(See also Overview of Movement Disorders.)
Types of Tremors
Tremors can be
Tremors are usually classified based on when they occur:
Action tremors include
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Intention tremor: Triggered by movement toward a target (for example, reaching for a glass)
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Kinetic tremor: Appearing at the end of a movement toward a target or during any voluntary movement, such as moving the wrists up and down or closing and opening the eyes
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Postural tremor: Triggered by holding a limb outstretched in one position
Tremors can also be classified by what causes them, as follows:
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Physiologic (the normal tremors that everyone has to some degree)
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Essential (a common hereditary disorder that rarely causes any other symptoms)
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Cerebellar (caused by damage to part of the brain called the cerebellum)
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Secondary (caused by a disorder or drug)
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Psychogenic (caused by psychologic factors)
Other important characteristics of tremors are
Physiologic tremor
Physiologic tremor is the normal tremor that everyone has to some degree. For example, most people's hands, when held outstretched, usually tremble slightly. Such slight, rapid tremor reflects the precise moment-by-moment control of muscles by nerves. In most people, the tremor is barely noticeable. However, a normal tremor may become more noticeable under certain conditions and may worry people. For example, the tremor may be more noticeable when people
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Feel stressed or anxious
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Are deprived of sleep
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Stop drinking alcohol or taking a sedative (such as a benzodiazepine) or an opioid
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Consume caffeine
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Take certain drugs, including theophylline and albuterol (which are used to treat asthma and chronic obstructive pulmonary disease, or COPD), corticosteroids, or recreational drugs (such as cocaine or amphetamines)
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Have certain disorders, such as an overactive thyroid gland (hyperthyroidism) that is causing other symptoms
Essential tremor
Essential tremor results from a problem in the nervous system, but people with this tremor rarely have any other symptoms of nervous system dysfunction (neurologic symptoms). The cause is unclear, but the tremor often runs in families.
Essential tremor usually begins during early adulthood but can begin at any age. The tremor slowly becomes more noticeable as people age. Thus, it is sometimes incorrectly called senile tremor. The tremor usually involves the arms and hands and sometimes affects the head. When it affects the head, people may look as if they are nodding yes or shaking their head no. These tremors are usually worsened by holding a limb outstretched (against gravity) or by moving a limb.
Usually, essential tremor remains mild. However, it can be troublesome and embarrassing. It can affect handwriting and make using utensils difficult. In some people, the tremor gradually worsens over time, eventually resulting in disability. Symptoms may resemble those of Parkinson disease, and sometimes essential tremor is misdiagnosed as Parkinson disease. Rarely, people have Parkinson disease and essential tremor.
Resting tremor
Resting tremor occurs when muscles are at rest. An arm or a leg shakes even when a person is completely relaxed. The tremor becomes less noticeable or disappears when the person moves the affected muscles. Resting tremors are often slow and coarse.
These tremors develop when nerve cells in the part of the brain called the basal ganglia are disturbed. The basal ganglia help initiate and smooth out intended (voluntary) muscle movements. Such disturbances usually result from
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Parkinson disease or disorders that cause the same symptoms as Parkinson disease (parkinsonism)
However, resting tremors can also result from use of drugs that can affect this part of the brain, such as antipsychotic drugs and some drugs used to relieve nausea.
Resting tremors may be socially embarrassing, but because they go away when people try to do something (such as drinking a glass of water), they typically do not interfere with daily activities.
Intention tremor
This tremor occurs during a purposeful movement, as when reaching for an object with the hand. People may miss the object because of the tremor. Intention tremors worsen as people get closer to the targeted object. These tremors are relatively slow and wide (coarse).
Intention tremors result from damage to the cerebellum, the part of the brain responsible for balance and coordination. Thus, cerebellar tremor and intention tremor may be used as synonyms.
Common causes of intention tremor include
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Certain hereditary disorders that affect the cerebellum (called spinocerebellar ataxias)
Other disorders and drugs can also cause the cerebellum to malfunction, resulting in an intention tremor. They include
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A tumor
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Overuse of sedatives or antiseizure drugs
Postural tremor
Complex tremor
Complex tremor is a tremor that has features of more than one type of tremor.
Common causes of complex tremors are
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Psychologic factors
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Widespread nerve damage such as that caused by diabetes or Guillain-Barré syndrome
Causes of Tremor
Many disorders can cause tremor.
