Ambulatory Electrodermal Monitoring: Effects of Ambient Temperature, General Activity, Electrolyte Media, and Length of Recording

The feasibility of long-term monitoring of electrodermal activity (EDA) from freely moving subjects was assessed by examining several confounding variables including epidermal hydration, ambient temperature, and physical activity. EDA was monitored from 12 subjects during a normal working day. A portable 4 channel cassette recorder (Medilog) was employed to record skin conductance, ambient temperature, and arm movements. The effects of epidermal hydration were assessed using different 0.05 KCl electrolyte media. EDA was quantified throughout the day during several 5-min rest periods and subsequent simple reaction time tasks. In order to distinguish between the influence of time of day and electrode/electrolyte aging, an extra pair of fresh electrodes was applied at each measurement period. Significant effects of temperature, electrolyte medium, and time of measurement on several indices of EDA were obtained. The implications of these data for long-term ambulatory EDA monitoring were discussed.