Noisy galvanic vestibular stimulation: an emerging treatment option for bilateral vestibulopathy.

Patients with bilateral vestibulopathy (BVP) suffer from persistent imbalance during standing and walking as well as an impaired gaze stabilization during head movements. Disabilities associated with BVP severely compromise patients' daily activities and are often linked to an increased risk of falls. Currently, the only established treatment option in BVP is physical therapy. However, treatment effects of physical therapy in BVP are most often limited and many patients do not adequately recover performance. Therefore, a number of technical therapeutic approaches are being explored that either try to substitute lost vestibular sensation with a congruent stimulation of other sense modalities or to artificially mimic vestibular function by means of an implantable vestibular prosthesis. Besides, attempts have recently been made to augment and optimize residual vestibular function in patients with BVP using an imperceptible noisy galvanic vestibular stimulation (nGVS). This approach is based on the natural phenomenon of stochastic resonance, wherein the signal processing in sensory systems can be improved by adding an appropriate level of noise to the system. Promising first study outcomes of nGVS treatment in patients with BVP indicate the feasibility of a future non-invasive sensory prosthetic device for BVP rehabilitation. This paper gives an overview about recent research on nGVS treatment in patients with BVP and discusses future research perspectives in this field.