Aphasics can distinguish permuted orders of phonemes--but only if presented rapidly.

Abstract

Speech consists of a rapid succession of phonemes, and receptive aphasia has been attributed to an impairment in temporal acuity that interferes with the ability to discriminate between different arrangements of brief sounds. The present study reports evidence that aphasic listeners could distinguish between permuted orders of steady-state vowels occurring at rates matching or exceeding those employed in natural speech production. They could not, however, distinguish between different arrangements when the rate of presentation was slowed, although this task could be accomplished with ease by nonaphasic listeners. Our results suggest that the poor comprehension of language by aphasics is not the consequence of deficits in the ordering of brief sounds, but rather involves difficulties in performing tasks requiring specific psycholinguistic skills.