and end are shown.
Relationships among the heart rate (HR) and heart rate variability (HRV) for Rest and Task
(a) HR and HRV in resting (black) and task performance (red)
Black and red dots respectively represent individual subjects in the resting and task blocks
The linear fits to the data are shown as the black and red straight lines
The Pearson correlations are \(r = - 0.32\)(resting) and \(r = - 0.23\) (task)
The insets at the bottom and on the right illustrate the marginal probability distributions
(b) Resting HR and the task related change in HR relative to resting (\(r = 0.11\))
(c) Resting HRV and the task related change in HRV relative to resting (\(r = - 0.96\))
Performance scores (not shown) also contained changes that were statistically significant
There did not appear to be a significant difference between the experiences of the Ring Transfer and Threading tasks
The non-response rate was a significantly greater for Ring Transfer than for the Threading task
The non-response rate was the rate at which a subject failed to respond to the stimulus before the next stimulus onset
Error type 10 was dropping a ring on the ring stack board; type 20 was dropping it outside the board; and type 30 was dropping it outside the trainer box
Outliers were defined as points greater than \(q_{3} + w(q_{3} - q_{1} )\) or less than \(q_{1} + w(q_{3} - q_{1} )\)
where \(q_{k}\) is the \(k^{th}\) quartile and \(w = 2\)
for assessing the performance of the linear regression (LR) and artificial neural network (ANN)
Regarding the individual features in Table 1
the Pearson correlations show that HR's mean and standard deviation tended to increase with the experienced difficulty as measured by the NASA-TLX score
Without reaching statistical significance both were individually positively correlated with it
Mean HR was negatively correlated with the Reaction Time and Non-response Rate
Higher HR generally implied quicker and more accurate response in the secondary task and fewer errors in the primary task
HRV appeared to be an even better predictor
The minimum value of HRV was significantly negatively correlated with the NASA-TLX score
Many HRV features were significantly positively correlated with the Reaction Time
This indicated that higher HRV (which is associated with respiratory modulation of HR and relaxation) degraded performance
was significantly negatively correlated with the Reaction Time
Those predictors do not have high degree of linear dependence on their target
that the value the Pearson coefficient is distinct from its statistical significance
(The latter is indicated by an asterisk in the table.) We used linear correlation only as a baseline to compare with the performance of groups of physiological metrics that had predictive utility via machine learning (the right column of the table)
With regard to the LR and ANN which used all available features (the last two columns on the right of Table 1)
the results indicated that the full set of features collectively outperformed any individual feature in predicting subject experience and performance
the table shows that \(R_{adj}\) and \(R_{CV}\) were greater than the absolute values of the individual Pearson correlations
except in predicting the Error Rate which was the unique case with \(R_{CV} < R_{adj}\)
Non-response Rate and Completion Time on HR are described
the same targets are shown plotted against HRV
since the NASA-TLX score was traditionally used as a measure of stress (as HR and HRV)
we also show in subplots g-i the same targets plotted against the NASA-TLX scores
In addition to the linear regression shown as the thin black line in each subplot
we also computed a best fit by including the square of the predictor
Only if the fit was statistically significant
we included this quadratic regression as a thick grey curve in the plot
When the quadratic regression was significant (subplots b
c and i) the best fits were U-shaped curves
suggesting that there was a performance optimum
while the NASA-TLX score (A) was the second best
For the task episodes only the beginning and end segments are shown since the task duration was different for each subject
The figure suggests that during task performance the HR and HRV reach values that are anti-correlated and
potentially contain comparable amounts of information about effort
the intra-episode time courses reveals a significant difference between these two measures
While the HR climbs gradually up to its maximum level within the first minute or so
the HRV attains its task-related minimum without any visible delay
This indicates that only the HRV of those subjects that have high resting HRV are affected by task performance
This paper showed that the cognitive load on novice trainees during LS training has physiological correlates
We showed that physiological indicators of cognitive load predict experience and performance
we calculated from N = 31 subjects the heart rate
We measured their subjective experience by the NASA-TLX reports and their performance in a dual-task setting
We used regression and artificial neural networks to discover relationships among the variables
Our hypothesis was that the residual capacity revealed traditionally by reports and other measures such as reaction time would be reflected in their physiology
The motivation was to develop new metrics to guide training so that surgeons train not only to become good at their primary technical tasks
but to have sufficient capacity for planning and for unexpected events
HRV and BR as well as NASA-TLX and dual-task performance have been used in the past to investigate workload in surgery
we are not aware of other studies which brought all of these variables and machine learning together
within the experimental setting of laparoscopy training
Given that the stress-performance curves may differ among surgeons
objectively evaluating them may improve training as well as optimise intra-operative conditions for performance
