Effects of experimental manipulations of auditory feedback upon vowels

Abstract

The role of auditory feedback upon intermediate vowel production was explored by manipulating the amount and type of information provided by a Nucleus multichannel cochlear implant. Four experimental conditions ,were examined: (a) two types of control conditions, the implant turned on versus off, and (b) two experimental conditions that varied the channels being stimulated. Twenty repetitions of the vowels [ɪ], [ɛ], [i], [u] in an hVd context were acquired from four adventitiously deafened adults using multichannel implants. Two of the vowels, [ɪ] and [ɛ], were selected because of previous work indicating significant changes in formant frequencies when the implant was turned on versus off. The vowels [i] and [u] were included as controls since previous work indicated that their formant frequencies failed to change when the implant was turned off. Recordings were digitized at a 20‐kHz rate and analyzed using CSpeech. Fundamental frequency, formant frequencies, and duration measures were acquired for each token. Data were statistically treated using a repeated measures ANOVA. Preliminary data indicates that the intermediate vowels rely upon relevant auditory information more heavily for their production than the control, point vowels. [Work supported by NIDCD.]