NEUROPSYCHOLOGICAL CHARACTERISTICS OF PARKINSONIAN-PATIENTS WITH LATERALIZED MOTOR IMPAIRMENT

Parkinsonians with predominantly unilateral signs provide an interesti ng experimental means to evaluate if asymmetric nigro-striatal degener ation may affect neuropsychological functions. The aim of our study wa s to establish if the side of onset of idiopathic Parkinson's disease, right (PDR) or left (PDL), determines a selective pattern of cognitiv e performances. Furthermore, we verified if PDR and PDL groups show a different frequency of dementia. PDR and PDL patients with at least se ven years of disease duration, matched for age, schooling, severity of extrapyramidal symptomatology and index of lateralization, were evalu ated by using an extensive neuropsychological battery aimed at assessi ng hemispheric cognitive asymmetries. Current side of greater motor im pairment was the same as the one affected at the onset of the disease. Only subtle differences in the profile of neuropsychological dysfunct ion emerged from the comparison of PDR and PDL subjects. Moreover, the number of parkinsonians showing dementia syndrome was the same in bot h groups. Our results suggest that the side of onset of motor impairme nt does not significantly influence the cognitive performances in PD. Subcortical anatomic and/or functional asymmetries seem to play a less important role in the intellectual functions than in motor activities .