The device harnesses sniffing â€” or breathing in and out through the nose â€” which involves the soft palate on the roof of the mouth. One patient wrote letters to her family for the first time since she had a stroke.
While no replacement for a true brain implant that would allow users to control devices with thoughts alone, the “sniff controller” works better for many patients than eyeblinks or other methods of communicating, the researchers reported in the Proceedings of the National Academy of Sciences.
“Indeed, sniffing allowed completely paralysed locked-in participants to write text and quadriplegic participants to write text and drive an electric wheelchair,” they wrote.
“The most stirring tests were those we did with locked-in syndrome patients. These are people with unimpaired cognitive function who are completely paralysed â€” ‘locked into’ their bodies,” Noam Sobel of The Weizmann Institute of Science in Rehovot, Israel, said. “Some wrote poignant messages to their loved ones, sharing with them, for the first time in a very long time, their thoughts and feelings.”
Sobel worked with other scientists from his institute and the Sackler faculty of medicine at Tel Aviv University to develop a way to convert sniffs â€” which the device measures as nasal pressure â€” into electrical signals.
Able-bodied individuals who tested the device, which consists of a small cannula, like the tubes used in hospitals to deliver oxygen to patients, that sits at the opening of the nostrils and is connected to a small pressure sensor, quickly learned to play PC games and write sentences by sniffing.
Encouraged by the results in the healthy trial participants, the researchers decided to test their device on quadriplegics and “locked-in” individuals. One, a woman who became locked-in following a stroke around seven months earlier, had to be retaught how to sniff. But within three weeks, she was able to use the sniff-controller to write.
And a quadriplegic woman with severe multiple sclerosis was able to write for the first time in 10 years, thanks to the sniff-controller. She also learned how to move a cursor on a computer screen by sniffing and now uses the device to surf the internet and write emails, the study says.
Ten quadriplegics who tested the device very quickly learned to use their noses to write words, open a web browser, and copy and paste words into a search engine.
Encouraged by their success in helping severely disabled people to communicate, the researchers decided to push the envelope of the new technology and devised a code to allow an electric wheelchair to be driven by sniffs. A 30-year-old man who had been paralysed from the neck down for six years was as good a sniff-driver as the healthy participants by his second attempt, the study says.