Assessment of heart rate and electrodermal activity during sustained attention to response tests

Heart rate variation and electrodermal activity are both affected by the autonomic nervous system's response to psychological and emotional activity. The objective of this work is to use measures of these indices of autonomic function to assess the emotional responses of subjects undergoing a sustained attention to response test (SART). Errors of commission (failure to withhold responding to the no-go target), errors of omission (failure to respond on go trials), and response times were analyzed in conjunction with heart rate and electrodermal measurements. Errors of omission were the most common errors made by participants while errors of commission occurred less frequently with both showing considerable skin conductance rises in subjects who made few errors. The RR interval tachogram showed little correlation to errors of commission, omission or electrodermal measures. However, the mean RR interval after a commission error increased in subjects with low error rates. Also analysis of the low frequency component of the RR interval variation displayed an amplitude variation, which did show close correlation and synchronization with electrodermal activity in some subjects. The results suggest that autonomic outflow affecting electrodermal activity during the SART test also affects heart rate variation and the use of both measures of autonomic function may give a beneficial and complementary insight into physiological responses to psychological and emotional states.