Vibratory Insoles Improve Walking in Individuals with Chronic Post-stroke Hemiparesis

Abstract Background Stroke survivors suffer from hemiparesis and somatosensory impairments, which adversely impact walking function, placing them at higher risks for trips and falls. Augmented somatosensory inputs have been demonstrated to improve static standing balance and postural control in non-neurologically impaired, and in people post-stroke. Effects of enhanced somatosensory input on post-stroke walking have not been investigated. Research question: We sought to investigate whether enhancing somatosensory input using vibratory insoles, can improve post-stroke gait. Methods Fifteen individuals with chronic post-stroke hemiparesis and 15 age-similar non-neurologically impaired controls participated in this cross-sectional study. Enhanced somatosensory stimulation was delivered using a pair of tactor-embedded insoles, providing suprathreshold vibratory stimulation to the bottom of the feet. Participants walk over an instrumented treadmill with self-selected speeds, under 5 stimulation conditions: No insole in shoe (NT), insoles in shoe with no vibration (BOFF), vibration under both feet (BON), vibration under one foot only (ION, CON), in a randomized order. Kinetics and kinematics during walking were recorded and analyzed offline. Results Our hypothesis that vibratory stimulations applied to the bottom of the feet would improve gait kinetics and kinematics in the paretic legs of individuals with chronic post-stroke hemiparesis was partially supported. We observed increased ankle dorsiflexion in the paretic legs with vibratory insoles. Significance Vibratory stimulations applied at suprathreshold intensity to the bottom of the feet to augment somatosensory feedback can be used as a low-cost solution to address the inadequate toe clearance during walking in people post-stroke, which is an important goal in post-stroke rehabilitation.