Most commonly, tremors are
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Physiologic tremor (most common overall)
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Essential tremor
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Due to Parkinson disease
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Due to a stroke or multiple sclerosis affecting parts of the brain that control movement
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Due to severe liver disease
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Due to alcohol withdrawal
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Due to an overactive thyroid gland (hyperthyroidism)
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Due to hereditary disorders involving the cerebellum, such as Friedreich ataxia and spinocerebellar ataxias
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Due to use of certain drugs or exposure to certain toxic substances
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Psychogenic tremor (due to psychologic factors)
Sometimes there is more than one cause of the tremors. For example, a person may have essential tremor and Parkinson disease.
Evaluation of Tremor
The following information can help people decide when a doctor's evaluation is needed and help them know what to expect during the evaluation.
Warning signs
When to see a doctor
People with warning signs should see a doctor immediately.
People without warning signs should see a doctor as soon as possible.
If people are under 50 years old and do not have a family history of essential tremors, they should see a doctor soon. Being evaluated by a doctor is important to make sure that the cause is not another disorder or a drug.
What a doctor does
Doctors first ask questions about the person's symptoms and medical history and then do a physical examination. What doctors find during the history and physical examination often suggests a cause and the tests that may need to be done (see table Some Causes and Features of Tremor).
Doctors ask about the tremor:
If the tremor began suddenly, doctors ask about events that may have triggered it (such as a recent injury or use of a new drug).
Doctors review the person's past medical history, looking for conditions associated with tremor. They ask about tremors in close relatives. They review the drugs taken and ask about use of caffeine, alcohol, and recreational drugs (particularly whether the person recently stopped using such drugs).
Doctors do a physical examination, paying particular attention to the neurologic examination (including the way the person walks). Doctors note which body parts are affected by the tremor. They observe how fast the shaking movements are in various situations:
The quality of the person's voice may be observed when holding a long note.
Doctors can usually identify the type of tremor based on its characteristics and results of the medical history and physical examination—for example,
Some Causes and Features of Tremor
|
Cause |
Features* |
Tests |
Postural tremor (tremor when a limb is held outstretched) |
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Alcohol or a sedative (such as a benzodiazepine) when use is stopped |
Agitation and a fine tremor starting 24–72 hours after the last use of alcohol or a benzodiazepine Sometimes high blood pressure, a rapid heart rate, or fever, especially in people who are hospitalized |
A doctor's examination |
|
Drugs, such as
|
History of drug use |
Stopping the drug to see whether the tremor goes away |
|
Hormonal, metabolic, and toxic abnormalities that affect the brain:
|
A tremor plus one or more of the following: For hyperthyroidism: Difficulty tolerating heat, excessive sweating, an increased appetite, weight loss, bulging eyes, and frequent bowel movements |
Tests to help identify the cause, such as blood tests |
|
Essential tremor |
A coarse or fine, slow tremor that No other symptoms of nervous system malfunction |
A doctor's examination |
|
Physiologic tremor |
A fine, rapid tremor that |
A doctor's examination |
Resting tremor |
||
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Parkinsonism triggered by a drug, such as certain antipsychotic drugs and drugs used to relieve nausea |
A history of drug use |
Stopping the drug to see whether the tremor goes away |
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A slow alternating tremor that
Often no family history of tremor and no lessening of tremor after drinking alcohol |
A doctor's examination Use of the drug levodopa to see whether improvement occurs |
|
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A sometimes coarse or jerky tremor that is often inconspicuous In older people who have difficulty looking down and eventually looking up, muscle stiffness, difficulty moving, early falls, and dementia |
A doctor's examination |
|
Intention tremor |
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A slow tremor that In some people, a family history of the disorder (as for Friedreich ataxia or spinocerebellar ataxias) |
MRI of the brain |
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Drugs, such as |
A history of drug use |
Stopping the drug to see whether the tremor goes away |
Complex tremors |
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Disorders that affect many of the nerves outside the brain and spinal cord (polyneuropathies): |
A tremor that |
Electromyography (stimulating muscles and recording their electrical activity) Other tests to identify the cause |
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Psychogenic tremor (due to psychologic factors) |
A tremor that |
A doctor's examination |
|
* Features include symptoms and results of the doctor's examination. Features mentioned are typical but not always present. |
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MRI = magnetic resonance imaging; SSRIs = selective serotonin reuptake inhibitors (a type of antidepressant). |
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Testing
Brain imaging with magnetic resonance imaging (MRI) or computed tomography (CT) is done if
Blood tests may be done to check for possible causes when the cause is unclear. Tests may include
Electromyography (stimulating muscles and recording their electrical activity) is rarely done. But if the cause is thought to be nerve damage, it may be done.
Treatment of Tremor
Any specific cause of the tremor is treated when possible—for example, by stopping a drug that is causing the tremor or by treating hyperthyroidism. Parkinson disease can be treated with levodopa and other drugs.
