Tremor

Physiologic tremor is the normal tremor that everyone has to some degree. For example, most people's hands, when held outstretched, usually tremble slightly. Such slight, rapid tremor reflects the precise moment-by-moment control of muscles by nerves. In most people, the tremor is barely noticeable. However, a normal tremor may become more noticeable under certain conditions and may worry people. For example, the tremor may be more noticeable when people

Essential tremor results from a problem in the nervous system, but people with this tremor rarely have any other symptoms of nervous system dysfunction (neurologic symptoms Introduction to Symptoms of Brain, Spinal Cord, and Nerve Disorders ). The cause is unclear, but the tremor often runs in families.

Essential tremor usually begins during early adulthood but can begin at any age. The tremor slowly becomes more noticeable as people age. Thus, it is sometimes incorrectly called senile tremor. The tremor usually involves the arms and hands and sometimes affects the head. When it affects the head, people may look as if they are nodding yes or shaking their head no. These tremors are usually worsened by holding a limb outstretched (against gravity) or by moving a limb.

Usually, essential tremor remains mild. However, it can be troublesome and embarrassing. It can affect handwriting and make using utensils difficult. In some people, the tremor gradually worsens over time, eventually resulting in disability. Symptoms may resemble those of Parkinson disease Parkinson Disease (PD) Parkinson disease is a slowly progressive degenerative disorder of specific areas of the brain. It is characterized by tremor when muscles are at rest (resting tremor), increased muscle tone... read more , and sometimes essential tremor is misdiagnosed as Parkinson disease. Rarely, people have Parkinson disease and essential tremor.

Resting tremor occurs when muscles are at rest. An arm or a leg shakes even when a person is completely relaxed. The tremor becomes less noticeable or disappears when the person moves the affected muscles. Resting tremors are often slow and coarse.

These tremors develop when nerve cells in the part of the brain called the basal ganglia are disturbed. The basal ganglia help initiate and smooth out intended (voluntary) muscle movements. Such disturbances usually result from

However, resting tremors can also result from use of drugs that can affect this part of the brain, such as antipsychotic drugs and some drugs used to relieve nausea.

Resting tremors may be socially embarrassing, but because they go away when people try to do something (such as drinking a glass of water), they typically do not interfere with daily activities.

This tremor occurs during a purposeful movement, as when reaching for an object with the hand. People may miss the object because of the tremor. Intention tremors worsen as people get closer to the targeted object. These tremors are relatively slow and wide (coarse).

Intention tremors result from damage to the cerebellum, the part of the brain responsible for balance and coordination. Thus, cerebellar tremor and intention tremor may be used as synonyms.

Common causes of intention tremor include

Other disorders and drugs can also cause the cerebellum to malfunction, resulting in an intention tremor. They include

This type of tremor is most obvious when a limb is held in a position that requires resisting the pull of gravity, as when people hold their arms outstretched.

The most common postural tremors are

Complex tremor is a tremor that has features of more than one type of tremor.

Common causes of complex tremors are

The following symptoms are cause for concern:

People with warning signs should see a doctor immediately.

People without warning signs should see a doctor as soon as possible.

If people are under 50 years old and do not have a family history of essential tremors, they should see a doctor soon. Being evaluated by a doctor is important to make sure that the cause is not another disorder or a drug.

Doctors first ask questions about the person's symptoms and medical history and then do a physical examination. What doctors find during the history and physical examination often suggests a cause and the tests that may need to be done (see table Some Causes and Features of Tremor Some Causes and Features of Tremor ).

Doctors ask about the tremor:

If the tremor began suddenly, doctors ask about events that may have triggered it (such as a recent injury or use of a new drug).

Doctors review the person's past medical history, looking for conditions associated with tremor Types of Tremors A tremor is an involuntary, rhythmic, shaking movement of part of the body, such as the hands, head, vocal cords, trunk, or legs. Tremors occur when muscles repeatedly contract and relax. (See... read more . They ask about tremors in close relatives. They review the drugs taken and ask about use of caffeine, alcohol, and recreational drugs (particularly whether the person recently stopped using such drugs).

Doctors do a physical examination, paying particular attention to the neurologic examination Neurologic Examination When a neurologic disorder is suspected, doctors usually evaluate all of the body systems during the physical examination, but they focus on the nervous system. Examination of the nervous system—the... read more (including the way the person walks). Doctors note which body parts are affected by the tremor. They observe how fast the shaking movements are in various situations:

The quality of the person's voice may be observed when holding a long note.

Doctors can usually identify the type of tremor based on its characteristics and results of the medical history and physical examination—for example,

Brain imaging with magnetic resonance imaging (MRI) or computed tomography (CT) is done if

Blood tests may be done to check for possible causes when the cause is unclear. Tests may include

Electromyography Electromyography and Nerve Conduction Studies Diagnostic procedures may be needed to confirm a diagnosis suggested by the medical history and neurologic examination. Electroencephalography (EEG) is a simple, painless procedure in which... read more (stimulating muscles and recording their electrical activity) is rarely done. But if the cause is thought to be nerve damage, it may be done.

Eliminating or minimizing the trigger may lessen physiologic tremor. For example, avoiding caffeine, getting enough sleep, and minimizing stress may help.

If many daily activities (such as using utensils and drinking from a glass at mealtime) become difficult or if the person's work requires steady hands, drug therapy may help.

People with a physiologic tremor and anxiety may benefit from taking a low dose of a benzodiazepine (a sedative), such as lorazepam. However, these drugs should be taken only occasionally.

If a physiologic tremor is worsened by taking prescribed drugs that are necessary or by feeling very anxious, propranolol (a beta-blocker Adrenergic blockers High blood pressure is very common. It often does not cause symptoms; however, high blood pressure can increase the risk of stroke, heart attack, and heart failure. Therefore, it is important... read more ) may help.

For some people, drinking alcohol in moderation may lessen the tremor, but doctors do not recommend this tactic as a treatment. Heavy drinking followed by suddenly stopping makes the tremor worse.

Antiseizure drugs (primidone, topiramate, or gabapentin) or propranolol may also be used if needed to control the tremor.

Benzodiazepines may be used to treat essential tremor if other drugs are ineffective.

Intention tremors are difficult to treat, but if the condition causing it can be corrected, the tremor may resolve.

If the condition cannot be corrected, a therapist may put wrist and ankle weights on the affected limb to reduce the tremor. Or people may be taught to brace the limb during activity. These measures sometimes help.

For this procedure, tiny electrodes are placed in the area of the brain involved in tremors—the basal ganglia (collections of nerve cells that help smooth out muscle movements). The electrodes send small amounts of electricity to the specific area of the basal ganglia responsible for the tremors and thus help relieve symptoms.

Deep brain stimulation is sometimes done when drugs cannot control a severe, disabling tremor. Sometimes essential tremors or tremors due to Parkinson disease or another disorder require such treatment. Such treatments are used only when drug therapy has been tried and has been not been effective. These treatments are available only at special centers.