Acoustic Neuroma

An acoustic neuroma is a benign tumour of the auditory (vestibulocochlear) nerve; the eighth of twelve cranial nerves. The presence of an acoustic neuroma is a rare occurrence, and they account for approximately 7 per cent of all brain tumours.

Cause

The exact causes of acoustic neuroma have yet to be identified. Some risk factors specific to acoustic neuroma have been identified, however, and include:

·         Age – individuals between the ages of 50 to 60 are at greatest risk;

·         Exposure of the head and neck area to low-dose radiation;

·         Frequent use of mobile telephones; and

·         Family history and/or incidence of Neurofibromatosis type II (NF-2).

NF-2 is a rare genetic disorder. It involves the inheritance of a faulty gene, causing acoustic neuromas to grow on the auditory nerves in both sides of the brain.

Symptoms and diagnosis

The primary symptom of an acoustic neuroma is the progressive loss of hearing. The onset of the impairment may be sudden, and the extent of the impairment may also fluctuate. Other common symptoms include:

·         Sensation of ringing in the ears;

·         Impaired sense of balance and consequently altered gait;

·         Pressure in the ear;

·         Headaches and dizziness; and

·         Depressed consciousness.

Treatment

For smaller tumours, physicians may recommend conservative treatment, involving surveillance by annual MRI to track growth. It is rare for growth rate of acoustic tumours to accelerate; for this reason, annual observation is generally sufficient. In even rarer cases, acoustic neuromas have been observed to shrink.

Clinical treatments usually prescribed for acoustic neuroma include surgical removal of the tumour, and radiotherapy.