Acoustic Neuroma

Acoustic neuroma also referred to as vestibular schwannoma, maybe a quite rare, noncancerous and a slow-growing tumour that happens on the most nerve – vestibular leading from the internal ear to the brain. The vestibular nerves are the eighth cranial nerves, which function by transmitting sound and equilibrium (balance) information from the inner ear to the brain.

This type of tumour usually grows slowly and does not spread through the body, instead, it affects hearing, balance and facial nerves of a patient. Though acoustic neuroma may be a non-cancerous tumour, it is often dangerous if they grow large and press against the brainstem or brain. As per the medical history and records of the patients, it is estimated that only one person in every 100,000 births is diagnosed with acoustic neuroma every year and this tumour can develop at any age and sex but most ordinarily found between the age of 40 to 50. 

What is Acoustic Neuroma?

Acoustic neuroma is quite a brain disorder or a brain tumour. It is also called a benign tumour since it is non-cancerous. It is a tumour that grows very slowly in the body, but it can push against vital brain structures and become life-threatening if not treated.

The nerve along which the tumour develops inside the brain is understood as the auditory nerve and it controls hearing sense. Acoustic neuromas grow as a sort of cell referred to as Schwann cell and surround nerve cells. It tends to grow slowly and sometimes it's too small and doesn't cause any signs and symptoms, but at the upper stage of acoustic neuromas, they are capable of interfering with the vestibulocochlear nerves. The size of an acoustic neuroma can vary from 2cm to 4cm or maybe more than that.

Causes of Acoustic Neuromas

The main explanation for acoustic neuromas appears to be an abnormal or non-functioning of a gene on a chromosome- NO -22. This gene produces a tumour suppressor protein that helps in controlling the growth of Schwann cells by covering the nerves. The exact cause of this tumour is still not identified by any scientists, and as per the studies and evaluations, about 8 out of 100 cases are caused by neurofibromatosis type 2 (NF2). NF2 is a rare genetic disorder and causes benign tumours in the nervous system. In most of the cases, there is no identifiable cause, but there may be some risk factors, including:

• Age

• Long-term exposure to loud noise

• A family history of acoustic neuroma

• Exposure to radiations during childhood.

Symptoms of  Acoustic Neuroma

The signs and symptoms of acoustic neuroma usually vary with the sort, size of a tumour. Some of the common symptoms of an acoustic neuroma are as mentioned below - 

• Earache

• Vomiting

• Dizziness

• Headaches

• Vision problems

• Facial numbness

• Unsteadiness or loss of balance

• Weakness or loss of muscle movement

• Loss of sensation to at least one side of the face and mouth

• Loss of the sense of taste on the rear half the tongue

• Tinnitus – a perception of noise or ringing within the affected ear

• Loss of hearing, usually gradual and occur on just one side or affected ear.

Diagnosis of Acoustic Neuroma

Acoustic neuroma is often difficult to diagnose in the early stages because signs and symptoms develop gradually over time. If any of the symptoms are analyzed, then certain physical tests are administered to check the presence of a tumour on the most nerve – vestibular. The most commonly used diagnostic tests are: 

• Physical examination of an ear

• MRI and CT scans of the head

• Audiometry – A test to see the functioning of the ear

• BAER – Brainstem auditory evoked response

Treatment for Acoustic Neuroma

The treatment usually depends on several factors, including:

• Patient’s age

• The general health of the person

• The size and location of the tumour.

There are several different treatments available to cure or stop the expansion of the tumour. The major treatments: 

• Surgery

• Microsurgery

• Radiation therapy

• Stereotactic radiosurgery.