Impact of Mild Cognitive Impairment on Quality of Life in Young and Typical Onset Parkinson's Disease.

INTRODUCTION

Younger age of onset and mild cognitive impairment (MCI) are both independently associated with poorer quality of life (QOL) in Parkinson's disease (PD).

OBJECTIVES

The primary objective was to determine whether MCI differentially impacts QOL in young-onset PD (YOPD) and typical-onset PD (TOPD).

METHODS

YOPD patients (n = 77) were diagnosed at age 50 or younger, TOPD (n = 77) were diagnosed after age 50, and the groups were matched for cognitive status, education, and disease duration. Patients' cognitive status was classified as MCI or cognitively normal (CN) based on MDS Level II criteria. QOL was assessed using the Parkinson's Disease Questionnaire (PDQ-39). ANCOVAs were conducted for each PDQ-39 subscale, with age of onset and cognitive status as between-subjects factors and several covariates included.

RESULTS

An interaction for the Cognition domain revealed that in TOPD, PD-MCI patients reported poorer QOL than CN patients, whereas there was no effect of MCI on cognitive satisfaction in YOPD. There was a main effect of age on Emotional Well-Being, as YOPD reported poorer QOL than TOPD in this domain. There were main effects of cognitive status, with PD-MCI patients reporting worse QOL than CN patients in the domains of Social Support, Communication, ADLs, and Mobility.

CONCLUSIONS

The interaction revealed that PD-MCI has a greater impact on degree of cognitive concerns ("cognitive QOL") in TOPD versus YOPD. A more nuanced understanding of the effects of age of onset, MCI, and their interactions on QOL in PD will inform interventions aimed at improving quality of life in this population.