Interpreting the Physiological Bases of Dysarthria from Perceptual Analyses: An Examination of Subjects with UMN Type Dysarthria

The perceptual speech characteristics of a group of 20 subjects with persistent dysarthria following Upper motor neurone (UMN) damage resulting from cerebrovascular accident (CVA) were compared with those of a normal non-neurologically impaired control group matched for age and sex. The perceptual assessments included an inventory of 32 perceptual speech dimensions, the Frenchay Dysarthria Assessment (FDA), and the Assessment of the Intelligibility of Dysarthric Speech (ASSIDS). The results revealed that the CVA subjects presented with features consistent with spastic dysarthria; however, the incidence of the dimensions identified was lower and the severity less than previously reported in the literature. Comparison between the CVA and the control groups revealed reduced speech intelligibility in the CVA group and deficits in all aspects of speech production including respiration, phonation, resonance, and prosody. The perceptual profile obtained from the assessments is interpreted with reference to the identification of the underlying pathophysiological bases of the perceived speech deficits. Limitations of perceptual assessments and the need for comprehensive physiological evaluation of the motor speech subsystems of subjects with UMN type dysarthria are identified and discussed.