Supplementary Material for: Impact of Mild Cognitive Impairment on Health-Related Quality of Life in Parkinson's Disease

<b><i>Background/Aims:</i></b> To assess the impact of mild cognitive impairment (MCI) or cognitive decline on health-related quality of life (HR-QOL) in Parkinson's disease (PD). <b><i>Methods:</i></b> HR-QOL measured by the Parkinson Disease Quality of Life Questionnaire (PDQ-39), MCI according to Movement Disorder Society Task Force criteria and cognitive decline from premorbid baseline were assessed in non-demented PD patients at 6 movement disorder clinics. <b><i>Results:</i></b> Among 137 patients, after adjusting for education, gender, disease duration, and Movement Disorder Society Unified Parkinson's Disease Rating Scale total score, MCI was associated with worse scores within the PDQ-39 dimension of communication (p = 0.008). Subjects were divided into tertiles of cognitive decline from premorbid level. Scores in the dimension of stigma were worst in the second tertile of cognitive decline (p = 0.03). MCI was associated with worse social support scores in the second tertile of cognitive decline (p = 0.008). <b><i>Conclusion:</i></b> MCI and cognitive decline from premorbid baseline are associated with reduced HR-QOL in communication, stigma, and social support domains. The cognitive decline from premorbid baseline modifies the association between MCI and HR-QOL in PD and knowing both will allow a better appreciation of difficulties patients face in daily life.