Stochastic Resonance Stimulation Improves Postural Stability in People with Chronic Ankle Instability During Walking

Chronic ankle instability (CAI) affects up to 40% of individuals following lateral ankle sprains, leading to persistent sensorimotor deficits and functional limitations. This investigation examined the immediate effects of stochastic resonance (SR) electrical stimulation on postural control during visually perturbed walking in individuals with CAI (NCT06484712). Twenty-one adults with unilateral CAI participated in this study. Participants walked on a self-paced treadmill while exposed to mediolateral visual perturbations, both with and without the SR stimulation applied at the ankle, shank, and hip. Using a motion capture system, we investigated foot placing techniques, subtalar joint kinematics, and center of mass (CoM) excursion during the first eight steps after perturbation onset. SR stimulation significantly reduced mediolateral CoM excursion (p = 0.013, η² = 0.272) and peak movement (p = 0.038, η² = 0.198) on the affected side without changing local joint kinematics or stepping strategies. These results imply that SR rather than peripheral motor processes influence higher-order sensorimotor integration. Especially in addressing ongoing sensorimotor deficits that affect daily mobility and function, the selective enhancement of global stability measures during functional locomotor tasks offers compelling support for SR's therapeutic potential in rehabilitation protocols for individuals with CAI.