A benign, slow-growing tumor type, acoustic neuromas affect the seventh and eighth cranial nerves in a part of the brain known as the cerebellar-pontine angle, or CPA. The eighth cranial nerve has two parts – the cochlear nerve that transmits sound between the inner ear and the brainstem, and the vestibular nerve that helps provide balance. Acoustic neuromas most commonly arise from schwann cells, which produce insulation for the vestibular nerve. Therefore, these tumors are often called vestibular schwannomas.

Early symptoms include hearing loss or deafness, pressure in the inner ear, impaired sense of balance and ability to walk, as well as vertigo with associated nausea and vomiting. About 80 percent of patients reported tinnitus, usually high-pitched ringing, roaring or hissing sounds.

Large tumors that press against the brainstem may affect other cranial nerves that result in less common symptoms like the loss of sensation in the face and mouth or altered swallowing and gag reflex. Larger tumors also may lead to increased intracranial pressure and associated symptoms like headache, vomiting and altered consciousness.