What is a Hemifacial Spasm?

Hemifacial spasm is a rare neuromuscular disorder that causes the muscles on one side of a person’s face to spasm, tic or twitch. In some cases, these spasms may be mild or nearly unnoticeable. In severe cases, hemifacial spasms can cause embarrassment and disruption of daily life.

While the tics associated with hemifacial spasm can be disruptive, they are usually not painful. They can occur at any time of the day and may even continue while a person is sleeping.

The condition is incredibly rare, affecting only 11 in every 100,000 people. Anyone can develop hemifacial spasm, but it is most common among those of Asian descent and in middle-aged or elderly women.

While researchers are not entirely certain what causes hemifacial spasm, it is believed to result from something irritating the facial nerve. This irritation can come from a variety of sources, including a vein putting pressure on the facial nerve, hereditary defects, a tumor pressing on the facial nerve, or injuries to the facial nerve.

In some cases, hemifacial spasm can be an early symptom of multiple sclerosis, though this is uncommon.

The seventh cranial nerve supplies the muscles to the face. In hemifacial spasm there can be compression of the nerve by an artery, which can irritate the nerve and make it hyperactive. Patients can get uncontrolled spams and twitching of the facial muscles on the side of the nerve being affected. Treatment options include Botox to temporarily relax the facial muscles.

Surgical option includes microvascular decompression, much like the approach for trigeminal neuralgia, in which a small piece of synthetic material is placed between the nerve and the offending artery.