The physiological metrics we have found correlated well with subjective and dual-task measures
We believe physiological correlates may contribute to surgery training not necessarily by eliminating other metrics but by providing additional
tools; especially if they are encapsulated in wearable systems
We have only considered cardiac and blink variables
but the number of relevant physiological metrics could be vast
given the complexity of the physiological processes
Although insight into such underlying mechanisms is still in progress
the metrics can still be used for prediction with the help of machine learning
our results do not depend on the specific modalities (fNIRS and EEG) which were used to extract this information
Their detection could be based on different principles
blinks can be extracted unobtrusively from video
We were also driven by the view that wearable sensors stand to play an important role in conveniently tracking the physiological correlates of skill
However future research needs to focus more on the effects of the sensors themselves on stress as well as on the normal range of physiological responses
These included: (i) Using ANNs without optimisation of parameters; (ii) Not implementing subject-specific calibration; (iii) Not controlling for levels of motivation or psychomotor aptitude among the novice subjects
although these variables may have accounted for the distribution in our results; (iv) Recruiting only novice subjects
while different known levels of expertise among the subjects would have provided additional insights; (v) Lack of training interventions accompanied by longitudinal tracking
We hope and expect that these limitations will provide opportunities for further study
Thirty-eight healthy adult volunteers without any prior experience in laparoscopic surgery participated in one main trial to perform pre-determined basic laparoscopic tasks on a laparoscopic simulator
We excluded seven participants; one could not enrol in the experiment due to participant’s hairstyle
that made it impossible to fit the cap and record EEG; for four participants
technical problems prohibited recording; two were excluded from the main analysis due to a problem with the time stamps routine
complete data sets from 31 participants were used in this study (17 females and 21 males
All participants provided their written informed consent prior to the study commencing and received gift vouchers for participating after the experiment was completed
Participants had normal or corrected to-normal vision
The Ethical Committee of the College of Science and Technology at the Nottingham Trent University approved the study and all research was performed in accordance with relevant guidelines
The experiment was conducted in a training lab that consists of a LS trainer box by Inovus Surgical Solutions (The Pyxus laparoscopic box trainer by Inovus Medical—43 cm × 33 cm × 31 cm) and a 21-inch monitor
Each trial took about an hour including total time spent by participants to perform the tasks and setting up the system and devices
participants received instructions about the session via a training video followed by a few minutes of hands-on introduction for orientation with the surgical equipment (Maryland Grasper and Needle Holder
UK) until they became competent before commencing on the training
The LS trainer box was equipped with a centrally mounted camera and a light source with entry ports of the instruments separated by 13.5 cm
The training bases (14 cm × 10 cm) were placed in the LS trainer box and centred in the camera’s field of view
Laparoscopic video was projected onto the monitor that was in the direct view of the participant
The experiment started by performing the secondary task alone for two minutes, which was considered as a baseline (Fig. 1)
participants performed primary and secondary tasks simultaneously
The primary tasks included two Fundamentals of Laparoscopic Surgery tasks
in alternating sequence (Task1 and Task 2) followed by repetition of the first task (Task 1 Repeated)
Fingertip blood samples were taken at baseline and immediately after completion of all three LS tasks to determine the serum cortisol and brain-derived neurotropic factor (BDNF) concentrations
participants filled in the NASA-TLX questionnaire for each LS task
A rest period of 2 min was taken after the initial secondary task performed alone and after each blood sample
Blood sample analysis is not included in this paper
Participants were instructed to stand in front of the LS trainer box during the performance of Laparoscopic and secondary tasks
with a maximum time on task of 15 min after which the participants were told to stop
lifting and relocating rings from one rod to another using both surgical instruments and was performed on a ring stack base (Inovus Medical
top right-hand and bottom right-hand corners on the ring stack base respectively
Four rings were initially put over rod A at the beginning of the trial
The procedure includes picking up a ring from rod A and placing it onto rod B with the left-hand only
After transferring all four rings to rod B
participants used their left-hand only to grasp and lift up each ring
pass it to the right-hand and place it on rod C
The procedure was completed by moving the rings individually from rod C to D using the right-hand only
If any rings were dropped during the task completion
they were placed back on the rod they were taken from by an experimenter
and participants were allowed to continue the trial
The Threading task consisted of passing a piece of string through the holes in a pre-determined order
The holes were labelled 1–7 in a zigzag pattern on the Threading base (Supplementary Fig
Participants could use both surgical tools
no restriction was made on the use of right
Timing began upon first grasp of the string that was initially placed on the right-hand side of the Treading base
In order to simulate the potential distractions or disruptions (e.g
