Differentiating linguistic and motor programming errors according to perceptual and acoustic measures in apraxia of speech

Apraxia of speech, considered to be a neuromotor programming disorder, may not be only the result of impaired articulatory planning. Apraxia also may encompass linguistic processing problems. Five participants were in this study. Four were older adults who displayed one of the following post stroke deficits: an apraxia of speech, a Broca's aphasia with accompanying apraxia, an anomia and a dysarthria. The fifth was an unimpaired control participant. Participants were recorded repeating words and nonwords. Recordings were analyzed for perceptual accuracy and for voice onset time (VOT) of the initial stop consonant. Participants also completed a rhyme judgment task in which they identified pairs of visually similar and nonsimilar rhyming and nonrhyming words. The participant with apraxia had errors similar to, but not as extensive as, the participant with Broca's aphasia and apraxia. This suggested that apraxia of speech encompasses impairments in motor programming as well as linguistic processing. These results suggest that treatment protocols for apraxia of speech should encompass linguistic processing as well as motor programming activities.