Preventing falls saves lives
By Liz Crumbley, College of Engineering
“If our research can save even one life, it will all be worthwhile,” says Thurmon Lockhart, an associate professor in the Grado Department of Industrial and Systems Engineering at Virginia Tech, discussing his efforts to find ways to prevent falls among the elderly.
Capitol Hill agrees with Lockhart about the critical importance of this type of research. The Safety of Seniors Act of 2007 directs the secretary of health and human services to expand research programs related to preventing elder falls. Falls are the leading cause of accidental deaths in the U.S. among people over the age of 75 and the second leading cause for those aged 45 to 75, according to the National Safety Council. The number of fatalities due to falls increased steadily from 14,900 in the year 2000 to 17,700 in 2005.
The Safety of Seniors Act calls for improved data collection (primarily in nursing homes) on elder falls and those at risk, as well as research aimed at preventing falls among elders at risk and improving the treatment and rehabilitation of fall victims.
“As many as 50 percent of people over 75 will either die or be forced to enter institutional care because of falls,” says Lockhart, who is an affiliate faculty member of the Virginia Tech Center for Gerontology and the Virginia Tech-Wake Forest University School of Biomedical Engineering and Sciences. “About one-third of the elderly living at home fall each year and one in 40 of them are hospitalized. Of those admitted to the hospital, only about 50 percent will be alive one year later. What I want to find out is why these falls happen.”
Since coming to Virginia Tech and founding the Locomotion Research Laboratory in 2001, Lockhart — whose research background is in biomechanics and human motor control — has devoted much of his time to learning how to prevent falls by investigating the relationship between aging and falling.
About five years ago in the locomotion lab, with funding from the Centers for Disease Control and Prevention (CDC) and the National Institutes of Health (NIH), Lockhart and his student research assistants began suiting up young and old volunteers in a harness and a network of sensors that test musculoskeletal and neuromuscular changes and biomechanical responses during slips and recoveries. As a test subject walks back and forth along an experimental platform in Lockhart’s lab, the sensors monitor muscle and joint activities in the feet, ankles, legs, hips, and arms. At a random moment, a student quietly sprays a slippery substance on the platform behind the subject. On the way back, the subject slips and goes through the motions of recovery (an actual fall is prevented by the harness).
All the data from the monitoring sensors is fed into a computer model, providing information about the subject’s gait while walking and the motions involved during slipping and recovery. Much of the success of the data collection is the result of the work of Jian Liu, a graduate student who for three years has been developing new and improved computer models for the lab.
“An important factor in our research is understanding the intrinsic changes to gait and balance brought about by aging,” Lockhart says. “As we age, our walking gait changes. For example, we might take slower and shorter steps, making a higher-velocity contact impact with our heels — which in turn seems to make slipping and falling more likely.”
Also as we age, he noted, sensory factors such as vision, inner ear, and touch sensitivity decline, and these changes make us less able to detect that we’re about to fall until it’s too late.
Solving the mysteries of stability and mobility
A number of projects focused on elder falls have followed those earlier studies in Lockhart’s lab, with funding coming from the CDC, NIH, National Science Foundation, and other agencies. Lockhart collaborated on an investigation of the “dynamic stability” differences between fall-prone and healthy adults with the late Kevin Granata, a professor of engineering science and mechanics and co-director of the Musculoskeletal Biomechanics Laboratory.
“Our study showed that the fall-prone group demonstrated poorer dynamic stability — or stability while walking — than healthy elders and young adults,” Lockhart says. “One interesting finding was that stability was not influenced by walking velocity, so differences in walking speed cannot fully explain the differences in stability.”
Walking, as Lockhart pointed out, is actually controlled falling — and much depends on the stability of a walker’s gait. Working on a National Institute on Aging-sponsored project with AFrame Digital Inc., a health monitoring system company in Falls Church, Va., Lockhart and Liu have developed a wrist monitor that can detect gait instabilities that might lead to its wearer suffering a fall.
A series of volunteers have tested the monitor on the platform in the locomotion lab and the project is about to enter its second phase — testing the monitor on nursing-home residents. The ultimate goal is a comfortable monitor that can alert wearers and caretakers of potential falls. “A final commercial device is a few years away,” Lockhart notes.
John Lach, an associate professor of electrical and computer engineering at the University of Virginia, is developing special accelerometers for another of Lockhart’s projects. Accelerometers are sensors that detect changes in speed and direction of motion, and Lockhart will use Lach’s sensor to measure mobility and stability.
“Subjects wearing the accelerometers will be monitored in daily living simulations in the locomotion lab,” Lockhart says. “They’ll sit, stand, simulate kitchen chores, and perform other activities associated with all areas of the home.” The tests also will include induced falls on the harness platform.
In June, Lockhart traveled to Sweden at the invitation of researchers at the University of Gothenburg to begin collaboration on an International Mobility Index. The Swedish research group, which includes Nobel laureate Arvid Carlsson, has been collecting data on mobility since the 1970s, Lockhart says.
The goal is to develop an index that can be accessed around the world and will enable healthcare providers to accurately measure levels of mobility. The index will help determine how likely people are to fall, as well as indicate specific problems, such as brain atrophy, Lockhart says. His job back at the locomotion lab will be to devise a system with sensors and a computer network that can test and measure levels of mobility.