Stress Assessment by Prefrontal Relative Gamma

Area of Science:

• Neuroscience
• Psychophysiology
• Biomedical Engineering

Background:

• Stress assessment utilizes biochemical and physiological markers.
• Neuroscience links stress to brain activity changes in limbic and frontal regions via fMRI and EEG.
• Existing EEG markers for stress are not well-established.

Purpose of the Study:

• To evaluate the prefrontal relative gamma power (RG) as a potential EEG marker for stress assessment.
• To investigate the correlation between prefrontal RG, stress levels, and heart rate (HR).

Main Methods:

• Six healthy subjects underwent the Montreal Imaging Stress Task (MIST) followed by relaxation.
• Electroencephalography (EEG) and electrocardiographic (ECG) signals were recorded during stress and relaxation periods.
• Prefrontal relative gamma power (RG) was analyzed and compared with other EEG metrics and HR.

Main Results:

• Prefrontal RG showed a significant correlation with expected stress levels and heart rate (HR = 0.8).
• Statistically significant differences (p < 0.01) in prefrontal RG were observed between stress and relaxation periods.
• Prefrontal RG demonstrated higher discriminative power for stress levels compared to alpha asymmetry and other power bands (theta, alpha, beta, gamma).

Conclusions:

• Prefrontal relative gamma power (RG) is proposed as a reliable EEG marker for stress assessment.
• RG offers superior temporal resolution compared to markers like HR or cortisol.
• The use of minimal, non-invasive dry electrodes facilitates real-time, ubiquitous stress monitoring devices.