Relationship between Depression Level and Bio-signals by Emotional Stimuli

Recent studies in mental/physical health monitoring have noted to improve health and wellbeing with the help of Information and Communication Technology (ICT) and in particular, application of biosensors has mainly done because signal acquisition by non-invasive sensors is relatively simple as well as bio-signal is less sensitive to social/cultural difference. Prior to developing a depression monitoring system based on non-invasive bio-signals, we examined a relationship of depressive level and changes of biological features during exposure of emotional stimuli. Ninety-six subjects' depressive level was measured by a self-rating depression scale (SDS). Electrocardiogram (ECG) and photoplethysmograph (PPG) were recorded during six baseline and emotional states (interest, joy, neutral, pain, sadness and surprise) and heart rate (HR) and pulse transit time (PTT) were extracted. Pearson's correlation was conducted to examine the relation of depressive level and biological features. The results showed that relation of depressive level and HR is positive in emotional states and there is a negative correlation between depressive level and PTT. We identified that they are meaningful biological features related to depression.