Help for Sleeping Legs

NEW HELP FOR SLEEPING LEGS:
SENSING DEVICE LETS DIABETICS 'FEEL' THEIR FEET AGAIN

by Don McLeod

Virgil Pyatt strides confidently across the laboratory floor, smiling at watching technicians and nimbly adjusting his gait for a ridge in the carpeting. It looks like an ordinary stroll—but in fact it is far from ordinary.

That's because for this bit of walking, Pyatt, one of an estimated 10 million Americans with diabetes whose feet have become numb and devoid of feeling, is finally able to "feel" his feet again.

This is due to a miracle of modern electronics—he's wearing ultrathin sensing devices inside his shoes. The sensors provide what in effect are artificial nerve endings, to replace the natural ones that no longer work.

Diabetes is a disease in which abnormally high blood sugar levels impair the body's ability to process energy. One outcome may be restricted circulation in the feet and legs, leading to a loss of feeling.

Pyatt is a participant in a government-funded, high-tech research experiment at Sabolich Research and Development, Inc., in Oklahoma City, one of the nation's largest prosthetic research facilities. It's a for-profit company that develops prosthetic and preventive technology for amputees or those in danger of losing limbs to disease.

If the experiment lives up to the hope of its developers, it may help diabetics with little or no feeling in their feet avoid an unwanted fate that thousands must now endure—partial or full amputation of one or both feet.

Without sensing devices, people like Pyatt are often unaware of pressured area on the feet caused by improper walking habits, stones in their shoes or even wrinkles in their socks, all of which can lead to sores and infections. The average person would feel pain in these instances, explains Martin Mussman, director of podiatric services for the Department of Veterans Affairs, but people with numb feet cannot.

By the time Pyatt and others like him notice a sore on one of their feet, Mussman says, infection often has had a long head start.

By then, the ailment sometimes is so advanced that part or all of the foot must be amputated. The American Diabetes Association says that each year 54,000 people, most of them over 65, lose a foot or leg to diabetes.

That's what happened last year to Claudio Torrez, 61, a technician in Oklahoma City who had diabetes and no feeling in his feet. By the time he discovered he had an ulcer in his heel, infection had already gotten into the bone. Surgeons eventually had to amputate the leg below his knee.

The aim of the research in which Pyatt participates, conducted with a grant from the National Institutes of Health (NIH), is to prevent many of these amputations. "If this device can make corrections" for the nerve loss in diabetics' feet," says Charles A. Wells, who is overseeing the grant for NIH, "we can prevent a very, very costly problem with these amputations." Wells is director of the Complications Research Program of NIH's Institute of Diabetes and Digestive and Kidney Diseases.

The device works this way: Sensors inside the shoes are connected to electrodes attached higher up on the person's body where he or she has feeling. When a sensor "feels" a pebble inside the shoe, or "feels" pressure when the foot hits the ground, it transmits a message to the electrode site, which then tingles.

The brain gradually adapts and begins to substitute these artificial sensations for those that were once felt in the now-numb foot. In time it feels to the patient as if the sensation is actually occurring in the foot.

Thus, as the patient walks, he can "feel" his foot rocking from heel to toe. He can "feel" a pebble in his shoe or a wrinkle in his sock.

Other organizations are conducting research on devices to detect the loss of nerve sensation. But so far as can be determine, this is the only research project aimed at producing a device that would actually "replace" lost nerve sensation.

So far, clinical observations of individuals such as Pyatt indicate that the device is promising.

Pressure measurements taken with sophisticated computerized equipment show that people wearing the device take shorter steps and apply less pressure on the bottoms of their feet when they walk. Researchers hope the change in walking style may help delay or possibly eliminate the need for amputation in some patients.

Sabolich has just received a new grant from NIH to conduct the second phase of the research-clinical trials that would track patients using the device to see if improved walking techniques actually prevent the development of foot ulcers.

Anticipated to begin this year, the research would last two years. If it is completed without a hitch, John Sabolich—a prosthetist and the president of the research facility—says he hopes that the device will be on the market soon thereafter.

The cost for people with diabetes would be in the $3,000 range, which would cover one device for each foot, Sabolich says. If the sensor prevented amputation, that would be a major savings, as the average amputation costs $40,000. Average lifetime expenses for prosthetic care for amputees range from $350,000 to $1 million. And, of course, people would obviously prefer to keep their flesh-and-blood feet.

Other uses for this general technology are also on the horizon. One is for amputees: Putting sensors inside the shoes worn by people with artificial legs could make them more surefooted by letting them "feel" the unevenness of the surface they're walking on.

Another application might be to help guard against sores and ulcers on patients confined to wheelchairs or beds. Such sores "are highly prevalent in nursing homes," says Sabolich, adding that treating people with bedsores can be expensive.

Although this device may enable thousands of patients to avoid foot amputations, "it is not going to be panacea" for everyone, he cautions. Some patients may have such severe circulatory problems, he says, that there is no medical alternative to amputation.