An acoustic neuroma, known as a vestibular schwannoma, is a benign (non-cancerous) growth that arises on the eighth cranial nerve leading from the brain to the inner ear. Acoustic neuromas usually grow slowly over a period of years. Symptoms typically begin with a reduction in hearing in one ear, often accompanied by ringing in the ear called tinnitus. Unsteadiness and balance problems or even vertigo, may occur during the growth of the tumor.
Source: Acoustic Neuroma Association (ANA)