Cognitive Correlates of Instrumental Activities of Daily Living Performance in Parkinson Disease Without Dementia.

The sample was relatively young, mostly White, highly educated, and had early or mild Parkinson disease without dementia, so the results may not apply to older, more diverse, or more advanced patients. Participants were tested once, so the study cannot show that cognitive changes caused daily task problems or that detecting them early changes outcomes. Cognitive screening used the MMSE and the CANTAB, which mainly uses visuospatial tasks, so verbal or more subtle cognitive problems may have been missed. The study did not include a self-report or informant-report daily function measure, so it is unclear how performance-based scores relate to everyday reports. Motor function was measured with general motor severity and motor speed, not task-specific hand dexterity or upper-extremity use during the activities. The associations were small, and several daily tasks did not differ between groups, so these findings do not prove a one-to-one link between a specific cognitive test and a specific daily task.

Do not treat normal computerized cognitive test scores as proof that daily planning and safety are intact. In this study, people with Parkinson disease without dementia still needed more cueing and took longer on everyday tasks despite similar scores on the cognitive tests.