What Is Benign Fasciculation Syndrome?


Fasciculation is a long word for muscle twitch. It doesn’t hurt, and you can’t control it. It’s involuntary.

A type of fasciculation that most people are familiar with is twitching of the eyelid. It has its own names, including:

  • eyelid spasm
  • blepharospasm
  • myokymia

Fasciculations can be a symptom for many types of conditions. About 70 percent of healthy people have them. They’re rarely a sign of a serious neuromuscular disorder. However, because they’re a symptom of some devastating disorders, like amyotrophic lateral sclerosis (ALS), having fasciculations can be a sign that you should seek medical attention. Doctors usually evaluate them thoroughly.

Benign fasciculation syndrome is rare. People with benign fasciculation syndrome may have twitches of their:

  • eye
  • tongue
  • arms
  • thumb
  • feet
  • thighs
  • calves, which is particularly common

Some people also have muscle cramps with fasciculations. People with this condition are otherwise healthy. There’s no underlying disorder or neurological reason for these cramps and twitches. Still, the symptoms can be bothersome both physically and psychologically. If cramps are severe, they can interfere with daily activities like work and chores.

Benign fasciculation syndrome symptoms

The main symptom of benign fasciculation syndrome is persistent muscle twitching, tingling, or numbness. These symptoms happen when the muscle is resting. As soon as the muscle moves, the twitching stops.

The twitches occur most often in the thighs and calves, but they may occur in several parts of the body. Twitching may only be every now and then, or it may be almost all the time.

People often worry that fasciculations are related to a serious neuromuscular condition like ALS. It’s worth noting that fasciculations aren’t the only symptoms of ALS. In benign fasciculation syndrome, fasciculations are the main symptoms. In ALS, fasciculations are also accompanied by other problems such as worsening weakness, trouble gripping small objects, and difficulty walking, talking, or swallowing.

Causes of benign fasciculation syndrome

Benign fasciculation syndrome is thought to be due to overactivity of the nerves associated with the twitching muscle. The cause is often idiopathic, which means it’s unknown.

Some studies have shown some association between fasciculations and:

  • a stressful time
  • trauma
  • anxiety or depression
  • high-intensity, strenuous exercise
  • fatigue
  • drinking alcohol or caffeine
  • smoking cigarettes
  • a recent viral infection

They’re often linked to symptoms that are associated with stress, including:

Diagnosing benign fasciculation syndrome

Fasciculations can be symptoms of several health problems. A serious neuromuscular disorder isn’t usually the cause. Other more common causes can include sleep apnea, hyperthyroidism(overactive thyroid), and abnormal blood levels of calcium and phosphorous.

Still, fasciculations can be a sign of severely debilitating neuromuscular problems. For that reason, doctors are likely to evaluate them carefully.

A common way to evaluate muscle twitches is with electromyography (EMG). This test stimulates a nerve with a small amount of electricity. Then it records how the muscle responses.

Doctors may also evaluate overall health and risks for fasciculations with:

  • blood tests
  • other nerve tests
  • a thorough neurological exam, including tests of muscle strength
  • a thorough health history, including psychiatric problems, physical symptoms from stress, and quality-of-life concerns

Benign fasciculation disorder is diagnosed when fasciculations have been a frequent, main symptom and there is no other sign of a nerve or muscle disorder or other medical condition.

Benign fasciculation syndrome treatment

There is no treatment to reduce benign fasciculations. They can resolve on their own, especially if the trigger is discovered and eliminated. Some people have had relief with supplements that decrease the excitability of nerves, including:

  • magnesium
  • l theanine
  • Ashwagandha

Counseling may also help.  Cramps may be eased with stretching exercises and massage.

Doctors may try other treatments for severe muscular twitches that interfere with daily life.