Questioning dual-task assumptions in Parkinson’s disease: heterogeneity, cognitive contributions and adaptative changes

Dual-task impairment is commonly assumed to characterize and challenge people with Parkinson’s disease (PD). We investigated dual-task performance in people with mild to moderate PD (n = 93) and healthy controls (HC, n = 40) using two dual-task paradigms. Contrary to hypotheses, the PD group did not show slower gait or response times more than HC group. In the PD group, longer response times in one task correlated strongly with both accuracy and executive function, suggesting that slower responses may sometimes reflect beneficial adaptations linked to higher cognitive ability. We also observed substantial within-group variability and overlaps between PD and HC across multiple performance outcomes. Exploratory analyses indicated that these unexpected findings largely reflect the influence of cognitive ability on dual-task performance. We caution against assuming changes during dual-tasking are negative and highlight the potential of individualized assessment of cognitive and dual-task abilities for improving clinical practice.