Bilateral vestibulopathy

Abstract

The leading symptoms of bilateral vestibulopathy (BVP) are postural imbalance and unsteadiness of gait, deficits of spatial memory and navigation. The etiology of BVP remains unclear in more than 50% of patients: in these cases neurodegeneration is assumed. Frequent known causes are ototoxicity mainly due to gentamicin, bilateral Menière's disease, autoimmune diseases, meningitis and bilateral vestibular schwannoma, as well as an association with cerebellar degeneration. The diagnosis of BVP is based on a bilaterally reduced or absent function of the vestibulo-ocular reflex (VOR). Head impulse test (HIT), video-oculography system (vHIT), crvical/ocular vestibular-evoked myogenic potentials (c/oVEMP) and dynamic visual acuity is an additional test supporting the diagnosis. There are four different subtypes of BVP depending on the affected anatomic structure and frequency range of the VOR deficit: impaired canal function in the low-and/or high-frequency VOR range only and/or otolith function only; the latter is very rare. There are four treatment options: first, detailed patient counseling to explain the cause, etiology, and consequences, as well as the course of the disease; second, daily vestibular exercises and balance training; third, if possible, treatment of the underlying cause, as in bilateral Menière's disease, meningitis, or autoimmune diseases; fourth, if possible, prevention, i.e., being very restrictive with the use of ototoxic substances, such as aminoglycosides.