Because the symptoms of acoustic neuroma are often subtle and slow to develop, they can be missed easily in their early stages. Gradual hearing loss, especially if it occurs only in one ear, always should be checked by a physician.
If your doctor suspects that you have an acoustic neuroma, he or she will examine you to look for other conditions that can cause similar symptoms. This examination usually will include:
Looking in your ears with a lighted magnifying lens
Using tuning forks to test your hearing
Examining your nose, throat and neck
Testing the nerves in your face
Checking your balance
Your doctor also may recommend a formal hearing test (audiogram) to determine the type and amount of the hearing loss.
Sometimes your doctor may recommend an auditory brain-stem response test, also called evoked potentials or evoked responses. In this test, electrodes are placed on the scalp to measure the brain's electrical responses to various noises. The test measures the speed that the sound is transmitted through the brain. This test will be abnormal and show a delay in the transmission if a tumor is pressing on the nerve that carries signals from the ear to the brain (the cochlear nerve).
If an examination and hearing testing indicate a possible acoustic neuroma, your doctor may order additional tests to confirm the diagnosis. Most commonly, he or she will recommend a magnetic resonance imaging (MRI) scan. MRI uses magnetic waves to create pictures of structures inside the body. These pictures can show whether you have an acoustic neuroma, how big the tumor is, and where it is located. An MRI can detect tumors as small as 2mm.