Hemifacial spasm

Date Updated: 10/31/2025

Overview

Hemifacial spasm is a nervous system condition that causes muscles on one side of the face to twitch or spasm. You cannot control hemifacial spasms. They usually start around one eye and may spread on that side of the face. The most common cause is a blood vessel pressing on the facial nerve. Sometimes there is no known cause. While hemifacial spasms are not life-threatening, they can be uncomfortable and affect social interaction.

Symptoms

Hemifacial spasms also are called muscle movements or contractions. These spasms often start in one eyelid. They might move to the cheek and mouth on the same side of the face. First, hemifacial spasms come and go. But over months to years, they occur almost all the time. How quickly they spread and how often they happen may be different for everyone.

Common symptoms of hemifacial spasm are usually painless but may include muscle movements:

On one side of the face.
That cannot be controlled.
That spread from the eye area to other areas on the same side of the face.
That happen more often over time.
That happen while you are sleeping.

Sometimes, hemifacial spasms occur on both sides of the face. However, they don't often occur on both sides of the face at the same time.

Certain things can increase hemifacial spasm symptoms, such as:

Moving the muscles in the face.
Anxiety.
Stress.
Being tired.

Causes

The most common cause of hemifacial spasms is a blood vessel touching a facial nerve. A tumor pressing against a facial nerve or a facial nerve injury also may cause them. Sometimes the cause isn't known.

Risk factors

Some studies show that these factors may increase the risk of hemifacial spasm:

High blood pressure, also called hypertension.
Age older than 40.
Being assigned female at birth.
Certain genes that give instructions to proteins that help carry cholesterol and other fats through the bloodstream, such as APOE e4.
Brain lesions or tumors, or conditions such as multiple sclerosis.
History of facial nerve injury or Bell's palsy.

Prevention

There is no known way to prevent hemifacial spasm. But managing stress, fatigue and anxiety may help lessen symptoms.

Diagnosis

Diagnosing hemifacial spasm typically starts with discussing your medical history. Your healthcare professional asks about your symptoms, including how long you've had them. Your healthcare professional also may perform physical and neurological exams to check muscle movement and look for other nerve issues.

You may have imaging tests such as magnetic resonance imaging (MRI). MRI uses a magnetic field and radio waves to create detailed images of the head. This can help show blood vessels pressing on the facial nerve. It also can show tumors or brain conditions.

Sometimes, you may have magnetic resonance angiography (MRA). During an MRA, a dye is put into the blood vessel to show whether it is touching the facial nerve.

Your healthcare professional may perform electromyography (EMG) though it's not commonly needed. An EMG measures electrical activity in the facial muscles. The test tells your care team whether nerves and muscles are sending and receiving signals as they should.

Diagnosing hemifacial spasm doesn't always need imaging tests. They are more likely if symptoms aren't typical or if your care team is planning surgery.

Treatment

Treatment for hemifacial spasm may include:

Oral medicines. Some medicines, such as antiseizure medicines and muscle relaxants, can relieve hemifacial spasm in some people. These medicines are used mainly in early or mild hemifacial spasms.
OnabotulinumtoxinA injections. A shot of onabotulinumtoxinA (Botox) into the affected muscles keeps the muscles from moving. This treatment needs to be repeated every few months to control spasms. It is the most common treatment and controls symptoms in most people.
Surgery. There are different types of surgery to help relieve hemifacial spasm. Studies have found that microvascular decompression (MVD) surgery is the most effective and long-term treatment. During MVD surgery, the surgeon makes an incision behind the ear to reach the brain. The surgeon places a small spongelike pad between the blood vessel and the facial nerve to relieve the pressure.

Recent research has found that endoscopic assistance may make the surgery more successful.

Other surgical treatments may include nerve massage, heat or high-frequency pulses of electricity to lessen feeling in affected nerves. Cutting or removing all or part of the nerve also may be an option. Radiofrequency thermocoagulation is another procedure that destroys parts of the facial nerve with heat and radio waves.
Acupuncture. Some studies have reported that acupuncture can treat symptoms of hemifacial spasm. More research is needed to learn about the effectiveness of this alternative medicine.