Safety and efficacy of vibrotactile feedback for adults with transtibial amputation: A randomized controlled...

Pain, social integration, and walking safely with divided attention challenge people with lower-limb amputation. Tactile feedback systems aim to improve sensations and rehabilitation by facilitating prosthesis utility and embodiment. The non-invasive vibrotactile feedback device Suralis® (Saphenus Medical Technology, Vienna, Austria) aims to improve gait, postural control, and pain treatment. This randomized controlled cross-over trial investigated 60-day effects of vibrotactile ground-contact feedback on gait performance and quality of life in adults with unilateral transtibial amputation without targeted reinnervation.

We conducted gait assessments before and after the unblinded intervention period and compared within-period changes to the control period without intervention, separated by a one-week washout. The primary outcome substitute was affected-leg stance time, and secondary outcome measures included instrumented-walkway gait speed and four-square-step-test. The trial enrolled 18 participants during the COVID-19 pandemic and ended prematurely due to limitations in recruitment and integrity of the substituted primary outcome between-leg stance time difference.

Five participants ended the study prematurely, the dropouts were unrelated to adverse events where one experienced concentration difficulties. Analyzing 13 participants showed that participants walking slower than 1.41 ms^-1 [1.34 ms^-1, 1.49 ms^-1] [95 % highest-density interval] with affected-leg stance times above 0.64 s [0.58 s, 0.69 s] responded most positively. Four-square-step-test times had the largest within-period effect size (mean 0.89; [0.44, 1.34] for 0.5 s [0 s, 1 s] improvement), followed by period-one (-0.37; [-0.56, -0.18]), and treatment (0.28; [0.095, 0.46]). Affected-leg stance time did not change (0.21; [-0.26, 0.66]).

Despite the learning effects present, vibrotactile feedback had a small positive effect on functional balance and gait performance in slower-walking participants.

The trial funded by the Austrian workers' compensation board AUVA and supported by Saphenus Medical Technology was retrospectively registered on clinicaltrials.gov (no. NCT05895253; registration date: 19.05.2023) after a premature termination due to the limited availability of participants during the COVID 19 pandemic.