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Communicate and Steer a Wheelchair by Sniffing
The nasal cannula is used to carry
nasal pressure to the sensor;
© Weizmann Institute
A device based on sniffing – inhaling and exhaling through the nose – might enable numerous disabled people to navigate wheelchairs or communicate with their loved ones.
Sniffing is a precise motor skill that is controlled, in part, by the soft palate – the flexible divider that moves to direct air in or out through the mouth or nose. The soft palate is controlled by several nerves that connect to it directly through the braincase. This close link led Sobel and his scientific team to theorise that the ability to sniff – that is, to control soft palate movement – might be preserved even in the most acute cases of paralysis.
To test their theory, 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 passive version of the device, which diverts airflow to the patient’s nostrils. About 75% of the subjects on respirators were able to control their soft palate movement to operate the device.
‘The most stirring tests were those we did with locked-in syndrome patients. With the new system, they were able to communicate with family members, and even initiate communication with the outside,” said Noam Sobel who developed this system.
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 function as a sort of steering mechanism for wheelchairs: Two successive sniffs in tell it to go forward, two out mean reverse, out and then in turn it left, and in and out turn it right. After fifteen minutes of practice, a subject who is paralysed from the neck down managed to navigate a wheelchair through a complex route – sharp turns and all – as well as a non-disabled volunteer.
Sniffs can be in or out, strong or shallow, long or short; and this gives the device’s developers the opportunity to create a complex ‘language’ with multiple signals. The new system is relatively inexpensive to produce, and simple and quick to learn to operate in comparison with other brain-machine interfaces. Sobel believes that this invention may not only bring new hope to severely disabled people, but it could be useful in other areas, for instance as a control for a ‘third arm’ for surgeons and pilots.
REHACARE.de; Source: Weizmann Institute
- More about the Weizmann Institute at www.weizmann.ac.il
( Source: REHACARE.de )