Hemifacial spasm is a neuromuscular disorder that causes frequent involuntary contractions to occur in the muscles on one side of the face.

Hemifacial spasm is believed to be due in part to compression of the facial nerve where it meets the brainstem. The compression can be cause by:

• A blood vessel pressing on the facial nerve (most frequent cause)
• Tumor
• Facial nerve injury
• Bony or other abnormalities that compress the nerve

Facial Nerve Innervation

The following factor increases your chance of developing hemifacial spasm:

• Being a middle-aged or elderly woman
• Hypertension

• Intermittent twitching of the eyelid muscle
• Forced closure of the eye
• Spasms of the muscles of the lower face
• Mouth pulled to one side
• Continuous spasms involving all the muscles on one side of the face

Your doctor will ask about your symptoms and medical history, and perform a physical exam. Tests may include the following:

• Electromyography (EMG) —a test that measures and records electrical activity generated in muscle at rest and in response to muscle contraction
• Magnetic resonance imaging (MRI) —a test that uses magnetic waves to make pictures of structures inside the head
• Computed tomography (CT) scan —a type of x-ray that uses a computer to make pictures of structures inside the head
• Angiography —an x-ray exam of the blood vessels when they are filled with a contrast material

Hemifacial spasm is usually a chronic condition. Remission of symptoms, although possible, has only been noted to occur in less than 10% of patients.

Talk with your doctor about the best treatment plan for you. Treatment options include:

• Carbamazepine—This is often used initially, with improvement in symptoms in up to half of patients who are treated.
  • According to the Food and Drug Administration (FDA), patients of Asian ancestry who have a certain gene, called HLA-B*1502, and take carbamazepine are at risk for dangerous or even fatal skin reactions. If you are of Asian descent, the FDA recommends that you get tested for this gene before taking carbamazepine. If you have been taking this medication for a few months with no skin reactions, then you are at low risk of developing these reactions. Talk to your doctor before stopping this medication.
• Gabapentin and baclofen—These may also be beneficial for treating hemifacial spasm in some patients.

Injecting botulinum toxin (ie, Botox) into the affected muscles can stop eyelid spasm for several months. However, these injections must be repeated, usually several times a year.

Microvascular decompression surgery repositions the blood vessel away from the nerve. This is successful in cases of hemifacial spasm where the cause is suspected to be a blood vessel compressing the facial nerve.