Abstract:

Auditory--Visual (AV) speech recognition is influenced by at least three primary factors: (1) the ability to extract auditory (A) and visual (V) cues; (2) the ability to integrate these cues into a single linguistic object; and (3) the ability to use semantic and syntactic constraints available within the context of a sentence. In this study, the ability of hearing-impaired individuals to recognize bandpass filtered words presented in isolation and in meaningful sentences was evaluated. Sentence materials were constructed by concatenating digitized productions of isolated words to ensure physical equivalence among the test items in the two conditions. Formulae for calculating k factors [Boothroyd and Nittrouer, J. Acoust. Soc. Am. 84, 101--114 (1988)], which relate scores for words and sentences, were applied to individual subject data obtained at three levels of isolated word-recognition performance approximating 30%, 50%, and 70% correct. In addition, A, V, and AV sentence recognition in noise was evaluated using natural productions of fluent speech. Two main issues are addressed: (1) the effects of intelligibility on estimates of k within individual subjects; and (2) the relations between individual estimates of k and sentence recognition in noise as a function of presentation modality. [Work supported by NIH Grant DC00792.]