Development of device for measurement of skin potential by grasping of the device

Abstract

In this study, we developed a device for measuring skin potential activity requiring the subject to only grasp the interface. There is an extant method for measuring skin potential activity, which is an indicator for evaluating Mental Work-Load (MWL). It exploits the fact that when a human being experiences mental stress, such as tension or excitement, emotional sweating appears at skin sites such as the palm and sole; concomitantly, the skin potential at these sites varies. At present, skin potential activity of the hand is measured by electrodes attached to the whole arm. Alternatively, if a method can be developed to measure skin potential activity (and in turn emotional sweating) by an electrode placed on the palm only, it would be feasible to develop a novel portable burden-evaluation interface that can measure the MWL with the subject holding the interface. In this study, a prototype portable load-evaluation interface was investigated for its capacity to measure skin potential activity while the interface is held in the subject’s hand. This interface, wherein an electrode is attached to the device, rather than directly to the hand, can measure the parameters with the subject gripping the device. Moreover, by attaching the electrode laterally rather than longitudinally to the device, a touch by the subject, at any point on the sides of the device, enables measurement. The electrodes used in this study were tin foil tapes. In the experiment, subjects held the interface while it measured their MWL. However, the amplitude of skin potential activity (which reflects the strength of the stimulus administered on the subjects) obtained by the proposed method was lower than that obtained by the conventional method. Nonetheless, because sweat response due to stimulation could be quantified with the proposed method, the study demonstrated the possibility of load measurements considering only the palm.