What is Hemifacial Spasm? What Are Its Symptoms? How Is It Diagnosed and Treated?

Hemifacial spasm is a very rare condition that affects only about 1 in every 10,000 people in the population. Usually appearing in the 50s and more frequently in women, this disorder can cause involuntary contractions in the muscles on one side of your face.

If you are wondering what a spasm is, it is actually a neuromuscular disorder. In other words, it can be defined as the involuntary contraction of your muscles as a result of a disorder in the nervous system. Hemifacial spasm usually starts around the eye area initially, but as the disease progresses, it can spread to the lower half of your face, causing your mouth to pull to that side. This condition can affect your daily life, so it is important to know the diagnosis and treatment options.

In this article, we will discuss what hemifacial spasm is, its symptoms, why it occurs, and how it can be treated in a clear and understandable language. You will also be able to find answers to the questions you are curious about regarding this condition.

What is hemifacial spasm?

Hemifacial spasm is a neuromuscular disorder characterized by the involuntary contraction of the muscles on one side of the face. Also known as "tic convulsif", this condition manifests itself as uncontrolled twitching of the muscles on one side of the face. Although this disorder is usually painless, it can be quite bothersome in daily life and significantly affect a person's quality of life.

What is a spasm and how does it occur?

Spasm is a medical term used for the sudden and involuntary contraction of a muscle or muscle group. Normally, one of the most important features of muscles is voluntary control - meaning we can move or stop our muscles when we want to. However, in a spasm, this control is lost and the muscle contracts on its own.

Specifically in hemifacial spasm, there is irritation or irritation of the facial nerve in the region where it emerges from the brainstem. This condition usually occurs as a result of a small artery compressing the seventh nerve (facial nerve) in the brainstem. It usually starts as mild and intermittent twitches, but can become more frequent and severe over time.

The role of facial muscles and the facial nerve

All mimic muscles that form our facial expressions are controlled by the seventh cranial nerve, also known as the facial nerve. This nerve emerges from the brain and branches into the facial muscles, managing many important functions such as blinking, speaking, eating, and emotional expressions.

After emerging from the brainstem, the facial nerve enters the temporal bone via the internal acoustic canal and then reaches the facial muscles by passing through a special canal called the facial canal. Because it is longer and more tortuous than other nerves and passes through a narrow canal, it is more susceptible to damage. In hemifacial spasm, when the normal functioning of this nerve is disrupted, the facial muscles contract and twitch involuntarily.

Which age groups are more frequently affected?

Hemifacial spasm is a very rare condition seen in 1 out of every 10,000 people in the population. According to statistics, this disorder is generally more common in middle-aged and older individuals, especially in the 40-60 age range. In a study, the average age of patients was determined to be approximately 59.5.

Looking at the gender distribution, women are more likely to be affected by hemifacial spasm than men. Research has shown that approximately 69.2% of patients are women. In addition, it has been reported to be more common in Asians.

Hemifacial spasm usually affects one side of the face (hemi means "half", facial means "face"), but in some cases it can be bilateral. In a study conducted, it was determined that symptoms were seen on the left side in 52.9% of the patients.

What causes hemifacial spasm?

There can be various reasons behind hemifacial spasm, which occurs as a result of abnormal activity of the facial nerve. Let's examine the factors leading to this disorder in more detail.

Neurovascular compression (vessel compression)

The most common cause of hemifacial spasm is the compression of a blood vessel on the facial nerve in the brainstem. This condition is medically called "neurovascular compression". When the facial nerve emerging from the brainstem is compressed, usually by an artery, irritation and abnormal signals occur in the nerve. The vascular structures most frequently responsible for this compression are the vertebral artery (59%), anterior inferior cerebellar artery (22.8%), posterior inferior cerebellar artery (13.7%), and basilar artery (4.5%), respectively.

Research has shown that vascular compression of the facial nerve is detected in 55% of hemifacial spasm patients. Interestingly, it has also been determined that this disorder is more common on the left side (75%) compared to the right side (25%).

In addition, hypertension has been detected in approximately 50% of hemifacial spasm patients. Some experts think that high blood pressure can lead to changes in the vertebrobasilar system and cause neurovascular compression.

