Effect of Intermittent Stimulation Patterns on the Sensation during Electrocutaneous Stimulation

For electrotactile displays to become useful for supplementary sensory feedback for transfemoral prosthesis users the interface needs to be optimized. A closer look is taken at the nature of adaptation during electrocutaneous stimulation. In this portion the effect of intermittent stimulation patterns on the sensation is investigated. Seven different intermittent stimulation signals and two continuous signals were applied to the subjects skin in random order. Each of the nine trials lasted for about fifteen minutes and during these trials the stimulation current was adjusted at 80% of the dynamic range, as recommended in a previous study. The Visual Analog Scale was used to record the course of sensation during the period of stimulation. Results suggest two things. One, a minimal stimulation time (Ton) of 0.5 seconds is required to reach a maximal sensation. Two, a minimal rest period of about 0.3 seconds is required in order to postpone the occurrence of full adaptation (Toff).