Consideration of Formative Mechanism of Electrodermal Activity-Skin Potential Activity and Skin Impedance Change

Electrodermal activity (EDA) is well known as sensing emotional activity and autonomous nerve activity easily. There are skin resistance change (SRC), skin impedance change (SIC) and skin potential activity (SPA) for measurement of EDA. SPA which consists of skin potential level (SPL) and skin potential reflex (SPR) has been used well in recent years. However, there are various kinds of patterns in SPR, and not enough is known about the formative mechanism of SPA. Then, we had examined these things. In the case of measurement of SPL, we require a rigid standard electrode accompanied by removing of stratum corneum. Since this treatment is accompanied by some pain to subjects, inadequate removing of the stratum corneum will tend to bring uncertainty of measurement result. Therefore, if the relationship between the degree of fall of SIL and fall of SPL accompanied by removing of stratum corneum are clarified, and sufficient removing for construction of standard electrode is checked by impedance, this approach is reasonable. Then we proposed the method. Furthermore, by the relation with environmental temperature, EDA measurements in various body surface parts were performed, and the relevance of thermal perspiration and mental perspiration was considered.