Phonemic characteristics of apraxia of speech resulting from subcortical hemorrhage

Reports describing subcortical apraxia of speech (AOS) have received little consideration in the development of recent speech processing models because the speech characteristics of patients with this diagnosis have not been described precisely. We describe a case of AOS with aphasia secondary to basal ganglia hemorrhage. Speech-language symptoms consistent with subcortical AOS and aphasia are reported as well as description of the patient's speech characteristics using broad phonemic transcription. Significantly more phoneme substitution errors were observed than other types of errors and these occurred significantly more often in the initial rather than the medial or final positions of words. No differences were observed in the number of errors produced for the various types of phonemes included in this analysis. These findings challenge the hypothesis that speech motor planning disorders are uniquely the result of cortical damage. They also argue against the notion that subcortical AOS is indistinguishable from the cortical syndrome.

The reader will learn (1) the phonemic characteristics of AOS due to subcortical brain damage, (2) the similarities and differences between AOS due to cortical versus subcortical lesions, and (3) the implications of these patterns for current models of speech motor processing.