Symptoms of Hemifacial Spasm

Hemifacial spasm is a cranial nerve hyperactivity disorder that causes involuntary contractions of the facial muscles on one side of the face. Symptoms often overlap with other movement disorders involving the face and can be misdiagnosed.

The spasms typically start around the eye and eventually affect other facial muscles, causing various degrees of discomfort. Over time, these movements can spread to other muscles in the face, including those involved in smiling, frowning, and raising the eyebrows. The contractions might become more frequent and severe, making it difficult to perform normal facial expressions or even talk. In severe cases, these contractions can spread to the neck muscles.

Hemifacial spasm symptoms are caused by compression or irritation of the facial nerve, which controls the muscles on one side of the face. The facial nerve is a complex nerve that is responsible for a range of functions, including facial expressions, taste, and tear production. The facial nerve exits the skull at the base of the brain, travelling through a small opening to reach the face. Any pressure or irritation on the facial nerve can cause it to malfunction, which can lead to involuntary muscle contractions.

Because our facial muscles are used in many aspects of our day, something as simple as enjoying a cup of coffee in the morning can become challenging with this disorder. In this article, we discuss the various symptoms of hemifacial spasm and provide answers to common questions that patients might have.

To start, let’s look at a list of common symptoms associated with hemifacial spasm and characteristics of the spasms themselves. Many of these symptoms can mimic other movement disorders involving the face. The following are a few of the possible symptoms and qualities of hemifacial spasms.

• Painless involuntary twitching near the eye on one side of the face.
• Twitching that progresses to other facial muscles.
• Impaired vision.
• Hearing changes (a “ticking” sound might be heard on the affected side).
• Spasms that persist during sleep.

These symptoms can develop gradually over time or appear suddenly. In some cases, the symptoms might start with mild twitching or facial spasms that are not noticeable. Over time, the spasms can become more frequent and severe, making it difficult to perform normal facial expressions. The onset of symptoms can be triggered or intensified by a variety of factors, including stress, fatigue, and caffeine intake.

The following are answers to some of the most common questions regarding hemifacial spasm symptoms.

Most of the time, hemifacial spasms occur as a result of the facial nerve being compressed or contacted by a blood vessel at the level of the brainstem. The facial nerve, also known as cranial nerve VII, is responsible for the movement of facial muscles and courses from its origin near the brainstem to the muscles of the face. We have a left and right facial nerve that controls the facial muscles on each side.

The pressure of the neighboring blood vessel can irritate the facial nerve and ultimately lead to the involuntary twitching associated with this condition. The facial nerve is also responsible for movement of a small muscle in the ear called the stapedius muscle. Contraction of this muscle can cause a “ticking” noise on the affected side.

Other possible but less common causes of hemifacial spasm include compression of the facial nerve from a tumor and viral inflammation of the facial nerve from a condition such as Bell’s palsy. In some cases, no specific cause can be found.

Hemifacial spasms often begin near the muscles around the eye and result in involuntary eye closure or squinting, making it difficult to see. The twitching can gradually expand to other facial muscles on the same side, such as those near the mouth. The development of hemifacial spasms is typically slow, although in some patients, the spasms can become severe in just a few months.

Over time, severe contractions of all facial muscles on the involved side can pull the corners of the eye and mouth into a grimace, which can cause significant stress and embarrassment. The spasms can be emotionally, psychologically, and economically disabling by interfering with daily life, activities of enjoyment, and work.

On average, patients suffer from hemifacial spasms for around 8 years before they receive treatment. Although hemifacial spasm usually involves only one side, 2% of patients experience spasms on both sides of their face. This condition occurs more commonly in adults during the fourth and fifth decades of life and affects twice as many women than men. If hemifacial spasms occur in a younger person, it could rarely be an indication of another neurological condition (for example, multiple sclerosis).

A rare neurological disorder that is similar to hemifacial spasm is facial myokymia. However, unlike the sharp intermittent contractions of hemifacial spasms, facial myokymia presents with subtle continuous contractions of the facial muscles typically involving the entire side of the face. These twitches can appear like flickering waves or worm-like movements under the skin that can be difficult to notice unless observing the face up close.

Patients with facial myokymia might feel like the side of the face affected is swollen or stiff. This stiffness can interfere with creating facial expressions. Unlike hemifacial spasms, facial myokymia can resolve on its own after a few weeks to months. Both hemifacial spasms and facial myokymia can be symptoms of multiple sclerosis or a brain tumor.

Although COVID-19 is associated predominantly with respiratory symptoms, eye twitching and facial spasms have also been reported. However, eye twitching can also be caused by caffeine, allergies, eye strain, stress, or dry eyes. The connection between hemifacial spasm and COVID-19 is currently unclear. The more common neurological symptoms associated with COVID-19 include the following:

• Loss of taste and/or smell
• Difficulty concentrating
• Fatigue
• Headaches

It is a common misconception that COVID-19 vaccines can cause facial paralysis or muscle twitching. Although these symptoms were reported in a few people during the vaccination trials, the frequency of this condition was within the expected rate for the general population.

• Symptoms of hemifacial spasm arise mainly from compression of the facial nerve by a blood vessel at the level of the brainstem.
• Understanding the signs and symptoms of hemifacial spasms is essential for proper and timely diagnosis.
• Hemifacial spasms can resemble other movement disorders of the face such as facial myokymia; however, each condition is its own distinct entity and presents with unique spasm characteristics.

• American Association of Neuromuscular & Electrodiagnostic Medicine
• National Institute of Neurological Disorders and Stroke