A noncancerous tumour affecting the vestibulocochlear (acoustic) nerve, which connects the ear to the brain
An acoustic neuroma is a rare tumour affecting the vestibulocochlear (acoustic) nerve, which carries auditory and balance information from part of the inner ear to the brain. The tumour usually affects the vestibulocochlear nerve on one side of the head only, but it may affect both nerves. The tumour is noncancerous but can cause severe nerve and brain damage. If detected early, it can be removed by surgery.
The cause of acoustic neuroma is unknown but, if the tumour affects both acoustic nerves, it may be associated with neurofibromatosis, an inherited condition in which multiple tumours grow from the sheaths around nerves. Acoustic neuroma is most common between the ages of 40 and 60.
The symptoms of an acoustic neuroma usually develop slowly, almost always affect only one ear, and may include:
Progressive hearing loss.
Ringing or buzzing noises in the ear (see Tinnitus).
Headache and pain in the ear.
Dizziness and a loss of balance (see Vertigo).
An acoustic neuroma is slow-growing, but as it enlarges it may press on part of the brain, causing lack of coordination of body movements. The tumour may also compress the nerves that supply the face, causing weakness of the facial muscles (see Facial palsy) and pain. Left untreated, a neuroma may cause permanent nerve damage.
An acoustic neuroma may be removed by surgery. This is often successful in eliminating many of the symptoms and, if the tumour is small, hearing may be restored in the affected ear. However, removal of a large tumour may damage the vertibulocochlear or facial nerves, which may result in permanent hearing loss in the affected ear and numbness, weakness, or paralysis of part of the face. Alternatively, it may be possible to treat the tumour using radiotherapy or by a technique called stereotactic radiosurgery (sometimes called a “gamma knife”), which delivers a very precise dose of radiotherapy to the tumour.
From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.