Tremor is an unintentional, somewhat rhythmic, muscle movement involving to-and-fro movements (oscillations) of one or more parts of the body. It is the most common of all involuntary movements and can affect the hands, arms, head, face, vocal cords, trunk, and legs. Most tremors occur in the hands. In some people, tremor is a symptom of another neurological disorder. The most common form of tremor, however, occurs in otherwise healthy people. Although tremor is not life-threatening, it can be embarrassing to some people and make it harder to perform daily tasks.
Tremor is generally caused by problems in parts of the brain that control muscles throughout the body or in particular areas, such as the hands. Neurological disorders or conditions that can produce tremor include multiple sclerosis, stroke, traumatic brain injury, and neurodegenerative diseases that damage or destroy parts of the brainstem or the cerebellum. Other causes include the use of some drugs (such as amphetamines, corticosteroids, and drugs used for certain psychiatric disorders), alcohol abuse or withdrawal, mercury poisoning, overactive thyroid, or liver failure. Some forms of tremor are inherited and run in families, while others have no known cause.
Some forms of tremor are better managed with medical or surgical therapies than others.
Gamma Knife is chosen as a minimally invasive treatment option for tremor for patients who wish to avoid an invasive surgical procedure as well as patients with conditions that may turn them into unacceptable candidates for invasive stereotactic neurosurgical intervention, including very elderly patients, high-risk surgical patients suffering from severe cardiac or pulmonary pathology, and those using anticoagulants.