Tremor is a rhythmic, back-and-forth movement of a body part.
People who experience tremor are unable to control the movement. There are several different types and causes of tremor. Tremor can occur while the body part is at rest (resting tremor) or while the body part is actively moving (action tremor). One of the most common causes of action tremor is a condition called essential tremor.
Essential tremor most commonly affects the arms and hands during activities. It is often noticeable while performing tasks such as drinking from a cup, writing, or reaching for an object. In most cases, both sides of the body are more or less equally involved. Essential tremor may also affect the head, causing shaking of the head in a side-to-side or up-and-down manner. If the voice is involved, there may be changes in the volume and smoothness of speech. The tremor of essential tremor usually remains mild and stable for many years but can slowly worsen over time.
The underlying cause of essential tremor is not fully understood. The condition can run in families, and about half of people with essential tremor have a family member who also has tremor.
The diagnosis of essential tremor is based on a medical history and physical examination performed by a health care professional. There is no single test to confirm the diagnosis. Other common causes of action tremor—such as side effects of certain medications or an overactive thyroid gland—should be ruled out.
Treatment of essential tremor depends on how severe the tremor is and whether it is interfering with activities. If the tremor is mild, it can be monitored over time by a doctor without treatment. Stress and caffeine intake can worsen tremors and should be minimized or avoided if possible.
If the tremor begins to interfere with activities, then treatment may be needed. Medications used to treat essential tremor include a class of medicines also used for controlling blood pressure (β-blockers) and some medicines also used to prevent seizures. If the tremor is not controlled by medications and remains severe, brain surgery can be considered. One type of brain surgery called deep brain stimulation involves placing a wire into deep brain structures and connecting the wire to a small battery-powered device that is implanted under the skin in the chest. This device can then be programmed to deliver electrical stimulation to areas of the brain that control movement and may help to decrease the tremor.
National Institute of Neurological Disorders and Strokewww.ninds.nih.gov/disorders/essential_tremor/essential_tremor.htm
International Parkinson and Movement Disorder Societyhttp://www.movementdisorders.org/MDS-Files1/Resources/PDFs/Essentialtremorpatientleaflet.pdf
To find this and previous JAMA Patient Pages, go to the Patient Page link on JAMA’s website at www.jama.com. Spanish translations are available in the supplemental content tab.
Sources: American Academy of Neurology, National Institute of Neurological Disorders and Stroke, International Parkinson and Movement Disorder Society
Christopher C. Muth. Essential Tremor. JAMA. 2016;316(20):2162. doi:10.1001/jama.2016.16376