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In clinical trials around the world is brain surgery that doesn’t need an incision or produce any blood, yet dramatically improves the lives of people with essential tremor, depression and more. The procedure, known as a focused ultrasound, targets sound waves at parts of the brain to interrupt faulty brain circuits that cause symptoms.
“Focused ultrasound is a non-invasive therapeutic technology,” said Neal Kassell, founder and president of the Focused Ultrasound Foundation. “We say that focused ultrasound is the most powerful sound you’ll ever hear, but a sound that could one day save your life.”
Kassell describes the way it works as “analogous to using a magnifying glass to focus beams of light on a point and punch a hole in a leaf.”
“With focused ultrasound, instead of using an optical lens to focus beams of light,” he added, “an acoustic lens is used to focus multiple beams of ultrasonic energy onto targets deep within the body with a high degree of accuracy, sparing tissue. adjacent normal”.
Kassell has served on the board of directors of Insightec – a leading manufacturer of focused ultrasound machines – for more than 10 years, according to an Insightec spokesperson. He still owns 0.03% of the company’s shares, but Kassell assured CNN that the financial aspect does not drive his interest in focused ultrasound procedures.
The procedure has been significantly beneficial for people with essential tremor, a neurological disorder that causes involuntary, rhythmic tremors. The disorder can affect almost any part of the body, but tremors most commonly occur in the hands – even during simple tasks like eating, drinking or writing.
Essential tremor is usually more prominent on one side of the body and may worsen with movement. It’s most common in people age 40 and older, and it affects nearly 25 million worldwide, according to a 2021 study.
This was the case of Brenda Hric, 80 years old, who recently underwent focused ultrasound at the University of Virginia, in the United States, a pioneering institution of the procedure.
Hric’s tremors made her uncomfortable in social situations because she was afraid of spilling or dropping something, she confessed to CNN.
But just 44 seconds of focused ultrasound waves rid her of the tremors.
“I looked down at my hand and I could see it wasn’t moving, and it was the first time I’ve been able to see my fingers in about 20 years,” Hric said. “I think it’s definitely a miracle, and I thank God for that.”
How it works
Focused ultrasound is a form of functional neurosurgery, which targets precise structures deep in the brain to change it, restore function or, in this case, to stop a tremor. It is an alternative treatment for those, like Hric, who are unresponsive or unaffected by conventional drug treatment, experts said.
“Simply put, you can imagine a bunch of abnormal neurons in this target that are firing uncontrollably, causing the tremor,” exemplified Kassell.
Focused ultrasound technology uses a transducer to force beams of sound waves to converge at a point to increase temperature and destroy tissue.
Before receiving the high-intensity focused ultrasound (HIFU) needed to treat essential tremor, patients need to shave their heads, as air can sometimes get trapped in the hair follicles.
The patient then undergoes an MRI and CT scan so that doctors can use the resulting images to map the structure of the brain and the target.
Insightec Exablate Neuro, a focused ultrasound platform, instructs how many beams to use to do the treatment, then neurosurgeons can take what Jeff Elias calls “test shots, just to be sure they’re focused on the center of the target”.
Elias, a UVA Health neurosurgeon who treated Hric, is a pioneer in treating essential tremor using ultrasound waves. In 2011, he led the critical clinical trials to gain regulatory approval for this procedure in the United States.
“These imaging tests are really low-energy, but we want to see that our treatment is exactly where we want it. This is our opportunity to see the crosshairs.”
Four 11-second doses of treatment significantly improved Hric’s tremor. The entire procedure took less than two hours, most of which was spent mapping the brain and testing the target.
Before, Hric had difficulty drawing within the lines. Focused ultrasound helped her color inside the lines.
Pros and cons
Generally, anyone diagnosed with essential tremor that does not respond to medication would be eligible for focused ultrasound treatment, said Nir Lipsman, a scientist at the Sunnybrook Health Science Center in Toronto and director of the Sunnybrook Harquail Neuromodulation Center.
People who can’t have MRI scans because of claustrophobia or because they have metal inside their bodies are not eligible for focused ultrasound, noted Noah Philip, professor of psychiatry and human behavior at Brown University’s Alpert School of Medicine. Philip is also a leader in mental health research at the VA RR&D Center for Neurorestoration and Neurotechnology.
Ideally, the benefits of focused ultrasound are permanent, Lipsman pointed out. “If we are able to destroy the part of the brain responsible for the tremor, it should be a permanent effect,” he said. “However, after a year, some of the patients will have a recurrence of their tremor, and we don’t know why.”
However, such a recurrence can also happen with drug treatment – which is why some patients with essential tremor turn to focused ultrasound in the first place.
But some patients have experienced benefits five years after they have had focused ultrasounds, according to a 2022 study.
The potential side effects of focused ultrasound are why the scanning and testing parts of the procedure are so important. If the wrong area is targeted or overtreated, the patient’s balance and stability can be impaired in the long term.
“The most common risks we find in patients are temporary numbness or tingling that can sometimes occur in the treated arm or lip area,” Lipsman said. “The vast majority of the time disappears with time.”
Other common but usually temporary risks include slight instability in the feet after the procedure. But doctors do not use general anesthesia or hospitalize patients for this procedure, he added.
Focused ultrasound technology is currently used worldwide in various stages, including clinical trials and approved regulatory use. There are more than 170 clinical uses — including for neurodegenerative disorders and tumors of the brain, breast, lung, prostate and more — and the field is growing, Kassell said.
“You can observe the treatment effect with ultrasound in real time while the treatment is being administered, whereas with radiation the treatment effect is invisible while it is being administered,” said Kassell. “And it takes weeks or months for the effect of radiation to become visible.”
Use for depression and obsessive-compulsive disorder is on the table, according to a small 2020 study by Lipsman and a team of researchers. They found that focused ultrasound was safe and effective in improving symptoms in people with severe depression and OCD. But more studies are needed.
One limitation of focused ultrasound is that not all skulls are the same, Lipsman pointed out.
“Skull density has a big impact on the ultrasound’s ability to pass through it,” he added. “It’s rare, but there are some patients that, no matter how hard we try, we can’t do an effective injury to the brain. The skull doesn’t allow the ultrasound to pass through. So this is a technical limitation, something we are actively working on.”
Focused ultrasound is not available for all conditions, but experts said they are hopeful that “medicine’s best kept secret” will one day become standard treatment.
“My conviction is that within 10 years, focused ultrasound will be a mainstream therapy that will affect millions of patients every year around the world.” It will be widely accepted,” Kassell envisioned.
*Adeline Chen contributed to this article
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