"Advancing Wearable Stress Monitoring: Multimodal Analysis of EEG, HRV," by Mohammad Haroon Ahmed

Date of Award

5-2025

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Biomedical Engineering and Sciences

First Advisor

Peshala Thibbotuwawa Gamage

Second Advisor

Mehmet Kaya

Third Advisor

Kenia Pedrosa Nunes

Fourth Advisor

Linxia Gu

Abstract

This research investigates multimodal physiological signal analysis for real-time stress classification, with a focus on identifying biomarkers suitable for wearable implementation. A standardized experimental protocol was developed involving rest, stress, guided meditation, and recovery phases. Participants completed cognitive stress tasks such as the Stroop test and mental arithmetic under controlled conditions while Electroencephalography (EEG), Electrocardiography (ECG), and Electromyography (EMG) signals were simultaneously recorded. Sessions were designed to isolate the physiological effects of acute stress and meditation across repeated trials. Advanced signal processing techniques were applied to extract relevant features for classification, and statistical analysis was conducted to assess significance.

The study evaluates HRV and trapezius muscle EMG as practical alternatives to EEG. Using both subject-specific and generalized machine learning models, HRV and EMG showed comparable accuracy to EEG, supporting their potential for continuous stress monitoring.

Stress responses were further analyzed in emergency room healthcare providers versus non-healthcare controls. While both groups followed similar stress response trends, ER providers exhibited stronger and faster physiological responses and quicker recovery, underscoring the importance of population-specific stress monitoring.

Additionally, guided meditation was examined as a stress-reduction strategy. Preliminary results from a small sample showed improvements in reaction time and accuracy, suggesting potential benefits that warrant further validation in larger cohorts.

Novel EMG features based on frequency bands and optimized sensor placement were introduced, demonstrating strong potential for stress classification.

The findings advance personalized, signal-based approaches for practical stress monitoring and lay the groundwork for developing efficient, accessible, and minimally obtrusive systems suitable for real-world deployment.

Available for download on Monday, May 10, 2027

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