Use of intracranial ultrasound helps treat people with tremor and depression

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Brain surgery that doesn’t need an incision or produce blood, but dramatically improves the lives of people with essential tremor, depression and more, is in clinical trials around the world. 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 said that focused ultrasound is the most powerful sound you’ll ever hear, but a sound that one day could save your life.”

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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 in the body with a high degree of precision and accuracy, saving time and effort. adjacent normal tissue”.

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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 such as eating, drinking or writing.

Essential tremor is usually more prominent on one side of the body and can get worse with movement. It is most common in people age 40 and older and affects nearly 25 million worldwide, according to a 2021 study.

This was the case for Brenda Hric, 80 years old, who recently underwent focused ultrasound at the University of Virginia, a pioneer institution in the procedure.

Hric’s tremors made her uncomfortable in social situations because she was afraid of spilling or dropping something, she told CNN .

But just 44 seconds of focused ultrasound waves got rid of her tremor.

“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 the Lord for that.”

How it works

Focused ultrasound is a form of functional neurosurgery, targeting precise structures deep within the brain to change it, restore function or, in this case, stop a tumor. It is an alternative treatment for those, like Hric, who do not respond or are no longer affected by conventional drug treatment, experts said.

“In a simplistic sense, you can imagine that there are a bunch of abnormal neurons in this target that are out of control, causing the tremor,” Kassell said.

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 needed to treat essential tremor, patients need to shave their heads, as air can sometimes become trapped in the hair follicles.

The patient then undergoes MRI and CT scans so doctors can use the resulting images to map the brain’s structure and target.

Insightec Exablate Neuro, a focused ultrasound platform, instructs how many beams to use to do the treatment, so neurosurgeons can do what Jeff Elias calls “test shots, just to make sure we’re focused on the center of the target.”

Elias, a neurosurgeon at UVA Health who treated Hric, is a pioneer in treating essential tremors using ultrasound waves. In 2011, he led the critical clinical trials to gain regulatory approval for this procedure in the United States.

“These (test shots) are really low energy, but we want to see that our treatment is exactly where we want it,” he said. “This is our chance to line up the rifle.”

Four 11-second treatment doses significantly improved Hric’s tremor. The entire procedure took less than two hours, with most of it mapping the brain and testing the target.

Previously, Hric had trouble drawing inside circle lines. Focused ultrasound helped her color inside the lines.

Pros and cons

In general, anyone diagnosed with essential tremor who does not respond to medication would be eligible for focused ultrasound treatment, said Nir Lipsman, a scientist at the Sunnybrook Health Sciences Center in Toronto and director of Sunnybrook’s Harquail Center for Neuromodulation.

People who cannot undergo MRI scans because of claustrophobia or because they have metal inside their bodies are not eligible for focused ultrasound, said Noah Philip, professor of psychiatry and human behavior at Brown University’s Alpert Medical School. Philip is also a mental health research lead at the VA RR&D Center for Neurorestoration and Neurotechnology.

Ideally, the benefits of focused ultrasound are permanent, Lipsman said. “If you are able to destroy the part of the brain responsible for the tremor, it should be a permanent effect,” he said. “Within a year, however, some of these patients will have a rebound or recurrence of their tremor, and we don’t know why this happens.”

This return can also happen with drug treatment – ​​which is why some patients with essential tremor resort to focused ultrasound in the first place.

But some patients have experienced benefits five years after focused ultrasound, according to a 2022 study by Elias.

The possible 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 run.

“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 it goes away with time.”

Other common but usually temporary risks include mild foot instability after the procedure. But doctors do not use general anesthesia or hospitalize patients for this procedure, he added.

What comes next

Today, focused ultrasound technology is used globally at 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 ultrasound treatment effect in real time while the treatment is being given, whereas with radiation, the treatment effect is invisible while it is being given,” Kassell said. “And it takes weeks or months for the effect of radiation to become apparent.”

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 major depression and OCD. But more studies are needed.

One limitation of focused ultrasound is that not all skulls are the same, Lipsman said.

“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 make an effective lesion in the brain. The skull does not allow ultrasound to pass through. So this is a technical limitation of the technology, something we are actively working on.”

Focused ultrasound isn’t available for all conditions, but experts said they hope that “medicine’s best kept secret” will one day become standard treatment.

“I believe that in 10 years,” Kassell said, “focused ultrasound will be a mainstream therapy that will affect millions of patients every year around the world. It will be widely accepted.”

*With information from CNN’s Adeline Chen

Source: CNN Brasil

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