AN EXAMINATION OF IMPAIRED ACOUSTIC-PHONETIC PROCESSING IN APHASIA

This research examines the nature of acoustic-phonetic impairments fou nd in aphasia, and the reliability of patient performance on phoneme d iscrimination and identification tasks. Aphasic patients were tested o n three phoneme discrimination tasks examining their ability to discri minate items on the basis of contrasts in sonorance, manner, place, or voicing using both spoken and synthetic stimuli. One of these tests i nvolving the discrimination of spoken, one-syllable items was given to patients on three occasions over the course of 1 year to examine shor t- and long-term test reliability. In addition to these measures, pati ents were tested on three phoneme identification tasks using stimulus items drawn from the discrimination tests. The results of these tests how that aphasic patients may display stable patterns of performance o n these measures over time and between tests. Furthermore, these findi ngs suggest that discriminations of synthetic speech do not necessaril y reflect patients' ability to discriminate spoken speech tokens. Thes e results are interpreted as evidence that aphasics display stable, di screte impairments in acoustic-phonetic processing, and that these def icits may be measured reliably using phoneme discrimination and identi fication tasks using natural speech. (C) 1996 Academic Press, Inc.