Speech perception without hearing

In this study of visual phonetic speech perception without accompanying aud itory speech stimuli, adults with normal hearing (NH; n = 96) and with seve rely to profoundly impaired hearing (IH; n = 72) identified consonant-vowel (CV) nonsense syllables and words in isolation and in sentences. The measu res of phonetic perception were the proportion of phonemes correct and the proportion of transmitted feature information for CVs, the proportion of ph onemes correct for words, and the proportion of phonemes correct and the am ount of phoneme substitution entropy for sentences. The results demonstrate d greater sensitivity to phonetic information in the IH group. Transmitted feature information was related to isolated word scores for the IH group, b ut not for the NH group. Phoneme errors in sentences were more systematic i n the IH than in the NH group. Individual differences in phonetic perceptio n for CVs were more highly associated with word and sentence performance fo r the IH than for the NH group. The results suggest that the necessity to p erceive speech without hearing can be associated with enhanced visual phone tic perception in some individuals.