Brain adaptations in challenging walking task of people with stroke: an experimental study

Complex walking tasks require enhanced cognitive control to meet sensorimotor integration demands, yet the neurophysiological mechanisms underlying how the post-stroke brain adaptively adjusts to such challenges remain insufficiently understood. The spectral distribution of electroencephalography (EEG) oscillations and the functional network construction method offer a window into real-time neural resource allocation and network reorganization during complex walking. One baseline control (steady-state level walking) and two challenging conditions were implemented: an asymmetrical board-walking task requiring dynamic balance control, and a visual-deprivation walking task that increased reliance on proprioceptive and vestibular feedback. Scalp EEG was recorded simultaneously during walking. Fifty-seven post-stroke participants completed all experimental conditions. A three-way repeated-measures ANOVA was applied to examine spectral power changes across tasks, frequency bands, and brain regions. The brain functional connectivity was computed using the weighted phase lag index. Additionally, a two-way repeated-measures ANOVA was conducted to analyze changes in brain network topological properties across different frequency bands and task conditions. Compared to steady-state walking, both the balance-challenged and visually deprived walking tasks consistently suppressed delta power in temporal regions and theta power across occipital and parietal areas (p < 0.05). Beta power was enhanced in temporal and parietal regions during both tasks (p < 0.05), while occipital alpha power increased specifically during visually deprived walking task (p < 0.05). Gamma-band activity remained unmodulated across conditions. The two challenging walking tasks increased functional connectivity in the alpha, beta, and gamma frequency bands but reduced theta-band connectivity. Graph-theoretical analysis demonstrated that both tasks elicited higher clustering coefficients in the alpha band (p < 0.05). In contrast, only visually deprived walking task led to a significant reduction in the delta-band clustering coefficient (p < 0.05). In response to locomotor challenges, people with stroke showed a neural reorganization involving suppressed low‑frequency oscillations and enhanced mid‑to‑high‑frequency activity, which may reflect a re‑allocation of neural resources toward cognitive‑motor integration demand. Trial registration The study protocol was registered on ClinicalTrials.gov (No. NCT06395142).