U.S. DEPARTMENT OF HEALTH

AND HUMAN SERVICES

Public Health Service

National Institutes of Health

Tremor

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Tremor

What is tremor?

Tremor is an unintentional, rhythmic muscle movement involving to-and-fro 

movements (oscillations) of one or more 

parts of the body. It is the most common of 

all involuntary movements and can affect 

the hands, arms, head, face, voice, trunk, 

and legs. Most tremors occur in the hands. 

In some people, tremor is a symptom of a 

neurological disorder or appears as side 

effect of certain drugs. The most common 

form of tremor, however, occurs in otherwise 

largely healthy people. Although tremor is 

not life-threatening, it can be embarrassing 

to some people and make it harder to 

perform daily tasks. 
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What causes tremor?

Tremor is usually generated in parts of the brain that control muscles throughout 

the body or in particular areas, such as the 

hands. Neurological disorders or conditions 

that can produce tremor include multiple 

sclerosis, stroke, traumatic brain injury, 

and neurodegenerative diseases that damage 

or destroy parts of the brain stem or the 

cerebellum. Other causes include the use 

of some drugs (such as amphetamines, 

corticosteroids, and drugs used for certain 

psychiatric disorders), alcohol abuse or 

withdrawal, mercury poisoning, overactive 

thyroid, or liver failure. Some forms of 

tremor are inherited and run in families, 

while others have no known cause.

What are the characteristics of tremor?

Characteristics may include a rhythmic shaking in the hands, arms, head, legs, 

or trunk; shaky voice; difficulty writing or 

drawing; or problems holding and controlling 

utensils, such as a fork. Some tremors may be 

triggered by or become exaggerated during 

times of stress or strong emotion, when the 

individual is physically exhausted, or during 

certain postures or movements.

Tremor may occur at any age but is most 

common in middle-aged and older persons. 

It may be occasional, temporary, or occur 

intermittently. Tremor affects men and 

women equally.
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A useful way to understand and describe 

tremors is to define them by the condition 

of activation that typically occurs. Resting

tremor occurs when the muscle is relaxed, 

such as when the hands are lying on the 

lap or hanging next to the trunk during 

standing or walking. It may be seen as a 

shaking of the hand or limb, even when 

the person is at rest. Often, the tremor 

only affects the hand or fingers. This type 

of tremor is often seen in patients with 

Parkinson’s disease. An action tremor

occurs during any type of movement of 

an affected body part. There are several 

sub-classifications of action tremor. 

Postural tremor occurs when the person 

maintains a position against gravity, such 

as holding the arms outstretched. Kinetic 

tremor appears during movement of a body 

part, such as moving the wrists up and 

down. Intention tremor is present during a 

purposeful movement toward a target, such 

as touching a finger to one’s nose during a 

medical exam, typically getting larger and 

larger toward the goal. Task-specific tremor

appears when performing highly skilled, 

goal-oriented tasks such as handwriting or 

speaking. Isometric tremor occurs during 

a voluntary muscle contraction that is not 

accompanied by any movement.
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What are the different categories 

of tremor?

Tremor is most commonly classified by its appearance and cause or origin. Some 

of the better-known forms of tremor, with 

their symptoms, include the following:

Essential tremor (previously also called 

benign essential tremor) is the most common 

form of abnormal tremor. Although the 

tremor may be mild and nonprogressive 

in some people over a long period of time, 

in others the tremor is slowly progressive, 

starting on one side of the body but affecting 

both sides within a few years. The hands 

are most often affected, but the head, voice, 

tongue, legs, and trunk may also be involved, 

however typically to a lesser extent than the 

hands. Tremor of the hands is typically an 

action tremor. Head tremor may be seen 

as a “yes-yes” or “no-no” motion. Essential 

tremor may be accompanied by mild gait 

disturbance. Tremor frequency may decrease 

as the person ages, but the severity may 

increase, affecting the person’s ability to 

perform certain tasks or activities of daily 

living. Heightened emotion, stress, fever, 

physical exhaustion, or low blood sugar 

may trigger tremors and/or increase their 

severity. Onset is most common after age 40, 

although symptoms can appear at any age. 

It may occur in more than one family member. 