provided an additional measure of the cognitive load on the participants in terms of reaction time and non-response rate
The beeps were generated with random frequencies (ranged from 1,000 to 2000 Hz)
intervals (ranged from 3,000 to 10,000 Hz) and durations (ranged from 500 to 1,000 ms)
These were combined with EEG electrodes into a single head-cap
The raw EEG and fNIRS data were analysed offline separately
EEG was used only for determining the eye blink event times and fNIRS was used only for extracting cardiac information
Analysis of brain activity is not included in this paper due to space limitations
the filtered EEG data underwent ICA decomposition using Extended-Infomax algorithm to decompose EEG data into independent components
Then the ADJUST method was applied to detect the independent components associated with eye blink
time series and topographic maps of the independent components were also visually inspected by the experimenter
After removing the components associated with artefacts
the pre-processed data was reconstructed for further analysis
we determined the blink times by detecting the sharp peaks in the associated independent components
The channel-averaged oxy-hemoglobin concentration changes contained a strong oscillatory component related to the cardiac pulsation
we assumed that the period of this signal (the interval between every other zero-crossing) was the period of the heartbeat
from the heart rate (reciprocal of the period) the heart rate variability was found
To prepare for the Fourier transform of the HR
we interpolated its values to the regular temporal grid of the original fNIRS signal
We separately considered components in the low-frequency range 0.01–0.15 Hz and the high-frequency range 0.15–0.8 Hz
The latter envelops the frequencies of normal respiration
in the low- and high-frequency ranges were computed
The heart rate variability was then calculated as \(HRV = {{HF} \mathord{\left/ {\vphantom {{HF} {\left( {HF + LF} \right)}}} \right
\kern-\nulldelimiterspace} {\left( {HF + LF} \right)}}\)
thus providing a measure of the extent to which the heart rate was modulated by the respiratory rhythms
For every participant and experimental episode we calculated the mean
and the maximum and minimum of the HR and HRV
only the episode mean was used since blinks were insufficiently frequent to allow reliable averaging within shorter time segments
These were used as features for predicting the cognitive load indexed by subjective experience or by performance
our predictors were the features derived from physiology while the targets of prediction were derived from NASA-TLX reports and behavioural quantities
following common usage in machine learning
we are using the term prediction to describe a statistical relationship
without implying that the predictor temporally precedes the target
In assessing group differences we used the Wilcoxon signed-rank test when the groups contained paired subjects (e.g
subjects that performed the first task v second task) and the Kolmogorov–Smirnov test when they did not (e.g
subjects that performed Ring Transfer v Threading as the first task)
These tests were deemed suitable for our study
as they were relatively conservative and did not presuppose the normal distribution
We did not utilise a null hypothesis whose rejection would have required multiple comparisons
kstest2 and signrank were utilized for implementing some of the calculations described above (Matlab R2017b
The data that support the findings of this study are available on request from the corresponding author
Laparoscopic versus open gastric bypass: A randomized study of outcomes
Economic impact of laparoscopic versus open abdominal rectopexy
Comparing the clinical and economic impact of laparoscopic versus open liver resection
Minimally invasive surgery: National trends in adoption and future directions for hospital strategy
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Measuring mental workload during the performance of advanced laparoscopic tasks
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Behavioural markers of surgical excellence
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Assessment of cognitive load in multimedia learning with dual-task methodology: Auditory load and modality effects
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The timing and temporal patterns of eye blinking are dynamically modulated by attention
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and ERICA: New Tools for Advanced EEG Processing
Hemodynamic correlates of spontaneous neural activity measured by human whole-head resting state EEG+ fNIRS
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The authors thank Bethany Twigge for her invaluable help in performing the experiments
Marc Garbey for help in designing the study
Joakim Andreassen for providing the original version of the audio stimulus software
Ojeme Amurun for creating the videos used in training the participants
This research was made possible in part by support from the School of Science and Technology at Nottingham Trent University
via QR funds provided by the Higher Education Funding Council for England (HEFCE) as a result of the Research Excellence Framework 2014 (REF2014)
These authors contributed equally: Zohreh Zakeri and Ahmet Omurtag
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DOI: https://doi.org/10.1038/s41598-020-69553-3
Volume 4 - 2023 | https://doi.org/10.3389/fnrgo.2023.1215376
Editorial on the Research Topic Effect of neurophysiological conditions and mental workload on physical and cognitive performances: a multidimensional perspective
could be administered to assess the psychological conditions of individuals during the execution of various tasks
Most of the studies published on this Research Topic have been focused on populations with special needs or pathologies. However, the first manuscript to be published was that of Rinella et al.
