Rehabilitation of patients with bilateral vestibulopathy using method of subthreshold galvanic vestibular stimulation

Abstract. Objective. To study the effect of noise galvanic vestibular stimulation (nGVS) on vestibular receptors in patients with bilateral vestibulopathy (BVP), to evaluate the possibility of using nGVS as a method of treatment and rehabilitation of patients with this disease. Patients and methods. The study included 40 patients (14 men and 26 women from 24 to 80 years old) with confirmed BVP. Patients were divided into 4 groups depending on the degree of vestibular receptor lesions: group I: hypofunction of ampullar receptors and preserved otolith function; group II: hypofunction of ampullar receptors and areflexia of otolith receptors; group III: areflexia of ampullar receptors and preserved otolith function; group IV: areflexia of both ampullar and otolith receptors. To study the effectiveness of the method, a commercial electrical stimulation device Neurostim, manufactured by Neurosoft (Russia), was used. A stimulation session lasted 30 minutes with a frequency from 0 to 30 Hz and an intensity from 0.1 to 1.3 mA. The effectiveness was evaluated according to the data of video head impulse test (gain was evaluated) and sensory integration test (L — length of statokinesiogram (mm), S — area of deviation of the center of pressure (CP) (mm²), v — velocity of movement of the center of pressure (mm/s), A — energy expenditure index for movement of the center of pressure (mJ/s) were analyzed). Results. Patients in groups I and II after the nGVS session showed a reliable decrease in the area of statokinesiogram S in the test on a hard surface with closed eyes. In groups III and IV, we did not observe a statistically significant increase of gain according to vHIT (video head impulse test) or improvement of stabilometry parameters after nGVS session. Conclusions. nGVS has the property of enhancing residual vestibular function in patients with BVP only in the absence of vestibular areflexia according to vHIT. The severity of the stimulation effect depends on the prevalence of vestibular lesion.