Myoclonus refers to a quick, involuntary muscle jerk. For example, hiccups are a form of myoclonus. So are the sudden jerks, or "sleep starts," you may experience just before falling asleep. These forms of myoclonus occur in healthy people and rarely present a problem.
Most often, myoclonus occurs as a result of a nervous system (neurological) disorder, such as epilepsy, or of a metabolic condition, or as a reaction to a medication.
Ideally, treating the underlying cause will help control your myoclonus symptoms. If the cause of myoclonus is unknown or can't be specifically treated, then treatment focuses on reducing the effects of myoclonus on your quality of life.
People with myoclonus often describe their signs and symptoms as jerks, shakes or spasms that are:
When to see a doctor
Myoclonus may be caused by a variety of underlying problems. Doctors often separate the types of myoclonus based on their causes, which helps determine treatment. Types of myoclonus include the following categories.
Symptomatic (secondary) myoclonus
Nervous conditions that result in secondary myoclonus include:
Preparing for your appointment
You'll probably first discuss your concerns with your family doctor, who may decide to refer you to a doctor trained in nervous system conditions (neurologist).
Because appointments can be brief, and because there's often a lot to talk about, it's a good idea to arrive well prepared for your appointment. Here's some information to help you get ready for your appointment, and what to expect from your doctor.
What you can do
Your time with your doctor is limited, so preparing a list of questions ahead of time will help you make the most of your time together. For myoclonus, some basic questions to ask your doctor include:
In addition to the questions that you've prepared to ask your doctor, don't hesitate to ask questions during your appointment at any time that you don't understand something.
What to expect from your doctor
Tests and diagnosis
To diagnose myoclonus, your doctor will review your medical history and symptoms and conduct a physical examination.
To determine the cause of myoclonus and rule out other potential causes of your condition, your doctor may recommend several tests, including:
In this procedure, doctors attach small electrodes to your scalp with paste or fine needles. You may be asked to breathe deeply and steadily for several minutes, look at bright lights or listen to sounds.
In this procedure, doctors put EMG surface electrodes on multiple muscles, especially on those muscles that are involved in the jerking. An instrument records the electrical activity from your muscle at rest and as you contract the muscle, such as by bending your arm. These signals help to determine the pattern and origin of the myoclonus. The test takes at least an hour to complete.
Magnetic resonance imaging (MRI)
An MRI scan uses a magnetic field and radio waves to produce detailed images of your brain, spinal cord and other areas of your body.
Treatments and drugs
Treatment of myoclonus is most effective when a reversible underlying cause can be found that can be treated — such as another condition, a medication or a toxin.
Most of the time, however, the underlying cause can't be cured or eliminated, so treatment is aimed at easing myoclonus symptoms, especially when they're disabling. There are no drugs specifically designed to treat myoclonus, but doctors have borrowed from other disease treatment arsenals to relieve myoclonic symptoms.
Deep brain stimulation (DBS) has been tried in some people with myoclonus and other movement disorders. Researchers continue to study DBS for myoclonus.
Last Updated: 2012-12-20
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