Electrodermal Activity on the Torso: Identification of Locations for Wearable Belt Monitors

The most common locations to acquire electrodermal activity (EDA) are the fingers, palms, or even the sole of the foot. While these areas provide clean, reliable signals, they are easily corrupted and are difficult to access for continuous, long term signal monitoring. This limits the use of the signal in potentially transformative settings. An alternative location such as an area located on the torso could potentially solve these issues as it is an easily accessible location. In this work, we collected EDA recordings from 10 subjects at their fingers, sternum, lower pectoralis, hip, and spine. They were exposed to cognitive stress through the Stroop task and physical stress using a cold pressor task. Several indices were derived from the EDA corresponding to each task. Using the fingers as reference, the performance of the various torso-based sites was compared. Significant differences were noted between stressor and baseline for the pectoral location when observing TVSymp, a time varying index of sympathetic activity, in addition to the spine location when observing Sympn, a similar index of the sympathetic response. As expected, the fingers demonstrated similar activation. A comparison of the metric as an aggregate of all subjects between each alternate location to the fingers showed low correlation. Further analysis including more subjects is required and will potentially clarify currently non-significant trends while strengthening initial significant relationships.