An acoustic neuroma is a benign (non-cancerous) fibrous tissue growth that arises from the balance nerve that leads from the brain to the inner ear. An acoustic neuroma can be also known as a vestibular schwannoma or neurolemmoma. They are non-malignant, meaning that they do not spread to other parts of the body. Most acoustic neuromas occur spontaneously without any evidence of heredity and are diagnosed in patients between the ages of 30 and 60.
In the majority of cases, acoustic neuromas grow slowly over a period of years. In other cases, the growth rate is more rapid and patients develop symptoms at a faster pace. Usually the symptoms are mild and many patients are not diagnosed until some time after their acoustic neuroma has developed. Many patients also exhibit no tumor growth over a number of years when followed by yearly MRI scans. Acoustic neuromas account for approximately 6 percent of all brain tumors.
As the acoustic neuroma grows, it typically first affects a patient's hearing because it extends from the internal auditory canal into an area behind the temporal bone (see below). Larger acoustic neuromas can press on another nerve in the area, the trigeminal nerve, the nerve that affects facial sensation. If the acoustic neuroma goes undiagnosed and grows large, it can cause severe pressure on the brainstem and cerebellum of the brain, where vital functions that sustain life can be threatened.
In the majority of patients, the first symptom of acoustic neuroma is a reduction of hearing in one ear. This hearing loss is often accompanied by tinnitus or ringing in the ears, and is usually subtle and slow in progression. There may also be a feeling of fullness and/or pressure in the affected ear. These early symptoms are sometimes mistaken for normal changes of aging and can prolong diagnosis.
Because the acoustic neuroma originates in the balance portion of the eighth nerve, a patient may experience unsteadiness and problems with balance as the tumor grows. Larger tumors can press on the trigeminal nerve causing facial numbness and tingling, which can be either occasional or constant.
Aural atresia refers to the absence of or incomplete formation of the outer ear or the external auditory canal. Atresia can also extend to the middle ear structures (ossicles or ear bones). It can be seen in varying degrees from a complete lack of the pinna (outer ear) to a partially malformed pinna. Aural atresia is often associated with a microtia (small ear). There are surgical options to help re-construct the ear and open the ear canal. However, patients must consult with an ear specialist (otologist) to determine if they are a candidate for reconstructive surgery. Atresia of the ear most likely occurs on one side and is associated with a conductive or mixed hearing loss. Children or adults with aural atresia often wear a bone conduction hearing aid to help them to hear in that ear.
For more information on microtia or aural atresia, please contact the Yale Hearing and Balance Center at (203) 785-2467.