Sniff-and-Go Technology Enables Paralyzed to Drive Wheelchairs

A device operated by nose sniffs allows disabled people, quadriplegics and those “locked in” by complete paralysis to use computers or operate wheelchairs, an Israeli study showed.

Quadriplegic patients were able to navigate wheelchairs as well as healthy people who used the device created by the researchers, according to the study published today in the Proceedings of the National Academy of Sciences. Two people in the study who were completely paralyzed with intact mental function used the technology to communicate by choosing letters on a computer screen to write.

The device may be among the tools to help paralyzed people communicate and get around, said study author Noam Sobel. It may be cheaper than products on the market for the severely disabled such as eye-tracking devices that cost as much as $20,000, he said.

“It has the potential to have a dramatic influence on the lives of people who have no other solutions,” said Sobel, a professor in the department of neurobiology at the Weizmann Institute in Rehovet, Israel, in a July 23 telephone interview. “Our solution may work in several cases where other solutions may not work.”

About 1.9 percent of the U.S. population, or 5.6 million people, reported they are living with some form of paralysis, according to the Christopher and Dana Reeve Foundation, a nonprofit research and advocacy organization. Stroke is the leading cause of paralysis, followed by spinal cord injury and multiple sclerosis.

Built in the Lab

The researchers made the device in their lab for $358. It would only cost “a fraction of this sum” once it’s mass produced, they said.

The Weizmann Institute has applied for a patent on the device and is trying to find partners to commercialize the product, Sobel said. He said he didn’t know when a partnership deal might be reached or how soon the device would be available to patients.

“The attractiveness of it is there are some people who are so disabled that they can’t operate a tongue-touch device or they may not be able to control it through a breath-control device,” said Adam Stein, chairman of physical medicine and rehabilitation at the North Shore-Long Island Jewish Health System in Great Neck, New York.

The researchers used 96 healthy people, 10 quadriplegic volunteers and three people who were completely paralyzed to test the device in the study.

Electrical Signals

The technology works by translating changes in nasal air pressure into electrical signals that are passed to a computer. Patients can sniff in certain patterns to select letters or numbers to compose text, or on the computer, to control the mouse. For getting around, sniffing controls the direction of the wheelchair -- two sniffs inhaled can mean moving forward and two sniffs exhaled may signal backward.

Sniffing requires movements of the soft palate, the soft spot located at the upper back part of the mouth that receives signals from cranial nerves often unaffected by paralysis, the researchers said.

Even people considered locked-in by complete paralysis were able to use the sniff device, the study found. For someone on a ventilator, air can be passed into the nose through a tube allowing the person to move the soft palate to make the device work, Sobel said.

Soft Palate Control

About 74 percent of healthy volunteers in the study could control their soft palate without practice. The researchers said “as to the remaining population, it remains to be seen what proportion can learn to control their soft palate.”

The study found two locked-in paralysis patients used the sniff device to write text at the rate of 3 letters and 1.5 letters per minute, respectively, a pace that “may seem frustratingly slow,” the authors wrote.

“Such writing speeds, however, are greeted with enthusiasm by locked-in individuals,” the researchers wrote. “The speed of this self-expression is less important to individuals who, put bluntly, have no other options.”

They cited the author of a novel made into a film, “The Diving Bell and the Butterfly,” who was a locked-in person. Jean-Dominique Bauby wrote the 1997 novel using eye movements at a rate of about one word every two minutes, the authors said.

The researchers are working to see if they can make the device faster. Sobel said future tests are needed to see if the device can work in people who are completely paralyzed and can’t move their eyes and those who are considered to be in a vegetative state.

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