Bilateral Vestibular Weakness and its Management

Bilateral vestibular weakness (BVW), while uncommon, causes significant disability. We review the epidemiology, etiologies, and diagnostic techniques for BVW, followed by a discussion of established and investigative therapeutics. Recent research increasingly suggests that some BVW cases previously designated as idiopathic may be due to RFC1 mutations. While the standard of care for BVW remains vestibular rehabilitation therapy, promising investigative therapeutics include noisy galvanic vestibular stimulation and prosthetic vestibular implants; research on vestibular hair cell regeneration is ongoing. Bilateral vestibular weakness (BVW) refers to pathological reduction of vestibular signals from one or more labyrinthine inputs on each side due lesions of the end organelles, or their afferent pathways, or some combination thereof. There are many etiologies of BVW. Symptoms include oscillopsia and unsteadiness. The diagnosis can be suspected from bedside examination techniques, but requires confirmation from instrumented vestibular testing. Potential mechanisms for recovery include healing of damaged (but not dead) vestibular hair cells, central compensation and sensory substitution. Vestibular rehabilitation therapy is the standard of care for BVW, and emphasizes adaptive techniques thought to improve gain of the vestibulo-ocular reflex, and sensory substitution. Investigational therapeutics include noisy galvanic vestibular stimulation, vestibular implantation, and vestibular hair cell regeneration. Prognosis is unfavorable.