arXiv subjects

Nathan Intrator

Publications and source records attributed to Nathan Intrator.

7 recordsLinked to original sources

arXiv2025

Personalized Detection of Stress via hdrEEG: Linking Neuro-markers to Cortisol, HRV, and Self-Report

Chronic stress is a risk factor for cognitive decline and illness, yet reliable individual markers remain limited. We tested whether two single channel high dynamic range EEG biomarkers, ST4 and T2, index stress responses by linking neural activity to validated physiological and subjective measures. Study 1 included 101 adults between 22 and 82 years of age who completed questionnaires on stress, resilience, and burnout, provided salivary cortisol, and performed resting, cognitive load, emotional, and startle conditions. Study 2 included 82 adults between 19 and 42 years who completed the State Trait Anxiety Inventory, underwent heart rate variability monitoring, and performed auditory, stress inducing, and emotional conditions. Correlations were considered meaningful when r was at least 0.30. Results showed that ST4 reflected physiological arousal and cognitive strain. In Study 1, resting ST4 was positively related to cortisol and lower in more resilient participants. In Study 2, ST4 correlated negatively with heart rate variability during stress and recovery. T2 reflected emotional and autonomic regulation. In Study 1, T2 tracked higher cortisol and was lower with greater resilience. In Study 2, T2 was higher with trait anxiety and correlated negatively with heart rate variability during stress and emotional conditions. Together, ST4 and T2 provide complementary portable markers of stress, supporting individualized assessment in clinical and real world contexts.

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arXiv2025

Dissociating Cognitive Load and Stress Responses Using Single-Channel EEG: Behavioral and Neural Correlates of Anxiety Across Cognitive States

Identifying neural markers of stress and cognitive load is key to developing scalable tools for mental state assessment. This study evaluated whether a single-channel high-density EEG (hdrEEG) system could dissociate cognitive and stress-related activity during a brief auditory task-based protocol. Sixty-eight healthy adults completed resting state recordings, cognitively demanding auditory tasks, and exposure to unpredictable literalized startle stimuli. Participants also rated their stress and anxiety using a modified State-Trait Anxiety Inventory (STAI). EEG analysis focused on frequency bands (Theta, Gamma, Delta) and machine-learning-derived features (A0, ST4, VC9, T2). A double dissociation emerged: Theta and VC9 increased under cognitive load but not startle, supporting their sensitivity to executive function. In contrast, Gamma and A0 were elevated by the startle stimulus, consistent with stress reactivity. ST4 tracked cognitive effort and worry, while T2 negatively correlated with self-reported calmness, indicating relevance to emotional regulation. These results demonstrate that a short, uniform assessment using portable EEG can yield multiple reliable biomarkers of cognitive and affective states. The findings have implications for clinical, occupational, and educational settings, and may inform future neurofeedback protocols targeting simultaneous regulation of attention and stress.

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arXiv2025

The Evaluation of Breathing 5:5 effect on resilience, stress and balance center measured by Single-Channel EEG

Slow-paced breathing is a promising intervention for reducing anxiety and enhancing emotional regulation through its effects on autonomic and central nervous system function. This study examined the neurophysiological and subjective effects of a 5:5 breathing protocol on stress-related EEG biomarkers using a mobile single-channel EEG system. Thirty-eight healthy adults were randomly assigned to either an intervention group (n = 20), which completed two sessions spaced two weeks apart with daily breathing practice, or a control group (n = 18), which completed one session. In each session, participants underwent an auditory EEG assessment with resting, mental load, and startle conditions. The intervention group also completed a guided breathing session during the first visit and practiced the technique between sessions. EEG biomarkers (ST4, Alpha, Delta, Gamma, VC0) and subjective anxiety levels (STAI) were assessed before and after the intervention. A significant reduction in Gamma power was observed in the intervention group immediately following the first breathing session during mental load (p = .002), indicating acute stress reduction. Across sessions, long-term breathing practice led to increased Alpha and Delta power and reduced ST4 activity, suggesting cumulative improvements in emotional regulation and cognitive efficiency. Correlational analyses revealed that changes in VC0 and Alpha were significantly associated with subjective reports of tension, focus difficulty, and calmness. Guided slow-paced breathing at a 5:5 rhythm produces both immediate and sustained effects on neural markers of stress and cognition, with corresponding improvements in subjective anxiety. These findings support EEG-based monitoring as a scalable method for evaluating breath-based interventions and promoting real-time emotional self-regulation.

