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Essential tremor is a disorder of the nervous system that causes tremor or involuntary shaking especially in the arms and hands

This type of tremor is usually not evident at rest and worsens under conditions of stress, fatigue, hunger, caffeine-use, and cigarette smoking

Several genes are believed to contribute to an individual’s risk of developing essential tremor

The most common neurological disorder

Also known as ‘benign essential tremor’ or ‘hereditary tremor’, this type of tremor is called ‘essential’, because it occurs in otherwise healthy people and does not have a known cause. Essential tremor (ET) has not been linked to other neurological conditions, is not caused by injury nor is it a side-effect of medication.

Comes in two main forms

This condition comes in two main forms: ET with head tremor and young-onset ET (i.e. that starts at an earlier age than is usual). If ET occurs in more than one member of a family, it is referred to as ‘familial’.

Characterized by hand-tremors when eating and writing

ET is sometimes confused with Parkinson´s disease. However, while Parkinson´s disease is characterized by resting tremor, stiffness and slowness of movement, ET is most frequently characterized by tremors that occur in certain postures of the body, for example in the arms or hands during voluntary movements such as eating and writing. There is sometimes also tremor of the head and voice, but legs are rarely affected. ET can be aggravated by emotional stress, fever, physical exertion, or low blood sugar. ET often impairs writing, drinking, eating and various other activities of daily life.

Many cases of essential tremor are undiagnosed

ET is most often diagnosed between adolescence and 40 years of age, but can develop from childhood and onwards. It is estimated that as many as 5% of people older than 40, and 20% over 65 may have ET. However, many individuals with ET are not diagnosed as such. It is thought that about ten million people have ET in the United States. With the exception of stroke, ET is the most common neurological disorder. It is eight to ten times more common than Parkinson´s disease.

Most cases are largely attributable to genetics

Environmental factors may play a role in the risk of developing ET, but the majority of ET cases are thought to be familial, that is, attributable largely to genetic factors. Linkage studies have identified regions on chromosomes 3q13 (ETM1) (4) and 2p24.1 (ETM2) that are thought to underlie some cases of familial ET. However, the actual sequence variants in these regions have yet to be identified.

deCODE scientists have found a variant associated with FET

Scientists at deCODE genetics have identified a sequence variant, located in the LINGO1 gene on chromosome 15q24.3, that is associated with an increased risk of developing ET. The associated risk was observed in both the familial and sporadic form of ET.

deCODEme can calculate your genetic risk for FET

The deCODEme Genetic Scan identifies this variant and provides an interpretation of the associated risk for the development of essential tremor for individuals of European descent. At this time risk information is not available for other ethnicities.

risk factors for essential tremor largely unknown

The only well-established risk factors for essential tremor are genetic variants and age.

Lifestyle suggestions for people with essential tremor

Essential tremor is not a dangerous or life-threatening condition, but people may find the tremors annoying and embarrassing and if severe, they can adversely affect daily activities and reduce the quality of life. Since the pathology of ET is largely unknown, few recommendations can be provided about how to prevent or delay the onset of the condition. For people who already have ET, the following lifestyle suggestions may, in some cases, help reduce or relieve tremors:

• Avoid stimulants. All stimulants including caffeine and nicotine, may make tremors worse.

• Use alcohol in moderation. Tremors may improve for a short while after drinking small quantities of alcohol, but once the effects of alcohol wear off the tremors tend to worsen.
• Avoid stress. Stress tends to make tremors worse, and relaxing can improve them. Although it may not be possible to eliminate all stress from life, people can learn to change how they react to stressful situations using a range of relaxation techniques. Many people also find that physical exercise can help reduce stress.
• Sleep and rest. Getting enough sleep is very important as fatigue can make tremors worse.

No single treatment works for all

The goal of ET treatment is to minimize functional disability, reduce social handicap, and improve the quality of life. In some cases, people may not require any treatment if their tremor symptoms are mild. There is no one treatment that works for all and sometimes several attempts must be made to find the most effective treatment for each individual. The options available consist of any, or a combination of, the following:

• Medications: Currently available medications cannot cure, prevent, or slow the rate of disease progression and are mainly used to reduce symptoms, the most commonly used are:

• Beta blockers, a group of medications normally used to treat high blood pressure, can help relieve tremors in some people. They may not be an option for people who also have asthma, diabetes or certain heart problems.
• Anti-seizure medications may be effective in people who do not respond to beta blockers.
• Tranquilizers are sometimes used to treat people whose tremors worsen with stress or anxiety.
• Botox injections, known for reducing facial wrinkles, can also be useful for treating some types of tremors, especially of the head and voice. Botox injections can only improve problems for up to three months at a time.
• Physical and/or occupational therapy can sometimes help reduce tremor and improve coordination and muscle control. In some cases using wrist weights can stabilize hands, as can the use of heavier plates, glasses and utensils when eating.
• Surgery may be an option for people whose tremors are severely disabling and who do not respond to medications. Deep brain stimulation is the most common surgical procedure, designed to interrupt signals from the thalamus, the area of the brain involved in causing the tremors.

more information

You can find out more information by talking with your doctor and visiting these Web sites:

• The International Essential Tremor Foundation
• MedlinePlus article on Familial Tremor
• National Institute of Neurological Disorders and Stroke: Tremor Fact Sheet

This content was last reviewed on February 08, 2010.

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