Gamma Knife Radiosurgery for Treatment of Essential Tremor

This research is being done because although multiple studies evaluating gamma knife for
essential tremor show good results, few studies evaluating patients prospectively have been
done. Prior studies have looked at patient outcomes following treatment - also known as
retrospective studies. In this study, data collection will initiate before treatment, to
obtain consistent baseline evaluations from all study participants undergoing the gamma knife
treatment and at specific intervals following treatment.

Inclusion Criteria:

- Men and women age 18 years or older

- Diagnosis of essential tremor as confirmed from clinical history and examination by a
neurologist or neurosurgeon

- Tremor following prior first line therapy with either propranolol or primidone

- Must be able to undergo MRI of brain and CT of head for treatment planning

- Postural or intention tremor severity score of greater than or equal to 2 in one
hand/arm as measured by the CRST rating scale

Exclusion Criteria:

- Prior ipsilateral stereotactic radiosurgical ablation of the thalamus, ipsilateral
deep brain stimulation, radiofrequency ablation of a ipsilateral thalamic target, or
ultrasound ablation of an ipsilateral thalamic target

- Prior whole brain radiation therapy

- Pregnancy