Brain Implant Allows Paralyzed ALS Patient to ‘Speak’ With Family Again
A novel system that involves electrodes implanted in the brain allowed a 34-year-old man with amyotrophic lateral sclerosis (ALS) who had completely lost the ability to move voluntarily — known as a “locked-in” state — to communicate with his family again.
Using the system, the man was able to actively participate in decisions about his own care, and to tell his young son, in his own words, that he loves him.
His case was described in the study, “Spelling interface using intracortical signals in a completely locked-in patient enabled via auditory neurofeedback training,” published in Nature Communications.
The man was diagnosed in 2015, at age 30, with a fast-progressing form of ALS. By the end of that year, he had lost much of his ability to walk and talk. He initially retained an ability to voluntarily move his eyes, and he used eye-tracking technologies to communicate.
“In the ALS community, we typically think of people who are locked-in as being unable to move their body with the exception of their eyes,” Neil Thakur, chief mission officer for the ALS Association, said in a press release.
“Some people with ALS are very proficient at using their eyes to communicate at a very high level with the help of assistive technology, such as eye-gaze machines,” added Thakur, who was not directly involved in this study.
By 2017, the man could no longer fix his gaze and continue to use eye-tracking technologies. No other way, until now, existed for people with this extremely advanced disease form to reliably communicate.
The patient’s family gave researchers permission to place two implants in the man’s motor cortex, the brain region responsible for voluntary movement. Each implant is about a tenth of an inch in size, and contains 64 needle-like electrodes to detect electrical signals from firing nerve cells.
People in locked-in states are fully aware, but unable to move their muscles.
Over the course of several weeks, the patient learned how to modulate his brain activity in a way that could be picked up by the electrodes and reliably used for communication.
Essentially, the patient altered his brain activity by instructing his body to move. Even when such movement is no longer possible, detectable electrical signals still occur in the brain. Using these signals, the patient would modulate an auditory tone to move up or down, allowing him to answer yes or no questions.
This system was then combined with a speller: the speller would read letters aloud, and the patient would select letters via the yes/no system to spell out words and communicate.
To ensure the system was working as intended, the man started by spelling out pre-defined words. Within the first three days of the speller’s use, he was able to spell his own name correctly, as well as his wife’s name and the name of their 4-year-old son.
“It shows that you can write sentences with the brain even if you are completely paralyzed without any eye movement or other muscles to communicate,” said Niels Birbaumer, the study’s lead researcher and director of the Institute of Medical Psychology and Behavioral Neurobiology at the University of Tubingen, in Germany.
The system was relatively slow — on average, the patient spelled at a rate slightly slower than one letter per minute — and independent observers judged that his output was intelligible for 44 of the 107 days the speller was used during the study.
Less than four months after the implant, the man moved to free spelling to express his thoughts and to participate in decisions about his care and comfort.
For example, on several occasions he used the system to request that his head or limbs be adjusted, or to ask for different types of food. He could also say when he wanted to wear socks, but not a shirt, to sleep at night, and to ask that his caregivers put gel on his eyes more often.
The system also gave him a voice to express his wants beyond medical care: on one day, he used the system to say “I would like to listen to the album by [the band] Tool loud.” He also gave suggestions to improve his speller performance: “turn on word recognition,” or “tell Alessandro [Tonin] I need to save, edit, and delete whole phrases.”
It also gave the patient a voice with which to connect to the people around him. One of the first times he freely used the spelling system, he took the opportunity to thank the researchers, saying, “first I would like to thank Niels [Birbaumer].”
And the system let the man talk to his 4-year-old son, offering to watch Disney movies together and giving him the chance to say: “I love my cool son.”