Effects of Altered Somatosensory Input on Lower Limb Mechanics via Different Shoes and Barefoot Walking in Individuals with Chronic Post-Stroke Hemiparesis

[Purpose/Hypothesis] Stroke is a leading cause of disability that results in various neurological deficits. Stroke can cause impaired somatosensory input, which results in decreased balance and gait speed, ultimately increasing fall risks. Therapies to increase somatosensory input have shown promise for people with stroke as well as other neurological populations. However, few studies have systematically investigated varying somatosensory input via different footwear to improve walking in people post-stroke. The purpose of this study was to investigate the effects of altering somatosensory input via different types of footwear (i.e., barefoot, self-selected shoes, and memory foam shoes) on gait kinetics and ankle kinematics during gait in individuals with chronic post-stroke hemiparesis. We hypothesized that increased somatosensory input via barefoot walking would improve paretic propulsive force, reduce paretic braking force, and improve paretic ankle kinematics. [Number of Subjects] 9 individuals post-stroke (62.9±11.2 years old; 5.9±4.4 years post-stroke) and 5 non-neurologically impaired (53.4±17.0 years old) individuals. [Methods/Materials] Reflective markers were placed over lower extremities landmarks, and surface electromyography sensors over ankle muscles. Participants then walked over a dual belt instrumented treadmill for 5 minutes, under self-selected walking speed, wearing self-selected shoes. Subsequently, trials were conducted barefoot and with memory foam shoes, in randomly assigned order. Peak propulsive force, peak braking force, peak plantarflexion angle at push-off, and peak dorsiflexion angle during swing phase were assessed using a 3 (Limbs: paretic, non-paretic, and non-impaired) X 3 (Shoes: self-selected footwear, memory foam shoes, and barefoot) mixed factorial ANOVA. A priori significance was set at p < 0.05. [Results] A statistically significant interaction was observed for Shoes x Limb for peak propulsive force (p=0.04). Additionally, simple main effects revealed that in non-impaired legs, greater propulsive forces were generated when wearing self-selected shoes compared to memory foam or barefoot. A statistically significant main effect of Shoes was observed for ankle angle at toe off (p < 0.01), suggesting that regardless of limb, wearing self-selected shoes increases plantarflexion at toe off, whereas wearing memory foam shoes increases dorsiflexion at toe off. A statistically significant main effect of Shoes was observed for peak dorsiflexion during swing (p < 0.01), indicating that regardless of limb, wearing memory foam shoes causes more dorsiflexion during swing than self-selected shoes. [Conclusion] We found that memory foam shoes can encourage paretic ankle dorsiflexion during swing phase of gait, which could be used to address foot-drop in post-stroke gait training. If the goal of gait training was to target propulsive force to increase walking speed, then memory foam shoes or barefoot is not recommended. [Clinical Relevance] Findings can help inform clinicians on appropriate footwear recommendations to ensure safety for community ambulation and may be incorporated into gait training paradigms in rehabilitation.