High-Intensity Focused Ultrasound Reduces Shaking from Essential Tremor

Duke Is One of the Few NC Centers Offering HIFU

By Morgan deBlecourt
January 20, 2023
A doctor examines a patient's hand

If you’ve been diagnosed with essential tremor and medication is not doing enough to control your involuntary shaking, focused ultrasound may be an option. This FDA-approved treatment requires no incisions and can reduce severe essential tremors by about 70%.1 Here, Duke neurosurgeon Nandan Lad, MD, shares how focused ultrasound works and what you can expect from this treatment.

How Focused Ultrasound Works

Focused ultrasound, also called high-intensity focused ultrasound or HIFU, relies on an MRI technique called diffusion tensor imaging to accurately target and direct sound waves to a tiny area of your brain that helps regulate movement. Like a magnifying glass concentrates sunlight, the focused ultrasound energy creates enough heat to selectively interrupt signals that cause tremors.  

“When we disconnect that tremor circuit, the tremor stops,” Dr. Lad said.

Why Choose Focused Ultrasound

Focused ultrasound targets the same area of the brain as other procedures like deep brain stimulation (DBS) and traditional thalamotomy surgery. However, focused ultrasound requires no incisions, implanted probes, ionizing radiation, or general anesthesia. The risk of infection and side effects are also lower with focused ultrasound.

“There are people who are aware of deep brain stimulation but think, ‘My tremor is not so bad that I want to have a brain surgery or wires and a pacemaker implanted inside my body,’” Dr. Lad said. Focused ultrasound is a much less invasive procedure that doesn’t require a hospital stay. “Basically, you could come in with severe tremors and see a significant improvement the same day, and that is something more and more people are interested in."

What to Expect During Focused Ultrasound Treatment

Because ultrasound beams don’t penetrate through hair very well, your head will be shaved before the procedure. Then your doctor will numb four spots on your scalp where a custom frame will be fitted. The frame keeps your head perfectly still during the procedure.

Next, you’ll lie on an MRI bed wearing a helmet-like device secured to the metal frame. The bed will move in and out of the MRI scanner as it maps your unique tremor brain circuit.

Once doctors have identified a target area in your brain, they will apply a low dose of focused ultrasound energy. This is like a test run, allowing doctors to fine-tune the target. Doctors may ask you to provide feedback, like whether you feel any tingling in your fingers. 

When your doctors have identified the final target area, they will apply the full dose of focused ultrasound treatment. Then your doctor will test the success of the treatment by asking you to complete a simple task, such as draw a spiral, write your name, or hold a cup.

Afterward, doctors will observe you for about an hour, remove the head frame, and make sure you’re comfortable before you go home. Many people experience some instability or what feels like “sea legs” for the first couple weeks after treatment. “That's usually from the swelling around the focused ultrasound lesion. It expands over the first several days, and then it contracts back to normal,” Dr. Lad said. Other side effects like numbness, tingling, and headaches typically resolve within a month.

Is Focused Ultrasound Right for Me?

If you are an adult with refractory essential tremor (meaning medications aren’t working well enough), focused ultrasound might be right for you. “I’m excited to offer this ‘cutting edge’ therapy that is completely incisionless. I believe this will become the dominant treatment for essential tremor over the next several years,” Dr. Lad said.

To learn more about focused ultrasound at Duke, call 1-833-Etremor (1-833-387-3667).