Children of a parent who has familial essential tremor have an approximate 50 percent 

chance of inheriting the condition. A variant 

in the gene LINGO1 has been identified as 

a risk-gene, although not all people with 
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essential tremor carry this variant. The 

gene also can be present in people without 

essential tremor. While essential tremor 

was thought not to be associated with any 

known pathology over many years, recent 

studies suggest there may be mild degeneration of certain parts of the cerebellum in 

patients with essential tremor.

Parkinsonian tremor is caused by damage 

to structures within the brain that control 

movement. This tremor, which appears 

typically as resting tremor, can occur as 

an isolated symptom or be seen in other 

disorders. It is often the first symptom of 

Parkinson disease. The tremor is classically 

seen as a “pill-rolling” action of the hands 

that may also affect the chin, lips, legs, 

and trunk. It can be markedly increased by 

stress or emotions. Onset of parkinsonian 

tremor is generally after age 60. Movement 

starts in one limb or on one side of the body 

and usually progresses to include the other 

side. In addition to the very characteristic 

resting tremor, more than 25 percent of 

those with Parkinson’s disease have an 

associated action tremor as well.

Dystonic tremor occurs in individuals of all 

ages who are affected by dystonia—a movement disorder in which sustained involuntary 

muscle contractions cause twisting and 

repetitive motions and/or painful and 

abnormal postures or positions, such as 

involuntary twisting of the neck (torticollis) 

or writer’s cramp. Dystonic tremor may 

affect any muscle in the body and is seen 

most often when the person is in a certain 
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position or moves a certain way. The pattern 

of dystonic tremor may differ from essential 

tremor. Dystonic tremors occur irregularly 

and often can be relieved by complete rest. 

Touching the affected body part or muscle 

may reduce tremor severity. The tremor 

may be the initial sign of dystonia localized 

to a particular part of the body.

Cerebellar tremor is a slow, large-amplitude 

tremor of the extremities that occurs at the 

end of a purposeful movement (intention 

tremor), such as trying to press a button or 

touching a finger to the tip of one’s nose. 

Cerebellar tremor is caused by lesions in or 

damage to the cerebellum resulting from 

stroke, tumor, or disease such as multiple 

sclerosis or some inherited degenerative 

disorder. It can also result from chronic 

alcoholism or overuse of some medicines. 

In classic cerebellar tremor, a lesion on one 

side of the brain produces a tremor in that 

same side of the body that worsens with 

directed movement. Cerebellar damage 

can also produce a type of tremor called 

rubral or Holmes’ tremor—a combination 

of rest, action, and postural tremors. The 

tremor is often most prominent when the 

affected person is active or is maintaining 

a particular posture. Cerebellar tremor 

may be accompanied by dysarthria (speech 

problems), nystagmus (rapid, involuntary 

movements of the eyes), gait problems, and 

postural tremor of the trunk and neck.
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Psychogenic tremor (also called functional 

tremor) can appear as any form of tremor 

movement. The characteristics of this kind 

of tremor may vary but generally include 

sudden onset and remission, increased 

incidence with stress, change in tremor 

direction and/or body part affected, and 

greatly decreased or disappearing tremor 

activity when being distracted. Many 

individuals with psychogenic tremor have 

a conversion disorder (defined as a psychological disorder that produces physical 

symptoms) or another psychiatric disease.

Orthostatic tremor is characterized by rhythmic 

muscle contractions that occur in the legs 

and trunk immediately after standing. The 

person typically perceives orthostatic tremor 

as unsteadiness rather than actual tremor. 

Because of its high tremor frequency, often 

the tremor cannot be seen, but sometimes 

be heard when putting a stethoscope to the 

thigh muscles. No other clinical signs or 

symptoms are present and the unsteadiness 

ceases when the individual sits, is lifted off 

the ground, or starts walking.

Physiologic tremor, the most common form of 

tremor, occurs in every normal individual. 

It is rarely visible to the eye and typically 

involves a fine shaking of the hands. 

Physiological tremor is not considered a 

disease and is not caused by the brain, 

but is due to mechanical properties of the 

body combined with body rhythms such 

as heart beat and muscle contractions. It 

may be heightened by strong emotion (such 

as anxiety or fear), physical exhaustion, 
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hypoglycemia, hyperthyroidism, heavy metal 

poisoning, stimulants, alcohol withdrawal, 

caffeine, or fever. It can occur in all voluntary muscle groups and can be detected by 

extending the arms and placing a piece of 

paper on top of the hands. Enhanced physiologic tremor is a strengthening of physiologic 

tremor to more visible levels. It is generally 

not caused by a neurological disease but by 

reaction to certain drugs, alcohol withdrawal, 

or medical conditions including an overactive 

thyroid and hypoglycemia. It is usually reversible once the cause is corrected.

