Categorical Perception of Speech in Hearing-impaired Adults

To investigate the effect of acquired sensorineural hearing loss on speech perception at the acoustic-phonetic level, eight hearingimpaired and eight normally hearing adults were asked to identify and discriminate between a number of synthetic speech stimuli. Two sets of six speech stimuli were used; one set varied in terms of the voicing dimension with endpoint stimuli of “coat” and “goat”, while the other varied by place cues, with endpoints of “date” and “gate”. Results failed to show any significant differences in perception of the voicing contrast between the normally hearing and hearing impaired listeners. All sixteen listeners identified stimuli categorically and discriminated between-category pairs more accurately. With perception of place of articulation, three out of the eight hearing impaired listeners showed grossly abnormal identification, although one of those showed good between-category discrimination. All of the hearing-impaired listeners showed impaired between-category discrimination of place cues compared to normally hearing listeners.