Background: Patients with sensory peripheral neuropathy (PN) commonly present with gait and balance problems increasing their risk of falls. The multi-site walk2Wellness trial investigates effects of long-term, home-based daily use of a wearable lower limb sensory neuroprosthesis on gait function, balance, quality of life and fall rates in a cohort of PN patients. The device (Walkasins®, RxFunction Inc., MN, USA) is designed to replace lost nerve function related to foot pressure sensation by providing directional tactile cues around the ankle reflecting foot pressure measurements during standing and walking activities. We hypothesized that previously shown short-term in-clinic improvements in gait and balance would be sustained after 10 weeks of use.
Methods: Participants had a PN diagnosis with loss of plantar sensation associated with gait and balance problems, a Functional Gait Assessment (FGA) score <23 (cut-off for high fall risk), and ability to sense Leg Unit tactile stimuli. Clinical outcomes included FGA, Gait Speed, Timed Up&Go (TUG) and Four-Stage Balance Test. Patient-reported outcomes included Activities-Specific Balance Confidence (ABC) scale, Vestibular Disorders Activities of Daily Living Scale (VADL), PROMIS participation and satisfaction scores, pain rating, and falls. Evaluations were performed at baseline visit and after 2, 6, and 10 weeks. Subjects were not made aware of any changes in outcomes and no additional balance interventions were allowed.
Results: Forty-five participants of 52 enrolled across four sites completed all in-clinic assessments. FGA scores improved from 15.0 at baseline to 19.1 at 10 weeks (p<0.000001), normal and fast gait speed from 0.86m/s to 0.95m/s (p<0.00005) and 1.24m/s to 1.33m/s (p<0.002), respectively, and TUG from 13.8s to 12.5s (p<0.012). Four-Stage Balance Test did not improve significantly. Several patient-reported outcomes were in normal range at baseline and remained largely unchanged. Interestingly, while FGA scores improved similarly across the baseline range, subjects with baseline ABC scores lower than 67% (cut-off for high fall risk) showed an increase in their ABC scores (from 49.9% to 59.3%, p<0.01), whereas subjects with baseline ABC scores above 67% showed a decrease (from 76.6% to 71.8%, p<0.019). Subjects who reported falls in the prior six months (n=25) showed a decrease in the number of fall-risk factors (from 5.1 to 4.3, p<0.023) as well as a decrease in fall rate from 13.8 to 7.4 falls/1000 days (p<0.014). Four subjects in the pre-study non-faller group (n=20) fell during the 10 weeks of the study.
Conclusion: A wearable sensory neuroprosthesis may provide a new way to treat gait and balance problems and manage falls in high fall-risk patients with PN.
Trial registration: ClinicalTrials.gov (#NCT03538756)
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