Definition and Overview
Bilateral vestibulopathy (BVP) is a vestibular disease that occurs when the vestibular function of both inner ears is simultaneously reduced or lost. The core symptoms are oscillopsia, which is a disturbance in the field of vision when walking or moving the head, and balance problems when walking. Unlike vestibular neuritis, which affects only one side, it is characterized by affecting both sides.
The ICD-10 code applies H81.8 (Other disorders of vestibular function).
cause
ototoxic drugs
Aminoglycoside antibiotics, including gentamicin, are the best known cause. It causes toxicity to vestibular sensory cells and reduces vestibular function on both sides simultaneously. It is characterized by oscillopsia and balance disorders during or after drug use.
Bilateralization of Meniere's disease
If Meniere's disease progresses to both ears, it can lead to bilateral vestibular function decline.
Idiopathic
Many patients are classified as idiopathic for which no clear cause can be found. In addition, forms accompanied by autoimmune disease, meningitis, hereditary vestibulopathy, and cerebellar degeneration have also been reported.
symptoms
Symptoms of bilateral vestibulopathy appear in relation to head movement and are more noticeable when moving or walking than when remaining still.
Main symptoms:
- oscillopsia: When you walk or move your head, your vision appears to waver.
- Gait imbalance, especially worse in the dark or on uneven surfaces
- Feelings of instability that worsen with eyes closed or in dark environments
- Difficulty reading by moving letters or signs
- increased risk of falls
Chronic instability and oscillopsia are the main causes rather than rotational dizziness or acute attacks.
diagnosis
Head impulse test and video head impulse test (vHIT)
If the gaze cannot maintain the target when turning the head quickly and corrective saccade occurs to catch up, it indicates a decrease in the vestibulo-ocular reflex. The video head impulse test (vHIT) quantitatively measures the gain of the vestibulo-ocular reflex in both semicircular canals.
caloric test
Decreased responses on both sides of the caloric test suggest bilateral vestibulopathy. The Bárány Society's diagnostic criteria suggest decreased bilateral horizontal semicircular canal vHIT gain or decreased caloric test response as the basis for diagnosis.
Rotating chair inspection
The rotating chair test complements the diagnosis by evaluating vestibular function in the low-frequency region.
Differential diagnosis
- Vestibular neuritis: Acute involvement of only one vestibule, accompanied by spontaneous nystagmus
- Cerebellar degeneration: with focal neurological signs and ataxia
- Polyneuropathy: Balance disorder due to decreased proprioception
treatment
vestibular rehabilitation
Vestibular rehabilitation is the key to managing bilateral vestibulopathy. It relieves oscillopsia and balance disorders by promoting central compensation using vision and proprioception. Gaze stabilization exercises, balance training, and gait training are performed step by step.
Cause Correction
If ototoxic drugs are the cause, discontinue the drug and consider alternative drugs. If the underlying cause, such as Meniere's disease or autoimmune disease, is identified, it is managed accordingly.
Life Care and Assistance
Be careful about activities in dark environments and use night lights and walking aids to prevent falls. Do regular exercise to maintain balance.
Clinical implications
Bilateral vestibulopathy presents with chronic oscillopsia and balance problems rather than rotational vertigo, making diagnosis more likely to be delayed. In patients who complain of balance problems that worsen in the dark and blurred vision when moving their head, it is important to check the history of ototoxic drug use and evaluate bilateral involvement with vHIT and caloric testing.