Instrumental activities of daily living are impaired in Parkinson's disease patients with mild cognitive impairment

Abstract

Objective: Although it is well known that Parkinson's disease (PD) with dementia results in functional decline, little is known about the impact of mild cognitive impairment in PD (PD-MCI) on day-to-day functioning.

Method: Forty-one individuals with PD-MCI, 56 PD patients with normal cognition (PD-NC), and 47 healthy older adults were administered two performance-based measures of instrumental activities of daily living (IADLs) that evaluated medication and financial management. Informants of the PD patients were also administered an IADL questionnaire.

Results: There were no significant differences between PD-NC and healthy older adults on the performance-based measures of medication and financial management. However, PD-MCI patients demonstrated significantly lower scores on the performance-based measures of medication and financial management compared with healthy older adults. PD-MCI patients were also impaired compared with PD-NC patients on performance-based medication management, but no difference between these groups was observed for ability to manage finances. Performance-based financial and medication management did not correlate with scores on neuropsychological measures in PD-MCI patients. PD-MCI and PD-NC patients showed comparable scores on the informant-based IADL questionnaire.

Conclusions: Performance-based measures of IADLs, particularly medication management ability, are sensitive to subtle functional declines in PD-MCI. Although impairment in performance-based measures is associated with cognitive status in PD, IADLs may be a separate domain of functioning from cognitive functioning in PD-MCI as these measures did not correlate with performance on the neuropsychological measures. Overall, performance-based assessment of IADLs may add to the clinical evaluation of PD-MCI.