in which the authors investigated the relationship between the digit ratio (D2:D4) and state and/or trait anxiety in healthy adults
and whether there are gender-specific differences
125 participants of both sexes filled in the State-Trait Anxiety Inventory (STAI-Y) questionnaire and their D2:D4 ratio was calculated
a low D2:D4 ratio (<1) can be considered a protective factor against anxiety in both men and women
and this protection appears to be lifelong
a significant negative relationship was found between age
In this sense, Rast and Labruyère discussed the use of sensor-based technology to monitor the motor activities of neuromotor impairments in infants and adolescents
The authors surveyed health professionals involved in pediatric rehabilitation for their opinions on the use of this technology
The results of the survey indicated that health professionals believe sensor-based outcomes can be beneficial for monitoring motor activities and delivering personalized interventions
the survey also revealed potential confounding variables that may influence the participants' responses
the paper discusses the prospective benefits and difficulties of using sensor-based technology in pediatric rehabilitation
Hardy and Hinkin used the NASA-Task Load Index questionnaire (Noyes and Bruneau, 2007) to assess the workload of performing a computerized monitoring task of 32 adults positive for the human immunodeficiency virus
The study found that tracking performance decreased as task difficulty increased
The scores on the Mental Demand subscale revealed substantial individual differences in workload
Mental Demand was discovered to be associated with age and a diagnosis of acquired immune deficiency syndrome
Post et al. aimed to investigate the effects of a 10-week resistance training program on motor behavior
and physical fitness in young adults with Down syndrome
The results showed significant improvements in locomotor and object control skills
The participants also reported increased self-confidence
The study suggests that a properly designed resistance training program can improve the health status and quality of life of people with Down syndrome
The study by Nhan et al. examined the effect of acute submaximal exercise on cognition and brain-derived neurotrophic factor (BDNF) in spinal cord injury patients
eight individuals with traumatic spinal cord injury performed submaximal intensity arm cycling or time-matched quiet rest
Serum and plasma levels of blood-borne BDNF were measured
and cognition was evaluated using the Stroop Test and Task-Switching Test
The results demonstrated that acute exercise based on guidelines did not increase BDNF or enhance aspects of cognition in spinal cord injury patients
This study lays the groundwork for future research on exercise as a therapeutic strategy for promoting mental health in spinal cord injury patients
Loria et al. examined the use of accelerometers to evaluate the function of the paretic limb during therapeutic exercises in stroke patients
The patients participated in an auditory-motor intervention in which reaching movements of the paralyzed limb were mapped onto digital musical instruments and sound tablets
To quantify the volitional control and temporal consistency of the paretic limb movements
the resulting acceleration profiles were analyzed
Significant improvements in the acceleration of the paretic limb correlated with improvements in clinical assessments of motor function
These results indicate that accelerometry-based measures may be beneficial in stroke rehabilitation
The research of Harro et al. investigated the effects of Nordic Walking exercise on walking function
and serum BDNF in individuals with idiopathic PD
Twelve participants with mild to moderate idiopathic PD participated in 6 weeks of supervised Nordic Walking exercise training with individualized instruction
followed by 14 weeks of independent Nordic Walking exercise with remote guidance
Results demonstrated that Nordic Walking exercise enhanced walking endurance
We believe that the articles on this Research Topic provide a fascinating summary of the current state of research on the effect of neurophysiological status and mental workload on human physical and cognitive performance
We hope that they will inspire additional research on this topic that should be not only scientifically rigorous but also highly applicable to real-world situations
monitoring physiological functions in healthy and pathological patients could pave the way for innovative evidence-based solutions in clinical practice and sports science to enhance the efficacy of training processes
DP and DF wrote the original draft of this editorial
All the authors have approved the submitted version of this editorial
Measuring mental workload with EEG+ fNIRS
PubMed Abstract | CrossRef Full Text | Google Scholar
CrossRef Full Text | Google Scholar
