THE ESSENTIAL
- Charcot’s disease, or amyotrophy lateral sclerosis, is characterized by the progressive loss of motor neurons, related to movement, speech and swallowing.
- About 7,000 people are affected in France.
- The system used in this study is currently only available for clinical research.
It is a revolution on the scale of science, and an upheaval on the individual scale. A 36-year-old man, completely paralyzed due to Charcot’s disease, managed to communicate thanks to two electrodes implanted in his brain. In Nature Communicationthe researchers explain how they managed to help this man, originally from Germany, to express himself.
A total paralysis
For two years, the team worked with this 30-year-old suffering from Charcot’s disease, a progressive neurodegenerative disease in which people lose the ability to move and speak. He also suffers from Locked-In Syndrome (LIS), which prevents him from speaking and moving, but not thinking or hearing. His paralysis is very important, for example, he cannot blink his eyes. “This study answers a long-standing question: whether people with Complete Locked-In Syndrome (CLIS), who have lost all voluntary muscle control, including eye or mouth movement, also lose the brain’s ability to generate communication commands”explains Jonas Zimmermann, PhD, neuroscientist at the Wyss Center in Geneva, and co-author of this study.
A brain-computer communication system
The researchers implanted two arrays of micro-electrodes in the motor cortex of this man’s brain. Each of them measures 3.2 mm across and has 64 needle-shaped electrodes capable of recording neural signals. These are picked up by the implanted microelectrodes and are decoded by a real-time interface. At the same time, an automatic spelling program reads the letters of the alphabet aloud. Using auditory neurofeedback, the participant is able to choose “yes” or “no” to confirm or reject the letter, ultimately forming whole words and sentences.
More than 100 days of adaptation
It took time for the patient to master this new tool. After 106 days, he managed to select letters and then form sentences. It takes him regarding a minute to choose a letter. On the 247th day, he told the medical team “Boys, it works so effortlessly“, that is “boys, it works effortlessly“. The 461st is for his four-year-old son: he offers to watch a Disney cartoon together.”This technique, which benefits a patient and their family, is an excellent example of how technological advances in the field of brain-computer communication can be translated to have a direct impact“, welcome the authors of the study.
