What Is Myoclonus? A Plain-Language Guide to the Sudden Jerks, What Causes Them, and How They're Managed
Updated: 3 days ago
Medically reviewed by Dr. Baraa Alnahhal, MD · Last reviewed: October 2026
Quick Answer: Key Facts About Myoclonus
Myoclonus is a sudden, brief, shocklike muscle jerk that you cannot control. [1] Often it is normal, as with hiccups and jerks when falling asleep. [1] It is a concern when jerks are frequent, lasting or interfere with eating, speaking or walking. [1] Causes include genetics, epilepsy and conditions like kidney failure. [1] Treatment addresses the cause or uses medicines. [2]
Question | Answer |
What it is | A sudden, brief, shocklike muscle jerk you cannot control. [1] |
Is it normal? | Often yes — hiccups and sleep-start jerks are common, harmless forms. |
When to worry | When jerks are frequent, lasting, or interfere with eating, speaking, or walking. [1] |
What causes it | Healthy-body triggers, genetics, epilepsy, or an underlying condition like kidney failure, infection, or a medication reaction. [1] |
How it's treated | By addressing the underlying cause when possible; otherwise tranquilizers, antiseizure medicines, botulinum toxin injections, or sometimes surgery. [2] |
What the research says
Experts have recently rebuilt how myoclonus is classified. A Delphi consensus of 15 international myoclonus experts produced a two-axis system: clinical and neurophysiology features (Axis I) and cause (Axis II). In the first survey round, 53 of 56 items reached more than 60% agreement, and physiological myoclonus had the lowest agreement. The authors expect the shared system to help investigators find better diagnostics and treatments. (Latorre et al., Parkinsonism Relat Disord, 2025 [5])
Myoclonus can be disabling and treatment can be challenging, but new options are being studied. A 2024 review describes myoclonus as a common hyperkinetic movement disorder and stresses that correct classification guides the workup and treatment. It highlights newly recognized triggers, including SARS-CoV-2 infection and surgery or anesthesia of the spine, new genetic causes, and promising preliminary results with perampanel. (Thomas & Frucht, Curr Opin Neurol, 2024 [4])
What Is Myoclonus?
Myoclonus refers to a quick jerking movement that you can't stop from happening. The movement is sudden, brief, not voluntary, and shocklike. It can affect one part of the body or the whole body, and it can vary widely in how often it happens and how strong it is. [1]
Most people have experienced myoclonus without ever knowing the word for it. Hiccups are a form of myoclonus. So are the sudden jerks or "sleep starts" you may feel just before falling asleep. These movements occur in otherwise healthy people and usually aren't serious. [1]
Other forms, though, may be due to a nervous system condition such as epilepsy. Jerking movements can also result from a metabolic condition or a reaction to a medicine. [1]
What Does Myoclonus Feel Like?
People with myoclonus often describe its sudden movements as jerks, shakes or spasms. [1] These movements share a recognizable pattern:
Feature | What it looks like |
Timing | Sudden and brief — over in a flash |
Control | Not voluntary; you cannot stop it |
Sensation | Shocklike, like a jolt or zap in the muscle |
Pattern | Variable — frequency and severity change from person to person |
Location | One part of the body, or all over the body |
Impact | Sometimes serious enough to affect eating, speaking, or walking |
If your myoclonus symptoms become frequent and lasting, talk to your healthcare professional about a diagnosis and treatment options. [1]
What Are the Different Types of Myoclonus?
Myoclonus can appear in different patterns, and specialists group these patterns into types to help describe what the jerking movements look like and what may be causing them. Experts recently updated how myoclonus is grouped and described, giving care teams a clearer and more consistent way to talk about the condition and to choose tests and treatments. [1]
How Do Doctors Classify Myoclonus Now?
The updated approach looks at myoclonus from two angles. The first angle is what the jerking movements look like — where they happen on the body, what brings them on (movement, sound, touch, or rest), how strong or frequent they are, and what simple nerve and muscle tests show. [1] This helps the care team understand how the jerks are being generated in the nervous system.
