Impact of gait-synchronized vibrotactile sensory feedback on gait in lower limb amputees

Background: Research on sensory feedback systems for prosthetic devices aims to enhance sensory capabilities to better meet user needs. Feedback systems for lower limb amputees (LLA) have been shown to reduce cognitive efforts, metabolic cost and phantom limb pain. This study evaluated the effect of a non-invasive, gait-synchronized, vibrotactile feedback system (VTFS) on the gait parameters of LLA. Methods: Four stimulators applied vibrotactile stimulation to the thigh of LLA during walking, corresponding to four pressure sensors located at the fore- and hindfoot embedded in a sock worn on the prosthetic foot. Standardized gait tests, such as the Timed “Up and Go” Test (TUG), the Four Square Step Test (FSST), the 10 Meter Walk Test (10 MWT) and the 2 Minute Walk Test (2 MWT), were performed to assess the risk of falling, coordination, walking speed and endurance before and after intervention. Results: After an average of 61.5 days using the VTFS, gait stability (TUG) improved significantly. Coordination (FSST) improved in 36% of subjects, while 45% showed a clinically relevant increase in gait speed (10 MWT). Conclusions: The results suggest an improved gait performance in the cohort. Though FSST lacked statistical significance, a p-value near 0.05 indicates a trend toward meaningful improvement. Notably, the participant with Targeted Sensory Reinnervation demonstrated the most favorable outcomes.