2018 Volume 34 Issue 1 Pages 38-44
Apraxia of speech (AOS)/anarthrie is a motor speech disorder characterized by core symptoms of distorted articulation and segmentation of syllables. However, little is understood with regard to the nature of AOS. We explained the neuropsychological and neuroanatomical features of patients with stroke-induced pure AOS (sAOS), patients with primary progressive apraxia of speech (PPAOS), and normal control adults. Based on the previous reports, all patients with sAOS could be classified into four subtypes: type I with prominent distorted articulation; type II with prominent segmentation of syllables; type III with similarly prominent distorted articulation and segmentation of syllables; or type IV with prominent distorted articulation and no signs of segmentation of syllables. In the investigation of PPAOS using the same methods as the above report, PPAOS with prominent distorted articulation. However, it was only PPAOS that the reduction of speech rate was prominent even though segmentation of syllables was not remarkable. The lesions of a patient with type I was located in the left precentral gyrus, type II in both the left precentral gyrus and left premotor cortex, type III in the white matter of the left periventricular region, type IV in the white matter of the left periventricular region and left striatum. Patients with PPAOS demonstrated significant reduction of regional cerebral blood flow in the left superior premotor cortex and bilateral supplementary motor area. We speculate that a focus on the contrast between distorted articulation, segmentation of syllables, and speech rate could be useful for sub-classification of AOS.
