What is tremor?
Tremor is a neurological disorder that causes shaking movements in one or more parts of your body, most often in your hands. It can also occur in your arms, legs, head, vocal cords, and torso. Its rhythmic pattern is caused by unintentional (involuntary) muscle contractions. The tremor may occur at separate times with breaks in between them or be constant. Tremor can occur sporadically (on its own) or happen as a result of another disorder.
Tremor is not life threatening. However, it can be challenging and even disabling, making it difficult or even impossible for you to perform work and daily life tasks such as bathing, dressing, writing, and eating.
Common symptoms of tremor may include:
- A rhythmic shaking in your hands, arms, head, legs, or torso
- A shaky voice
- Difficulty doing tasks with your hands, such as writing or drawing
- Problems holding and controlling utensils, such as a spoon, or other items
Some tremor may be triggered by or become worse during times of stress or strong emotion, when you are physically exhausted, or when you are in certain postures or make certain movements.
Who is more likely to get tremor?
Tremor is most common among middle-aged and older adults, although it can occur at any age. The disorder generally affects men and women equally.
Generally, tremor is caused by a problem in the deep parts of the brain that control movements. Most types of tremor have no known cause, although there are some forms that appear to be inherited and run in families.
Tremor can occur on its own or be a symptom associated with a number of neurological disorders. Some known causes include:
- Medicines. Several drugs can cause tremors, including certain asthma medications, amphetamines, corticosteroids, and drugs used for certain psychiatric and neurological disorders.
- Alcohol abuse or withdrawal. This can cause the nervous system to be hyperactive and lead to shaking.
- Diseases or disorders, such as stroke, multiple sclerosis, traumatic brain injury, or Parkinson's disease.
- Mercury poisoning from food or the environment. This can cause muscle weakness, tremor, and poor coordination.
- Too much caffeine. Overstimulating the nervous system can worsen a tremor.
- Overactive thyroid. Thyroid proteins affect nerve activity and too much protein can cause tremors and other symptoms.
- Liver or kidney failure. Excess protein can cause movement symptoms such as tremor and myoclonus (a sudden, brief unintended twitching or jerking of a muscle or group of muscles).
- Low blood sugar. Hypoglycemia, or low blood-sugar level, can cause tremor, problems seeing, seizures, and loss of consciousness.
- Stress, anxiety, heightened emotions, or panic. A rush in adrenaline caused by stress or other causes can increase muscle tension and cause tremor.
Classifications (types) of tremor
Tremor can be classified into two main categories: resting and action.
Resting tremor occurs when the muscle is relaxed, such as when your hands are resting on your lap. Your hands, arms, or legs may shake even when they are at rest. Often, the tremor only affects the hand or fingers. This type of tremor is often seen in people with Parkinson's disease.
Action tremor occurs with the voluntary movement of a muscle. Most types of tremor are considered action tremor. There are several sub-classifications of action tremor, many of which overlap.
- Postural tremor occurs when you are holding a position against gravity, such as keeping your arms outstretched.
- Kinetic tremor is associated with any voluntary movement, such as moving your wrists up and down or closing and opening your eyes.
- Intention tremor starts when you make an intended movement toward a target, such as lifting a finger to touch your nose.
- Task-specific tremor only appears when you are 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, such as when you are holding a heavy book in the same position.
Categories of tremor
Tremor is most commonly classified by its appearance and cause or origin. There are more than 20 types of tremor and some of the most common forms include the following:
Essential tremor—Essential tremor (previously also called benign essential tremor or familial tremor) is one of the most common movement disorders. Its key feature is a tremor in both hands and arms during action and when standing still. It also may affect your head and voice and how you walk. Although the tremor can start at any age it most often initially appears during adolescence or in middle age (between ages 40 and 50). It can be mild and stay the same, or slowly get worse.
The exact cause of essential tremor is unknown. Studies show essential tremor is accompanied by a mild degeneration of the cerebellum, which is the part of your brain that controls movement. About 50 percent of the cases of essential tremor are thought to be caused by a genetic risk factor (referred to as familial tremor). Children of a parent who has familial tremor have greater risk of inheriting the condition. Familial forms of essential tremor often appear early in life.
Dystonic tremor—Dystonic tremor occurs in people who are affected by dystonia—a movement disorder where incorrect messages from the brain cause muscles to be overactive, resulting in abnormal postures or sustained, unwanted movements. Dystonic tremor usually appears in young or middle-aged adults and can affect any muscle in the body. Symptoms may sometimes be relieved by complete relaxation or the severity may be reduced by touching the affected body part or muscle.
