Speechreading and its association with reading among deaf, hearing and dyslexic individuals.

Reading and speechreading are both visual skills based on speech and language processing. Here we explore individual differences in speechreading in profoundly prelingually deaf adults, hearing adults with a history of dyslexia, and hearing adults with no history of a literacy disorder. Speechreading skill distinguished the three groups: the deaf group were better speechreaders than hearing controls, who were better than the group with a history of dyslexia. The dyslexic group, while within range of hearing controls in terms of reading, nevertheless showed a residual deficit in speech/language processing when tested with silent speech. Within-group correlations suggested different associations between speechreading subtasks, reading and language skills. In particular, in the deaf and dyslexic groups, but not in the hearing controls, speechreading skill correlated with reading ability.