To quantify dual-task interference (DTI) in individuals with Parkinson’s disease (PD) using a comprehensive functional mobility assessment platform.

Gait impairments in PD worsen under dual-task (DT) conditions, contributing to falls and reduced independence. Loss of striatal dopamine disrupts movement automaticity and increases cortical burden during complex motor tasks, such as stair ambulation under DT conditions. Stair ambulation poses elevated motor and cognitive demands but is rarely evaluated in traditional mobility assessments.

Twenty-three individuals with PD completed a mobility task using the Stair Ambulation and Functional Evaluation of Gait (Safe-Gait) system, which includes five phases: Ascent, Departure, Turn, Return, and Descent, providing a comprehensive assessment of stair ambulation, flat-ground walking, and turning. Participants performed the task under single-task (ST) and DT (serial 7s subtraction) conditions. Spatiotemporal data were collected, and DTI was calculated as the percent difference in segment duration between ST and DT conditions. Linear mixed models were used to estimate completion time differences between conditions.

Across all five phases, durations were significantly longer under DT conditions compared to ST (p<0.05). Average DTI for each phase was: Return - 22%, Departure - 20%, Ascent - 19%, Descent - 14%, and Turn - 13%, with an 18% increase in overall trial time under DT conditions.

The Safe-Gait system captured clinically relevant DTI across various functional mobility domains, including stair ambulation and turning. Data from robust assessment tools like Safe-Gait can reveal consequential gait impairments that may be missed by traditional assessments. This platform offers a promising tool for ecologically valid evaluation of mobility impairment in PD and provides data that can be leveraged to inform clinical decision-making and improve patient outcomes.