The most common cause of tremor (shaking) is essential tremor (ET). ET causes tremor but no other abnormalities. ET almost always first affects the hands, although other parts of the body such as the head or voice may eventually become involved. ET is always most pronounced when the hands are being used, whereas in Parkinson’s Disease the hands usually shake most when at rest and less when they are being used. Certain medications, such as asthma medications, Ritalin or lithium, as well as stress and caffeine, make most tremors worse. Occasionally other diseases such as thyroid disease or Parkinson’s disease can mimic ET; these should always be excluded and neurological review may be required.
ET can develop at any age, including childhood, but becomes increasingly common with advancing age, affecting up to 10-25% of older people. ET is familial in 50% of cases, and the cause is unknown in the remainder. If ET runs in the family, each child with an affected parent will have a 50% chance of inheriting the disorder.
In most people, ET is more embarrassing than disabling. In some people it can interfere with day to day activities such as drinking from a cup, eating or writing.
Many people with ET do not require treatment once they are reassured that they do not have an alternative disease. Known triggers such as caffeine should be avoided. The most commonly prescribed medications are propranolol and primidone. Propranolol is a blood pressure tablet that people with asthma or a history of asthma must not take. Primidone is an anti-epileptic medication. Other less commonly used medications that have been shown to be effective are alprazolam, gabapentin and topiramate. In the rare person with disabling ET, deep brain stimulation is a highly effective treatment.
ET can gradually worsen over many years, but is usually slowly progressive. It rarely becomes moderately or severely disabling.
Further Information and Support
National Institute of Neurological Disorders and Stroke
International Essential Tremor Foundation
Reviewed by Dr Victor Fung, MB BS (Hons) PhD FRACP, Director, Movement Disorders Unit, Department of Neurology, Westmead Hospital, Westmead.