For mild tremor, no treatment is needed. If tremors become bothersome, some simple measures can help:
Assistive devices may include rocker knives, utensils with large handles, and, particularly if the tremor is severe, button hooks, Velcro fasteners (instead of buttons or shoe laces), zipper pulls, straws, and shoe horns.
Physiologic tremor
Eliminating or minimizing the trigger may lessen the tremor. For example, avoiding caffeine, getting enough sleep, and minimizing stress may help.
If many daily activities (such as using utensils and drinking from a glass at mealtime) become difficult or if the person's work requires steady hands, drug therapy may help.
People with a physiologic tremor and anxiety may benefit from taking a low dose of a benzodiazepine (a sedative), such as lorazepam. However, these drugs should be taken only occasionally.
If a physiologic tremor is worsened by taking prescribed drugs that are necessary or by feeling very anxious, propranolol (a beta-blocker) may help.
Essential tremor
For some people, drinking alcohol in moderation may lessen the tremor, but doctors do not recommend this tactic as a treatment. Heavy drinking followed by suddenly stopping makes the tremor worse.
Antiseizure drugs (primidone, topiramate, or gabapentin) or propranolol may also be used if needed to control the tremor.
Benzodiazepines may be used to treat essential tremor if other drugs are ineffective.
Intention tremors
Intention tremors are difficult to treat, but if the condition causing it can be corrected, the tremor may resolve.
If the condition cannot be corrected, a therapist may put wrist and ankle weights on the affected limb to reduce the tremor. Or people may be taught to brace the limb during activity. These measures sometimes help.
Deep brain stimulation
For this procedure, tiny electrodes are placed in the area of the brain involved in tremors—the basal ganglia (collections of nerve cells that help smooth out muscle movements). The electrodes send small amounts of electricity to the specific area of the basal ganglia responsible for the tremors and thus help relieve symptoms.
Deep brain stimulation is sometimes done when drugs cannot control a severe, disabling tremor. Sometimes essential tremors or tremors due to Parkinson disease or another disorder require such treatment. Such treatments are used only when drug therapy has been tried and has been not been effective. These treatments are available only at special centers.
Essentials for Older People: Tremor
Many older people think that developing a tremor is a part of normal aging and may not seek medical attention. Nonetheless, older people should talk to their doctor, who can ask them questions and do a physical examination to check for possible causes of tremor. Doctors may then recommend strategies or possibly drugs to lessen the tremor.
Also, older people are more likely to be taking drugs that cause tremor and are more vulnerable to side effects of these drugs. Thus, when prescribing such drugs to older people, doctors try to prescribe the lowest effective dose. Such a dose may be lower than the doses used to treat younger adults. Doctors, if possible, avoid using anticholinergic drugs in older people.
Tremor can significantly affect quality of life in older people, interfering with their ability to function, especially if they have other physical or mental impairments. Physical and occupational therapists can provide simple coping strategies, and assistive devices may help older people maintain quality of life.
Key Points about Tremor
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Tremors can be classified based on when they occur—whether at rest (resting tremor) or when moving (action tremor)—and action tremors can be classified as those occurring at the end of a movement toward a target or during any voluntary movement (kinetic tremor), when moving toward a target (intention tremor), or when holding a limb outstretched (postural tremor).
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Most tremors are physiologic (normal) tremors, and some are essential tremor or are caused by other disorders.
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Tremors that occur during rest are often caused by Parkinson disease.
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Doctors can usually identify the cause based on the history and physical examination.
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If a tremor begins suddenly or is accompanied by other neurologic symptoms, people should see a doctor right away.
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If people are under 50, have a tremor, but do not have a family history of essential tremors, they should see a doctor soon.
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The cause of the tremor is treated if possible, but otherwise, some simple strategies (such as avoiding circumstances that trigger tremors) and sometimes drugs can help control the tremors.
Drugs Mentioned In This Article
| Generic Name | Select Brand Names |
|---|---|
Amitriptyline |
No US brand name |
Cyclosporine |
NEORAL, SANDIMMUNE |
theophylline |
ELIXOPHYLLIN |
Haloperidol |
HALDOL |
propranolol |
INDERAL |
topiramate |
TOPAMAX |
gabapentin |
NEURONTIN |
Tacrolimus |
PROGRAF |
phenytoin |
DILANTIN |
primidone |
MYSOLINE |
lorazepam |
ATIVAN |
albuterol |
PROVENTIL-HFA, VENTOLIN-HFA |
levodopa |
Levodopa |
Lithium |
LITHOBID |