Cerebellar tremor—Cerebellar tremor is typically a slow, easily visible tremor of the arms, legs, hands, or feet that occurs at the end of a purposeful movement such as pressing a button. It is caused by damage to the cerebellum and its pathways to other brain regions, often from a stroke or tumor, injury from a disease or an inherited disorder, or from chronic damage due to alcoholism.
Psychogenic tremor—Psychogenic tremor (also called functional tremor) can appear as any form of tremor. Its symptoms may vary but often start and stop suddenly and may affect all body parts. The tremor increases in times of stress and decreases or disappears when you are distracted.
Physiologic tremor—Everyone has physiologic tremor. It is rarely visible to the eye and typically involves a fine shaking of both of the hands and also the fingers. It is not considered a disease but is a normal human phenomenon that is the result of physical properties in the body (for example, rhythmical activities such as heartbeat and muscle activation). Enhanced physiologic tremor is a more noticeable case of physiologic tremor that can be easily seen. 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.
Parkinsonian tremor—Parkinsonian tremor is common and one of the first signs of Parkinson's disease, although not all people with Parkinson's disease have tremor. Its shaking is most noticeable when the hands are at rest and may look as if someone's trying to roll a pill between the thumb and a finger. Parkinson's tremor may also affect the chin, lips, face, and legs. The tremor may initially appear in only one limb or on just one side of the body but may spread to both sides as the disease progresses. The tremor is often made worse by stress or strong emotions.
Orthostatic tremor—Orthostatic tremor is a rare disorder characterized by rapid muscle contractions in the legs that occur when you stand up. The tremor is usually relieved when you sit or walk. Standing may make you may feel unsteady or unbalanced, causing you to immediately try to sit or walk. Because the tremor has such a high frequency (very fast shaking) it may not be visible to the naked eye but can be felt by touching the thighs or calves or can be detected by a doctor examining the muscles with a stethoscope. In some cases, the tremor can become more severe over time. The cause of orthostatic tremor is unknown, and many doctors don't understand the condition.
How is tremor diagnosed and treated?
Your doctor will perform a physical exam and review your medical history. Your doctor may also order a neurological exam, which would test muscle strength, reflexes, muscle tone, balance, and speech, and evaluate:
- Whether the tremor occurs when the muscles are at rest or in action
- The location of the tremor on the body (and if it occurs on one or both sides of the body)
- The appearance of the tremor (tremor frequency and visibility)
You may also be asked to give blood or urine samples to rule out certain medications or other contributing factors to your tremor. Diagnostic imaging may help determine if the tremor is the result of damage in the brain. An electromyogram, which measures involuntary muscle activity and muscle response to nerve stimulation, may identify muscle or nerve problems.
Additional tests may be administered to determine any functional limitations such as difficulty with handwriting or the ability to hold a fork or cup. You may be asked to perform a series of tasks or exercises such as placing a finger on the tip of their nose or drawing a spiral.
Although there is no cure for most forms of tremor, treatments are available to help manage symptoms. In some cases, your symptoms may be mild enough that they do not need treating. Treating any underlying health condition can sometimes cure or reduce your tremor.
Medications can slow tremor. Some medications commonly used to treat tremor include:
- Beta-blocking drugs are normally used to treat high blood pressure but can treat essential tremor and other types of action tremor in some people.
- Anti-seizure medications can be effective in people with essential tremor who do not respond to beta-blockers. However, it is important to note that some anti-seizure medications can cause tremor.
- Tranquilizers (also known as benzodiazepines) may be prescribed to temporarily help some people with tremor. However, these medications can negatively affect sleep, concentration, and coordination, and there may be the chance of physical dependence on the medication and withdrawal symptoms when stopped abruptly.
- Parkinson's disease medications (levodopa, carbidopa) are used to treat movement issues and tremor associated with Parkinson's disease.
Botulinum injections can treat almost all types of tremor and are especially useful for head tremor and dystonic tremor. Although botulinum toxin injections can improve tremor for roughly three months at a time, they can also cause muscle weakness and difficulty swallowing in some instances.
This treatment for essential tremor uses magnetic resonance imaging to deliver focused ultrasound that creates a lesion in tiny areas of the brain's thalamus thought to be causing the tremors. The treatment is approved only for those individuals whose essential tremor does not respond well to anti-seizure or beta-blocking drugs.
