Neuropsychiatric Symptoms in Parkinson’s Disease with and without Mild Cognitive Impairment

Abstract

Abstract Objective Neuropsychiatric symptoms (NPS) are common clinical features of patients with Parkinson’s disease (PD). However, such symptoms in non-demented PD patients have scarcely been investigated. To address this issue, we describe the neuropsychiatric profile in PD patients with and without Mild Cognitive Impairment (MCI). Participants and Method Eighty non-demented PD patients were included. The patients were divided into two groups depending on the presence or absence of MCI (PD-MCI and PD-nMCI, respectively). MCI diagnosis was made according to the Movement Disorder Society Task Force Level I criteria. NPS were evaluated using the Neuropsychiatric Inventory (NPI). For each domain, the presence and magnitude of symptoms (frequency x severity) was calculated. The total NPI score was also computed, in which higher scores suggest greater behavioral disturbance. Results PD-nMCI (n = 59, 74%) and PD-MCI (n = 21, 26%) groups were similar in the disease stage and years since diagnosis. In contrast with the PD-nMCI group, participants in the PD-MCI group were older. Fourteen PD-MCI (66%) and 45 PD-nMCI (76%) patients reported at least one neuropsychiatric symptom in the previous month. In both groups, the most frequent NPS were sleep disorders, depression, anxiety, apathy, irritability, and disinhibition. Additionally, the proportion of these symptoms between groups did not differ significantly (p > 0.05). There was only a tendency of greater score in the disinhibition subscale in PD-MCI group (p < 0.02). In both groups, NPS were not associated with clinical variables (years since diagnosis, Unified Parkinson's Disease Rating Scale -III) after adjusting for age. Conclusions Preliminary findings suggest that NPS are frequent in PD patients independent of the degree of cognitive impairment, and they may encompass non-motor features of the clinical spectrum of the disease. Further longitudinal investigations are needed to determine whether such symptoms may predict the cognitive decline in these patients.