Tumors and cysts

Tumors located in the brainstem or in the region where the facial nerve passes can cause hemifacial spasm by putting pressure on the nerve. Besides this, certain types of cysts can also lead to this disorder:

Arachnoid cysts: These are fluid-filled structures in the subarachnoid space and can sometimes grow and compress cranial nerves.

Epidermoid cysts: These are benign tumors frequently seen around the facial nerve, and although they grow slowly, they can compress the nerve.

Since tumors do not have a pulse like arteries and grow more slowly, they less frequently cause hemifacial spasm.

Multiple sclerosis and other neurological diseases

Multiple sclerosis (MS) is a disease characterized by the loss of the myelin coating of nerve fibers in the brain. If there is demyelination in the facial nerve, there is a possibility of developing hemifacial spasm.

However, the following diseases can also cause hemifacial spasm:

Structural anomalies of the posterior fossa (Chiari malformation)

Infections (otitis, meningitis)

Cerebellopontine angle tumors

Stroke (in the brainstem region)

Parkinson's disease

Conditions developing after a history of facial paralysis

During the recovery period of patients who have had facial paralysis, errors can sometimes occur during the regrowth of nerve fibers. This condition can lead to a disorder called "synkinesis". For example, nerve fibers that should normally go to the lip muscles may go to the eyelid, and this condition can cause involuntary movements such as blinking while speaking.

The most important difference between synkinesis and hemifacial spasm is that it begins a few months after a known facial paralysis. Although these conditions developing after facial paralysis are generally not as severe as hemifacial spasm, they can cause prominent complaints in some patients.

In summary, hemifacial spasm can stem from various causes, but its most common cause is the compression of a vessel on the facial nerve in the brainstem. Evaluating these causes in detail is important for an accurate diagnosis.

What are the symptoms of hemifacial spasm?

The most distinctive feature of hemifacial spasm is involuntary contractions occurring on only one side of your face. These symptoms can seriously affect your daily life and generally worsen in situations of stress, fatigue, or excitement.

Involuntary contractions in the eyelid

Hemifacial spasm usually first manifests itself with mild twitches in your eyelid. These contractions can become severe over time, leading to the complete closure of your eye. This condition is medically called "blepharospasm". Unlike normal eye twitches, eye contractions in hemifacial spasm are much more severe and can be powerful enough to cause complete closure of the eye. Especially these involuntary movements in the eyelid are considered an early symptom of the disease and can spread to other areas of the face in later periods.

Twitching in the mouth and jaw area

After contractions in the eyelid, the disorder generally progresses to the mouth and jaw area. Twitches in the cheeks and involuntary movements at the corner of the mouth can be observed. These contractions can be triggered during speech, smiling, or emotional expressions and can cause your mouth to pull to the side on that side of your face. As the disease progresses, contractions can begin all over your face and become constant.

Pain behind the ear and hearing changes

Pain behind the ear and hearing changes can also be seen in some patients. The reason for this is that parts of the facial nerve related to hearing function are also affected. Auditory abnormalities such as mild hearing loss, clicking in the ear, or tinnitus can generally be seen in hemifacial spasm patients.

Spasms continuing during sleep

One of the most distinctive features of hemifacial spasm symptoms is that the spasms continue during sleep. This feature helps distinguish hemifacial spasm from other facial region disorders, especially trigeminal neuralgia. The fact that muscles continue to contract even during sleep is an important indicator that this condition originates from the nervous system.

Facial asymmetry and functional blindness

Long-term hemifacial spasm can cause permanent asymmetry in your face. In addition, the long-term closure of your eye as a result of continuous contraction of the muscles around the eye can lead to a condition called "functional blindness", which severely restricts your daily activities. This condition, especially in severe cases, can significantly reduce patients' quality of life.

Hemifacial spasm symptoms are generally painless but quite bothersome. They can appear at unexpected times and can become even more severe in stressful situations. Therefore, it is important to consult a neurology specialist when you notice these symptoms.

How is hemifacial spasm diagnosed?

Doctors use various methods to determine the cause of involuntary movements in your facial muscles. Hemifacial spasm diagnosis usually starts with a clinical evaluation, but a few different tests may be required to determine the underlying cause.

