People with severe disabilities - including so-called locked-in syndrome - have been enabled to communicate with a new device controlled by sniffing.
The new system, developed by the Weizmann Institute’s Neurobiology Department, identifies changes in air pressure inside the nostrils and translates them into electrical signals.
Users were able to navigate a wheelchair around a complex path or play a computer game with nearly the speed and accuracy of a mouse or joystick.
"The most stirring tests were those we did with locked-in syndrome patients. These are people with unimpaired cognitive function who are completely paralyzed – 'locked into' their bodies," says Professor Noam Sobel.
"With the new system, they were able to communicate with family members, and even initiate communication with the outside. Some wrote poignant messages to their loved ones, sharing with them, for the first time in a very long time, their thoughts and feelings."
Because sniffing is largely controlled by nerves that connect to the soft palate directly through the braincase, Sobel theorized that the ability to sniff – that is, to control soft palate movement – might be preserved even in the most acute cases of paralysis.
Functional magnetic resonance imaging lent support to the idea.
So the researchers created a device with a sensor that fits on the nostril’s opening and measures changes in air pressure. For patients on respirators, they developed a version which diverts airflow to the patient’s nostrils. About three quarters of those on respirators were able to operate the device.
Sniffs can be in or out, strong or shallow, long or short, creating the opportunity to create a complex ‘language’ with multiple signals.
One patient who had been locked in for seven months following a stroke learned to use the device over a period of several days, writing her first message to her family.
Another, who had been locked in since a traffic accident 18 years earlier wrote that the new device was much easier to use than one based on blinking. Another ten patients, all quadriplegics, succeeded in operating a computer and writing messages through sniffing.
In addition to communication, the device can be used to steer wheelchairs. After fifteen minutes of practice, a subject who is paralyzed from the neck down managed to navigate a complex route.
The new system is relatively cheap to produce, and simple and quick to learn to operate.
Sobel believes that it could be useful in other areas, for instance as a control for a ‘third arm’ for surgeons and pilots.