Essential tremor

Essential tremor is a disorder of the nervous system that involves involuntary shaking of parts of the body, usually without any other symptoms.

Essential tremor is a relatively common and usually mild condition that may affect up to 5% of New Zealand adults. However, in some cases the disorder can be severe and affect daily activities like writing, eating, and getting dressed.

Essential tremor does not indicate a serious underlying disorder of the nervous system and does not alter life expectancy. It can be mistaken for Parkinson’s disease so referral to a neurologist can assist with diagnosis.

Causes and risk factors

Essential tremor occurs as the result of abnormal communication between certain areas of the brain. A genetic cause for essential tremor has been identified in 50–70% of cases and, as a result, it has a strong tendency to run in families (the condition is sometimes referred to as familial tremor).

While essential tremor can affect people of all ages, the average age of onset is 35–45 years. The condition may get worse over time. It occurs equally in men and women, and can affect all ethnic groups.

Signs and symptoms

Tremors are usually the only symptom of essential tremor. In the early stages of the condition tremors may only be noticed periodically and may be very mild. It is possible for symptoms to plateau – where the condition remains stable without worsening for many years.

Essential tremor most commonly affects the arms, hands, and head. It can also affect the jaw, face, and vocal cords and, rarely, the torso and legs.

There is considerable individual variation as to the severity of the condition. Symptoms can differ from person to person and change from day to day.

Three distinct types of tremor can be observed in the condition:

• Postural tremor: This is the most common type of tremor experienced in essential tremor. It is seen when a person is voluntarily maintaining a fixed position, eg: having outstretched arms. It may be a relatively fine and rapid tremor.
• Kinetic tremor: This type of tremor is obvious when performing tasks, such as writing, drinking from a cup, or buttoning a shirt. It is a more severe tremor and it is the tremor that can interfere most with daily activities.
• Internal tremor: This is a feeling of general shakiness, often accompanied by a sensation of vibration inside the body.
• Factors that can increase the severity of tremors include fatigue, anxiety, foods containing caffeine (eg: chocolate, cola, coffee), excessive alcohol, and smoking.

Diagnosis

Diagnosis of essential tremor is based on medical history, family history, physical examination, and assessment of symptoms. There is no specific test to diagnose essential tremor.

Blood tests may be done to determine if tremor symptoms are due to a side effect of certain prescription drugs (eg: dopamine, lithium, tricyclic antidepressants), chemical poisoning (eg: alcohol, arsenic, caffeine, DDT, lead, nicotine), or some other disorder (eg: hyperthyroidism, kidney disease, liver disease, vitamin B12 deficiency).

Due to similarities between essential tremor and Parkinson’s disease, a referral to a neurologist (a doctor who specialises in brain and nervous system disorders) is usually required before an accurate diagnosis can be made.

Treatment

Treatment of essential tremor aims to relieve its symptoms. However, if the tremor does not interfere with daily living, treatment may not be necessary. Treatment options include:

Lifestyle changes

The first step in treatment often involves lifestyle changes. These may include:

• Avoiding food and drinks containing caffeine
• Not smoking
• Avoiding excessive alcohol
• Managing stress
• Getting adequate amounts of rest to reduce fatigue.

Alternative therapies

Alternative therapies such as yoga, biofeedback and tai chi may be useful in relieving symptoms – especially in those whose symptoms worsen with stress and anxiety.

Physical or occupational therapy

Physical or occupational therapy may be recommended. Physical therapists can teach people with essential tremor exercises to improve their muscle strength, control, and coordination. Occupational therapists can help people to adapt to living with essential tremor.

Medications

If further treatment is required, a type of medication called a beta-blocker – most commonly propranolol – may be prescribed. Beta-blockers inhibit the action of adrenaline (a hormone that is released as part of the body's fight-or-flight response to stress) and reduce the severity of tremors. They tend to work best for hand tremors.

Anti-seizure medications – most commonly primidone – may be effective for reducing the severity of tremor in people who do not respond to beta blockers.

Sedative medications, eg: benzodiazepines, may be beneficial in people for whom anxiety worsens their tremors.

Surgery

This is only considered in very severe, disabling cases, where all other forms of treatment have been unsuccessful. Surgery involves operating on, or electrically stimulating, an area of the brain called the thalamus. The thalamus is involved in the control of movement and surgery to this area can reduce the severity of tremors.

Further information and support

For further information and support about essential tremor, contact you doctor, or the New Zealand Essential Tremor Support Group. Their details are as follows:

New Zealand Essential Tremor Support Group Inc.

Freephone: 0508 TREMOR (873 667)
E-mail: [email protected]
Web: www.essentialtremor.org.nz

References

Burke, D.A. (2018). Essential tremor (Web page). Medscape Drugs and Diseases. New York, NY: WebMD LLC. http://emedicine.medscape.com/article/1150290-overview [Accessed: 29/05/20]
Mayo Clinic (2019). Essential tremor (Web Page). Rochester, MN: Mayo Foundation for Medical Education and Research. http://www.mayoclinic.org/diseases-conditions/essential-tremor/home/ovc-20177826 [Accessed: 29/05/20]
O’Toole, M.T. (Ed.) (2017). Essential tremor. Mosby’s Dictionary of Medicine, Nursing & Health Professions (10th ed.). St Louis, MI: Elsevier.

Last reviewed – June 2020

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