What causes ET?
Essential tremor is due to abnormal communication between certain areas of the brain, including the cerebellum, thalamus and brain stem. In the majority of people with ET, the tremor seems to be inherited as an autosomal dominant trait. This means that each child of a parent with ET has approximately a 50% chance of inheriting a gene that causes ET. Researchers have already located two genes that predispose to ET and are currently trying to locate others. Not everyone who inherits a gene develops symptoms, and some people have ET and do not have a family history of tremor, possibly suggesting other causes. At this time, there is no genetic test for ET.
ET is thought to be due to oscillations of brain cell activity involving a part of the brain called the inferior olive which projects to the muscles via cerebellum, thalamus, and cortex. Interruption of tremor signals along this pathway may be the basis for the effectiveness of thalamic (ventral intermediate thalamus – Vim) stimulation in the treatment of essential tremor. Treating Essential Tremor Patients with significant functional impairment often opt for treatment. For some patients, the tremor may not be functionally disabling, but instead may be a source of severe embarrassment causing social isolation so that they also opt for treatment. The decision to treat with medications is made when the degree of impairment or discomfort outweighs the side effects of treatment. When patients do not achieve satisfactory control of their tremor with non-medical or medical therapies, and there is significant functional impairment, surgical options should be considered.
Essential tremor is thought to be caused by electrical fluctuations in the brain that send abnormal signals out to the muscles. Several areas of the brain have been implicated in generating these abnormal signals. The signals travel through a variety of brain regions before they make it out to muscles. These regions include the cerebellum, red nucleus, globus pallidus, thalamus and cortex. Interruption of tremor signals along this pathway may be why thalamic (ventral intermediate thalamus – Vim) stimulation using a surgically implanted device is often effective in treating essential tremor. Treating Essential Tremor Patients with significant functional impairment usually opt for some form of treatment. Less impaired patients may choose to forgo treatment all together. Some patients that aren’t functionally impaired desire treatment because their tremor is a significant source of embarrassment.
