Home > Encyclopedia of Neurological Disorders > Vestibular Schwannoma

Definition

A vestibular schwannoma is a type of benign (non-cancerous) tumor that affects the eighth cranial nerve.

Description

The eighth cranial nerve is involved in both hearing (the auditory or acoustic component of the nerve) and balance (the vestibular component of the nerve). Like all cranial nerves, the eighth cranial nerve (also called the acoustic or auditory nerve) is paired, meaning that there is one on each side of the body. Each eighth cranial nerve runs from the inner ear to the brain, passing through a bony canal called the internal auditory canal. This canal is shared with the seventh cranial nerve, the facial nerve.

Like many nerve fibers, the eighth cranial nerve is wrapped in a sheath composed of specialized Schwann cells that serve to speed the transmission of information along the nerve. When the Schwann cells grow in an uncontrolled fashion, they can develop into a tumor, called...