Perceptual characteristics of consonant production by apraxic speakers

Single-word repetitions by 4 brain-damaged adults with apraxia of speech (AOS) but without concomitant aphasia were transcribed using a standard narrow phonetic transcription system. Analysis of consonant productions yielded a profile of AOS slightly different from the traditionally accepted one. Among the results was the atypical finding that consonant distortions exceeded all other error types including sound substitutions. In addition, errors predominated in the medial position of words, and monosyllabic words had approximately the same error rate per number of consonants as did multisyllabic words. Results are discussed with reference to previous perceptual descriptions of AOS and in relationship to Broca's aphasia. Results are also interpreted relative to linguistic and motoric components of speech production models.