Acoustic Neuroma – Symptoms, Causes & Treatments
An Acoustic Neuroma (also known as Vestibular Schwannoma) is a rare, growth that develops on the hearing/balance nerve between the brain and inner ear, often causing hearing loss, tinnitus or balance problems.
What Causes an acoustic neuroma?
Acoustic neuromas are rare. In over 95% of cases they occur spontaneously and are not related to lifestyle or other health issues nor are they inherited. There is no known cause for this type of acoustic neuroma.
Symptoms of an acoustic neuroma:
Small acoustic neuromas may not cause any symptoms and are often found when someone has a scan for other reasons.
The most common symptoms are:
Reduced hearing in one ear
Nine out of 10 people with an acoustic neuroma will experience hearing loss on one side (on the side where the growth is). The loss of hearing is usually gradual and is due to the pressure of the growth on the hearing nerve. There may also be a feeling of fullness in the affected ear.
Ear noise or ringing in the ear may be heard on the affected side. However, the majority of people with tinnitus do not have an acoustic neuroma.
Dizziness and balance problems
The balance portion of the hearing/balance nerve is where the growth arises and thus may cause problems of balance, unsteadiness or vertigo. However, not everyone experiences this.
Less likely, the following symptoms may occur if the growth continues to grow:
- Numbness, tingling or pain on one side of the face.
- Facial weakness or twitching.
- Double vision.
- An increase in pressure inside the head (hydrocephalus).
How is an Acoustic Neuroma Diagnosed?
A hearing test is required to establish unilateral (one sided hearing loss). If you sense you may have hearing loss, you should contact your local Audiologist for a full hearing assessment they will be able to diagnose unilateral loss and may refer you to your GP for further investigation if this is the case.
An MRI (magnetic resonance imaging) scan is used to produce a picture of the inside of the brain. A CT scan (computerized tomography), which may be used for people unable to have an MRI scan. These brain scans will be used to confirm the presence of an acoustic neuroma.
How is an acoustic neuroma treated?
Acoustic Neuromas grow very slowly (or not at all in many cases), so there’s no need to rush into a decision about treatment, all options should be carefully discussed with your consultant and include the following:
- Observation/ monitoring the growth.
Surgery to remove the growth.
- Stereotactic Radiosurgery/ Radiotherapy to stop the growth.
The treatment that is recommended for you will depend on your wishes and, your age/ general health and the size and position of the growth.
As acoustic neuromas are benign growth, observation over a period of time is an appropriate option for many patients. MRI’s are performed periodically to study the growth pattern of the growth over time. In two-thirds of patients, the growth remains the same size, however, even when the growth remains stable, you may continue to lose hearing on that side.
During this stage, many people benefit from wearing a hearing aid on the affected side.
The type and style that best suits your needs can be discussed with your Audiologist, a good relationship with your Audiologist is important as regular hearing tests are advisable during this time to ensure your hearing aid is always set/ adjusted according to your current hearing level, which may be variable.
If the growth remains stable then no further intervention is required and you will continue to be monitored with scans. However, if the growth increases in size you will usually be advised to have treatment by either Stereotactic Radiosurgery or by surgery.
This is a surgical procedure that can be carried out in a single day, with no need to stay overnight in hospital. You are awake during this procedure. In some cases patients may be told they need to undergo the delivery of radiation in multiple doses. If this is required it will be discussed in greater detail with your Consultant.
The aim of surgery is to remove the growth. However, in some cases, some growth is left behind to reduce the risk of injury to the facial nerve (situated very close to hearing/ balance nerve). The residual growth will be monitored by a series of MRI scans.
Patients who present with an acoustic neuroma usually have a degree of hearing loss on the affected side. Following treatment, hearing on the affected side is NOT restored and most likely hearing will be totally lost on this side.
The loss of hearing will cause you difficulty in locating the direction that sound is coming from and following conversation in an environment where there is background noise will also be a challenge. Your Audiologist will be best placed to advise you of your options if this is the case.