The place of perceptual analysis of dysarthria in the differential diagnosis of corticobasal degeneration and Parkinson's disease

Objective To characterize the dysarthria in patients with corticobasal degeneration (CBD) and determine if analysis of speech in isolation helps to distinguish CBD patients from patients with Parkinson's disease (PD). Methods 60 subjects were assessed by means of perceptual analysis of speech: 15 patients with CBD, 15 patients with PD and 30 control subjects. A detailed profile was furnished with the help of 33 perceptual items. A global perceptual approach was used to classify patients by judges blind to the medical diagnosis. Rating scales were adapted to quantify the degree of spasticity and hypokinesia in the speech of each patient. Results Dysarthria was frequent in CBD even though it remained mild for a long period of time. Group analysis revealed the importance of temporal errors of speech control in CBD patients while voice disturbances were most frequent in PD patients. However, attempts to classify patients according to global perceptual analysis remained below a reasonable level of clinical acceptability. Finally, even though the widespread neuropathological changes suggest that deviant speech dimensions of several types of dysarthria might be found in CBD, evidence for a mixed dysarthria with presence of spastic elements could not be established. Conclusion The findings support the view that even though perceptual analysis is mandatory in the management of dysarthric patients, it does not help in the clinical differential diagnosis of CBD.