Vibrating Insoles Improve Balance in Elderly
Researchers hope device reduces the number of falls
THURSDAY, Oct. 2, 2003 (HealthDayNews) -- Among elderly men and women, falls are a leading cause of injuries, hospitalizations, and death, according to the American Red Cross. One of every three U.S. adults 65 or older falls each year.
Now results of a small study have shown that vibrating gel-based insoles significantly improve balance control in elderly people, and may eventually help to prevent falls.
"We have demonstrated that by introducing sub-sensory mechanical noise, very weak vibrations, on the soles of subjects' feet through vibrating insoles, we can improve their balance," says lead researcher James Collins, a professor of biomedical engineering at Boston University.
Reporting in the Oct. 4 issue of The Lancet, Collins and his colleagues note that somatosensory function, which provides both touch and position sense, declines with age. Collins' team studied 13 subjects, who were an average of 23 years of age and 12 subjects who were an average of 73 years of age.
With the vibrating insoles, "each group showed a significant improvement in balance control," Collins says. "Even more among the elderly than in the young. We found that we could take 73-year-olds and improve their balance to that of the 20-year-olds," he adds.
During the trial, subjects remained standing with their eyes closed, while the investigators measured the degree of sway with and without vibration.
Collins believes that vibration through the feet to improve balance works because the vibrations enhance the ability of the nervous system to detect weak somatosensory signals.
"The vibrations cause the neurons in the soles of the feet to be more sensitive to weak pressure change signals. This information is then used by the balance control mechanism to maintain a more stable stance," he explains.
"The hope is that vibrating insoles may turn out to be useful in enhancing balance control in older individuals and reduce their risk for falling," Collins says.
Collins believes that his prototype vibrating insoles can be made cheaply enough and with a light enough power source to be practical for elderly patients.
Several of the researchers, including Collins, are shareholders in the Afferent Corp. of Providence, R.I., which is working to commercialize technology using low-level electrical stimulation to treat sensory dysfunction that results from disease and injury.
"The finding by Collins is interesting and promising," comments Mary Tenitti, a professor of medicine at Yale University and a leading expert on falls among the elderly. However, one of the problems with the study, according to Tenitti, is that balance tested during swaying does not correlate well with balance during walking.
"The clinically important question is whether this vibrating helps people's balance when they walk," she says. "It is too early to say whether these vibrating insoles will be useful clinically, but it is certainly a first step."
In another study, British researchers report on deaths among elderly patients after fractures of the neck of the femur (hip fracture). According to the study, which appears in the Oct. 4 issue of the British Medical Journal, deaths from hip fractures had declined from the 1960s to the 1980s.
However, "there has been no decline in death rate among elderly patients who suffer fractures of the neck or the femur during the past 20 years," says lead author Stephen Roberts from Oxford University.
In the study, Roberts and his associate Michael Goldacre collected data on 32,590 individuals 65 years of age and older admitted to hospitals for hip fractures between 1968 and 1998.
They also found that death rates increased sharply with age and were higher in men than women. During the first month after fracture, death rates were 16 times higher in men and 12 times higher in women compared with the general population of the same age. They were also higher among poorer patients, Roberts and Goldacre report.
Roberts says that more should be done to prevent hip fractures and also perhaps to find better ways of reducing mortality after fracture.
Tinetti says that this study confirms what was already known. She also believes that if a similar study were done in the United States, the results would be the same.
She believes that the leveling off of the death rate seen over the past two decades can be accounted for, in part, by the increasing age of those who suffer from hip fractures.
It is older and frailer people who are dying, Tinetti says. "The healthy elderly people get through it very well."
"The question remains, have we reduced mortality from fractures as much as we can?" she adds. "We certainly have to increase our efforts in preventing hip fractures among the elderly."