Bilateral vestibulopathy.

Area of Science:

• Neurology
• Ophthalmology
• Audiology

Background:

• Bilateral vestibulopathy (BVP) is characterized by postural imbalance and gait unsteadiness, often exacerbated by poor lighting or uneven surfaces.
• Symptoms may include oscillopsia (visual blurring during head movement), particularly during ambulation.
• Diagnosis relies on identifying a bilaterally reduced or absent vestibulo-ocular reflex (VOR).

Purpose of the Study:

• To outline the diagnostic criteria and methods for identifying bilateral vestibulopathy (BVP).
• To discuss the various etiologies and subtypes of BVP.
• To present current and potential future treatment strategies for BVP.

Main Methods:

• Assessment of the vestibulo-ocular reflex (VOR) using bedside head impulse test (HIT) for high frequencies and caloric testing for low frequencies.
• Quantification of angular VOR using video-oculography (vHIT) when bedside HIT results are equivocal.
• Evaluation of dynamic visual acuity and vestibular-evoked myogenic potentials (c/oVEMP) to assess otolith function.

Main Results:

• BVP diagnosis is confirmed by bilaterally impaired VOR function, detectable via HIT, caloric testing, and vHIT.
• Reduced or absent c/oVEMP responses indicate compromised otolith function.
• Etiologies are diverse, with neurodegeneration suspected in over 50% of cases; known causes include ototoxicity, Menière's disease, autoimmune disorders, meningitis, and vestibular schwannoma.

Conclusions:

• BVP presents with significant balance and gait disturbances due to vestibular dysfunction.
• Diagnosis involves a combination of clinical tests assessing VOR and otolith function.
• Management strategies include patient education, vestibular rehabilitation, treating underlying conditions, and preventative measures against ototoxic exposures; long-term functional recovery is generally limited.