Essential Tremor
Cheryl A. Faber, M.D.

Definition:

A neurologic disorder involving involuntary tremors (shaking) that typically occur with activity and purposeful movement.

Causes, incidence, and risk factors:

Essential tremor (ET) affects about 6 out of 100,000 people. It is the most common form of tremor. If ET occurs in more than one member within a family group it is termed a familial tremor. Tremors occur at any age but are most common in older people.

ET is a relatively benign condition affecting movement and/or voice quality but with no other effects. It involves a rhythmic, moderately rapid tremor of muscles. Purposeful movements may make the tremors worse. There may be difficulty holding or using small objects (such as eating or writing utensils). Emotional stress may also increase the tremors. The tremors can also worsen with use of caffeine or certain medications. Over time, the tremors may affect the hands, arms, head, voice box (larynx), eyelids, or other muscles. ET less commonly involves the legs or feet. The cause is unknown.

Symptoms:

• Involuntary shaking, usually of the hands, arms or head.
• Can affect the vocal cords, resulting in a shaky or quavering voice.
• Less commonly affects the legs.
• Can be asymmetrical (more on one side than the other)
• Occur primarily with movement or activity.
• Worsened by stress, fatigue, and caffeine.
• Improved following alcohol consumption.

Signs and tests:

Diagnosis is usually made on the basis of the patient's history, and an examination that reveals tremors on voluntary movement and no other abnormalities.

No other tests may be required. However, testing may rule out other causes of tremors such as excessive caffeine, alcohol withdrawal, medication use, hyperthyroidism, pheochromocytoma, or other disorders. Laboratory tests and a head CT scan, MRI, X-rays, or other tests are usually normal if they are performed.

Treatment:

Treatment may not be necessary unless tremors interfere with the patient's ability to perform daily activities. Medications are variable because of individual responses to medications. Medications that may reduce tremors include propranolol, Mysoline and other anticonvulsants, and mild tranquilizers.

Caffeine (in substances such as coffee and soda) and other stimulants should be avoided because they commonly worsen tremors.

Expectations (prognosis):

ET is not a dangerous condition but can be annoying and embarrassing. If it is severe, ET can interfere with activities, especially fine motor skills such as writing. The tremor does typically worsen over time but in most cases does not lead to disability. ET is not related to Parkinson's disease, a neurological condition that causes a different type of tremor.

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