Section 6. Brain, Spinal Cord, and Nerve Disorders

Chapter 96. Cranial Nerve Disorders

Topics: Introduction | Internuclear Ophthalmoplegia | Palsies of Cranial Nerves That Control Eye Movement | Trigeminal Neuralgia | Bell's Palsy | Hemifacial Spasm | Glossopharyngeal Neuralgia | Hypoglossal Nerve Disorders

Hemifacial Spasm

Hemifacial spasm is involuntary twitching of one side of the face.

Hemifacial spasm affects men and women but is more common among middle-aged and older women. The spasms are caused by an abnormally positioned artery or loop of an artery that compresses cranial nerve VII where it exits from the brain stem. Muscles on one side of the face twitch involuntarily, usually beginning with the eyelid and then spreading to the cheek and mouth. Twitching may be intermittent at first but may become almost continuous. The disorder is essentially painless but can be embarrassing.

The diagnosis is made by seeing the spasms. Magnetic resonance imaging (MRI) rarely detects the abnormal artery but should be performed to rule out a tumor.

Botulinum toxin is the drug of choice. It is injected into the affected muscles. If this treatment is unsuccessful, surgery may be performed to separate the abnormal artery from the nerve by placing a small sponge between them.