Essential tremor Health Article

Definition

Essential tremor is a type of involuntary shaking movement in which no cause can be identified. Involuntary means you shake without trying to do so.

See also:

• Drug-induced tremor
• Tremor

Alternative Names

Tremor - essential; Familial tremor; Tremor - familial

Causes, incidence, and risk factors

Essential tremor is the most common type of tremor. In general, tremors occur when there is a problem with the nerves supplying certain muscles. However, everyone has some essential tremor but the movements are usually so small that they can't be seen.

The specific cause for essential tremor is unknown. Some research suggests that the cerebellum, the part of the brain that controls muscles movements, does not work correctly in patients with essential tremor.

Noticeable essential tremors can be seen at any age but are most common in people older than 65.

Essential tremor can also occur with other neurological conditions, including dystonia, parkinsonism, and certain inherited nerve conditions such as Charcot-Marie-Tooth disease.

If an essential tremor occurs in more than one member of a family, it is called a familial tremor. This type of essential tremor is passed down through families (inherited), which suggests that genes play a role in its cause.

Familial tremor is usually a dominant trait, which means that you only need to get the gene from one parent to develop the disorder. It usually starts in early middle age, but may be seen in people who are older or younger.

Symptoms

The tremor is usually most obvious in the hands, but may affect the arms, head, eyelids, or other muscles. The tremor rarely affects the legs or feet. People with essential tremor may have trouble holding or using small objects such as silverware or a pen.

The shaking usually involves small, rapid movements -- more than 5 times a second.

Specific symptoms may include:

• Head nodding
• Shaking or quivering sound to the voice if the tremor affects the voice box
• Difficulty writing, drawing, drinking from a cup, or using tools if the tremor affects the hands

The tremors may:

• Occur when you move (action-related tremor), and may be less noticeable with rest
• Come and go, but generally get worse as you age
• Get worse with stress, caffeine, and certain medications
• Not affect both sides of the body the same way