What Is Hemifacial Spasm?

woman touching her face after a hemifacial spasm

Hemifacial spasm is a rare nervous system disorder that causes muscles on one side of the face to twitch involuntarily. The muscle contractions typically aren’t painful but can be embarrassing and interfere with vision. 

Anyone can develop hemifacial spasm, but it’s more common in women over 40. The condition typically starts with sporadic events but worsens over several months to years until the spasms occur almost constantly.  

There is no cure for hemifacial spasm, but medications or surgery can provide relief. 

What Causes Hemifacial Spasm?

The most common cause of this type of facial spasm is a blood vessel (the anterior inferior cerebellar artery) pressing on the seventh cranial nerve, causing it to misfire. This nerve subdivides into five branches that control muscles that move the lips and mouth, close the eyes, and move the eyebrows. 

Other causes include Bell’s palsy and pressure on the seventh cranial nerve from a tumor. 

Hemifacial spasm most often starts near the eye and expands to other areas of the face. Less often, the condition starts at the chin and progresses upward on the face. 

Is Lip Twitching a Sign of Hemifacial Spasm?

It’s common for muscles in the lips and around the body to twitch now and then. Twitching can be a sign of a medical condition, but if it’s minor and infrequent, it generally isn’t cause for concern. Getting too much caffeine, taking certain medications, experiencing high stress levels, and other stimuli can cause muscle twitches. 

How Do Doctors Diagnose Hemifacial Spasm?

If you suspect you may have hemifacial spasm, your doctor will take a medical history and perform a physical exam. They may also order an imaging scan called an MRI to determine if pressure from a blood vessel is causing the condition or if another medical issue like a brain tumor or aneurysm is at fault for random spasms on your face. 

In addition, your doctor may order an electromyogram (EMG) in conjunction with a nerve conduction velocity (NCV) study. These tests measure electrical activity in your facial muscles and nerves. 

How Is Hemifacial Spasm Treated?

The three main treatments for this condition are:

  • Medications. Anticonvulsant drugs can keep the affected nerve from firing randomly. These medications may be used in combination with muscle relaxants. This therapy can be successful, particularly with mild cases, but there are side effects, including nausea, skin rash, unsteadiness, and dependence.
  • Botulinum toxin (Botox) injections. Botox is a bacteria-produced substance that paralyzes muscles by blocking electrical signals to them. Botox injections for hemifacial spasm have an effect within three days and last approximately three months. Patients can receive these injections indefinitely, but their effectiveness declines over time. Side effects include temporary weakness in affected muscles, eye irritation, eyelid drooping, and sensitivity. 
  • Surgery. If medications and injections don’t control the spasms, a surgeon can perform a microvascular decompression (MVD). It involves making a hole at the back of the skull and inserting a Teflon sponge between the blood vessel causing the problem and the facial nerve. This surgery, like all surgeries, has risks. There are also potential side effects like facial muscle weakness and decreased hearing. 

Learn More About Hemifacial Spasm from Baptist Health

If you experience facial twitching that concerns you, contact your doctor. They can do testing to determine the cause and may refer you to a neurologist for specialized care.