WEDNESDAY, May 12, 2021 (HealthDay News) – A microchip implanted in the brain allowed a paralyzed man to communicate by text – at speeds close to the typical smartphone user.
This achievement is the latest advance in “brain-computer interface” (BCI) systems.
Scientists have been studying BCI technology for years, with the goal of one day giving people with paralysis or limb amputation greater independence in their daily lives.
It basically works like this: tiny chips are implanted in areas of the brain related to movement, where they harness the electrical activity of cells. When a person imagines performing a movement, the affected brain cells begin to fire. These electrical signals are then transmitted through wires to a computer, where they are “decoded” by sophisticated algorithms and translated into action, allowing people to control assistive devices with their own mental power.
Researchers at a few universities have used BCI to allow a small number of patients to mentally control robotic limbs or move computer cursors to “type” text.
In the new study, researchers at Stanford University were able to speed up the latter skill in a man with whole body paralysis. Instead of having him mentally move a computer cursor, the researchers asked him to imagine handwriting.
The approach ultimately allowed him to produce text at a rate of around 18 words per minute, double what he had achieved with the mind-punching tactic.
The man’s accelerated performance is almost equivalent to that of the typical smartphone user, the researchers said.
“We think it’s pretty remarkable,” said lead researcher Dr. Jaimie Henderson, professor of neurosurgery at Stanford University in California.
Henderson pointed out, however, that the technology is confined to the research lab for now. It still requires equipment, cables, and technical expertise that are unrealistic for home use.
Krishna Shenoy, professor of electrical engineering at Stanford and the other lead author of the study, said: “We cannot predict when there will be devices that can be used in the clinic.”
These caveats were made, the two researchers said the findings represented advancements in the field.
“We are very encouraged by the future,” said Henderson.
The study participant – called T5 – lost almost all movement under the neck after sustaining a spinal cord injury in 2007. Nearly a decade later, Henderson implanted two microchips in the motor cortex of the body. human, an area of the outermost layer of the brain that purposely governs movement.
Each chip is the size of a baby aspirin and contains electrodes that pick up signals from neurons involved in hand movement.
In a 2017 study, T5 and two others with paralysis learned to mentally move a cursor around a keyboard displayed on a computer screen, simulating typing. T5 was finally able to type 40 characters – or about eight words – per minute.
This time, the researchers tested a new approach, where computer algorithms decode mental writing.
First, T5 imagined himself writing individual letters, using a pen on a yellow legal pad. (“He was very specific about it,” Henderson noted.) Through repetition, the computer software “learned” to recognize the brain signals associated with T5’s effort to write a given letter.
He then moved on to mental sentence writing and, over time, algorithms improved to read his neural trigger patterns, until he was able to create 90 characters, or 18 words, by minute.
It turns out that visualizing handwriting – with its curves and changes in speed – provides a “rich signal” that is easier to decode than the straight-line movement of a cursor, Shenoy explained.
Jennifer Collinger is an associate professor at the University of Pittsburgh and develops BCI technology.
She called the new findings significant scientific advancement, but warned that a lot of work remains to be done before BCI enters the real world.
“These systems will need to be wireless, reliable and up and running when you need them,” Collinger said.
The hardware itself, she added, will have to last for many years.
Collinger got to see how different BCI systems in development could come together: A mind-controlled robotic limb could have many everyday uses – but, Collinger said, it might not be a great tool to send. SMS.
The research, reported on May 12 in the journal Nature,was funded by government and private grants. Stanford University has applied for a patent on the intellectual property associated with the work.
The Christopher and Dana Reeve Foundation has more on paralysis.
SOURCES: Jaimie Henderson, MD, professor, neurosurgery, Stanford University Medical Center, Stanford, California; Krishna Shenoy, PhD, professor, electrical engineering, Stanford University; Jennifer Collinger, PhD, associate professor, physical medicine and rehabilitation, University of Pittsburg; Nature, May 12, 2021, online
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