Mental stress assessment based on pulse photoplethysmography

Mental stress is accompanied by dynamic changes in autonomic nervous system activity. Heart rate variability (HRV) analysis is fast emerging as a non-invasive research and clinical tool for assessing cardiac and autonomic nervous system function. However, in this study describes a method of stress assessment based on Pulse photoplethysmography (PPG). We assessed the possibility of using the pulse rate variability (PRV) extracted from the PPG signal as an alternative measurement of the HRV signal. Further, to demonstrate the accuracy and feasibility of HRV extraction from PPG signal, finger-tip PPG and standard lead II ECG signals were simultaneously. A comparative analysis of time domain and frequency domain measures of PRV was carried out. Finally, we present a method of PRV analysis to evaluate mental stress by simple PPG. These results suggest that PRV based on PPG could be used as a surrogate of HRV for the purpose of stress assessment.