抄録
We describe a novel artificial tactile system for transmitting a few words (verbal information) in which two-channel electrotactile stimulation capable of generating apparent movements is applied to the dorsal carpal area of the left hand via surface concentric electrodes. The utility of the system was demonstrated in psycophysical experiments using 15 healthy subjects. Verbal information was provided regarding the direction in which an object was located, with directions selected from “forward”, “left” and “right” and objects selected from “human”, “car” and “obstruction.” Consequently, nine kinds of verbal information could be sent. We therefore designed six stimulation patterns (duration, 600-900 ms) comprising several burst profiles in which each burst was composed of several pulses (interval of biphasic pulses, 2.85 μs) modulated in amplitude. The recognition experiment showed that the mean (±SD) percentage of correct answers was about 92 ± 4.2% and the mean reaction time was about 2.9 ± 0.1 s. The recognition percentage improved with experience, prior explanation about each stimulation pattern, and by increasing the range of stimulus intensity. These basic findings suggest the possible applicability of the proposed verbal information transmission method to assist auditory impaired persons and prosthetic hand users.
