Walking speed does not modulate electrocortical alpha response to intermittent visual occlusions

Visual processing is crucial for the preparation, guidance, and stabilization of human locomotion. Responses to visual perturbations appear more adaptive at slower rather than faster walking speeds. Intermittent visual occlusions during walking cause widespread alpha synchronization across brain regions and can improve balance training. We investigated whether the response to intermittent loss of vision during human walking would change with different gait speeds. Fifteen healthy adults (5 male, 10 female) stood stationary and walked on a treadmill at speeds of 0.4, 0.8, 1.2, 1.6 m/s while viewing a static scene through liquid crystal lenses that alternated between transparent and opaque. We source-localized high-density dual-layer EEG recordings to identify activity in occipital and posterior parietal cortices. We hypothesized that the alpha power increase during visual occlusions would be reduced with faster walking. Across all walking speeds, occlusions induced alpha (8-13 Hz) and beta (14-30 Hz) power increases after occlusion onsets. Walking speed did not significantly modulate the timing or magnitude of these event-related spectral perturbations. Average alpha power differed only between standing and walking speeds 1.2 m/s and 1.6 m/s. Results indicate that in healthy young adults the cortical disengagement from visual processing induced by brief intermittent occlusions remained stable across locomotor speeds. Gait speed does not appear to be a relevant confounder in the use of intermittent visual occlusions for balance training or studying sensory reweighting during gait.NEW & NOTEWORTHY We found that walking speed did not affect the electrocortical alpha synchronization response to intermittent visual occlusions in the occipital and parietal cortex. At faster gait speeds, there is less time in the gait cycle to correct movement errors and increased kinetic energy provides greater potential for injuries in the event of a fall. Our findings indicate that the brain's primary electrical response to loss of vision during walking is independent of walking speed.