A body tremor is an involuntary muscle contraction with a rhythmic pattern that causes shaking in one or more body parts.
This article outlines the different types of body tremors and their causes. We also describe the available treatment options for body tremors.
Medical experts classify body tremors into two categories. These categories are resting tremors and action tremors.
Resting tremors occur in a body part that is relaxed and completely supported by gravity. For example, a person may experience a resting tremor in their hands when the hands are resting on their lap.
Resting tremors decrease during voluntary movements.
Action tremors occur during voluntary muscle movements.
There are five different subcategories of action tremor:
- Kinetic tremor: Shaking occurs with any type of voluntary movement.
- Intention tremor: Shaking occurs with target directed movements, such as touching the nose. The tremor typically worsens as a person draws closer to the target.
- Task specific tremor: Shaking is only present when performing highly skilled or goal oriented tasks. For example, a person may experience this tremor when writing, drawing, or speaking.
- Postural tremor: Shaking occurs when trying to maintain a position against gravity, such as when holding the arms outstretched.
- Isometric tremor: Shaking occurs during a voluntary muscle contraction that does not involve movement. For example, a person may experience this tremor when holding a heavy object in a fixed position.
Medical experts have further classified the different categories of body tremors into different types.
The following table summarizes the categories and their associated types.
|Category of body tremor||Type of body tremor|
|Task Specific||Primary writing tremor|
Read on for more detail about some of these tremor types:
The characteristic Parkinsonian tremor (PT) is a relatively slow tremor that begins in the fingers.
Doctors sometimes refer to PT as “pill-rolling tremor” because the motion resembles rolling pills or other small items between the fingers. In time, the tremor may progress to the forearm.
Other symptoms of Parkinson’s disease include:
- slow movements
- muscle rigidity
- instability when standing or keeping balance
Essential tremor typically occurs on both sides of the body, but symptoms are more noticeable on the dominant side.
The characteristic feature of essential tremor is a tremor in the hands and arms during action and sometimes at rest.
Essential tremor may also occur in other parts of the body, including:
- the head
- the vocal cords
- the legs and feet
A cerebellar tremor occurs when a person is about to complete a purposeful movement.
For example, a person may experience this type of tremor when bringing a fork to their mouth.
A cerebellar tremor is low in frequency and high in amplitude. Frequency refers to the speed of the tremor, while the amplitude is the degree of movement of the body part.
Doctors typically diagnose cerebellar tremors in people with multiple sclerosis and other neurological disorders.
Dystonic tremors involve involuntary twisting or jerking of the limbs. Certain hand and arm positions may cause the tremors to stop.
Dystonic tremors are rare and typically occur in people who are under 50 years of age.
All people have a physiologic tremor, a high-frequency, low-amplitude tremor that occurs at rest and during movement.
Physiologic tremors typically do not affect a person’s day-to-day activities. However, the following factors may exacerbate this type of tremor:
In some cases, body tremors are due to a dysfunction in the deep areas of the brain that control movement. This type of dysfunction may occur as a result of the following neurological conditions:
- traumatic brain injury
- neurodegenerative diseases, such as Parkinson’s disease and multiple sclerosis (MS)
Certain medications may also cause body tremors. Examples include:
- asthma medications
- hypoglycemic agents
- some psychotic, neurological disorder, and anti-depressant medications
Some other potential causes of body tremor can include:
When diagnosing body tremors, a doctor may use physical and neurological examinations and diagnostic tests.
Physical and neurological exams
The physical examination involves checking the following:
- whether muscle contractions occur at rest or during action
- where the tremor occurs on the body
- whether the tremor is bilateral on both sides or unilateral on one side only
- tremor frequency and amplitude
When conducting a neurological examination, a doctor will look for the following:
- increased muscle stiffness
- impaired balance
- speech abnormalities
Other diagnostic tests
A doctor may also order the following diagnostic tests to determine the cause of body tremors:
- Blood and urine tests: These tests may help rule out certain causes of body tremors, such as:
- medication side effects
- drug interactions
- chronic heavy drinking
- thyroid dysfunction
- Diagnostic imaging tests: AnMRI or CT will help detect any brain damage that may be causing the tremors. A positron emission tomography scan (PET) or a SPECT procedure, where a healthcare professional injects a chemical into the vein, is sometimes appropriate if a doctor suspects Parkinson’s.
- Electromyogram (EMG): This test records electrical activity in the muscles. A doctor may use it to measure involuntary muscle activity in response to nerve stimulation.
Specific treatments may help to reduce the frequency and severity of body tremors. What treatment a person receives will depend on the cause, type, and severity of their tremor.
Some treatment options follow here:
Medications can help to manage body tremors. The table below shows the different classes of drug a doctor may prescribe for body tremors, along with examples of each.
|Parkinson’s disease medications||levodopa|
In some cases, doctors have successfully used
In some cases, a doctor may recommend a nonsurgical procedure to help control body tremors. Examples include focused ultrasound and radiofrequency ablation.
The thalamus is the part of the brain that plays a role in movement. Damage or disruption to nerve cells in the thalamus can lead to muscle tremors.
Focused ultrasound delivers a fine beam of ultrasound waves to the dysfunctional nerve cells in the thalamus. This destroys the cells, thereby alleviating a person’s tremors.
Radiofrequency ablation uses radio waves to generate an electric current. This current heats the dysfunctional nerve and interrupts its ability to send and receive signals.
Surgical interventions that may help to manage body tremors include deep brain stimulation (DBS) and thalamotomy.
Deep brain stimulation
Deep brain stimulation is the most common surgical treatment for tremor. The procedure involves surgically implanting electrodes into the thalamus. A surgeon attaches electrodes to a device called a pulse generator, which they implant in a person’s chest.
The pulse generator sends an electrical current to the electrodes in the thalamus. The pulse then enters the thalamus, interrupting the tremor.
Thalamotomy is a surgical procedure that permanently destroys the problematic part of the thalamus.
Doctors usually reserve this surgery for a particularly severe tremor that has not responded to other treatments. Where possible, doctors will perform radiofrequency ablation as an alternative to thalamotomy.
Some lifestyle changes may alleviate body tremors or help people to manage their condition. Examples include:
According to the National Institute of Neurological Disorders and Stroke (NINDS), some people may have a genetic predisposition to developing body tremors.
Researchers at NINDS are currently working to identify genes that may lead to early-onset essential tremor.
Other scientists are researching whether certain gene mutations or abnormalities can increase the risk of essential tremor.
Body tremors can sometimes signal an underlying medical condition. Anyone who experiences body tremors should see a doctor for a diagnosis and appropriate treatment.
A person who suspects that their tremor is a side effect of medication should raise their concerns with a doctor. Where possible, the doctor may adjust the dose or recommend switching to an alternative medication.
A person should not stop taking a medication unless their doctor says it is safe to do so.
There are many different types of body tremors. The type a person experiences can sometimes indicate the cause.
Sometimes, body tremors are due to an underlying neurological condition, such as stroke, Parkinson’s Disease, or multiple sclerosis. However, they may also be a side effect of medications, anxiety, fatigue, or stimulant use.
A doctor will work to determine the cause and provide appropriate treatments. Correct treatment may reduce the frequency and severity of the tremors.