Classification of drivers' mental workload levels: comparison of machine learning methods based on ECG and infrared thermal signals
A self-analysis of the NASA-TLX workload measure
PubMed Abstract | CrossRef Full Text | Google Scholar
Prediction of state anxiety by machine learning applied to photoplethysmography data
Central and peripheral thermal signatures of brain-derived fatigue during unilateral resistance exercise: a preliminary study
Priego-Quesada JI and Merla A (2023) Editorial: Effect of neurophysiological conditions and mental workload on physical and cognitive performances: a multidimensional perspective
Received: 01 May 2023; Accepted: 05 May 2023; Published: 17 May 2023
Edited and reviewed by: Klaus Gramann
Copyright © 2023 Perpetuini, Formenti, Priego-Quesada and Merla. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY)
*Correspondence: David Perpetuini, ZGF2aWQucGVycGV0dWluaUB1bmljaC5pdA==
A new factory for the production of solar panels will be built near the town of Omurtag (Bulgaria). The developer is the Bulgarian company Solar Panel EOOD
which will invest BGN 7.35 million in the project. The investment is expected to create 45 new jobs
This became clear during the Class "A" project certificate awarding ceremony given by the Minister of Innovation and Growth
(Note: These certificates are awarded by the Bulgarian government to encourage and ease priority investments)
Modern machinery and equipment necessary for the production process will be purchased for the new plant. It will have a capacity of 200 mW per year
The Omurtag production base will also feature a production workshop
a warehouse for finished products and an administrative wing
The investor company points out that it decided to build the plant given the rapid development of electricity production from renewable sources
Solar Panel EOOD was established in 2022 with a capital of EUR 0.5 million
It’s owned by the Radita construction company
The Bulgarian company Solar Panel EOOD will produce solar panels from "100% European materials" at its plant in Omurtag
The automated line was built by the Italian manufacturer of components for solar installations Ecoprogetti and has a capacity of 250 MW
We learned about the investment in March when the company received a class "A" certificate for the project
The new production plant is in Preslav and a total of BGN 7.35 million will be invested in it
This innovative plant is not only the first of its kind in the country but also sets a new standard in terms of technological progress and commitment to sustainability in the Bulgarian solar industry," added the Italian company reps
This is achieved thanks to the advanced level of plant automation
Each stage of the production process is optimized to ensure maximum efficiency and precision with as little labor as possible
The machines supplied to Solar Panel are of the highest level of automation
with modern methods for full traceability and production monitoring
Designed to produce high-efficiency solar panels suitable for both residential buildings and solar parks
the new production line incorporates the latest solar cell technologies and materials suitable for both PERC/PERT and TOPCON technologies
The all-electric laminator sets the production line apart from its competitors
especially those that rely on conventional manufacturing methods
allowing the company to provide a product warranty of up to 30 years on the modules
The line is quickly filling its full capacity with an expected production of about 1,400 panels per day or about 30,000 panels per month
the announcement represents another step towards affirming the European production of components for photovoltaic installations
Ecoprogetti is based in Italy with offices in the Philippines
the US and the UAE and claims its production equipment is "100% made in Europe"
Foreign Minister Georgi Georgiev has left for Washington
where he will participate in the Munich Leaders Meeting (May 5-7
The forum is organised by the Munich Security Conference
The foundation Unity- Kočani has sent an open letter to key Bulgarian institutions
expressing gratitude for the support and humanitarian assistance provided by Bulgaria after the tragedy of the fire at a nightclub in Kočani
The foreign ministers of Bulgaria and Greece Georg Georgiev and Giorgos Gerapetritis signed a joint declaration on the use of the waters of the river Arda on 2 May
the BNR reports citing an announcement published by the Greek Foreign Ministry..
people will be able to withdraw money from ATMs only in the new currency
according to the website of the Bulgarian.
helicopters of the Bulgarian Air Force will fly at low altitude over Sofia in preparation for a military parade marking the Day.
The Bulgarian student teams that participated in the European Olympiad of Experimental Sciences EOES 2025 in Zagreb have returned with.
