Brain implant helps 5 people recover – 12/11/2023 – Science

Traumatic brain injuries have left more than 5 million Americans permanently disabled. They have difficulty concentrating on even simple tasks and often have to abandon their jobs or studies.

A study published on the 4th gave them a little hope. Five people with moderate to severe brain injuries had electrodes implanted in their heads. As the electrodes stimulated their brains, their performance on cognitive tests improved.

If the results are confirmed in larger clinical trials, the implants could become the first effective therapy for chronic brain injuries, researchers say.

“This is the first evidence that you can change the course of this problem,” said Nicholas Schiff, a neurologist at Weill Cornell Medicine in New York who led the study.

Gina Arata, one of the volunteers who received the implant, was 22 years old when a car accident left her with fatigue, memory problems and uncontrollable emotions. She abandoned her plan to study law and, unable to hold down a job, lived with her parents in Modesto, California.

In 2018, 18 years after the accident, Arata received the implant. Her life then changed completely, according to her.

“I can be a normal human being and have a conversation,” Arata said. “It’s amazing how much I’ve improved.”

Schiff and his colleagues developed the test based on years of research into the structure of the brain. These studies suggested that our ability to focus on tasks depends on a network of brain regions that are interconnected by long branches of neurons. Regions send signals to each other, creating a feedback loop that keeps the entire network active.

Sudden jolt to the brain — in a car accident or a fall, for example — could sever some of the long-distance connections in the network and send people into a coma, Schiff and his colleagues thought. During recovery, the network may be able to reactivate. But if the brain is severely damaged, it may not recover completely.

The researchers identified a structure deep within the brain as a crucial point in the network. Known as the central lateral nucleus, it is a thin layer of neurons about the size and shape of an almond shell.

The human brain has two structures of this type, one in each hemisphere. They seem to help the brain settle down for sleep at night and perk up in the morning. Schiff’s research has shown that stimulating neurons in these regions can wake a sleeping mouse.

These studies have raised the possibility that stimulating the central lateral nuclei could help people with traumatic brain injuries regain focus and attention.

Surgeons regularly implant electrodes in patients with Parkinson’s disease. The small electrical pulses, released by the implants hundreds of times per second, direct neighboring neurons to emit their own signals, restoring some brain functions.

In 2018, Schiff and his colleagues began recruiting volunteers, including Arata, who had suffered from chronic problems for years following accidents. Before inserting the electrodes, the researchers subjected the volunteers to a battery of tests to assess their ability to concentrate and switch tasks. In one exam, for example, they were given a sheet of paper covered in letters and numbers and had to draw a line connecting them in order as quickly as possible.

Before surgery, researchers scanned each volunteer’s brain to make an accurate map. Jaime Henderson, a neurosurgeon at Stanford University, guided the electrode through the brain to the central lateral nucleus.

Henderson implanted the electrodes in six volunteers, but one of them had to leave the study after developing a scalp infection. Starting one month after surgery, the remaining five volunteers underwent follow-up tests. On the letter and number exam, their scores increased by 15% to 52%.

To get a broader picture of the volunteers’ experiences, medical ethicist Joseph Fins of Weill Cornell Medicine conducted a series of interviews with them and their families. Most of the volunteers, including Arata, said the implant made them more like their former selves.

The volunteer who showed the greatest improvement in cognitive tests, on the other hand, had a lukewarm reaction. “I don’t think it hurt,” he said. “But I don’t know if it helped much.” This patient’s son observed significant changes.

Neurologist Steven Laureys of the University of Liège in Belgium, who was not involved in the study, said the results support the theory that attention and other forms of thinking depend on the brain network throughout the brain. “There’s enough reason to believe it’s worth continuing,” he said of the research.

Schiff and his colleagues plan a much larger study of brain implants. “We have to see how the data develops,” he said.

The central lateral nuclei are not the only regions showing promise as hubs in the brain network, said neurosurgeon Alex Green of the University of Oxford, who was not involved in the study.

“We don’t really know the best place to stimulate yet,” Green said. He and his colleagues are preparing their own brain lesion test to test electrodes in a region called the pedunculopontine nucleus.

Laureys acknowledged that implant surgeries are expensive, but said society should consider the millions of people who suffer from traumatic brain injuries. “This is a silent epidemic,” said the neurologist.