The second angle is what is causing the jerks — genetic conditions, metabolic or chemical imbalances, infections or inflammation, or structural changes in the brain or spinal cord. [1]
Looking at both the features and the possible causes gives a clearer overall picture. You may not hear the technical terms during a visit, but the updated system helps the care team describe myoclonus in a more organized and consistent way behind the scenes.
What Are the Main Types?
Type | Plain-language meaning | Typical cause |
Physiological | Normal jerks in healthy people; rarely needs treatment | Everyday triggers — anxiety, exercise, sleep transitions |
Essential | Jerks that occur on their own, usually with no other symptoms | Often unknown; sometimes inherited |
Epileptic | Jerks that occur as part of epilepsy, a brain condition that causes seizures | Epilepsy |
Symptomatic (secondary) | Jerks caused by an underlying medical condition | Injury, infection, organ failure, medication reaction, brain disease |
What Causes Myoclonus?
Myoclonus can happen for many different reasons, and the cause shapes the treatment plan. Here is what each type looks like in detail.
Physiological Myoclonus
This type occurs in healthy people and rarely needs treatment. Examples include hiccups, sleep starts, shakes or spasms due to anxiety or exercise, and infant muscle twitching during sleep or after a feeding. [1]
Essential Myoclonus
Essential myoclonus occurs on its own, usually without other symptoms and without being related to an illness. The cause is often not known. [1] Sometimes essential myoclonus is passed down in families, known as a genetic trait. [1]
Epileptic Myoclonus
This type occurs as part of a brain condition that causes seizures, known as epilepsy. [1]
Symptomatic (Secondary) Myoclonus
Symptomatic myoclonus results from a medical condition. It is sometimes called secondary myoclonus. [1] The causes fall into two broad groups:
Cause group | Examples |
General medical causes | Head or spinal cord injury; infection, including COVID-19; kidney or liver failure; lipid storage disease; medicine reaction or chemical poisoning; long-term reduction in oxygen levels; autoimmune inflammatory conditions or metabolic conditions [1] |
Nervous system conditions | Stroke; brain tumor; Huntington's disease; Creutzfeldt-Jakob disease; Alzheimer's disease, frontotemporal dementia, or Lewy body dementia; Parkinson's disease; corticobasal degeneration; multiple system atrophy [1] |
Who Is at Higher Risk of Myoclonus?
Risk of myoclonus is higher in people who have nervous system conditions. This includes epilepsy, Parkinson's disease, and Huntington's disease, among others. [1] It also can occur in people with other conditions, such as an infection, a brain tumor, or a spinal cord injury. [1]
Risk factor | Why it raises risk |
Nervous system conditions (epilepsy, Parkinson's, Huntington's) | The jerks arise from how the affected nervous system misfires |
Infection | Inflammation can trigger abnormal nerve signaling |
Brain tumor | Pressure on brain structures can cause jerking |
Spinal cord injury | Disrupted signaling between brain and muscles |
Family history of essential myoclonus | The condition can run in families as a genetic trait |
Essential myoclonus can run in families, so your risk is higher if a family member has it. [1]
Can Myoclonus Be Harmless?
Yes — and this is worth repeating. Hiccups, sleep starts, anxiety- or exercise-related shakes, and infant twitching during sleep or after feeding are all forms of myoclonus that occur in healthy people and rarely need treatment. The key difference is not the word but the pattern: normal myoclonus is occasional and harmless, while jerks that become frequent and lasting, or that interfere with eating, speaking, or walking, deserve a medical evaluation.
How Is Myoclonus Diagnosed?