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A 50-year-old man from the village of Dolna Hubavka
has filed a total of 1140 fake signals to the 112 emergency hotline in a week
the Regional Police Directorate in the northeastern town of Targovishte reported
The tip-off about the abuse was received Friday by the Regional Police Directorate in Omurtag
The man was found to have given a huge number of emergency calls in the period August 18 –August 25
with the offender facing a fine of BGN 2000 – 5000
Under Bulgaria's National Emergency Call System Act with a single European number 112
the fine soars to BGN 10 000 – 20 000 if the false alert resulted in the mobilization of emergency response units
Police forces in the town of Veliko Tarnovo
said Friday they had captured a 28-year-old man from Gorna Oryahovitsa
who had used his cell phone for a prank murder call on the 112 emergency number at 21:45 on Thursday
The 28-year-old was busted shortly after the abuse and was detained for 24 hours by officers from the Regional Police Directorate in Gorna Oryahovitsa
The offender is being subjected to fast-track proceedings
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A 9-year-old girl has died at a school in Veliko Tarnovo
and an investigation is underway to determine the cause of death
Three Dutch nationals convicted of producing and synthesizing precursors for high-risk drugs have been sentenced to prison
Three individuals sustained injuries following the explosion at the pulp factory near Svishtov
A severe storm accompanied by hail struck Sliven and surrounding areas last evening
was arrested during a police operation at the municipal administration
Excitement mounts as the Regional Ministry announces the commencement of the much-anticipated highway construction linking Ruse to Veliko Tarnovo
An 18-year-old girl who had been reported missing in Haskovo has been found dead
A 33-year-old man from the village of Semchinovo
has been taken into custody by the police for physically assaulting a 10-year-old child
A 12-year-old boy from Lukovit has been hospitalized with two broken arms and head injuries after reportedly being assaulted and thrown from a bridge
the director of the Plovdiv Customs Office
was arrested earlier today for allegedly facilitating a new smuggling route for cigarettes
The Sofia Police has launched a targeted operation against drivers of electric scooters and electric motorbikes who engage in reckless behavior in the city's central areas
opened fire with a gas pistol near a kindergarten in Sofia's Lyulin district
Google Street View Cars Return to Bulgaria for Major Mapping Update
Housing Prices Soar in Bulgaria’s Major Cities as Demand and Supply Strain Increase
A dramatic drop in oil prices offers mixed results for motorists across the globe – from hefty savings at US pumps to a rare price hike in Venezuela
These images taken by Reuters photographers over the last few weeks show how
despite all countries having access to the same oil prices on international markets
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former boxing champion and current leader of the Ukrainian party UDAR
was nominated by the city organization of the party for a candidate for mayor of Kiev
Klitschko said on Wednesday his main goal was to eliminate corruption and to the destroy the barriers that keep Kiev from developing freely and successfully
our first priority is corruption prevention
It's Kiev's transparent budget and dismissal of corrupt officials,” Klitschko said
The Kiev administration should be controlled by society
The third priority is the use of the Kiev budget for meeting the needs of the people of Kiev."
The paid "blue zone" parking service in Varna will cease operations on December 16
With the national and European Parliament elections drawing near
Bulgarian political parties are making significant strides in finalizing their candidate lists
It has been 15 days since 17-year-old Ivana from Dupnitsa went missing
The search for the Bulgarian girl in Dupnitsa and the surrounding area continues for another day
Mayor Vasil Terziev of Sofia has voiced his intention to usher in a new era for the capital city by seeking a replacement for the current chief architect
The European Commission is proposing significant changes to EU regulations concerning road safety and vehicle registration
According to preliminary data from Eurostat
the eurozone economy grew by 0.4% in the first quarter of the year compared to the previous three months
doubling the 0.2% increase recorded at the end of 2024
The European Commission has announced a €910 million investment under the European Defence Fund (EDF) to enhance defence manufacturing capabilities across the European Union
The European Commission has strongly condemned the circumstances surrounding the death of Ukrainian journalist Viktoriia Roshchyna
Friedrich Merz is poised to become Germany's next chancellor following the approval of a coalition agreement between his CDU/CSU bloc
European countries are struggling to mobilize even 25,000 troops to Ukraine for a potential peacekeeping mission
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By Carl Collen2009-04-08T11:02:01+01:00
Rewe Group-Owned discount retailer Penny Market has revealed that it will invest up to €100m this year on expanding its operations in Bulgaria
which operates stores across Europe in the likes of Austria
plans to construct a total of 10 stores and a logistics centre in the village of Stolnik near Sofia
According to Penny's CEO for Bulgaria Vasil Fechko
while the distribution centre will cost up to €30m
The supermarkets will be opened following the launch of the distribution centre
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more than 1000 schools have been closed in Bulgaria
Primary schools in small towns often struggle to survive
In areas with predominant minority population
pupils’ poor Bulgarian language proficiency creates additional obstacles to teachers and the problem of children dropping out of the education system continues to be on institutions' agenda
a village school has been described as one that has “jumped into the future." The Primary School "Dr
Peter Beron" in the village of Plustina is central to the Omurtag municipality
It has about 160 students from 13 settlements
10-15% of the children are Romani and the rest are of Turkish origin
The latest training technologies have been applied here for 12 years now
Classrooms have been equipped with electronic boards and laptops for each teacher
an indoor gym with fitness equipment and an outdoor playground
Modern school equipment undoubtedly requires a lot of resources
"The school owns about 50 acres of farmland
The money from rent goes into the school," Deputy Director Nursen Isufova explains
“We have been actively working on European and national programs
When the first national programs started to be implemented back in 2007/2008
We have built a wonderful sports playground
In the indoor sports hall we have fitness equipment and children can also use it in their free time
We have also introduced school uniforms because we see how the difference in clothing created embarrassment for some of the students.”
