Hemifacial spasm causes the muscles on one side of the face to contract. In its mildest form this may cause no more than a slight inconvenience, although the symptoms may still be disfiguring and socially embarrassing.
In more severe cases, the contractions may interfere with vision. However, since the other eye is usually unaffected, it rarely causes loss of sight.
Hemifacial spasm affects both men and women and usually develops in middle age. It is thought to affect more than 4,000 people in the UK.
Hemifacial spasm may develop gradually. Initially, the muscles surrounding the eye may be affected by muscle spasms. The spasms may then spread to other muscles on the same side of the face, particularly the muscles of the jaw and mouth. Some patients experience a clicking sound in the ear on the affected side each time there is a muscle spasm. Hemifacial spasm tends to affect the left side of the face more often than the right.
Symptoms of hemifacial spasm are similar to facial dystonia but the spasms are usually less variable than many focal dystonias, although some of those affected do find that their condition worsens under stress and improves when lying down.
Hemifacial spasm only affects one side of the face while dystonia can affect both sides.
The causes of hemifacial spasm are not yet fully understood, but current medical opinion suggests that the condition may be caused by irritation of the facial nerve.
This is a key difference from dystonia which is thought to be caused by a problem in the basal ganglia, an area deep within the brain.
There is no cure for hemifacial spasm but there are treatments that enable a significant improvement in symptoms for most people.
Botulinum toxin injections, which weaken the muscles affected by spasm, are the most common treatment benefitting around three quarters of patients. Injections need to be repeated every three months or so. In cases where little improvement results from the injections, it may be because the key areas have not been accurately targeted, or the dose needs adjusting, or a different type of botulinum toxin is required.
Side effects, which are not common and usually temporary, include droopy eyelids, double vision and some weakness of the muscles below the eye, but these usually disappear within a week or two.
Surgery can also alleviate symptoms although it is not suitable for most patients. A number of specialised surgical procedures are available. These are often effective, but may be associated with potentially serious side effects. They are generally reserved for patients with severe and disabling hemifacial spasm, for those who do not respond to treatment with botulinum toxin, or for younger patients who opt for them.
Drugs may provide benefit for some individuals but none is universally effective. Drugs need to be taken on a long-term basis and may also produce side effects in some people.
Self-help measures such as relaxation techniques appear to help some people, whereas homeopathy, acupuncture and dietary management appear to offer little benefit for hemifacial spasm sufferers.
A positive attitude is important. Learning about hemifacial spasm and talking to other people may help you to come to terms with your condition and enable you to find ways of coping with your symptoms. Although hemifacial spasm is not strictly classified as a dystonia, the two conditions have much in common and the Dystonia Society is a good source of support and information.
Support from family and friends is also important. They may also benefit from learning more about hemifacial spasm so that they can better understand your condition.
An international online support community for people with hemifacial spasm is available at the following web address:
For more information, call our helpline on 0845 458 6322
Last reviewed January 2013
The Dystonia Society provides the information on this page as general information only. It is not intended to provide instruction and you should not rely on this information to determine diagnosis, prognosis or a course of treatment. It should not be used in place of a professional consultation with a doctor. The Dystonia Society is not responsible for the consequences of your decisions resulting from the use of this information, including, but not limited to, your choosing to seek or not to seek professional medical care, or from choosing or not choosing specific treatment based on the information. You should not disregard the advice of your physician or other qualified health care provider because of any information you receive from us. If you have any health care questions, please consult the relevant medical practitioner.