How precise are activities of daily living scales for the diagnosis of Parkinson's disease dementia? A pilot study.

BACKGROUND Beside the presence of cognitive deficits, impaired activities of daily living (ADL) are crucial for the diagnosis of dementia in Parkinson's disease (PD). Several scales can be used to evaluate PD patients' ADL (dys)function. However, only a few of them sufficiently discriminate between demented and non-demented PD patients. It is well-known that the diagnostic accuracy of ADL scales for Parkinson's disease dementia (PDD) is influenced by confounding variables such as motor worsening. OBJECTIVE To evaluate the diagnostic accuracy of ADL scales for PDD. METHODS In a cohort of 106 patients (21 with dementia), we evaluated observer-based activities of daily living rating scales (e.g. Pill Questionnaire, Schwab & England Scale), caregiver assessments, and patient questionnaires (e.g. Lawton Instrumental Activities of Daily Living Scale). RESULTS Each inventory showed moderate or even high specificity for dementia (>75.3%). Sensitivity was highest for the Pill Questionnaire (90.5%). Interestingly, the ratings of caregivers and trained clinical observers overestimated the presence of dementia. CONCLUSIONS Standardized activities of daily living assessments like the Pill Questionnaire accompanied by neuropsychological testing can be a helpful tool for the diagnosis of PDD. Further studies are needed to verify these first results in larger cohorts.