Trait Impulsivity Is Independent of Mild Cognitive Impairment in a Parkinson's Disease Cohort.

Ashani Jeyadevan,Rick Stell,Sarah Mcgregor,Sue Walters,Malcolm Horne,Michelle Byrnes,Ryan S Anderton,Tess Evans,Jade Kenna,Soumya Ghosh,Frank L Mastaglia,Megan C Bakeberg

doi:10.1155/2019/2672075

Abstract

Introduction Patients with Parkinson's disease (PD) commonly experience cognitive deficits and some also develop impulse control disorders (ICDs); however, the relationship between impulsivity and cognitive dysfunction remains unclear. This study investigated whether trait impulsivity associates with mild cognitive impairment (MCI), or is altered in a PD patient cohort with MCI. Methods A total of 302 patients with idiopathic PD were recruited sequentially from three Australian Movement Disorder clinics. Based on cognitive scores, participants were divided into two groups, one defined as having mild cognitive impairment (PD-MCI; n = 113) and the other with normal cognitive function (PD-C; n = 189). Trait impulsivity was evaluated using the Barrett Impulsiveness Scale 11 (BIS-11). Total impulsivity scores, as well as subscale scores, were compared between PD-C and PD-MCI groups. Results The PD-MCI cohort had significantly lower scores in all cognitive domains, and mirrored expected clinical differences in medication, motor symptoms, and disease duration, when compared to the PD-C cohort. Self-reported impulsivity was not significantly different between groups, nor was there a difference within first-order subscale scores: attention (p=0.137), cognitive instability (p=0.787), self-control (p=0.503), cognitive complexity (p=0.157), motor impulsivity (p=0.559), or perseverance (p=0.734) between the PD-MCI and PD-C groups. Conclusions These findings suggest that impulsive traits and behaviors are independent of changes in cognitive state and are not altered in PD patients with mild cognitive impairment.

Highlights

Patients with Parkinson’s disease (PD) commonly experience cognitive deficits and some develop impulse control disorders (ICDs); the relationship between impulsivity and cognitive dysfunction remains unclear. is study investigated whether trait impulsivity associates with mild cognitive impairment (MCI), or is altered in a PD patient cohort with MCI
Cognitive Characteristics of PD-C and PD-MCI Groups. e cohort was initially divided into two groups based on the presence or absence of mild cognitive impairments (PDMCI and PD-C, respectively), as determined by Addenbrooke’s Cognitive Examination-Revised (ACE-R) scores
ACE-R subdomains were compared between cognitive groups, revealing significant differences in each subdomain. roughout attention and orientation (p < 0.001), memory (p < 0.001), fluency (p < 0.001), language (p < 0.001), and visuospatial (p < 0.001) domains, significant differences were present between the PD-C and PD-MCI subgroups (Table 1)

Summary

Introduction

Patients with Parkinson’s disease (PD) commonly experience cognitive deficits and some develop impulse control disorders (ICDs); the relationship between impulsivity and cognitive dysfunction remains unclear. is study investigated whether trait impulsivity associates with mild cognitive impairment (MCI), or is altered in a PD patient cohort with MCI. Patients with Parkinson’s disease (PD) commonly experience cognitive deficits and some develop impulse control disorders (ICDs); the relationship between impulsivity and cognitive dysfunction remains unclear. Ese findings suggest that impulsive traits and behaviors are independent of changes in cognitive state and are not altered in PD patients with mild cognitive impairment. A 20-year longitudinal Australian study revealed that over 80% of PwP develop increasing cognitive impairment as the disease progresses and eventually become demented [3]. Heightened trait impulsivity is present in a subset of PD patients, males [10], and is considered a risk factor for the development of ICDs. e neural substrate of ICDs and increased impulsivity in PD is thought to involve dysregulation in mesolimbic and mesocortical networks, and changes in dopamine receptor (D2 and D3) binding in the ventral striatum [5, 11], but specific neuropathological correlates have not been identified. Based on the disease staging studies by Braak et al, it might be envisaged that changes in impulsivity could correlate with Stage V, in which the Lewy pathology extends to the mesolimbic cortex, and could precede, or overlap with, the development of impaired cognition, as there is further extension to neocortical areas in Stage VI of the disease [12]

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