Deep dysphasia in a case of phonemic deafness: role of the right hemisphere in auditory language comprehension.

Deep dysphasia, an analogue of deep dyslexia in the auditory modality is a rare and peculiar pattern of repetition disturbance, which has been used to validate Morton's (Deep Dyslexia, pp. 189-196. Routledge & Kegan Paul, London, 1980) logogen theory. Such a case is reported here in which there was strong evidence of destruction of the left temporal lobe auditory areas. Examination of linguistic performance emphasized levels of auditory speech decoding. It was found that this patient had a profound phonemic discrimination deficit, yet could accomplish many lexical operations. It is argued that this case, in which a left temporal lobe lesion was associated with impaired phonological analysis, provides evidence that deep dysphasia may reflect the right hemisphere's non-phonological mode of speech processing.