Hemifacial Spasm

What is hemifacial spasm?

A spasm is a a sudden, involuntary contraction of a muscle or a group of muscles. Hemifacial means half of the face.

The muscles of the face are all controlled by the facial nerve. There is a facial nerve for each side of the face. It starts deep inside your brain and makes its way past many structures to reach the face. The facial nerve carries signals from the brain to make your facial muscles contract or relax. For example, the facial nerve makes you blink, twitch your nose and pout your lips.

If something presses on the nerve somewhere along its course, it can affect how the signals are carried to the face. This may cause muscles to twitch (or contract), or go into spasm, when you don’t want them to.

How common is it?

Hemifacial spasm is a rare condition. In the UK there are thought to be about 4,000 people with hemifacial spasm. It affects men and women, although women tend to be affected slightly more often than men. Symptoms usually start in middle age.

What causes it?

The cause of hemifacial spasm is not fully understood. At the moment, doctors believe the main cause is pressure on the facial nerve from a structure or abnormality within the brain. The most common finding is a blood vessel at the base of the brain, pressing on the nerve. There are other, rare causes too such as infections or strokes. Sometimes there is no obvious cause and doctors may then call it idiopathic (of unknown cause) hemifacial spasm.

Is it inherited?

Because the causes of hemifacial spasm are not inherited, it is unlikely that you will pass the condition on to your children.

What are the symptoms of hemifacial spasm?

Twitching usually begins around the eye. At first the twitching spasms may come and go. Gradually the spasms become worse and the spasm may become permanent. The left side is more often affected than the right. The twitches may spread to involve other muscles on the same side of the face. The mouth and jaw are often involved. The corner of the mouth can become pulled up by permanent spasm. Some people also hear a clicking sound on the side that is affected when the spasm comes.

Some people may have a quite mild condition that causes inconvenience and embarrassment. Others find the spasms may affect their vision. As the other eye is not affected, they are still able to see.

For some people the spasms may become worse when they are tired and stressed. They may also improve when they lie down.

How do doctors diagnose it?

If you are worried about twitching on one side of your face, you should see your GP. They will ask questions about what has happened and how it is affecting you. They may examine you. If they think it might be hemifacial spasm, they will refer you to a consultant who specialises in nerves – a neurologist. Some neurologists specialise in movement disorders, such as hemifacial spasm.

What treatments are available for hemifacial spasm?

Although there is no guaranteed cure currently, a variety of treatments is available.


These can be helpful when the spasms are mild or infrequent. Anti-epileptic medicines such as carbamazepine and topiramate can be helpful in some people with hemifacial spasm. These medicines work by quieting nerve impulses. Benzodiazepine medicines such as diazepam and clonazepam are sedatives. They can relax muscle spasms but may also make you feel sleepy. The response to these medicines can vary and it may take time to get the right dose. They will need to be taken on a long-term basis.


Botulinum toxin is produced by the bacterium Clostridium botulinum. It is usually associated with causing botulism (food poisoning) but, when it is used in controlled doses, it is safely used to relax excessive muscle contraction. It is injected into the facial muscles and blocks the signal from the nerve. This helps to stop the spasms. The effects of the injection last for two to three months and it starts to work within a few days. About 7-8 people out of 10 with hemifacial spasm are helped by botulinum injections.

There can be side-effects of the injection. These are commonly drooping of the eyelid and double vision. They usually wear off after 1 or 2 weeks.


There are several surgical procedures that can be done. Microvascular decompression is one type. It involves removing the blood vessel that may be pressing on the facial nerve. They may be curative but they are often unsuitable for many patients with hemifacial spasm. There are some serious side-effects that may occur as a result of surgery. For this reason, surgery is usually reserved for cases where the spasms are severe and disabling. Surgery is also used when other treatments have failed to work or if you are particularly young.

Is there anything I can do to help myself?

Learning relaxation techniques may benefit some people. Educating yourself about your condition and staying positive can also help. Other complementary therapies such as homeopathy or acupuncture do not seem to help this condition.

What is the outlook?

Hemifacial spasm is usually a long-term condition. It is not fatal but may affect your quality of life. It very rarely improves completely without treatment.

Further help and information

The Dystonia Society
2nd Floor, 89 Albert Embankment, Vauxhall, London, SE1 7TP
Tel: 0845 458 6211 Helpline: 0845 458 6322 Web: www.dystonia.org.uk
Hemifacial spasm is a type of dystonia. There are various types of dystonia and the Dystonia Society provide support, advice and information for people with any type of dystonia.

References and Disclaimer | Provide feedback


  • Gulevich S, Hemifacial Spasm, Medscape, Jun 2010
  • Huh R, Han IB, Moon JY, et al; Microvascular decompression for hemifacial spasm: analyses of operative complications in 1582 consecutive patients. Surg Neurol. 2008 Feb;69(2):153-7. [abstract]
  • Costa J, Esp´┐Żrito-Santo C, Borges A, Ferreira JJ, Coelho M, Moore P, Sampaio C. Botulinum toxin type A therapy for hemifacial spasm. Cochrane Database of Systematic Reviews 2005, Issue 1. Art. No.: CD004899. DOI: 10.1002/14651858.CD004899.pub2.
  • Han IB, Chang JH, Chang JW, et al; Unusual causes and presentations of hemifacial spasm. Neurosurgery. 2009 Jul;65(1):130-7; discussion 137. [abstract]


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