Surgical procedures may be performed when tremor does not respond to drug therapies or severely impacts daily life.
- Deep brain stimulation (DBS) is the most common form of surgical treatment of tremor. This effective, low risk treatment uses surgically implanted electrodes to send high-frequency electrical signals to the thalamus, the deep structure of the brain that coordinates and controls some involuntary movements. A small pulse generating device placed under the skin in the upper chest (similar to a pacemaker) sends electrical stimuli to the brain to temporarily stop tremor. DBS is currently used to treat parkinsonian tremor, essential tremor, and dystonia.
- Radiofrequency ablation uses a radio wave to generate an electric current that heats up a nerve and disrupts its signaling ability for typically six or more months. It is usually performed on only one side of the brain to improve tremor on the opposite side of the body.
Self-care or lifestyle changes
Learn as much as you can about your tremor and share that information with your doctor, family, and caregivers.
Certain lifestyle changes and techniques may provide some relief if you have mild to moderate tremor.
- Physical, speech-language, and occupational therapy may help you to control tremor and meet daily challenges caused by the tremor.
- Eliminate or reduce caffeine, alcohol, or certain medications that can cause or worsen your tremor.
- Talk with your doctor or therapist about assistive tools, such as special plates, spoons, or heavier utensils, that can lessen tremor or make it easier to eat.
- Take your medications on time.
- Reduce stress or stressful situations that can aggravate your tremor.
- Wear clothes that make it easier to dress, such as those that use Velcro instead of buttons. Also consider slip-on or no-tie shoes with Velcro closers.
- Get enough sleep. Some tremors worsen when you are tired or sleepy. You may need to adjust your work schedule or physical activity to prevent fatigue and get restful sleep.
What are the latest updates on tremor?
The National Institute of Neurological Disorders and Stroke (NINDS), a component of the National Institutes of Health (NIH), the leading supporter of biomedical research in the world, is the primary federal funding agency on tremor and other neurological disorders.
Researchers are working to better understand the underlying brain functions that cause tremor, identify the genetic factors that make individuals more susceptible to the disorder, and develop new and better treatment options.
Identifying brain functioning and disease markers
NINDS researchers are using non-invasive neuroimaging techniques to identify structural and functional changes in the brain. By developing sensitive and specific markers for movement disorders such as Parkinson's disease and essential tremor, researchers can track changes as each disease progresses. Other researchers are using functional magnetic resonance imaging technology to better understand normal and diseased brain circuit functions and associated motor behaviors. Scientists hope to design therapies that can restore normal brain circuit function in diseases such as Parkinson's disease and tremor.
Essential tremor may have a strong genetic component affecting multiple generations of families. NINDS researchers are building on previous genetics work to identify susceptibility genes for familial early-onset (before age 40) essential tremor. Researchers are focusing on multigenerational, early tremor onset families to better detect linkages. Additionally, NINDS scientists are researching the impact of genetic abnormalities on the development of essential tremor.
Medications and other treatment methods
Medications are effective in about 50 percent of individuals with tremor. In order to develop assistive and rehabilitative tremor-suppressing devices for people with essential tremor, researchers are exploring where and how to minimize or suppress tremor while still allowing for voluntary movements.
Many people with essential tremor respond to ethanol (alcohol); however, it is not clear why or how. NINDS researchers are studying the impact of ethanol on tremor to determine the correct dosage amount and its physiological impact on the brain and whether other medications without the side effects of ethanol can be effective.
Other NIH researchers hope to identify the source of essential tremor, study the effects of currently available tremor-suppressant drugs on the brain, and develop more targeted and effective therapies.
How can I or my loved one help improve care for people with tremor?
Consider participating in a clinical trial so clinicians and scientists can learn more about tremor and related disorders. Clinical research uses human volunteers to help researchers learn more about a disorder and perhaps find better ways to safely detect, treat, or prevent disease.
All types of volunteers are needed—those who are healthy or may have an illness or disease—of all different ages, sexes, races, and ethnicities to ensure that study results apply to as many people as possible, and that treatments will be safe and effective for everyone who will use them.
For information about participating in clinical research visit NIH Clinical Research Trials and You. Learn about clinical trials currently looking for people with tremor at Clinicaltrials.gov.
Where can I find more information about tremor?
The following resources may provide information about tremor:
Diann Shaddox Foundation for Essential Tremor
International Essential Tremor Foundation
Phone: 913-341-3880 or 888-367-3667