Module 12 · Disease pages

Bilateral vestibulopathy

Oscillopsia and bilateral high-frequency loss
Clinical vignette
A 71-year-old man describes 18 months of progressively worse unsteadiness, particularly in the dark and on uneven surfaces. He has developed bouncing of his visual field when walking or driving over rough roads (oscillopsia). Romberg is positive only with eyes closed. Bedside head impulses are abnormal in both directions for the lateral canals. vHIT shows bilateral horizontal canal gain reduction (0.32 right, 0.28 left) with prominent overt saccades on both sides.
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What it is

Bilateral vestibulopathy (BVP) is a chronic vestibular syndrome characterised by bilaterally reduced or absent vestibular function. The classic clinical picture is the triad of gait unsteadiness (particularly in low-light or unstable environments), oscillopsia during head movement, and a normal hearing examination. The Bárány Society diagnostic criteria published in 2017[Strupp M 2017] are:

  • Chronic vestibular syndrome with unsteadiness and/or oscillopsia,
  • plus a bilaterally reduced or absent VOR documented by horizontal vHIT gain < 0.6 bilaterally, or caloric responses < 6°/s peak SPV bilaterally, or reduced bilateral rotational chair gain.

The vHIT pattern

Symmetric reduction in lateral canal gain with prominent corrective saccades on both sides is the canonical finding. The vertical canals are often partially preserved, particularly in idiopathic and ageing-related cases; in aminoglycoside ototoxicity all six canals tend to be affected uniformly.

Bilateral vestibulopathy — six-canal panel
0100200R latg=0.300100200L latg=0.320100200R antg=0.550100200L antg=0.580100200R postg=0.620100200L postg=0.60
Severe symmetric reduction of lateral canal gain with bilateral overt saccades. Vertical canals moderately reduced. Typical of severe bilateral vestibulopathy from aminoglycoside exposure.

Causes

The cause is identifiable in only about half of cases. The main aetiologies are:

  • Aminoglycoside ototoxicity — historically gentamicin and tobramycin. Often profound and irreversible. See the dedicated ototoxicity chapter.
  • Bilateral sequential Meniere disease — relatively rare. The hearing loss usually precedes the bilateral vestibular loss by years.
  • Bilateral schwannomas — in NF2.
  • Autoimmune inner ear disease — usually accompanied by hearing loss, often responsive to immunosuppression.
  • Cerebellar ataxia, neuropathy, vestibular areflexia syndrome (CANVAS) — a slowly progressive late-onset hereditary syndrome featuring bilateral vestibular loss, sensory neuropathy, and cerebellar ataxia.
  • Idiopathic — typically older adults, slowly progressive.

Identifying the cause matters because some are treatable (autoimmune, ongoing aminoglycoside exposure) and some inform genetic counselling (CANVAS, NF2).

Why hearing is usually normal

Hearing loss accompanies vestibular loss only in conditions that affect both organs of the inner ear (Meniere disease, autoimmune disease, congenital labyrinthine disorders, ototoxicity at higher doses, infections). The commonest cause of idiopathic BVP spares hearing, distinguishing it clinically from broader inner-ear pathology. A patient with progressive bilateral SNHL plus bilateral vestibular loss merits a more aggressive workup — autoimmune, infiltrative, and metabolic causes need to be considered.

Key teaching points

  • Diagnostic triad: oscillopsia, gait unsteadiness in the dark, and bilateral vHIT lateral canal gain < 0.6 (Bárány 2017).
  • Hearing is usually preserved in idiopathic BVP; bilateral SNHL with bilateral vestibular loss broadens the differential.
  • Bedside HIT often misses bilateral loss because compensation is symmetric; vHIT is the confirmatory test.
  • Recovery of VOR is limited; rehab focuses on substitution strategies rather than VOR repair.

References

  1. Strupp M, Kim JS, Murofushi T, Straumann D, Jen JC, Rosengren SM, Della Santina CC, Kingma H. Bilateral vestibulopathy: diagnostic criteria consensus document of the Classification Committee of the Bárány Society. Journal of Vestibular Research 2017;27:177–89. doi:10.3233/VES-170619
  2. Aw ST, Todd MJ, Aw GE, Weber KP, Halmagyi GM. Gentamicin vestibulotoxicity impairs human electrically evoked vestibulo-ocular reflex. Neurology 2008;71:1776–82. doi:10.1212/01.wnl.0000335971.43443.d9
  3. Halmagyi GM, Chen L, MacDougall HG, Weber KP, McGarvie LA, Curthoys IS. The video head impulse test. Frontiers in Neurology 2017;8:258. doi:10.3389/fneur.2017.00258
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