Dual vs. Single Tasking During Circular Walking: What Better Reflects Progression in Parkinson's Disease?

Background and Aim: Sensitive measures of dual-task–related gait impairments may reveal Parkinson’s disease (PD) progression not evident during single-task walking. This study aimed to identify quantitative markers of progressive gait deficits in idiopathic PD during circular walking under single-task and dual-task conditions, and to evaluate the added value of dual-task assessment for tracking disease progression.

Methods: Twenty-two early-stage PD patients, 27 middle-stage PD patients, and 25 healthy controls were assessed every 6 months for up to 5 years. Gait was evaluated during circular walking alone and during two dual-task conditions: box checking and serial subtraction. Twenty-seven accelerometry-derived gait features were analyzed longitudinally using generalized estimating equations, accounting for age, gait speed, and medication state when appropriate. Dual-task interference on gait, cognitive performance, and their combination was also examined.

Results: Several gait features previously identified as progression markers during single-task circular walking were confirmed as valid and robust. In contrast, fewer gait features derived from dual-task conditions showed sensitivity to disease progression. Progressive worsening of dual-task interference was not clearly observed, although group differences between PD stages and controls were detected for gait and concurrent tasks.

Conclusions: Dual-task assessment did not provide added value over single-task circular walking for monitoring PD progression. While single-task walking appears sufficiently sensitive, dual-tasking may introduce additional variability and reflect complex combinations of motor and cognitive performance rather than specific progression markers.