Hemifacial spasm

Hemifacial spasm is an involuntary contraction (spasm) of the muscles on one side of the face. This chronic constricting condition can become almost permanent over time and evolve into a disabling disfigurement and social embarrassment. Learn more about the condition, its diagnosis and the different treatment options available.



Despite the many similarities between the two, hemifacial spasm is not a dystonia. The distinguishing characteristic of hemifacial spasm is the involuntary contraction of the muscles on the side of the face innervated by the facial nerve (forehead, eyebrows, eyelids and the angle of the lips and mouth). It usually starts with occasional twitching of the eyebrows before spreading to the other facial muscles on the same side of the face, and to the superficial muscles in the neck.


Symptoms and impact on health

The condition develops gradually, starting with twitching around the eye, which then spreads to all areas on the same side of the face – cheek, lips and chin – and the neck. Patients can develop the fairly characteristic “facial grimacing” where the eye appears to wink, the side of the mouth is stretched, the forehead contracted and one eyebrow raised. Some patients also hear a clicking noise on the affected side, which is caused by contraction of a small ear muscle during the spasm.

At first, these uncontrollable muscular contractions are rare and come and go quickly. Periods of remission are possible, but the spasms tend to become more frequent and prolonged over time and lead to a practically permanent facial disfigurement that may even affect the vision in one eye. Day-to-day, fatigue and stress can make the symptoms worse, and they generally persist during sleep.

Hemifacial spasm can have a disabling effect on patients’ daily life, both in terms of their vision and social relations, because of the grimacing it produces.


Risk factors

Hemifacial spasm is caused by a lesion of the facial nerve. Where it exits the brain stem, the nerve is compressed by a blood vessel or a tumor, or it has been damaged by a trauma or by the after-effects of facial paralysis. Although these causes are not uncommon, it can be difficult to identify the trigger.



Hemifacial spasm generally appears between the ages of 50 and 70 and is more common in women than in men.

Generally appears between the ages of 50 and 70

More common in women

Brain MRI to aid diagnosis

Last update 13/04/2017