Alexandra Lebenthal, 55, has had essential tremor since she was a child but wasn’t officially diagnosed until her early forties. This neurologic condition is characterized by involuntary shaking of the hands, and sometimes of the head, voice, or other body parts. Although the tremor in both hands didn’t keep her from doing anything she wanted to do, it was embarrassing and made her feel ashamed and self-conscious—and she never talked about it.

Those feelings changed in 2017 when Lebenthal underwent a then-experimental therapeutic procedure called focused ultrasound—a minimally invasive method of targeting and zapping the area of the brain responsible for tremors—to reduce or eliminate the tremor in her left hand, which is her dominant hand.

For Lebenthal, a high-powered financial executive, the treatment was life-altering. “Before the procedure, I had to hold a cup of coffee with two hands,” she says. “And using my smartphone was a disaster.” After the procedure, she could type and text on her phone and even take a video.

When once she was too ashamed to talk about her tremors, Lebenthal now tells anyone who will listen about it, often demonstrating how steady her left hand is compared with her still-shaky right hand.

Focused ultrasound—approved by the US Food and Drug Administration for essential tremor in 2016 and for tremors in Parkinson’s disease (PD) in 2018—relies on two types of technology: MRI and sound waves. Surgeons use MRI scans to locate the target, and after guiding the laser to the specific area, they send more than 1,000 beams of sound waves to burn and destroy it. No incision or radiation is needed.

“The fundamental principle is analogous to using a magnifying glass to focus beams of sunlight on a single point to burn a hole in a leaf,” says Neal Kassell, MD, professor of neurosurgery at University of Virginia and chairman of the Focused Ultrasound Foundation, a nonprofit organization created to accelerate the development and adoption of focused ultrasound as a treatment. “Instead of using an optical lens to focus beams of light, focused ultrasound uses an acoustic lens to focus multiple beams of ultrasound energy on a specific target.”

Emerging research supports the benefits of focused ultrasound. In a 2019 study, published in Movement Disorders, 62 percent of patients showed improvements in their Parkinson’s-related tremor compared with a group that had a sham treatment. In a 2017 study, published in the Journal of Neurosurgery, of 30 patients (18 of whom had essential tremor, nine with Parkinson’s, and three with essential tremor-PD), all showed significant improvement in their tremor up to six months after treatment.

Less than 40 years ago, the only surgical treatment for essential tremor required inserting a probe in the skull to either freeze or coagulate the thalamus, the relay station for motor and sensory signals and a key area implicated in tremor symptoms. In 1997, deep brain stimulation (DBS) was approved to treat essential tremor and the tremors of Parkinson’s disease. The surgery involves drilling a small hole in the skull and implanting electrodes in the brain, which deliver electrical stimulation to the thalamus or the globus pallidus, another area related to Parkinson's symptoms, to stop the tremors. The amount of stimulation is controlled by a battery-operated pacemaker-like device placed under the skin in the upper chest.

The Path to Treatment

In most cases, essential tremor is managed first with medication, including beta blockers, anti-seizure or anti-anxiety medications. If pharmaceuticals are not effective, patients are usually referred to a surgical movement disorders team for DBS and, increasingly, focused ultrasound.

“For the expected benefits to outweigh the risks [of surgery], the signs and symptoms of disease must be severe enough to affect the patient’s quality of life,” explains Binit Shah, MD, assistant professor of neurology in the Parkinson’s disease and movement disorders division at the University of Virginia in Charlottesville. “If not, we would continue prescribing medications, as those side effects can be more manageable than complications from a surgical procedure.”

Before undergoing focused ultrasound, patients are evaluated by neurologists, who assess the patient’s general physical condition, risk factors for bleeding, adverse reactions to MRI, and other intracranial or cognitive impairments. Patients who have a pacemaker or kidney disease or who can’t tolerate an MRI are ineligible. The selection process is rigorous to ensure the appropriate candidates are selected. Eligible patients would then discuss the pros and cons with their physicians and surgeons.

Focused ultrasound doesn’t require general anesthesia or any incisions. It’s an outpatient procedure, and most patients can leave the hospital within hours. The most common side effect is numbness in the hands or face, which is generally mild and short-lived. Other side effects may include headache, nausea, dizziness, balance problems, and a burning scalp sensation.

A disadvantage is that the treatment is only approved for one side of the body, and if the procedure is unsuccessful—the tremor isn’t eliminated or gets worse—it cannot be adjusted or reversed, says Paul S. Fishman, MD, PhD, professor of neurology at the University of Maryland School of Medicine and chief of neurology at the Veterans Affairs Maryland Health Care System in Baltimore. In addition, insurance coverage is limited. The procedure is covered by Medicare in 38 states and by some private insurers. Otherwise, the out-of-pocket cost can be as much as $25,000.

“My tremor has improved almost 100 percent,” says Lebenthal. “About 5 percent of the time when I lift a glass, my hand kind of jerks rather than shakes. Each time I lift a glass or cup of coffee, I marvel at how hard it used to be and how easy it is now.”

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What to Expect from Focused Ultrasound

More Information on Focused Ultrasound Treatment

• Brigham and Women's Hospital, Boston; 617-732-5500
• Stanford University School of Medicine, Stanford, CA; 650-723-4000
• Swedish Medical Center, Neuroscience Institute, Seattle; 206-320-4145
• University of Maryland School of Medicine, Baltimore; 410-706-3100
• University of Pennsylvania Health System, Philadelphia; 800-789-7366
• University of Virginia Health System, Charlottesville, VA; 434-243-5377
• Weill Cornell Medical Center, New York; 212-746-5454