Noisy vestibular stimulation improves dynamic walking stability in bilateral vestibulopathy

OBJECTIVE:To examine the effects of imperceptible levels of white noise galvanic vestibular stimulation (nGVS) on dynamic walking stability in patients with bilateral vestibulopathy (BVP). METHODS:Walking performance of 13 patients with confirmed BVP (mean age 50.1 ± 5.5 years) at slow, preferred, and fast speeds was examined during walking with zero-amplitude nGVS (sham trial) and nonzero-amplitude nGVS set to 80% of the individual cutaneous threshold for GVS (nGVS trial). Eight standard gait measures were analyzedstride time, stride length, base of support, double support time percentage as well as the bilateral phase coordination index, and the coefficient of variation (CV) of stride time, stride length, and base of support. RESULTS:Compared to the sham trial, nGVS improved stride time CV by 26.0% ± 8.4% (p < 0.041), stride length CV by 26.0% ± 7.7% (p < 0.029), base of support CV by 27.8% ± 2.9% (p < 0.037), and phase coordination index by 8.4% ± 8.8% (p < 0.013). The nGVS effects on walking performance were correlated with subjective ratings of walking balance (ρ = 0.79, p < 0.001). Effect of nGVS on walking stability was most pronounced during slow walking. CONCLUSIONS:In patients with BVP, nGVS is effective in improving impaired gait performance, predominantly during slower walking speeds. It primarily targets the variability and bilateral coordination characteristics of the walking pattern, which are linked to dynamic walking stability. nGVS might present an effective treatment option to immediately improve walking performance and reduce the incidence of falls in patients with BVP. CLASSIFICATION OF EVIDENCE:This study provides Class IV evidence that in patients with BVP, an imperceptible level of nGVS improves dynamic walking stability.