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arXiv2023

Evaluation of Parkinsons disease with early diagnosis using single-channel EEG features and auditory cognitive assessment

Parkinsons disease (PD) diagnosis is challenging due to subtle early clinical signs. F-DOPA PET is commonly used for early PD diagnosis. We explore the potential of machine-learning (ML) based EEG features extracted from single-channel EEG during auditory cognitive assessment as a noninvasive, low-cost support for PD diagnosis. The study included data collected from 32 participants who underwent an F-DOPA PET scan as part of their standard treatment and 20 cognitively healthy controls. Participants performed an auditory cognitive assessment recorded with Neurosteer EEG device. Data processing involved wavelet-packet decomposition and ML. First, a prediction model was developed to predict 1/3 of the undisclosed F-DOPA results. Then, generalized linear mixed models were calculated to distinguish between PD and non-PD subjects on the frequency bands and ML-based EEG features (A0 and L1) previously associated with cognitive functions. The prediction model accurately labeled patients with unrevealed scores as positive F-DOPA. Novel EEG feature A0 and the Delta band showed significant separation between study groups, with healthy controls exhibiting higher activity than PD patients. EEG feature L1 activity was significantly lower in resting state compared to high-cognitive load. This effect was absent in the PD group, suggesting that lower activity in resting state is lacking in PD patients. This study successfully demonstrated the ability to separate patients with positive vs. negative F-DOPA PET results with an easy-to-use single-channel EEG during an auditory cognitive assessment. Future longitudinal studies should further explore the potential utility of this tool for early PD diagnosis and as a potential biomarker in PD.

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arXiv2020

Continuous monitoring of cognitive load using advanced computerized analysis of brain signals during virtual simulator training for laparoscopic surgery, reflects laparoscopic dexterity. A comparative study using a novel wireless device

Simulation-based training is an effective tool for acquiring practical skills, specifically to train new surgeons in a controlled and hazard-free environment, it is however important to measure participants cognitive load to decide whether they are ready to go into a real surgery. In the present study we measured performance on a surgery simulator of medical students and interns, while their brain activity was monitored by a mobile EEG device. 38 medical studentswere underwent 3 experiments undergoing a task with Simbionix simulator, while their brain activity was measured using a single-channel EEG device (Aurora by Neurosteer). On each experiment, participants performed 3 repeats of a simulator task using laparoscopic hands. The retention between tasks was different on each experiment, to examine changes in performance and cognitive load biomarkers that occur during the task or as a results of night sleep consolidation. The participants behavioral performance improved with trial repetition in all 3 experiments. In Exps. 1 & 2, the theta band activity significantly decreased with better individual performance, as exhibited by some of the behavioral measurements of the simulator. The novel VC9 biomarker (previously shown to correlate with cognitive load), exhibited a significant decrease with better individual performance shown by all behavioral measurements. In correspondence with previous research, theta decreased with lower cognitive load and higher performance and the novel biomarker, VC9, showed higher sensitivity to load changes. Together, these measurements might be for neuroimaging assessment of cognitive load while performing simulator laparoscopic tasks. This could potentially be expanded to evaluate efficacy of different medical simulations to provide more efficient training to medical staff and to measure cognitive and mental load in real laparoscopic surgeries.

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arXiv2020

Reduced neural activity during volatile anesthesia compared to TIVA: evidence from a novel EEG signal processing analysis

Post-operative cognitive decline is a well-known phenomenon and of crucial importance especially in the elderly. General anesthesia can be accomplished by inhalation-based (volatile) or total intravenous anesthesia (TIVA). While their effects on post-operative symptoms have been investigated, little is known about their influence on brain functionalities during the surgery itself. To assess differences 17 patients were divided to receive either volatile anesthesia (n=9), or TIVA (n=8). The level of anesthesia was kept to be equal in both groups. A single bipolar EEG electrode (Neurosteer system) was placed on the participants foreheads. It presented real-time activity and collected their data during the surgery. The dependent variables included frequency bands (delta, theta, alpha, and beta), and three features (VC9, ST4, and A0) previously extracted with the device and provided by Neurosteer. All surgeries were uneventful, and all patients showed bispectral index (BIS) score less than 60. Feature activity under volatile anesthesia (in comparison to TIVA) was significantly lower for the delta, theta and alpha frequency bands and for the three features. Further analysis showed that the largest difference between anesthesia types was for feature A0. The EEG frequency bands and novel brain activity features provide evidence that volatile anesthesia further reduces components of brain activity in comparison to TIVA anesthesia. Specifically, A0, which previously showed a correlation with cognitive decline severity and cognitive load, exhibited the most prominent difference between anesthesia types. Together, this study suggests that measuring brain activity during anesthesia using sensitive features, enables revealing that different anesthesia types may affect brain activity differently, which could affect the recovery from anesthesia, and consequently reduce post-operative cognitive decline

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arXiv2020

Single-channel EEG features during n-back task correlate with working memory load

Working Memory (WM) load is an important cognitive feature that is highly correlated with mental effort. Several neurological biomarkers such as theta power and mid-frontal activity show increased activity with increasing WM load. Such correlations often break down in cognitively impaired individuals, making WM load biomarkers a valuable tool for the detection of cognitive impairment. However, most studies have used a multi-channel EEG or an fMRI, which are not massively accessible. In the present study, we evaluate the ability of novel features extracted from a single-channel EEG located on the forehead, to serve as markers of WM load. We employed the widely used n-back task to manipulate WM load. Fourteen participants performed the n-back task while their brain activity was recorded with the Neurosteer inc Aurora EEG device. The results showed that the activity of the newly introduced features increased with WM load, similar to the theta band, but exhibited higher sensitivity to finer WM load changes. These more sensitive biomarkers of WM load are a promising tool for mass screening of mild cognitive impairment.

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