What is Hemifacial Spasm?

Hemifacial spasm is a rare neuromuscular disorder characterized by irregular, involuntary muscle contractions (also known as twitching or “tics”) on one side of the face. The twitching is usually not painful, but it can be embarrassing and interfere with normal expression and vision.

This disorder is caused by injury to the facial nerve, a tumor or blood vessel compressing the nerve, or Bell's palsy (a form of temporary facial paralysis resulting from damage or trauma to the facial nerves). It occurs in both men and women but more frequently affects middle-aged or elderly women and is much more common in the Asian population.

Symptoms of Hemifacial Spasm

Hemifacial spasm typically begins as an intermittent twitching of the eyelid muscle, which can lead to forced closure of the eye. The spasm may then gradually spread to the muscles of the lower face, potentially pulling the mouth to one side. Eventually, the spasm may involve all of the muscles on one side of the face, almost continuously.


Your physician will begin with a careful review of your medical history and a complete neurological exam. Several tests may be performed, including electromyography (EMG, a test that measures and records electrical activity of muscles), magnetic resonance imaging (MRI, a test that uses magnetic waves to create images of structures inside the head), computed tomography (CT scan, a series of X-ray images taken from different angles to produce cross-sectional images), and angiography (an X-ray exam of the blood vessels when they are filled with a contrast material).

Treatment Options

The most common therapy to relieve hemifacial spasm is injections of botulinum toxin into the affected areas. Surgical treatment in the form of microvascular decompression, which relieves pressure on the facial nerve, may also eliminate hemifacial spasm.

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