Bilateral vestibulopathy revisited.

Bilateral vestibular failure (BVF) is an often undetected disorder of the peripheral labyrinths or the eighth nerves. Key symptoms are oscillopsia during locomotion or head movements and unsteadiness, particularly in the dark. Diagnosis is made by a bedside test for defective vestibulo-ocular reflex and the absence of nystagmic reaction to both caloric and rotatory pendular testing. Most frequent etiologies include ototoxicity, cerebellar degeneration, meningitis, neuropathies, sequential vestibular neuritis, autoimmune disorders, tumors, and miscellaneous otological diseases. Idiopathic BVF is found in more than twenty percent of the patients. Recovery is possible but mostly incomplete. Somatosensory and visual input largely substitute the vestibular deficit for spatial orientation, postural balance and ocular motor control.