ExAblate Transcranial MR Guided Focused Ultrasound for the Treatment of Essential Tremors

This study is evaluating a new technique for performing Thalamotomy for tremor control. While
current techniques have possible invasive or radiation effects, the use of ExAblate if
totally non-invasive and without any radiation. After informed consent and screening,
eligible subjects will be randomized to either an ExAblate treatment or an ExAblate Sham or
"fake" procedure. The chance of randomization to Sham is one out of four. Subjects who are
randomized to Sham Control will undergo the same procedure and follow-up visits through their
Month 3 visit. After the Month 3 assessments are complete, all subjects will be unblinded and
those in the Sham treated group will have the option for an actual ExAblate treatment in an
unblinded fashion, as long as they still qualify for ExAblate treatment. All subjects will be
followed at 6 and 12 months and for up to 5 years as directed by their doctor.

Inclusion Criteria:

- Men and women, age 22 years and older

- Subjects who are able and willing to give informed consent and able to attend all
study visits

- Subjects with a diagnosis of Essential Tremor as confirmed from clinical history and
examination by a neurologist or neurosurgeon specialized in movement disorder

- Subject exhibits a significant disability from their ET despite medical treatment

- Subjects should be on a stable dose of all ET medications for 30 days prior to study
entry

- Subject is able to communicate sensations during the ExAblate Transcranial procedure

Exclusion Criteria:

- Subjects with unstable cardiac status

- Severe hypertension

- Subjects with standard contraindications for MR imaging such as non-MRI compatible
implanted metallic devices including cardiac pacemakers, size limitations, etc.

- Known intolerance or allergies to the MRI contrast agent including advanced kidney
disease or severely impaired renal function

- Significant claustrophobia that cannot be managed with mild medication

- Current medical condition resulting in abnormal bleeding and/or coagulopathy

- Receiving anticoagulant (e.g. warfarin) or antiplatelet (e.g. aspirin) therapy within
one week of focused ultrasound procedure or drugs known to increase risk or hemorrhage

- History of intracranial hemorrhage

- History of multiple strokes, or a stroke within past 6 months

- Subjects who are not able or willing to tolerate the required prolonged stationary
supine position during treatment

- Are participating or have participated in another clinical trial in the last 30 days

- Subjects unable to communicate with the investigator and staff

- Subjects with a history of seizures within the past year

- Subjects with brain tumors