Vertigo, dizziness and disequilibrium in vestibular schwannoma

Vertigo, dizziness and disequilibrium in vestibular schwannoma are neglected! An acoustic neuroma or vestibular schwannoma is a rare benign growth that originates from the vestibular (balance nerve). It is inevitable that the symptoms will include vertigo, dizziness, and disequilibrium.

It is important to note that although a lot of emphasize is placed on hearing that the vestibular system is neglected. It was shown by Saman et al that disequilibrium and imbalance is the most, negative predictor of general Quality of life (QOL) scores when compared with hearing loss or tinnitus in patients with vestibular schwannoma.

So what is really the issue then? The issue is that patients should be informed regarding their risk(s) if deciding on a specific management option.

When suffering with a vestibular schwannoma the risk of experiencing an acute attack of vertigo (sensation of motion) is about 25%.  Luckily this seems to be less with large tumours but how do you know? This is a serious risk to any patient’s health as it can occur at any time and without any warning. The risk of falling, loss of balance an injuring itself becomes a major risk if the patient drives, work with dangerous machinery or climb on ladders and work on heights for instance. Imagine if such a patient drives the school bus of your children daily?

Vertigo, dizziness and disequilibrium in vestibular schwannoma

A VEMP test showing the effect of a vestibular schwannoma on the left inferior vestibular nerve.

With larger tumours the inner ear function gets destroyed and the risk of acute vertigo reduces. At this point the typical problem is that of momentary imbalance when moving the head. The incidence of balance disorders in patients with vestibular schwannoma (acoustic neuroma) is 50%.  At this point disequilibrium can usually be managed effectively with vestibular rehabilitation.

At the stage that the tumour reaches such a size that it presses and distorts the vestibular nucleus in the brainstem, constant imbalance and dizziness will occur. This type of dizziness does not respond well to any medication or rehabilitation and only surgical removal will help. In fact, it has been shown that radiation therapy at this stage will aggravate this and that more than 50% of patients will suffer balance problems after radiation!

It is of vital importance that every patient, especially those that are followed up have vestibular function tests before, during and after their treatment. It is inevitable that patients who have received surgery will be followed up regarding their vestibular function.

Vertigo, dizziness and disequilibrium in vestibular schwannoma can be assessed with specialized tests. Vestibular tests (VNG, caloric tests, VEMP, VHIT and central tests) will indicate the extent of damage and involvement of the vestibular system by a vestibular schwannoma. Not only should the vestibular function be known at all times during treatment but any treatment should include the prognosis and outcome of vestibular function.