Physical examination and patient history

The first step in diagnosing hemifacial spasm is a comprehensive physical examination and obtaining your patient history. Your doctor gathers detailed information about the onset, duration of symptoms, and previous facial injuries. They also inquire about your family health history. During the physical examination, your facial muscles and nerve functions are carefully evaluated. The characteristic tic of the disease is usually diagnostic. This method is sufficient for diagnosing hemifacial spasm in most cases.

During the neurological examination, your reflexes, muscle strength, and sensory functions are also evaluated. In hemifacial spasm, there are irregular, uncontrolled twitches on one half of the face, usually triggered by speaking, smiling, or emotional expressions. These twitches are so typical that making a diagnosis is quite simple for an experienced clinician.

Magnetic Resonance Imaging (MRI)

Your doctor will usually request Magnetic Resonance Imaging (MRI) to confirm the diagnosis and determine the cause of hemifacial spasm. MRI helps detect abnormalities by examining the structures around the brainstem and facial nerve. Especially thin-slice 3D MRI imaging is the most important testing method to see small blood vessels touching the facial nerve.

However, studies have shown that MRI results were normal in 53.8% of patients. Therefore, not being able to see the vessel on MRI does not completely eliminate the possibility of vascular compression. As a result of MRI imaging, periventricular white matter hyperintensities were detected in 38.5% of patients and a dolichoectatic basilar artery in 3.8%.

Electromyography (EMG)

Electromyography (EMG) is a test that measures the electrical activity of your facial muscles. This test can help confirm the diagnosis of hemifacial spasm and ensures it is distinguished from other muscle diseases. EMG can show pathognomonic findings that can make significant contributions to the diagnosis, especially in atypical cases.

Differential diagnosis: tic, dystonia, blepharospasm

Hemifacial spasm symptoms can be mimicked by many different conditions, so differential diagnosis is important for accurate diagnosis. Your doctor will evaluate to rule out the following conditions:

Bell's Palsy: Sudden weakness or paralysis in facial muscles

Facial tics: Involuntary muscle contractions that are usually triggered by stress

Blepharospasm: A disorder proceeding with contractions in both eyelids

Oromandibular dystonia: Involuntary contractions in mouth, jaw, and tongue muscles

The distinction between blepharospasm and hemifacial spasm is particularly very important, because blepharospasm patients do not benefit from surgical treatment. Other differential diagnoses also include facial myoklonus, hemimasticatory spasm, and psychogenic hemifacial spasm.

How is hemifacial spasm treated?

There are several different approaches for the effective treatment of hemifacial spasm. Treatment options include drug therapy, botulinum toxin injections, and surgical intervention. Which treatment will be applied may vary depending on the severity of your disorder and the underlying cause.

Drug therapy and its effects

Regrettably, there is no effective drug therapy for hemifacial spasm. However, muscle relaxants and drugs used in trigeminal neuralgia can be tried in some cases, but their benefits are quite limited. Drugs such as pregabalin and clonazepam can alleviate symptoms in some patients by calming the nervous system, but in most cases, these drugs are not sufficiently effective.

Botulinum toxin (Botox) application

Botulinum toxin (Botox) is a frequently used treatment option in the management of hemifacial spasm. In this method, small amounts of toxin are injected into the affected facial muscles. Botox temporarily blocks the nerve transmission causing contractions and thus reduces the intensity of spasms. Many patients state that they can control their face more comfortably and their social life improves after this application.

The effect of Botox treatment generally lasts for 3-6 months and needs to be repeated regularly. When applied at the correct dose to the appropriate muscles around the face and eyes, it allows patients to have a quite comfortable period. However, it is important to remember that it is not a permanent solution.

Microvascular decompression surgery

The most effective and permanent treatment for hemifacial spasm is microvascular decompression surgery. In this surgical procedure, a small incision is made behind the ear to reach the root of the fifth cranial nerve. Vessels compressing the nerve are identified and moved away from the nerve. A Teflon-like polytetrafluoroethylene (PTFE) pad is placed in between to prevent the vessel from touching the nerve again.

