Stereotactic Radiosurgery for Essential Tremor and Parkinsonian Tremor

Tremor is the most common of all movement disorders. Patients with essential tremor (ET) or Parkinsonian tremor (PT) may be severely disabled by their tremor. When the tremor is inadequately controlled by medications, surgical options are often offered. However, some patients may prefer a noninvasive treatment approach and some patients are not surgical candidates for medical reasons.

Stereotactic radiosurgery (SRS) is a treatment that uses high-energy highly-focused radiation (X-rays) to destroy a tiny region in the brain that causes tremor to occur. This region is known as the ventral intermedius nucleus of the thalamus and is the same area targeted by surgical deep brain stimulator (DBS) treatment or neurosurgical operation (thalamotomy). Multiple case series publications using Gamma Knife stereotactic radiation have been reported that show stereotactic radiosurgery is safe and effective treatment for ET and PT, making it a standard treatment for inoperable and inadequately controlled tremor patients. However, radiation treatment by linear accelerator machines are much more common than Gamma Knife treatment machines in the United States, and there are no reports of large series of ET and PT patients treated using linear accelerator-based SRS using a noninvasive mask-based targeting system.

This clinical trial asks the question of whether linear accelerator-based SRS is as safe and effective as that reported for Gamma Knife procedures, and whether it is a valid alternative to surgical thalamotomy or implantation of a deep brain stimulator (DBS) device. The primary measurements are quality of life related to tremor before and after stereotactic radiosurgery treatment, and secondary measurements are degree of tremor severity and usage of tremor-related medications.

Stereotactic Radiosurgery (SRS) is a standard-of-care treatment for patients with severe tremor. This clinical trial is a questionnaire-based trial that only involves completion of 2 questionnaires at the consultation appointments with neurology and radiation oncology. The questionnaires only take a few minutes and will provide us with valuable information about how severe the patient's tremor is before and after SRS treatment at 3-month intervals for 1 year. Currently we are only performing SRS treatment on one side of the brain (effects one side of the body) so the side with the worst tremor is treated.

Financial: All associated steps listed below are considered the Standard of Care to receive SRS treatment for tremor and are billed to the patient's insurance per the usual routine. Patients can receive this treatment without participating in the clinical trial questionnaires. There is no financial support, no compensation, and no travel stipend available to patients who participate in this trial.