An experimental device, the implantation of which significantly improved the mental functions of patients who have suffered a traumatic brain injury, seems to give hope.

So far, in the experimental research of the scientists in the USA they received five people aged 22 to 60 years, with moderate to severe brain injuries.

The next step is clinical trials in more patients, and if the positive results are confirmed, the implants could be the first effective treatment for chronic brain injuries.

Dr. Nicholas Schiff, a neurologist at Weill Cornell Medicine and lead author of the study, and his team designed the clinical trial based on years of research on the structure of the brain.

Studies focus on the neurons that send signals to brain areas and then to each other, creating a feedback loop that keeps the entire network active.

Sudden shock to the brain — in a car accident, for example — can disrupt some of the network’s connections and lead to coma, Dr. Schiff and colleagues. Depending on the severity of the injury, the brain may not fully recover.

Before the electrodes were implanted, the researchers assessed the volunteers’ skills by putting them through a test. In one of the tests, volunteers had to connect 25 dots together as fast as they could, so doctors could assess mental skills such as speed of thought and ability to process information.

Skills such as attention and other forms of thinking depend on the network covering the entire brain, says Dr. Steven Loreis, a neurologist at the University of Liege in Belgium.

“There are several reasons to think it’s worth pursuing,” he said of the study.