Gender may be related to the side of the motor syndrome and cognition in idiopathic Parkinson's disease

Background and Sex and cognitive profile may be related to the laterality of motor symptoms in idiopathic Parkinson's disease. Introduction Parkinson's disease (PD) is well recognised as an inherently asymmetric disease with unilateral onset of motor symptoms. The laterality of motor symptoms may be linked to sex, clinical and demographic variables, and neuropsychological disorders. However, the available data are inconsistent. This study aimed to explore the potential association between the laterality of motor symptoms and clinical and demographic variables and deficits in specific cognitive domains. Material and methods We retrospectively recruited 97 participants with idiopathic PD without dementia; 60 presented motor symptoms on the left side and 37 on the right side. Both groups were comparable in terms of age, age at disease onset, disease duration, and severity of the neurological deficits according to the Unified Parkinson's Disease Rating Scale and the Hoehn and Yahr scale. Results Participants with left-side motor symptoms scored lower on the Schwab and England Activities of Daily Living scale. Our sample included more men than women (67% vs. 33%). Both sexes were not equally represented in the 2 groups: there were significantly more men than women in the group of patients with left-side motor symptoms (77% vs. 23%), whereas the percentages of men and women in the group of patients with right-side motor symptoms were similar (51% vs. 49%). Both groups performed similarly in all neuropsychological tasks, but women, independently of laterality, performed better than men in the naming task. Conclusion We found a clear prevalence of men in the group of patients with left-side motor symptoms; this group also scored lower on the Schwab and England Scale. Female sex was predictive of better performance in the naming task. Sex should always be considered in disorders that cause asymmetric involvement of the brain, such as PD.