Twitching may occur only occasionally at first but may become almost constant.
Doctors diagnose hemifacial spasm based on symptoms but do magnetic resonance imaging to check for other disorders that can cause similar symptoms.
Hemifacial spasm is treated with botulinum toxin or another drug, but if drugs are ineffective, surgery may be necessary.
(See also Overview of the Cranial Nerves.)
Hemifacial spasm affects men and women but is more common among middle-aged and older women.
The spasms may be caused by
Hemifacial spasm is diagnosed when doctors see the spasms.
Magnetic resonance imaging (MRI) should be done to rule out tumors, other structural abnormalities, and multiple sclerosis, which can cause similar symptoms. Also, MRI can usually detect the abnormal loop of artery pressing against the nerve.
Botulinum toxin (used to paralyze muscles or to treat wrinkles) is the drug of choice for hemifacial spasm. It is injected into the affected muscles. The same drugs used to treat trigeminal neuralgia—carbamazepine, gabapentin, phenytoin, baclofen, and tricyclic antidepressants—may be tried but are usually not helpful.
If drug treatment is unsuccessful, surgery may be done to separate the abnormal artery from the nerve by placing a small sponge between them.