It is a clinical syndrome caused by compression of the vestibular nerve. The main clinical feature is brief recurrent spells of vertigo.
Nerve compression or damage due to by
- blood vessels – microvascular compression (MVC)
- vestibular neuritis
- atumour -such as an acoustic neuroma
- radiation -such as post gamma knife
- surgery on the 8th nerve.
Microvascular compression is one of the most common reasons for vestibular paroxysmia.
The patient may complain of spells of vertigo or dizziness that last for seconds to minutes and may occur several times per day.
The following tests are advised for evaluating the condition and its severity.
MRI with gadolinium enhancement – If available, 3D MRI with FT-FISS or CISS is preferable. Positive in 95% (Hufner et al., 2008)
VNG/ENG — positive in 66% according to Hufner et al. (2008)
EEG – to rule out seizures
Audiometry– positive in 50% (Hufner et al.)
Fasting blood glucose – to rule out fluctuating sugar level
Neurovascular compression of the cochleovestibular nerve causes vestibular paroxysmia. Treatment with carbamazepine or oxcarbazepine is usually effective. Response to these medicines also serves as a diagnostic tool. Vestibular suppressants are not effective in this condition. If medical treatment does not have the desired outcome surgery may be done. Microvascular decompression of a vascular loop compressing the vestibular nerve may be done endoscopically with minimal morbidity in expert hands.