Sudden vestibular failure is the condition that arises due to acute loss of unilateral vestibular (balance) function.

While in some case the cause may be obvious, such as trauma, viral infection, problems with blood supply, chronic ear infection; in many the cause may be unidentifiable.

This condition is characterised by sudden onset of severe rotatory vertigo associated with nausea and vomiting. The vertigo lasts for several hours but the patient is often unwell for a number of days or weeks while his balance gradually recovers. If a sensorineural
hearing loss accompanies the dizziness, it is termed labyrinthitis. In vestibular neuronitis, only the vestibular system is only involved and there is no hearing loss.

Balance recovers by a process of compensation, which occurs gradually over a period of weeks.
In the initial phase, the acute symptoms are treated with medication (vestibular sedatives) and bed rest.
Once the acute phase has resolved, this medication is withdrawn. Compensation is enhanced by
vestibular rehabilitation (balance retraining) exercises.