Differences in gait and prefrontal cortical activity between recurrent fallers and non-fallers with Parkinson's disease during single- and dual-task walking.

BACKGROUND: Falls are common in people with Parkinson's disease (PD) and are associated with gait impairments, particularly under dual-task conditions. Although gait characteristics differ between fallers and non-fallers, it remains unclear whether walking-related prefrontal cortex (PFC) activity also differs according to fall history. This study compared PFC activity and gait parameters between recurrent fallers (≥2 falls/year) and non-fallers with PD during single- and dual-task walking. METHODS: Participants with PD were classified as non-fallers (n = 34) or recurrent fallers (n = 18). They performed single- and dual-task walking (digit vigilance task) at a self-selected speed. PFC activity was assessed using mobile fNIRS, and gait parameters were obtained using an electronic walkway. A two-way ANOVA examined group and task effects, with task as a repeated measure. RESULTS: Recurrent fallers exhibited higher PFC activity than non-fallers, regardless of walking task (p = 0.027). A significant group*task interaction was found for step length variability (p = 0.032), with increased variability in fallers during dual-task walking (p = 0.004), but not in non-fallers (p = 0.662). Dual-task walking increased PFC activity, step time, and variability of step length and swing time, while reducing step length, gait velocity, and swing time in both groups (all p ≤ 0.021). CONCLUSIONS: Recurrent fallers with PD exhibited greater PFC activity across both walking conditions, which may reflect greater attentional demands and compensatory recruitment of PFC resources. Dual-task walking increased step length variability in recurrent fallers, suggesting that cognitively demanding walking conditions may reveal subtle gait impairments associated with fall history that are not evident during single-task walking.