Evaluation of Autonomic Nervous System, Saliva Cortisol Levels, and Cognitive Function in Major Depressive Disorder Patients

Figure 1

Experiment protocol. After the participants arrived, ECG and PPG sensors were placed on their chests and index finger. They were allowed to become familiar with WCST for 5 min and then started the recording of ECG and PPG during resting period for 15 min. After that saliva was collected from them for first time collection. They were allowed to conduct WCST test for 15–20 min and right after their finishing, the second saliva sample was collected. Participants were then allowed to relax on the chair for the next 20 min in the recovery period. After the recovery period, the ECG and PPG recording ended and the participants were dismissed. The beginning of ECG and PPG recording. The end of ECG and PPG recording. ECG: electrocardiogram; PPG: photoplethysmography; WCST: Wisconsin card sorting test; : time; min: minutes.