Symptoms:

The tremors are usually most obvious in the hands, but may affect the arms, head, eyelids, or other muscles. The tremors rarely affect the legs or feet. People with tremors 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.

The tremors may:

• Occur when you move (action-related tremor), and may be less noticeable with rest
• Disappear during sleep
• 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

Signs and tests:

Your doctor can make the diagnosis by performing a physical exam and asking questions about your medical and personal history.

A physical exam will show shaking with movement. There are usually no problems with coordination or mental function.

Further tests may be needed to rule out other reasons for the tremors. Other causes of tremors may include:

• Alcohol withdrawal
• Cigarette smoking
• Hyperthyroidism
• Pheochromocytoma
• Too much caffeine
• Use of certain medications
• Wilson's disease

Blood tests and imaging studies (such as a CT scan of the head, brain MRI, and x-rays) are usually normal.