The presence of cortical as well as subcortical damage in patients with PSP and those with multiple system atrophy is indicated by the presence of pervasive cognitive and motor disturbances in the former, substantial motor disorganization in the latter, and the finding of ideomotor apraxia in some patients with these diseases. Furthermore, the discovery that tests of motor and gesture best identified all patients vs control subjects is consistent with the existence of a common motor disorganization in these parkinsonian syndromes, in agreement with the known damage to the corticostriatal pathways in these conditions.

The lack of correlation between disease severity and psychiatric disturbances indicates that psychiatric disorders progress nonlinearly, possibly because of differential degeneration of the striatal-cortical circuits; the possibility that psychiatric disorders are prevalent in certain families with a member who has Huntington's disease is being further investigated. The lack of correlation between CAG length and cognitive and psychiatric variables needs further investigation.

No abstract

The study was conducted on 120 patients (76 men and 44 women) affected by idiopathic Parkinson's disease (IPD) responsive to L-dopa and observed for many years. Sixty had clinical onset between the ages of 20-40, representing 10.2% of our PD population; in the others the symptoms began after the 40th birthday. The two groups were matched for sex and length of illness. In all patients a diagnosis of IPD depended on history and clinical and neuroradiological findings. Clinical, pharmacological, evolutive, and epidemiological data were collected on all patients. Thirty-six patients from each group performed motor dexterity tests (reaction time to expected and unexpected stimuli) and cognitive tests (Wechsler Adult Intelligence Scale. Benton, Short tale, and Zazzo's speed and accuracy test). To assess the prevalence of dementia and the severity of psychiatric side effects of L-dopa administration, the 60 patients with early-onset PD were compared with 134 consecutive unselected PD patients. Five percent of early-onset PD patients had a family history of the disorder. Our study showed that early-onset PD does not differ fundamentally from the late-onset form except that the former is characterized by a more rapid establishment of the full-blown parkinsonian clinical picture and deterioration of the therapeutic efficacy of L-dopa, with an earlier appearance of side effects. The results of our neuropsychological investigations suggest that early-onset PD may be a "pure" form of extrapyramidal compromise with exclusively motor manifestations.

One hundred ninety L-dopa-treated parkinsonian patients have been studied according to the age at onset and to age at last examination. The frequency of major mental disturbances was significantly higher in patients older than 60 years, whereas abnormal involuntary movements and on-off phenomenon were more frequent in patients with onset before age 60. The association of normal aging and of Parkinson's disease may be responsible for the prevalence of mental disease in older patients.