By Amy Norton
HealthDay reporter
WEDNESDAY, May 12, 2021 (HealthDay News) – A microchip implanted in the brain enabled a paralyzed man to communicate by text – at speeds approaching the typical smartphone user.
The success is the latest advancement in BCI systems (Brain-Computer Interface).
Scientists have been working with BCI technology for years with the aim of enabling people with paralysis or limb amputations to one day be more independent in their daily lives.
Basically, it works like this: Tiny chips are implanted in movement-related areas of the brain, where they use the electrical activity in cells. When a person imagines making a movement, the relevant brain cells start to fire. These electrical signals are then transmitted via cables to a computer, where they are “decoded” by sophisticated algorithms and converted into measures that enable people to control aids with their own power of thought.
Researchers at some universities have used BCI to enable small numbers of patients to mentally control robotic limbs or move computer cursors to “type” text.
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In the new study, Stanford University researchers managed to accelerate this latter ability in a man with total body paralysis. Instead of letting him move a computer cursor mentally, the researchers asked him to imagine a handwriting.
The approach allowed him to produce text at about 18 words per minute or double what he had achieved with mental typing tactics.
The man’s improved performance is almost on par with the typical smartphone user, the researchers said.
“We think that’s pretty remarkable,” said co-senior researcher Dr. Jaimie Henderson, Professor of Neurosurgery at Stanford University in California.
However, Henderson emphasized that the technology will be limited to the research laboratory for the time being. It continues to require devices, cables, and technical expertise that are not realistic for home use.
Krishna Shenoy, professor of electrical engineering at Stanford and the other lead author on the study, said, “We cannot predict when there will be devices that can be used clinically.”
Both researchers said the results represent advances in this area.
“We are very encouraged about the future,” said Henderson.
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The study participant, known as T5, lost almost all movements under the neck in 2007 after a spinal cord injury. Almost a decade later, Henderson implanted two microchips in the man’s motor cortex, an area in the outermost layer of the brain that voluntarily governs movement.
Each chip is the size of a baby aspirin and contains electrodes that pick up signals from neurons that help move the hand.
In a 2017 study, T5 and two other people with paralysis learned to mentally move a cursor on a keyboard displayed on a computer screen to simulate typing. T5 was ultimately able to type 40 characters – or about eight words – per minute.
This time, the researchers tested a new approach in which the computer algorithms deciphered mental handwriting.
First, T5 imagined writing individual letters with a pen on a yellow notepad. (“He was very specific about it,” noted Henderson.) By repetition, the computer software “learned” to recognize the brain signals associated with T5’s efforts to write a particular letter.
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He would then mentally write sentences, and over time the algorithms could read his neural ignition patterns better, until he could get 90 characters, or 18 words per minute.
It turns out that visualizing handwriting, with its curves and speed changes, provides a “rich signal” that is easier to decode than moving a cursor in a straight line, Shenoy explained.
Jennifer Collinger is an Associate Professor at the University of Pittsburgh and develops BCI technology.
She called the new finding a major scientific advance, but cautioned that there was still a lot of work to be done before BCI moves into the real world.
“These systems need to be wireless, reliable, and functional when you need them,” said Collinger.
The hardware itself, she added, must last for many years.
Collinger saw how various BCI systems in development could come together: A mind controlled robotic limb could have many daily uses – but, according to Collinger, it may not be a great tool for texting.
The research, published May 12 in the journal Nature, was funded by government and private grants. Stanford University has filed for an intellectual property patent related to the work.
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More information
The Christopher and Dana Reeve Foundation is more concerned with paralysis.
SOURCES: Dr. Jaimie Henderson, Professor of Neurosurgery, Stanford University Medical Center, Stanford, California; Krishna Shenoy, PhD, Professor of Electrical Engineering, Stanford University; Jennifer Collinger, PhD, Associate Professor of Physical Medicine and Rehabilitation, University of Pittsburg; Nature, May 12, 2021, online
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