[Frontal syndrome of progressive supranuclear palsy].

Neuropsychological findings in 10 clinical cases of progressive supranuclear palsy are presented. Patients were aged 52 to 80 and the duration of their illness was 1 to 5 years. Severe psychological disturbances e.g. depression or outbursts of irritability were prominent features in 5 patients. Formal neuropsychological testing disclosed mental slowing, impaired attention, reduced verbal fluency and elaborated linguistic abilities, poor abstract thinking and reasoning, mild to moderate memory loss, dynamic apraxia, grasping, motor impersistence, imitation and utilization behaviour. The clinical similarities between these neuropsychological changes and frontal lobe syndromes, together with the lack of cortical involvement, suggest that the "dementia" of progressive supranuclear palsy could be explained by deactivation of the frontal cortex by subcortical lesions. The special importance of pallidal and mesencephalic reticular involvement in the syndrome is hypothetized.