Video-based sympathetic arousal assessment via peripheral blood flow
  estimation
Bjoern Braun Daniel McDuff Tadas Baltrusaitis Christian Holz
Electrodermal activity (EDA) is considered a standard marker of sympathetic
activity. However, traditional EDA measurement requires electrodes in steady
contact with the skin. Can sympathetic arousal be measured using only an
optical sensor, such as an RGB camera? This paper presents a novel approach to
infer sympathetic arousal by measuring the peripheral blood flow on the face or
hand optically. We contribute a self-recorded dataset of 21 participants,
comprising synchronized videos of participants' faces and palms and
gold-standard EDA and photoplethysmography (PPG) signals. Our results show that
we can measure peripheral sympathetic responses that closely correlate with the
ground truth EDA. We obtain median correlations of 0.57 to 0.63 between our
inferred signals and the ground truth EDA using only videos of the
participants' palms or foreheads or PPG signals from the foreheads or fingers.
We also show that sympathetic arousal is best inferred from the forehead,
finger, or palm.