Perceptual analysis is not sufficient enough to identify specific dysarthria 
types. In order to improve the discrimination between dysarthria types, we 
developed a standardized evaluation of different functions controlling speech 
motor performances. This was applied to 90 patients suffering from hypokinetic, 
spastic or ataxic dysarthria and 15 control subjects. A discriminate analysis 
showed that 71.4 p. 100 of the cases were correctly classified. This model was 
validated within a new group of 21 patients and showed that the less severe 
dysarthric parkinsonian patients were difficult to distinguish from control 
subjects. The discriminate analysis was then used for 20 patients with atypical 
parkinsonism. Seven patients with progressive supranuclear palsy were considered 
to have hypokinetic dysarthria. The 6 patients with multisystem atrophy and 7 
with corticobasal degeneration were classified among the 3 dysarthric types. We 
suggest that motor speech evaluation may contribute to differential diagnosis 
within groups of patients suffering from atypical parkinsonism.