The performance of eight subjects was assessed on a closed-set tactual test battery to evaluate efficiency of the speech feature encoding strategy currently used in the University of Melbourne multichannel electrotactile speech processor. The test battery included twelve subtests of suprasegmental and segmental speech feature contrasts. Results showed that all subjects scored significantly above chance on suprasegmental features such as syllable number, stess and vowel length. In addition, seven of the eight subjects scored significantly above chance for vowel format frequency discrimination. Scores for manner of articulation contrasts were more variable, with better performance for the higher frequency, longer duration fricatives and affricates. Scores for voicing contrasts suggested that improvements to the tactual coding of this feature could be achieved. The second study examined the contribution of the tactual input to consonant feature identification for subjects using the electrotactile aid in combination with either a low-pass filtered auditory input or different levels of aided residual hearing and lipreading. Results for four normally-hearing subjects showed increased voicing and manner identification scores with the addition of tactual input. Similar results were found for two hearing-impaired subjects, one using the tactual input in combination with lipreading and one using the tactual input in combination with aided residual hearing.
|Number of pages||16|
|Journal||Australian Journal of Audiology|
|Publication status||Published - 1989|