Nursen Isufova says that thanks to successful implementation of 2 European
projects totaling about 240 thousand euros
the school management continued to improve the conditions in the school and on the other hand provided the opportunity for pupils to travel all over Bulgaria
participating in forums and festivals and creating partnerships with other schools
The students also often go to sports camps and excursions
Do your pupils ever want to go on school recess at all
The announcement of a two-week Christmas holiday actually was not to the liking of some pupils
The efforts of an ambitious team of pedagogues combined with interactive teaching methods have yielded amazing results
during the 2014 National External Assessment in Mathematics
the school in Plustina achieved an average score of 5.13 and became the only one in the country with a score above 5
The unemployment rate in the region is high
so some families work abroad and children are raised by their grandparents
"We often need to be in the role of substitute parents," the deputy principal says
They seek help and assistance in every way
We have been trying to provide them with what they are missing at home."
financially distressed families were provided with computers so that children can do their homework and the school also has a dressing room
It seems the school management has accomplished everything
"Not everything," Nursen Isufova says and adds:
"We need to continue developing in the digital sphere
Our idea is that students would come to school with just one flash drive with them
This would be the newest thing to happen in our school.”
Only on the Day of Bravery and Holiday of the Bulgarian Army (May 6)
we will provide our visitors with the opportunity to enter three of perhaps the most interesting machines from our outdoor exhibition
Dozens of enthusiasts and nature lovers will kick off the 44th edition of the Move and Win campaign with a spring hike to Bozhur Hut
The meeting point will be the Vladishki Bridge in Veliko Tarnovo
The third edition of the Samardala Festival will be held on 3 May in the central square of Nova Zagora
is used as a spice and is harvested at the peak of its flowering in May
we will provide our visitors with the opportunity to enter three.
The German discount supermarket chain Penny Market will invest EUR 100 M in Bulgaria until the end of 2009
That was announced by company's CEO for Bulgaria
Currently Penny Market plans to construct a total of 10 stores in Bulgaria's Lovech
Their biggest project will be a logistics center in the village of Stolnik near capital Sofia
and will be built on an area of 78 decares
The main contractor for the construction is the Bulgarian Mix Construction
Penny Market is a discount shops chain which operates 5000 stores around Europe (Germany
It is owned by the German retail and tourism company REWE Group
Penny Market has been in the Bulgarian market since 2005
the company is looking for terrains in Sofia and bigger Bulgarian cities
All the supermarkets will be opened after the logistics center construction is finished
former Ukrainian Commander-in-Chief and current Ambassador to the U.K.
has provided insights into the pivotal role of the joint Ukrainian-U.S
Germany has deployed its first permanent military brigade abroad since World War II
A recent report from Germany’s Federal Intelligence Service and the Bundeswehr has revealed concerns that Russia is likely preparing for a large-scale conflict with NATO
A nationwide strike by German airport workers led to the cancellation of 12 flights between Bulgaria and Germany on Monday
A 40-year-old German man from Ludwigshafen has been detained in connection with the car ramming attack in Mannheim that left at least two people dead and 11 others injured
all retailers in Bulgaria will be required to display prices in both leva and euros
a major British tour operator specializing in holidays to Bulgaria
has halted all its operations effective April 24
Wage growth in Bulgaria is projected at 9.3 percent for 2025
a 15.4 percent rise in the minimum wage since January
The World Bank has revised down its forecast for Bulgaria’s economic growth in 2025
Bulgaria is approaching the final stages of preparation for transitioning card payments from the national currency
Minister of Economy and Industry Petar Dilov held a meeting with Susan Falatko
the Charge d'Affaires at the US Embassy in Bulgaria
The town of Targovishte (Northeastern Bulgaria) hosts the orienteering competition 2025 Velikden Cup
Moldova and Ukraine have arrived in the city to take part in the orienteering competition
The program includes middle-distance and long-distance events on challenging terrain with numerous rocks
The program also features a mass start near the village of Ugledno (Omurtag Municiplity)
has climbed one place in the Association of Tennis Professionals (ATP) rankings
Last week Dimitrov took part in the Masters 1000 tournament in the Spanish capital Madrid
Bulgaria’s junior group won all three gold medals at the 2025 Rhythmic Gymnastics European Cup in Baku (Azerbaijan)
Bulgaria won the gold medal in the Senior Group Cross Battles at the 2025 Rhythmic Gymnastics European Cup in Baku (Azerbaijan)
Danaya Atanasova and Viktoria Georgieva performed.
