SOME TEMPORAL CHARACTERISTICS OF IMITATIVE SPEECH IN NON BRAIN-INJURED, APHASIC AND APRAXIC ADULTS
The purpose of this study was to extend the previous research on temporal acoustic characteristics in the imitative speech of non brain-injured, aphasic and apraxic adults. Voice onset time, vowel duration, final consonant duration and syllable duration were measured within single syllables. Two and three syllable segments were measured. Verbal response time and intersyllable intervals were also analyzed.
Four females and six males were selected for participation in this investigation. Each subject's imitative productions of 198 items were tape recorded, spectrographically displayed and measured.
Within CVC component measures, apraxic adults showed significant differences from non brain-injured and aphasic adults in their performance on CVC syllable duration, final consonant duration and on variability of CVC productions. Within silent interval measures, apraxic adults differed from non brain-injured and aphasic adults in their performance on verbal response times, intersyllable intervals and in variability of those performances. Among segment duration measures, apraxic adults differed from non brain-injured and aphasic adults in their mean segment durations and in the variability of their performance on these measures.
Inferences were made relating the apraxic subjects' longer latency effects and their total response duration effects. Results support the concept of apraxia of speech as a motor programming disorder separate from, but co-occurring frequently with aphasia.