Evaluation of a 32‐channel electrotactile vocoder

Abstract

Previous evaluations of laboratory prototype multichannel tactile aids have shown them to provide useful speech information. However, few of these prototypes have been successfully converted into wearable devices. The present study evaluated a device that has recently become commercially available, the Audiotact (Sevrain‐Tech, Inc.), a 32‐channel electrotactile vocoder worn on the abdomen. Four subjects pacticipated in the study, two of whom had previous experience with other tactile aids. In addition, a visual display designed as a training aid for new users of the Audiotact was evaluated. This display provides a visual representation of the activity on the tactile array. Two of the subjects were instructed to use this visual information while wearing the Audiotact. Results of testing with minimal pairs and small set phoneme identification tasks showed that manner features were transmitted quite well. Subjects were also able to integrate information available through lipreading with information from the Audiotact. However, preliminary results for connected discourse tracking with the Audiotact showed only a small improvement over lipreading alone. The results of this study are discussed in terms of comparability to other multichannel tactile devices.