Brain implants have helped five people recover after traumatic injuries

Traumatic brain injuries leave more than five million Americans permanently disabled. They have difficulty concentrating on even simple tasks and often have to quit their jobs or drop out of school.

A study published on Monday has offered them a glimpse of hope. Five people with moderate to severe brain damage had electrodes implanted in their heads. As the electrodes stimulated their brains, their performance on cognitive tests improved.

If the results hold up in larger clinical trials, the implants could become the first effective therapy for chronic brain injury, the researchers said.

“This is the first evidence that you can switch the dial on this problem,” says Dr. 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 when a car accident left her with fatigue, memory problems and uncontrollable emotions. She abandoned her plans for law school and lived with her parents in Modesto, California, where she was unable to hold down a job.

In 2018, 18 years after the crash, Ms Arata received the implant. Her life has changed dramatically, she says. “I can be a normal person and have a conversation,” she said. “It’s amazing how I’ve seen myself improve.”

Dr. Schiff and his colleagues designed the test based on years of research into the structure of the brain. Those studies suggested that our ability to focus on tasks depends on a network of brain areas connected by long branches of neurons. The regions send signals to each other, creating a feedback loop that keeps the entire network active.

Sudden movements of the brain – for example in a car accident or a fall – can sever some long-distance connections in the network and cause people to fall into a coma, Dr. hypothesizes. Schiff and his colleagues. During recovery, the network may be able to power itself again. But if the brain is severely damaged, it may not recover completely.

Dr. Schiff and his colleagues have identified a structure deep in the brain as a crucial node in the network. Known as the central lateral nucleus, it is a thin layer of neurons the size and shape of an almond shell.

The human brain has two such structures, one in each hemisphere. They seem to help the brain calm itself at night for sleep and restart the brain in the morning. Stimulating the neurons in these regions can wake a sleeping ratDr.’s research has shown that Schiff demonstrated.

These studies 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 little electrical pulsesreleased by the implants hundreds of times per second commands neighboring neurons to fire their own signals, restoring some brain functions.

In 2018, Dr. Schiff and his colleagues recruited volunteers like Ms. Arata, who suffered from chronic problems for years after their accident. Before inserting the electrodes, the researchers gave the volunteers a series of tests to assess their ability to concentrate and switch tasks. For example, in one exam, the volunteers were each given a sheet of paper full of letters and numbers and had to draw a line connecting them as quickly as possible.

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

Dr. Henderson implanted the electrodes in six volunteers, but one of them had to stop the study after developing a scalp infection. Starting one month after surgery, the remaining five volunteers underwent follow-up testing. On the letters and numbers exam, their scores rose anywhere from 15 to 52 percent.

To gain a broader understanding of the volunteers’ experiences, Dr. Joseph Fins, a medical ethicist at Weill Cornell Medicine, conducted a study series of interviews with them and their family members. Most volunteers, like Ms. Arata, said the implant made them look more like their former selves.

In contrast, the volunteer who saw the greatest improvement on cognitive tests responded tepidly. “I don’t think it hurts,” he said. “I just don’t know if it helped much.”

And yet that patient’s son observed significant changes, especially in his father’s self-awareness. “It is day and night,” said the son.

Dr. Steven Laureys, a neurologist at the University of Liege in Belgium who was not involved in the study, said the results supported the theory that attention and other forms of thinking depend on the brain-wide network. “There’s plenty of reason to believe it’s worth pursuing,” he said of the study.

Dr. Schiff and his colleagues are planning a much larger study of brain implants. “We’ll have to see how the data shakes out,” he said.

The central lateral nuclei are not the only regions that show promise as nodes in the brain network, said Dr. Alex Green, a neurosurgeon at the University of Oxford who was not involved in the study.

“We don’t really know yet what the best place to stimulate is,” said Dr. Green. He and his colleagues are preparing a brain injury study of their own to try electrodes in an area called the pedunculopontine nucleus.

Dr. Laureys acknowledged that implant surgeries would be expensive, but argued that society should recognize the millions of people who suffer from traumatic brain injuries. “This is a silent epidemic,” he said.