Tremor can result from other conditions as 

well. Alcoholism, excessive alcohol consumption, or alcohol withdrawal can kill certain 

nerve cells, resulting in tremor, especially 

in the hand. (Conversely, small amounts of 

alcohol may even help to decrease essential 

tremor, but the mechanism behind this is 

unknown. Doctors may use small amounts of 

alcohol to aid in the diagnosis of certain forms 

of tremor but not as a regular treatment for 

the condition.) Tremor in peripheral neuropathy may occur when the nerves that supply 

the body’s muscles are traumatized by injury, 

disease, abnormality in the central nervous 

system, or as the result of systemic illnesses. 

Peripheral neuropathy can affect the whole 

body or certain areas, such as the hands, and 

may be progressive. Resulting sensory loss 

may be seen as a tremor or ataxia (inability 

to coordinate voluntary muscle movement) 

of the affected limbs and problems with 

gait and balance. Clinical characteristics 

may be similar to those seen in people with 

essential tremor.
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How is tremor diagnosed?

During a physical exam a doctor can determine whether the tremor occurs 

primarily during action or at rest. The doctor 

will also check for tremor symmetry, any 

sensory loss, weakness or muscle atrophy, or 

decreased reflexes. A detailed family history 

may indicate if the tremor is inherited. Blood 

or urine tests can detect thyroid malfunction, other metabolic causes, and abnormal 

levels of certain medications that can cause 

tremor. These tests may also help to identify 

contributing causes, such as drug interaction, 

chronic alcoholism, or another condition or 

disease. Diagnostic imaging using computerized tomography or magnetic resonance 

imaging may help determine if the tremor is 

the result of a structural defect or degeneration of the brain.

The doctor will perform a neurological exam 

to assess nerve function and motor and sensory 

skills. The tests are designed to determine 

any functional limitations, such as difficulty 

with handwriting or the ability to hold a utensil 

or cup. The person may be asked to place a 

finger on the tip of her or his nose, draw a 

spiral, or perform other tasks or exercises.

The doctor may order an electromyogram to 

diagnose muscle or nerve problems. This test 

measures involuntary muscle activity and 

muscle response to nerve stimulation.
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Are there any treatments?

T here is no cure for most tremors. The appropriate treatment depends 

on accurate diagnosis of the cause.

Some tremors respond to treatment of the 

underlying condition. For example, in some 

cases of psychogenic tremor, treating the 

individual’s underlying psychological 

problem may cause the tremor to disappear.

Symptomatic drug therapy is available for 

several forms of tremor. Drug treatment for 

parkinsonian tremor involves levodopa and/

or dopamine-like drugs such as pramipexole 

and ropinirole. Other drugs used to lessen 

parkinsonian tremor include amantadine 

hydrochloride and anticholinergic drugs.

Essential tremor may be treated with 

propranolol or other beta blockers (such 

as nadolol) and anticonvulsant drugs such 

as primidone.

Cerebellar tremor typically does not respond 

well to medical treatment. Dystonic tremor 

may respond to clonazepam, anticholinergic 

drugs, and intramuscular injections of 

botulinum toxin. Botulinum toxin is also 

prescribed to treat voice and head tremors 

and several movement disorders.

Clonazepam and primidone may be 

prescribed for primary orthostatic tremor.

Enhanced physiologic tremor is usually 

reversible once the cause is corrected. If 

symptomatic treatment is needed, beta 

blockers can be used.
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Eliminating tremor “triggers” such as 

caffeine and other stimulants from the 

diet is often recommended

Physical therapy may help to reduce tremor 

and improve coordination and muscle control 

for some patients. A physical therapist will 

evaluate the individual for tremor positioning, muscle control, muscle strength, 

and functional skills. Teaching the person 

to brace the affected limb during the tremor 

or to hold an affected arm close to the body 

is sometimes useful in gaining motion control. 

Coordination and balancing exercises may 

help some individuals. Some therapists 

recommend the use of weights, splints, 

other adaptive equipment, and special 

plates and utensils for eating.

