Sex specific cognitive differences in Parkinson disease

Tyler Harrison Reekes,Christopher Ian Higginson,Richard Matthew Zweig,Elizabeth Ann Disbrow,Christina Raye Ledbetter,Niroshan Sathivadivel

doi:10.1038/s41531-020-0109-1

Abstract

Parkinson disease (PD) is a progressive neurodegenerative disorder that is 1.5 times more common in males than in females. While motor progression tends to be more aggressive in males, little is known about sex difference in cognitive progression. We tested the hypothesis that there are sex differences in cognitive dysfunction in non-demented PD. We evaluated 84 participants (38 females) with PD and 59 controls (27 females) for demographic variables and cognitive function, including attention, working memory, executive function, and processing speed. Multivariate ANOVA revealed no significant differences between groups for demographic variables, including age, years of education, global cogntition, daytime sleepiness, predicted premorbid IQ, UPDRS score, PD phenotype, or disease duration. For cognitive variables, we found poorer performance in males versus females with PD for measures of executive function and processing speed, but no difference between male and female controls. Specifically, PD males showed greater deficits in Verbal Fluency (category fluency, category switching, and category switching accuracy), Color Word Interference (inhibition), and speed of processing (SDMT). There were no differences in measures of working memory or attention across sex and inconsistent findings for switching. Our data indicate that males with PD have significantly greater executive and processing speed impairments compared to females despite no differences in demographic variables or other measures of disease severity. Our findings are consistent with the steeper slope of disease progression reported in males with PD.

Highlights

Parkinson disease (PD) is a progressive neurodegenerative disorder traditionally characterized by motor signs[1]; cognitive dysfunction has been shown in patients even in the absence of Parkinson disease dementia (PDD), including impairments in executive function[2,3,4], processing speed[5,6,7], and spatial working memory[8,9]
Multivariate ANOVA (MANOVA) revealed that there were no significant differences across sex in either control or PD groups for demographic variables including age (F(3, 139) = 0.928, p = 0.429), years of education (F(3, 139) = 0.647, p = 0.586), global cognition (Mini-Mental State Examination (MMSE)) score (F(3, 139) = 0.396, p = 0.756), daytime sleepiness (Epworth Sleepiness Scale, ESS) (F (3, 139) = 2.179, p = 0.093), or NART-R (F(3, 139) = 1.573, p = 0.199)
There were no significant differences between sexes on any Unified Parkinson’s Disease Rating Scale (UPDRS) subscale scores (Table 2), total score (F(1, 74) = 0.311, p = 0.579), or Hoehn and Yahr Scale (H&Y) scale score (F(1, 73) = 0.469, p = 0.496), nor were there differences in disease duration (F(1, 68) = 1.744, p = 0.191)

Summary

Introduction

Parkinson disease (PD) is a progressive neurodegenerative disorder traditionally characterized by motor signs[1]; cognitive dysfunction has been shown in patients even in the absence of Parkinson disease dementia (PDD), including impairments in executive function[2,3,4], processing speed[5,6,7], and spatial working memory[8,9]. PD is associated with increased risk for progressive cognitive decline from mild cognitive impairment (MCI) to dementia[8]. Females often develop a more benign PD tremor dominant (TD) phenotype[12] (67% compared to 48% in males) associated with less severe motor deterioration and localized basal ganglia degeneration as opposed to more widespread disease. Studies have shown that males more often present with a postural instability dominant phenotype including gait disturbances (PIGD), freezing of gait (56% males), and falling (59% males)[14,15]

Methods

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Conclusion