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What is Sleep Myoclonus?
The clinical term for a sudden, involuntary muscle contraction at any time is myoclonus (see “Types of Myoclonus” sidebar below). Twitching while sleeping is called sleep myoclonus. It may be so mild that you and your bed partner are unaware it’s happening. But it can also be a big enough movement—and occur often enough at night—that your bed partner notices it.
Why Do People Twitch in Their Sleep?
The cause of myoclonus isn’t completely understood, though researchers believe it may be due to an excessive reaction by the part of the brain that control muscle movement. This overreaction could be triggered by light, sound or other stimuli during sleep.
Not all examples of twitching while sleeping are myoclonus. In some cases, the movement is simply a muscle spasm. Leg cramps and spasms at night are actually somewhat common. A muscle spasm can be caused by muscle fatigue.
The possible causes of twitching while sleeping are almost endless, in fact. Nerve damage from cancer treatment can lead to involuntary muscle movement. So can diabetes, arthritis, and thyroid disease. Peripheral artery disease (PAD), a condition characterized by narrowed blood vessels in the legs, can sometimes cause nighttime leg twitches. Even pregnancy can trigger twitching while sleeping.
Sleep-Related Conditions That Cause Twitching
While involuntary muscle spasms and movements may be due to any number of conditions, two sleep-related health issues are at the root of many nighttime twitches. These include periodic limb movement disorder (PLMD) and restless leg syndrome (RLS).
PLMD may be related to issues with your nervous system; research, however, has yet to find that it indicates any serious abnormalities. PLMD isn’t considered a serious health problem unless it’s contributing to insomnia and daytime sleepiness. Yet PLMD may sometimes indicate a condition such as anemia or diabetes.
RLS is a more serious neurological disorder. People with RLS get an uncomfortable feeling—usually in the legs—that can sometimes be relieved by moving their muscles. But RLS includes more than twitching while sleeping. If you have RLS, you may have the urge to move your legs even while you’re sitting down. Unfortunately, RLS symptoms are triggered by lying down and trying to rest, so it can keep people from falling asleep. PLMD is actually a symptom experienced by many people with RLS.
Twitching While Sleeping: Prevention and Treatment
If you’re twitching while sleeping, and it’s because of PLMD or RLS, you may be prescribed medications to control your symptoms. These can include dopaminergic agents, such as carbidopa/levodopa (Sinemet), which is used to treat Parkinson’s disease. Other drugs include benzodiazepines such as diazepam (Valium). These drugs are usually recommended for short-term use only, however.
If you’re looking for techniques to prevent you from twitching in your sleep that don’t involve powerful medications, you may want to try a few other steps first. For example, try going to bed without any caffeine in your system. Your muscle movements may or may not be triggered by that extra cup of coffee earlier in the day. But caffeine is associated with PLMD, so try an experiment. Avoid caffeine for several days and see how it affects your sleep and any twitching while sleeping. (See also “Do I Have a Caffeine Addiction?“)
While you’re skipping caffeine, don’t skip exercise. Research suggests that physical activity during the day may help your twitching muscles stay a little more inactive while you sleep. Whether it’s one intense workout during the day or a lot of walking and other activity throughout the day (which is optimal), exercise may be your key to reducing nighttime twitching.
Other potentially helpful sleeping techniques include sticking to a regular schedule of bedtime and wake-up time. This is just good sleep hygiene. If you can stick to a regular seven-nights-a-week routine, you may find that twitching while sleeping and other sleep problems recede. Further, a hot bath may help relax your muscles so they don’t twitch. And a gentle leg massage is also recommended before bedtime.
TYPES OF MYOCLONUS
Under the umbrella term “myoclonus”—the condition that causes jerking or twitching while sleeping—there are a number of forms. The causes and effects for each are different, and responses to each can vary widely. According to the National Institute of Neurological Disorders and Stroke (NINDS), these are the most commonly described:
- Action myoclonus: “Characterized by muscular jerking triggered or intensified by voluntary movement or even the intention to move,” the NINDS reports. “Action myoclonus is the most disabling form of myoclonus and can affect the arms, legs, face, and even the voice. This type of myoclonus often is caused by brain damage that results from a lack of oxygen and blood flow to the brain when breathing or heartbeat is temporarily stopped.”
- Cortical reflex myoclonus: May be a type of epilepsy, one that originates in the cerebral cortex. “In this type of myoclonus, jerks usually involve only a few muscles in one part of the body, but jerks involving many muscles also may occur.”
- Essential myoclonus: Tends to be “stable without increasing in severity over time,” the NINDS says, adding that essential myoclonus “occurs in the absence of epilepsy or other apparent abnormalities in the brain or nerves.” It may be an inherited disorder but can also crop up randomly in people with no family history.
- Palatal myoclonus: Occurs in one or both sides of the rear of the roof of the mouth (the soft palate) as regular, rhythmic contractions. Palatal myoclonus contractions may be accompanied by twitching in other muscles, including those in the face, tongue, throat, and diaphragm. “The contractions are very rapid, occurring as often as 150 times a minute,” the NINDS explains, “and may persist during sleep. The condition usually appears in adults and can last indefinitely.” It can appear as “clicking” sounds, and can also cause severe pain in some people.
- Progressive myoclonus epilepsy (PME): Refers to a group of diseases characterized by myoclonus, epileptic seizures, and other serious symptoms (difficultly speaking or walking, for example). “These rare disorders often get worse over time,” the NNDS reports, “and sometimes are fatal.” PME has been linked to an abnormality in the gene that codes for the protein cystitis B, which regulates enzymes that break down other proteins.
- Reticular reflex myoclonus: Believed to be a form of generalized epilepsy originating in the brain stem, which connects to the spinal cord and controls such vital functions as our heartbeat and our breathing. Voluntary movement or external stimuli can trigger reticular reflex myoclonus.
- Stimulus-sensitive myoclonus: A variety of sources—light, noise, movement—can trigger this form of myoclonus.
- Sleep myoclonus: Can occur during the first phases of sleep, and can be stimulus-sensitive. Sleep myoclonus may not require treatment for some, but myoclonus “may be a symptom in more complex and disturbing sleep disorders, such as restless legs syndrome,” the NINDS says. If so, it may require treatment by your healthcare provider.
Originally published in 2016, this post is regularly updated.