A Boston University researcher thinks he has found a way to reduce the falls that injure and kill thousands of elderly people each year.
James J. Collins, a professor of biomedical engineering, found that coin-sized vibrators installed in the shoes of elderly test subjects improved their sense of balance - a key to keeping them on their feet.
Collins reported in a study published this fall that people in their 70s sway more than people in their 20s, but the elderly regained their balance when imperceptible random vibrations were sent shooting through the soles of their feet.
Collins began searching a few years ago for ways to cut back on the falls that kill 10,000 senior citizens and send 1.5 million to emergency rooms every year.
He said vibrating insoles won't eliminate the problem because they don't address many of the factors that contribute to old-age loss of balance - including diminished reflexes, poorer vision and weaker muscles.
But he's convinced that his technology is a step in the right direction. "The idea was to come up with vibrating insoles that could be beneficial to an 80-year-old Mrs. McGillicuddy out there who's having trouble keeping her balance," he said.
Collins' study trained cameras on reflective markers worn by 15 young people (average age 23) and a dozen elderly people (average age 73) to measure their steadiness. Each volunteer stood on gel insoles equipped with battery-powered vibrators, while their tendency to sway was measured, with and without vibrations at 30-second intervals.
The gel insoles spread the vibrations through the foot, and the vibrations were of such low intensity that the volunteers could not detect them, Collins said, noting that sending out random vibrations made the neurons in the feet more sensitive, a signaling concept studied for the past decade and known as stochastic resonance.
Other researchers said Collins' findings have potential for anyone with balance problems. "It's an outstanding piece of work, it's broken new ground and it could have a big impact," said Frank Moss, a researcher at the University of Missouri, St. Louis, who has studied stochastic resonance in fish.
Researchers have known for years that the brain uses neurons to send signals throughout the body to monitor positions of the knee, ankle and other joints. But Moss said the neurons degrade with age. "In principle [the vibrating insole] has the potential to improve balance by making the neurons more sensitive," he said.
Afferent Corp., a Rhode Island-based company that turns Boston University research into commercial products, plans to develop the insoles for consumers. Collins, a stockholder, said it will be at least two years before clinical trials are completed and the insoles are on the market. The trials, funded by the National Institutes of Health, will determine whether the technology could benefit stroke patients and diabetics with neurological problems, he said.
There also are design problems - including coming up with a power source small enough to fit in a shoe. "We can't expect 80-year-old Mrs. McGillicuddy to be walking around with a car battery on her back," Collins said.