Currently, the most common technology for people who have disabilities that impair speech or movement, are eye tracking devices. By looking at a screen with words or letters, eye movements are detected and the words are then spoken by a computer. Most will recognize this kind of communication as the method used by Stephen Hawking, however his is a bit different. He moves certain muscles in his face, since his disability involves drooping eyelids and eye movements are hard to detect. This latest research takes the technology up a level by actually reading brain signals, rather than muscle movements.
It started with training the monkeys to type letters they saw on a screen. Letter by letter passages of text were typed by the animals. At the same time, brain waves were recorded with the use of strategically placed electrodes implanted in the brain to directly read signals from the part of the brain that controls hand and arm movements when using a computer mouse. Then it became about developing algorithms to decode those signals. That number crunching is what resulted in improved typing accuracy and speed over previous studies that had shown ability, but lacked speed and were often full of mistakes.
In a press release from Stanford Nuyujukian said, “The interface we tested is exactly what a human would use. What we had never quantified before was the typing rate that could be achieved. Our results demonstrate that this interface may have great promise for use in people. It enables a typing rate sufficient for a meaningful conversation.”
The results were published September 12 in the Proceedings of the IEEE. The team stressed that using the interface in humans might work differently. People are likely to type slower as they consider their thoughts and what they want to say. Also, there is the factor of distraction in humans that doesn’t exist among the monkeys in the lab environment. Another benefit of the study is that it showed the implanted electrodes can stay stable for up to four years, since the monkeys had electrodes that were used in prior research and had been in their brains without any loss of efficiency.
The study was conducted by Bio-X engineers in conjunction with the Brain-Machine Interface initiative of the Stanford Neurosciences Institute which has several projects ongoing in the field of brain-machine interface technology. A clinical trial of this most recent work is starting now with humans. Jaimie Henderson, a Stanford professor of neurosurgery is assisting in that trial. The short video clip below shows how the monkeys select letters to type a passage.
Sources: Stanford, Factor Magazine, International Business Times