To diagnose myoclonus, your healthcare professional reviews your medical history and symptoms and gives you a physical exam. You may have tests to look for the cause of your symptoms, and imaging tests or nerve tests may also be needed. [2]
Test | What it does |
Laboratory tests (blood/urine) | Check for metabolic conditions, autoimmune diseases, diabetes, and kidney or liver disease; look for signs of toxins or medicines; genetic testing may also be recommended [2] |
EEG (electroencephalography) | Records the brain's electrical activity through electrodes on the scalp; activities like deep breathing, bright lights, or sounds may help find irregular electrical activity and where symptoms begin [2] |
EMG (electromyography) | Electrodes placed on multiple muscles record electrical activity at rest and when contracted, determining the pattern and origin of the jerks [2] |
Evoked potential studies | Measure electrical activity in the brain, brainstem, and spinal cord triggered by touch, sound, sight, and other stimuli [2] |
MRI | Uses a magnetic field and radio waves to check for structural changes or tumors inside the brain or spinal cord [2] |
How Is Myoclonus Treated?
Treatment works best if the cause can be addressed — for example, another condition, a medicine, or a toxin that is causing symptoms. [2] Most of the time, though, the cause can't be cured or eliminated. In that case, treatment is aimed at reducing symptoms, especially when they're disabling. [2]
An important fact to know: there are no medicines designed to treat myoclonus. Instead, treatments for other diseases may help relieve symptoms, and more than one medicine may be needed. [2]
Treatment approach | How it works |
Treat the cause | Focus on the underlying condition, medicine, or toxin producing the jerks |
Tranquilizers | Clonazepam (Klonopin) is the most common drug; side effects can include loss of coordination and drowsiness [2] |
Antiseizure medicines | Levetiracetam (Keppra, Spritam), valproic acid, zonisamide (Zonegran, Zonisade), and primidone (Mysoline) can reduce symptoms; piracetam is also effective but not available in the United States [2] |
Botulinum toxin injections | OnabotulinumtoxinA (Botox) blocks the chemical messenger that triggers muscle contractions, especially helpful when only a single area is affected [2] |
Surgery | An option when a brain or spinal cord tumor causes the symptoms; may also benefit people with myoclonus affecting the face or ear [2] |
Deep brain stimulation | Electrodes implanted in certain brain areas produce electrical signals to block the irregular impulses; still being studied for myoclonus [2] |
Medicine side effects vary: valproic acid may cause nausea, levetiracetam may cause fatigue and dizziness, and primidone may cause sedation and nausea. [2]
How Should I Prepare for a Doctor's Appointment?
You're likely to see your healthcare professional first, and you might then be referred to a specialist trained in nervous system conditions, called a neurologist. [2]
Here is what to bring with you: awareness of any pre-appointment restrictions (ask if there's anything you need to do in advance), a written list of your symptoms noting triggers and anything that makes them better, a list of all your medicines including vitamins and supplements with doses, and written questions for your healthcare professional. [2]
Some basic questions worth asking include: What's the most likely cause of my symptoms? Are there other possible causes? What kinds of tests do I need? Is my condition likely short term or long lasting? What is the best course of action? What are the alternatives? How can I best manage my other health conditions together with this? Are there any restrictions I need to follow? [2]
Your healthcare professional is likely to ask you questions too. Be ready to answer: When did you first start having symptoms? Do you have a history of seizures or other nervous system conditions? What medicines do you take? Have you taken illegal drugs or been exposed to chemicals? Do you have a family history of myoclonus or epilepsy? Have your symptoms been constant or do they come and go? How bad are your symptoms? Does anything improve or worsen them? [2]
In addition to the questions you've prepared, don't hesitate to ask questions during your appointment at any time that you don't understand something.
What is the bottom line on myoclonus?
Most myoclonus — the hiccups and sleep-start jerks everyone experiences — is normal and needs no treatment. But when jerks become frequent, lasting, or start interfering with daily life, they can signal an underlying condition that deserves a proper diagnosis. The good news is that today's doctors use an updated classification system to pinpoint both what the jerks look like and what's causing them, and there are multiple paths to reducing symptoms when they're disabling. If your myoclonus is no longer an occasional quirk, the next best step is a conversation with your healthcare professional.
