Association of Cognitive Activities of Daily Living (ADL) Function and Nonmotor Burden in Nondemented Parkinson's Disease Patients

Objective: In Parkinson's disease (PD), nonmotor symptoms (NMS) considerably influence disease progression and cognitive decline. Depression, anxiety, sleep disturbances, and hallucinations (DASH), may indicate a risk for dementia (PDD). Mild impairments in activities of daily living (ADL) caused by cognitive dysfunction are also present in the prodromal stage of PDD. The association of both factors has been sparsely investigated. Aim was to evaluate these specific NMS in a large nondemented PD cohort and their co-occurrence with cognitive dysfunction and ADL impairments. Method: Data of 226 PD patients was analyzed. Using corresponding items, two DASH scores were constructed from the NMS-Scale and Parkinson's disease Questionnaire (PDQ-39). Correlations between DASH scores and PDD risk factors were examined. PD patients with mild cognitive impairment (PD-MCI) were additionally split into patients with low and high DASH burden, the latter group additionally stratified by presence of cognitive-driven ADL impairment. Results: DASH-NMS scores differed significantly between PD-MCI and cognitively normal (PD-CN) patients (p = .04), while the DASH-PDQ did not (p = .73). The only significant predictor of the DASH-NMS score was cognitive-driven ADL (p = .01). PD-MCI patients with a high DASH burden and more cognitive ADL impairment presented with worse global cognition than patients with a low burden (p = .045). Conclusion: Our results show that the DASH-NMS is superior to the DASH-PDQ score, related to the severity of cognitive impairment, and strongly influenced by cognitive-driven ADL impairment. Presence of DASH symptoms and cognitive-ADL in PD-MCI patients may define a risk group for PDD conversion. Key Points Question: A key research priority in Parkinson's disease is the identification of risk factors that can predict cognitive decline and conversion to dementia. Findings: The present study suggests that a specific burden of nonmotor symptoms in combination with cognitive-driven activity of daily living impairment is related to more severe cognitive impairment in Parkinson's Disease. Importance: This association may be able to characterize a group at risk of developing Parkinson's Disease dementia within a short time period. Next Steps: Longitudinal studies are now needed to determine progression of these factors and their suitability for assessing conversion to dementia in Parkinson's disease.