FDA Approval of Focused Ultrasound to Help Treat Tremors in Parkinson's

On December 18, 2018, the United States Food and Drug Administration (FDA) approved the use of focused ultrasound therapy for the treatment of tremor-dominant Parkinson’s disease (PD) with the use of the Insightec Exablate Neuro device.¹ This procedure was approved for PD patients with medication-refractory essential tremor (meaning that medication had worked to control the patient’s tremor but the medications no longer control the tremor) and is used to perform an incisionless thalamotomy.

Tremor is the primary symptom in 10-20% of PD patients, and it can have a devastating effect on a PD patient’s independence, quality of life, and activities of daily living.¹

Clinical trials looking at focused ultrasound therapy

Tremor-dominant PD (TDPD) is a specific subtype of PD. Patients with TDPD, do not have as much stiffness or instability as their symptoms, but rather, a tremor that may be resistant to medications dopamine replacement therapy, unlike other forms of PD.² TDPD patients also find that their non-motor symptoms may develop more slowly than their counterparts with other forms of PD. Previous treatment of TDPD required invasive procedures that required cutting into the brain and included a number of risks and adverse outcomes.²

Researchers studied the use of focused ultrasound guided by MRI in a trial of 27 TDPD patients. Twenty patients were given focused ultrasound thalamotomy, a non-invasive procedure that uses ultrasound therapy like a magnifying glass to make an opening in the part of the brain that is responsible for causing the tremor. Seven patients were treated with a sham procedure (similar to a placebo medication).² The study was double-blinded, meaning neither the patients nor the researchers knew who was getting the focused ultrasound or who was getting the sham procedure.

Patients receiving the focused ultrasound had a 62% improvement in hand tremors after receiving the therapy, while patients who received the sham procedure only had a 22% improvement in hand tremors.² Of the patients who received the focused ultrasound therapy, 13 continued to have improvement of tremors 12 months post-treatment.

Side effects of focused ultrasound therapy

No treatment is without side effects. The most common side effects that were reported during the trial were:²

• Finger and facial paresthesias or numbness and tingling with no explained cause
• Ataxia or imbalance and lack of coordination
• Hemiparesis or muscle weakness or paralysis on one side of the body
• Dysmetria or the inability to judge scale
• Mild vocal changes

Very few of these side effects were persistent; most of them went away within a few months of treatment. Some of the side effects were reported to be from the magnetic resonance imaging (MRI) that guides the ultrasound, and not from the ultrasound therapy itself.

Not all people with TDPD are eligible for this procedure, so you will need to talk to your medical team to find out if the focused ultrasound thalamotomy is the best procedure for your needs.³ The downside to this procedure is that it is so new that most insurances will not cover the treatment, which can run upwards of $30,000.⁴

While focused ultrasound thalamotomy is still a new and expensive procedure, it has the potential to change the quality of life in many people with TDPD. It also leads the way for research for other effective PD treatments, which have the potential to change the lives of many PD patients.