Open-set word identification by an adult with profound hearing impairment: integration of touch, aided hearing, and speechreading.

The ability of an adult with profound hearing impairment to integrate speech information from touch, aided hearing, and speechreading in identification of open-set words was investigated. A list was obtained of 735 words that the subject failed to identify using any single modality: touch, with either the Tacticon 1600, a multichannel electrocutaneous vocoder (TV), or the Tactaid II, a 2-channel vibrotactile aid (TA); aided hearing (H); or speechreading (S). To test integration, observed word identification performance in combined-modality conditions was compared with predicted performance calculated from single-modality scores. Words were randomly assigned to seven conditions: (a) S+H, (b) H+TV, (c) H+TA, (d) S+TV, (e) S+TV+H, and (f) S+TA+H. Results indicated that the subject integrated speech information across modalities, with highest performance in the S+TV+H and S+TA+H conditions. Integration also occurred when both speechreading and touch were used and when both speechreading and aided hearing were used.

Multisensory narrative tracking by a profoundly deaf subject using an electrocutaneous vocoder and a vibrotactile aid.

A congenitally, profoundly deaf adult who had received 41 hours of tactual word recognition training in a previous study was assessed in tracking of connected discourse. This assessment was conducted in three phases. In the first phase, the subject used the Tacticon 1600 electrocutaneous vocoder to track a narrative in three conditions: (a) lipreading and aided hearing (L + H), (b) lipreading and tactual vocoder (L + TV), and (c) lipreading, tactual vocoder, and aided hearing (L + TV + H). Subject performance was significantly better in the L + TV + H condition than in the L + H condition, suggesting that the subject benefitted from the additional information provided by the tactual vocoder. In the second phase, the Tactaid II vibrotactile aid was used in three conditions: (a) lipreading alone, (b) lipreading and tactual aid (L + TA), and (c) lipreading, tactual aid, and aided hearing (L + TA + H). The subject was able to combine cues from the Tactaid II with those from lipreading and aided hearing. In the third phase, both tactual devices were used in six conditions: (a) lipreading alone (L), (b) lipreading and aided hearing (L + H), (c) lipreading and Tactaid II (L + TA), (d) lipreading and Tacticon 1600 (L + TV), (e) lipreading, Tactaid II, and aided hearing (L + TA + H), and (f) lipreading, Tacticon 1600, and aided hearing (L + TV + H). In this phase, only the Tactaid II significantly improved tracking performance over lipreading and aided hearing. Overall, improvement in tracking performance occurred within and across phases of this study.