Have sudden, frequent muscle jerks that won't slow down? Don't try to self-diagnose — a healthcare professional can trace the cause and build a plan. Book your appointment today and take the first step toward fewer jerks and more control.
Frequently Asked Questions
What is myoclonus in simple terms?
Myoclonus is a quick, sudden, shocklike jerking movement that you cannot stop from happening. It is brief, not voluntary, and can occur in one part of the body or all over. Everyday examples include hiccups and the little jerks people feel just before falling asleep.
Are hiccups and sleep jerks really myoclonus?
Yes. Hiccups and the sudden jerks or "sleep starts" felt just before falling asleep are forms of myoclonus. They occur in otherwise healthy people and usually aren't serious. Shakes from anxiety or exercise and infant muscle twitching during sleep or after feeding are also normal forms.
Is myoclonus the same thing as epilepsy?
No. Epilepsy is a brain condition that causes seizures, and one form of myoclonus — epileptic myoclonus — occurs as part of epilepsy. But most myoclonus is not epilepsy, and physiological and essential forms occur without any seizure disorder.
What causes myoclonus?
It depends on the type. Physiological myoclonus comes from everyday triggers like anxiety or exercise. Essential myoclonus happens on its own with an often-unknown cause. Epileptic myoclonus is tied to epilepsy. Symptomatic (secondary) myoclonus results from an underlying condition — head or spinal cord injury, infection (including COVID-19), kidney or liver failure, medicine reactions, stroke, brain tumors, or diseases such as Parkinson's or Huntington's.
Is myoclonus dangerous?
Not usually. Most forms in healthy people are harmless and rarely need treatment. However, myoclonus can sometimes be serious enough to affect how people eat, speak, or walk. Frequent and lasting symptoms should be evaluated by a healthcare professional.
Can myoclonus run in families?
Yes, essential myoclonus can be passed down in families as a genetic trait, and your risk is higher if a family member has it.
How is myoclonus diagnosed?
Doctors review your history and symptoms and perform a physical exam, then may order lab tests (blood or urine), an EEG to record brain electrical activity, an EMG to record muscle electrical activity, evoked potential studies, and an MRI to check for structural changes or tumors.
Is there a medicine made for myoclonus?
No. There are no medicines designed specifically to treat myoclonus, but treatments for other conditions — such as the tranquilizer clonazepam or antiseizure medicines like levetiracetam and valproic acid — often help reduce symptoms, and more than one medicine may be needed. Botulinum toxin injections, and sometimes surgery or deep brain stimulation, are options for specific situations.
Related Reading
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References
Mayo Clinic Staff. Myoclonus: Symptoms & causes. Mayo Clinic. August 11, 2026. https://www.mayoclinic.org/diseases-conditions/myoclonus/symptoms-causes/syc-20350459
Mayo Clinic Staff. Myoclonus: Diagnosis & treatment. Mayo Clinic. August 11, 2026. https://www.mayoclinic.org/diseases-conditions/myoclonus/diagnosis-treatment/drc-20350462
National Institute of Neurological Disorders and Stroke. Myoclonus. National Institute of Neurological Disorders and Stroke. Publication date March 2021. https://www.ninds.nih.gov/publications/myoclonus
Thomas B, Frucht SJ. Myoclonus: an update. Curr Opin Neurol. 2024;37(4):421-425. PMID 38785158. https://doi.org/10.1097/WCO.0000000000001276
Latorre A, van der Veen S, Pena A, et al. IAPRD new consensus classification of myoclonus. Parkinsonism Relat Disord. 2025;132:107216. PMID 39665962. https://doi.org/10.1016/j.parkreldis.2024.107216
Medical disclaimer
This article is for general informational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read here. If you are experiencing medical emergency symptoms, call your local emergency number immediately.
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