“…Various biomarkers and physiological measurements have been proposed as objective metrics to evaluate the physical and cognitive state of human beings, including electrocardiogram (ECG), electroencephalogram (EEG), electromyography (EMG), electrodermal activity (EDA), photoplethysmography (PPG), and skin temperature. The ECG, EEG, and EMG signals are measurements used to evaluate and monitor the function of the heart [ 7 , 8 ], brain [ 9 , 10 ], and muscles [ 11 , 12 ], respectively. EDA measures the variation in the skin conductivity caused by sweat secretion [ 13 , 14 , 15 ], whereas PPG is a measure used to detect the change in the blood volume using optical devices [ 16 , 17 ].…”