Benign essential tremor (ET) is a movement disorder most commonly characterized by shaking in the hands. It occurs in as much as 10% of people over the age of 60. It may also cause shaking of the head, voice, arms, and trunk, and less often, of the legs and feet. Two types of tremor are common with ET:

• Postural tremor—shaking in certain positions only, such as with arms outstretched
• Kinetic or action tremor—shaking that gets worse during activities, such as eating or shaving

In some cases, ET can be socially isolating. It may interfere with normal daily activities, such as writing or speaking. If so, contact your doctor for an evaluation.

The cause of ET is unknown. However, it does run in families. When inherited, it is often called familial tremor. Children of parents with ET have a 50% chance of inheriting the condition.

In cases where there is no family history of tremor, other factors, such as toxins, may play a role, though this is far from clear. It is thought that essential tremor arises from abnormalities of specific circuits in the brain. This is an area that researchers are studying.

Family history of tremors is the only known risk factor for ET. Although the condition may occur at any age, it is more likely to occur in people older than 40 years old.

ET is generally not serious, but its severity may vary and worsen over time. Symptoms may include:

• Tremor that occurs when standing or moving the limbs, but not usually at rest
• Uncontrollable, rhythmic, up-and-down movement
• Shaking in hands, arms, head, voice, trunk, legs, or feet on both sides
• Shaking only in certain positions or during activity
• Trouble with fine motor skills, such as drawing, sewing, or playing an instrument
• Shaking that gets worse from caffeine, stress, fatigue, or heat
• Hearing loss (Some cases are associated with hearing loss.)
• Problems with social, functional, or occupational abilities (More severe cases interfere with these abilities.)

To be considered as having ET, tremors must not be related to other health conditions.

Your doctor will ask about your symptoms and your medical and family history. He will also do a physical exam, paying particular attention to the central nervous system. At this time, there are no special tests to diagnose ET. But, you may have blood, urine, or other tests (eg, MRI ) to rule out other causes, like:

• Parkinson's disease
• Elevated thyroid hormone
• Low blood sugar
• Stroke
• Medications

Most people with ET do not require treatment. Mild tremors may be relieved or even eliminated by simple measures, including:

• Staying well-rested
• Avoiding caffeine
• Avoiding stimulants often found in over-the-counter medications, like cold remedies
• Avoiding temperature extremes

Talk to your doctor about any medications that may be contributing to your symptoms. If your symptoms are troubling, the following treatment options may be helpful: