Electro-Tactile Stimulation Enhances Cochlear-Implant Melody Recognition: Effects of Rhythm and Musical Training.

Abstract

Electro-acoustic stimulation (EAS) enhances speech and music perception in cochlear-implant (CI) users who have residual low-frequency acoustic hearing. For CI users who do not have low-frequency acoustic hearing, tactile stimulation may be used in a similar fashion as residual low-frequency acoustic hearing to enhance CI performance. Previous studies showed that electro-tactile stimulation (ETS) enhanced speech recognition in noise and tonal language perception for CI listeners. Here, we examined the effect of ETS on melody recognition in both musician and nonmusician CI users. Nine musician and eight nonmusician CI users were tested in a melody recognition task with or without rhythmic cues in three testing conditions: CI only (E), tactile only (T), and combined CI and tactile stimulation (ETS). Overall, the combined electrical and tactile stimulation enhanced the melody recognition performance in CI users by 9% points. Two additional findings were observed. First, musician CI users outperformed nonmusicians CI users in melody recognition, but the size of the enhancement effect was similar between the two groups. Second, the ETS enhancement was significantly higher with nonrhythmic melodies than rhythmic melodies in both groups. These findings suggest that, independent of musical experience, the size of the ETS enhancement depends on integration efficiency between tactile and auditory stimulation, and that the mechanism of the ETS enhancement is improved electric pitch perception. The present study supports the hypothesis that tactile stimulation can be used to improve pitch perception in CI users.