Surgical intervention such deep brain stimulation or thalamotomy may ease certain 

tremors. These surgeries are usually 

performed only when the tremor is severe, 

cannot be controlled satisfactorily with drugs, 

and will have a significant impact on the 

daily life of an individual with tremor. 

Deep brain stimulation (DBS), the most 

common form of surgical treatment of 

tremor, uses implantable electrodes to 

send high-frequency electrical signals to 

the thalamus. The person uses a hand-held 

magnet to turn on and turn off a pulse 

generator that is surgically implanted 

under the skin. The electrical stimulation 

temporarily disables the tremor and can 

be “reversed,” if necessary, by turning 

off the implanted electrode. Batteries in 
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the generator last about 5 years and can 

be replaced surgically. DBS is currently 

used to treat parkinsonian tremor, essential 

tremor, and dystonia.

Thalamotomy, involving the creation of 

lesions in the brain region called the thalamus, is quite effective in treating patients 

with essential, cerebellar, or parkinsonian tremor. This in-hospital procedure is 

performed under local anesthesia, with the 

individual awake. After the patient’s head 

is secured in a metal frame, the surgeon 

maps the person’s brain to locate the 

thalamus. A small hole is drilled through 

the skull and a temperature-controlled 

electrode is inserted into the thalamus. 

A low-frequency current is passed through 

the electrode to activate the tremor and 

to confirm proper placement. Once the 

site has been confirmed, the electrode 

is heated to create a temporary lesion. 

Testing is done to examine speech, 

language, coordination, and tremor 

activation, if any. If no problems occur, 

the probe is again heated to create a 3-mm 

permanent lesion. The probe, when cooled 

to body temperature, is withdrawn and the 

skull hole is covered. The lesion causes the 

tremor to permanently disappear without 

disrupting sensory or motor control.

The most common side effects of tremor 

surgery include dysarthria (problems 

with motor control of speech), temporary 

or permanent cognitive impairment 

(including visual and learning difficulties), 

and problems with balance.
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What research is being done?

T he National Institute of Neurological Disorders and Stroke, a unit of the 

National Institutes of Health (NIH) within 

the U.S. Department of Health and Human 

Services, is the nation’s leading federal 

funder of research on disorders of the 

brain and nervous system. The NINDS 

sponsors research on tremor both at its 

facilities at the NIH and through grants 

to medical centers across the country.

Scientists at the NINDS are evaluating 

the effectiveness of 1-octanol and octanoic 

acid, substances closely related to alcohol 

but not intoxicating, for treating essential 

tremor. Results of previous NIH studies 

have shown these agent to be promising 

as potential new treatments. Furthermore, 

an ongoing study is trying to find out how 

alcohol is capable of reducing tremor in 

essential tremor.

Other researchers are trying to determine 

if transcranial Direct Current Stimulation, 

which uses small electrodes placed on the 

scalp to deliver continuous low electrical 

current to areas of the brain involved with 

movement, can improve essential tremor.

NINDS further conducts research to search 

for genes that can cause essential tremor.
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Where can I get more information?

For more information on neurological disorders or research programs funded 

by the National Institute of Neurological 

Disorders and Stroke, contact the Institute’s 

Brain Resources and Information Network 

(BRAIN) at: 

BRAIN

P.O. Box 5801

Bethesda, MD 20824

800-352-9424

www.ninds.nih.gov

Information also is available from the 

following organizations:

International Essential Tremor Foundation

P.O. Box 14005

Lenexa, KS 66285-4005

913-341-3880

888-387-3667

www.essentialtremor.org

Tremor Action Network

P.O. Box 5013

Pleasanton, CA 94566-5013

510-681-6565

925-462-0111

www.tremoraction.org

National Ataxia Foundation

2600 Fernbrook Lane North

Suite 119

Minneapolis, MN 55447-4752

763-553-0020

www.ataxia.org
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WE MOVE (Worldwide Education & 

Awareness for Movement Disorders)

5731 Mosholu Avenue

Bronx, NY 10471

347-843-6132

www.wemove.org


NIH . . . Turning Discovery into Health

Prepared by:

Office of Communications and Public Liaison

National Institute of Neurological 

Disorders and Stroke

National Institutes of Health

Department of Health and Human Services

Bethesda, Maryland 20892-2540

NIH Publication No. 12-4734 July 2012