Studies of Tactile Speechreading Enhancement in Deaf Adults

Abstract

The purpose of this report is to review results from a series of studies of tactile speechreading enhancement in deafened adults. The dependent variable in each study was the percentage of words recognized in everyday sentences of known topic. In the first study, eight subjects obtained an average enhancement of 9 percentage points using a 16-channel, spatiotemporal, tactile display of voice fundamenta l frequency (Fo). In a second study, three of these eight subjects obtained a mean enhancements of 10 and 8 percentage points, respectively, with the 16-channel display of Fo and a single-channel, temporal-only, display. In a third study, one of the eight subjects, who had received an enhancement of 9 percentage points with the 16-channel display of Fo, obtained a 5 percentage point enhancement from a 7-channel display of the speech spectrum. In a fourth study, a highly experienced tactile aid user obtained a 20 percentage point enhancement using single-channel tactile presentation of the low-frequency components of the acoustic speech signal. The presence of similar and significant speech-reading enhancements with a variety of tactile displays is encouraging, but findings from auditory Fo enhancement studies indicate that even better results should be possible. Coding and training strategies need to be addressed in continuing efforts to improve tactile devices as aids to speechreading.