Anticipatory coarticulation in a patient with apraxia of speech.

Articulatory anticipation of vowel gestures was assessed in an apraxic patient, a dysarthric patient, and three normal speakers. The technique of assessment included perceptual identification of gated speech stimuli. The speech material consisted of /getVte/ utterances with the target vowels /i/, /y/, and /u/. In the case of the apraxic patient the gated vowels were identified at a later instant relative to the preceding plosion burst than in the normal speakers. This result was interpreted as reflecting a delayed onset of coarticulatory gestures, in particular lip rounding. The identification rates for the dysarthric's vowels rather reflected the general reduction of this patient's vowel space.