Background: Cognitive deficits are evident throughout the course of Parkinson's disease (PD), with 24% of patients experiencing subtle cognitive disturbances at the time of diagnosis, and with up to 80% of patients developing PD dementia (PDD) at advanced stages of the disease PD patients with mild cognitive impairment (MCI), an at-risk phenotype of PDD, present with heterogeneous clinical characteristics that complicate the management of PD.
Objectives: This study aims to examine the characteristics of PD-MCI by using the Movement Disorder Society (MDS) diagnostic criteria and evaluate the validity of global cognitive scales in identifying PD-MCI.
Methods: Seventy-nine (79) PD patients completed neuropsychological assessments and a comprehensive cognitive battery. PD-MCI was classified according to the level 2 MDS task force criteria. Mini-Mental State Examination (sMMSE), Montreal Cognitive Assessment (MoCA) and Parkinson's Disease Cognitive Rating Scale (PDCRS) were examined against a level 2 dichotomised PD-MCI diagnosis. Characteristics of PD-MCI were evaluated using logistic regression analysis.
Results: Twenty-seven patients met criteria for PD-MCI (34%). The MoCA and PDCRS demonstrated high validity to screen for PD-MCI. Impairments in multiple cognitive domains were observed in 77.8% of PD-MCI patients. There were significantly more males in the PD-MCI group compared to PD patients without MCI (p < 0.01).
Conclusions: PD patients with MCI exhibited impairments in the attention/working memory, executive function and memory domains. Heterogeneous cognitive characteristics in PD warrant further investigation into specific cognitive subtypes to advance understanding and effective evaluation of PD-MCI.
Keywords: Parkinson's disease; characteristics; global scales; mild cognitive impairment; validity.
© 2023 The Authors. International Journal of Geriatric Psychiatry published by John Wiley & Sons Ltd.