can be seen in the National Archeological Museum
It was discovered on November 7 by associate Professor Diana Gergova at the historical and archeology preserve in Sboryanovo
which is included in the UNESCO world cultural heritage list
The unique find marked the 30th anniversary since the start of the archeological research in Sboryanovo
where the capital of the Thracian tribe Getty was situated
sanctuaries and necropolises reveal the history of the one-time political and cultural center
Here is an interesting fact: series of researches show that the so-called King’s necropolis and the other necropolises of the Getty tribe were projected in accordance with a star map- as reflections of different constellations
The start was given by Bulgarian and Italian experts
A monumental tomb with pillars of the Doric style dating back to the end of the 4th and the beginning of the 3rd century BC was found there
Some experts say that it was of a 7th magnitude at the Richter scale
which aimed to reveal how this solid mound was built
when we have such powerful machinery we find it hard to excavate this mound”
Other researches were also made in the Omurtag mound
used for the assembling of the stone blocks as well as studies of the bones found at this place
we are very dependant on the geophysical equipment”
“Due to the new equipment provided to us 10 years ago
we managed to spot the central construction at the mound
We can expect to find there a tomb or other major construction.”
The site has not been explored for 7-8 years due to the lack of financing and powerful machinery
the archeologists received excavation machinery from sponsoring companies
On the 3rd day of the exploration they came across a small part of crumbly soil
According to Diana Gergova this is a unique find
because it was discovered at a high place in a very impressive mound
Each stage of its construction was connected to certain ceremonies of immortalization
This is why experts suppose that this treasure was in fact a funeral gift
the archeologists need more funds and better organization to reveal more interesting facts
“We are talking about 2 groups of memorials
The first one includes applications to a horse harness
among which is a beautiful diadem with figures of various animals and mythical creatures
There are 4 golden bracelets with a spiral form and a wonderful golden ring with an embossment of God Eros
The interesting thing here is that we found many golden fibres and tiny cylindrical and round golden beads
which were once placed over a veil interwoven with gold
We are very pleased that there is another effigy in the Kazanlashka tomb (which was also included in the UNESCO cultural heritage list)
which reveals the one-time funeral procession
A woman with a veil walks behind the man with the casket
So we have a full exemplification of a ritual
which was once practiced by the Thracian people”
said associate professor Gergova in conclusion
The site is now to be prepared for the winter
scientists will make new geophysical research of the place
archeologists will be better prepared for their next researches
"You must have strong faith and pray - then the saint will help you and carry your prayer to God," says Father Georgi Markov of the Church of St
Athanasius the Great in Gorni Lozen near Sofia
He adds that he has often witnessed the miracles of St.
marks 1160 years since the baptism of our Bulgarian people into the Orthodox faith and 1170 years since the creation of the Bulgarian alphabet and Slavic literature
the Varna and Veliki Preslav Bishopric Metropolis.
Bulgaria celebrates 149 years since the April Uprising – an event that led to the liberation of Bulgaria after almost five centuries of Ottoman rule
we must not forget that every participant in the April.
DNB Stories Africa
While some amount of stress is actually good in that it helps one to be motivated and alert
but if stress levels escalate it could lead to infertility and lower sperm count
For couples who are planning to conceive it is necessary to control the stress levels as it affects conception in a big way
meditation and mental exercises are suggested to help in controlling stress levels
Diet has a huge impact on sperm count and its quality
Diets high in meat and dairy are not just bad for waistlines
they have a negative impact below the waist too
A good number of studies have listed foods like bananas
dark chocolate and garlic as super foods for sperm building
Lower sperm counts have long been associated with conditions such as diabetes
varicose veins on the testicles and sexually transmitted diseases such as gonorrhea or HIV
Lying on your couch watching back-to-back episodes of “Game of Thrones” won’t do you any favors in the baby-making game
“If you’re not getting 150 minutes of moderate exercise every week,” Urologist and fertility specialist Dr
obesity is one of the key culprits of low sperm production
Researchers at Ambroise Paré University Hospital in Paris found that among obese men
32.4 percent had a low sperm count and 6.9 percent had no viable sperm
“Tobacco affects motility and shape of the sperm,” says Dr
a reproductive endocrinologist and reproductive specialist in St
His conclusions are in line with a 2016 study
which showed that smokers’ DNA and sperm were damaged in ways that reduce the chances of fertilization
Omurtag also says that marijuana and opioid use affect sperm production
“They effectively disrupt how the brain talks to the testicles,” he says
Advice from doctors to men with fertility problems
keeping laptops away from laps and having less sex to give the sperm enough time to build up
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