The success rate of this surgery is quite high and reaches up to 92% today. The effect of the surgery is usually seen immediately, and patients mostly notice that the contractions on their face have passed before being discharged.

Post-treatment recovery process and complications

The recovery process after microvascular decompression surgery is usually fast. Some patients may feel a slight weakness in their face after surgery, but this condition is mostly temporary. As with any surgical procedure, there is a risk of infection, cerebrospinal fluid leakage, and the possibility of not benefiting from the surgery, but these risks are quite low.

One of the most serious complications is hearing loss on the operated side, and this rate has been reported in the literature as approximately 4%. The risk of death is quite rare. The complication rate in microvascular decompression procedures performed by experienced surgeons is below 1%.

In conclusion, the most effective method in hemifacial spasm treatment is microvascular decompression surgery. Nevertheless, Botox treatment offers a good alternative for patients who do not want surgery or are not suitable for surgery.

7 Frequently Asked Questions

We have compiled some important questions that patients wonder about and their answers. This information will help you gain a better understanding of your condition.

1. Is hemifacial spasm permanent?

When left untreated, hemifacial spasm can worsen over time. While Botox applications provide temporary relief, microvascular decompression surgery can offer a permanent solution. After the surgical procedure, a large portion of patients completely recover from their spasms or experience a significant reduction.

1. How long does Botox treatment last?

The effect of Botox treatment generally lasts for 3-6 months and then it needs to be applied again. The treatment effect starts about a week after injection. When applied at appropriate doses to your facial muscles, it allows you to spend a quite comfortable period during this time.

1. Is surgery risky?

As with any surgical procedure, microvascular decompression carries some risks. The most serious complication is hearing loss on the operated side, and this rate is approximately 4%. However, when performed by surgeons who are experts in their subject, the mortality rate is close to 0%. Complication rates are quite low in experienced teams.

1. In which cases is surgery recommended?

Surgical intervention is generally recommended when other treatment methods remain insufficient. When Botox treatment is not effective or when being uncomfortable with its continuous repetition, surgery can be an option. In addition, surgery is generally recommended in young patients because it is a permanent solution.

1. Can spasms be bilateral?

Hemifacial spasm usually affects one side of the face. However, in severe cases, it can rarely be bilateral as well. Bilateral spasms can create difficulty in terms of diagnosis. It generally develops in the form of starting on one side and then spreading to the other side.

1. Is hemifacial spasm psychological?

No. Patients often encounter the misconception that their condition is psychological, but hemifacial spasm is a physical condition that occurs as a result of the facial nerve emerging from the brainstem remaining under vessel compression. Although it can lead to psychological distress when left untreated, its origin is neurological.

1. What happens if it is not treated?

Untreated hemifacial spasm can progress over time and cause contractions in the entire half of the face. In advanced cases, complications such as social isolation, psychological distress, and muscle atrophy can be seen. In addition, when nerve fibers responsible for tear production are affected, dry eye syndrome and even permanent vision loss can occur.

Conclusion

In conclusion, hemifacial spasm is a rare condition that significantly affects quality of life. This disorder, which manifests as involuntary contractions on one side of the face, is usually caused by a vessel compressing the facial nerve in the brainstem. Although it starts with twitches in the eyelid initially, it can progress towards the lower part of the face over time and make your daily life difficult.

Undoubtedly, accurate diagnosis is the first step in treating this disorder. Your doctor will perform a physical examination and try to determine the underlying cause using methods such as MRI imaging. Among treatment options, botulinum toxin injections provide temporary relief, while microvascular decompression surgery offers a more permanent solution.

It is important to remember that when left untreated, hemifacial spasm can worsen over time and lead to psychological distress. Therefore, it is advisable to consult a neurology specialist when you notice recurring twitches in your face.

Beyond all these, thanks to advanced diagnostic and treatment methods today, the vast majority of hemifacial spasm patients can return to their normal lives. High success rates, especially in microvascular decompression surgery, give hope to patients. Early diagnosis and an appropriate treatment approach are the key to minimizing the effects of this disorder.

Hemifacial spasm is a rare condition characterized by involuntary contraction of facial muscles. Discover symptoms, causes, and treatment options in this article.