Auditory-visual speech integration by adults with and without language-learning disabilities

Auditory and auditory-visual (AV) speech perception skills were examined in adults with and without language-learning disabilities (LLD). The AV stimuli consisted of congruent consonant-vowel syllables (auditory and visual syllables matched in terms of syllable being produced) and incongruent McGurk syllables (auditory syllable differed from visual syllable). Although the identification of the auditory and congruent AV syllables was comparable for the two groups, the reaction times to identify all syllables were longer in the LLD compared to the control group. This finding is consistent with previous research demonstrating slower processing in learning disabled individuals. Adults with LLD also provided significantly fewer integration-type or McGurk responses compared with their normal peers when presented with speech tokens representing a mismatch between the auditory and visual signal. These results suggest the poor integration for auditory-visual speech previously documented in children with poor language skills also occurs in adults with LLD. The reader will be able to (1) describe the McGurk effect; (2) describe group differences (language learning disabled and control adults) in auditory and auditory-visual speech perception of consonant-vowel syllables.