Published in the Fall 2015 University of North Carolina at Greensboro Research Magazine
By Whitney L.J. Howell
Ever since its early days, UNCG has had a strong reputation for excellence in sports, sports medicine, and movement-related health. Today’s kinesiology department has not let that legacy fade. Instead, the faculty are picking up the mantle and carrying it to exciting new places.
Maintaining optimal movement is crucial at any age. It’s vital that we know what impacts motion, how we can preserve it, and — in the worst case scenarios — how to recapture it after injury. Unexpectedly, the big answers aren’t coming in the form of little pills or injections. They’re taking shape as high-tech solutions merged with interventions based on personal physical effort.
At every turn, UNCG is leading the charge not only for the healthy to hold onto their capabilities, but for the injured and cognitively-impaired to reclaim their abilities as well.
Virtual Reality — Not Just For Video Games Anymore
If you walk into Dr. Chris Rhea’s research lab, you might think you’ve walked onto an animated movie set or into the planning stages for video game graphics. At any given point, there’s likely someone covered in reflective dots, walking on a treadmill, or being filmed by a 3D high-definition camera that records the body as a stick figure.
But what you’re really seeing is novel, state-of-the-art research into how individuals who’ve suffered a stroke or had an amputation might learn to reclaim their normal walking patterns.
Rhea’s lab is one of roughly 10 nationwide contributing to this type of research. The main tool supporting his work is virtual reality, or VR. VR itself isn’t new, but it’s just now being applied to this type of medical research, making Rhea’s investigations groundbreaking.
To help individuals who’ve suffered strokes, Rhea pairs the treadmill with a complicated mathematical pattern recognition algorithm and a software program. The software measures the body’s angles, trunk rotation, and limb symmetry to record exactly what the walker does and then runs that data through the algorithm.
Doing so creates an objective, baseline assessment, he says, that is used to build an avatar, which is projected on a split-screen alongside the participant’s walking pattern. Individuals use the avatar as a guide, trying to copy its movements to retrain their bodies into healthy walking patterns.
“Most healthy people have a range of movements within certain signatures, but if you get outside that range, it increases your risk for an injury due to a fall. That’s what we see with stroke patients,” he says. “The software and algorithms give us a quantitative way to measure walking patterns in different clinical populations and help them make changes.”
So far, Rhea’s team has mostly tested this technique with undergraduate students — approximately 600. But nearly 100 participants recruited from local doctors’ offices have contributed as well.
Rhea also works with individuals with amputations, but in a slightly different way. Working closely with clinicians, he and his students designed a VR program that helps these individuals learn how to walk with prosthetic devices without falling. Input from the community clinicians who treat these individuals frequently is critical, he says, to creating a program that pushes a participant’s abilities without exhausting him or her too quickly.
These participants wear a headset, called the Oculus Rift, which simulates a walk through the woods or down a street, so individuals can move at their own pace. Obstacles appear at intermittent times and heights, and participants must navigate around or over them to successfully complete the task.
“The goal with this project is to see if we can train these individuals in a virtual environment to step over objects,” Rhea says. “And can they transfer that ability to the real world?”
As with the research with stroke patients, the lab is still finetuning this technique, using undergraduate students to tweak the methods. It won’t be ready for clinical use until the team has identified which programs are most effective and efficient.
The wait, though, has its benefits. Over the next few years, Rhea’s VR rehabilitation advancements will likely be more affordable and accessible for the broader clinical community. Not only is the software required to run the programs rapidly becoming open-source, meaning it’s freely available to anyone, but the Oculus Rift headset the participants with amputations use to simulate walks is much cheaper than similar equipment purchased in previous years. For example, when Rhea’s group purchased a VR headset in 2011, its price tag was $37,000. Today, the smaller, more portable Oculus Rift exists for a fraction of the cost — $350.
Rhea’s lab has also invested in a new omnidirectional, lowfriction, bowl-shaped treadmill called the Virtuix Omni that is roughly half the size of a standard treadmill. When paired with the lower-cost Oculus Rift, the $500 Virtuix creates an effective rehabilitation system for less than $1,000, well within the budgets of most clinics.
Other elements of Rhea’s work have applications far outside the traditional clinic. With $1 million in funding from the U.S. Department of Defense, his team is designing a smartphone-based app to test whether soldiers injured in the field have sustained a concussion severe enough to be removed from duty.
“This research is important because concussion can range from mild to severe, with the mild version being more difficult to detect — yet it could still have serious implications on balance and cognitive ability,” he says. “There’s not really a good way to test in the field for mild concussions. But the last thing you want is someone with a concussion making life-and-death decisions for themselves or their entire unit.”
Time available to test whether a soldier has sustained a concussion is limited in a combat zone, and usually a combat medic, not a doctor, is the only medical personnel available. Consequently, the military needs an easy-to-use, accurate tool that can diagnose concussion severity within minutes. Rhea’s team is using existing smartphone technology to create one.
Most smartphones contain accelerometers, devices that detect speed, as well as orientation changes. That means they can pick up on subtle balance shifts, Rhea says, making them perfect tools for concussion diagnosis. A field medic can simply Velcro a smartphone with this app to the injured soldier’s thigh and have him or her walk in place for two minutes while the phone collects data on acceleration and side-to-side movements. After 15 seconds of analysis, a green, yellow, or red light will appear, signaling whether the soldier should be removed from duty and given medical attention.
This app could also be useful on the sidelines of high school and college football games, he adds.
Rhea’s team is currently collecting data from and testing the app with civilian patients, some who are healthy and some concussive, as well as with healthy and concussive military personnel. He hopes to have a perfected app to the Department of Defense in less than two years.
Exercise for a Lean, Strong Mind
Physical activity has always been important to Dr. Jennifer Etnier, but she never wondered about how it might impact mental capacity and thought processes until her parents repeatedly asked her to help program their VCR to record football games. Her mother eventually grasped the concept, but her father never did.
“I wondered if there were differences in older adults’ ability to learn and retain novel tasks and whether exercise and physical activity influenced that,” says Etnier. “Can exercise and physical activity help preserve cognitive ability into advanced age?”
To date, that answer has been unclear. Being able to say “yes” could make it easier to motivate older adults to exercise more — if they’re concerned about maintaining their cognitive capacity. Now, Etnier is beginning to do just that. Initial results from her two-year National Institutes of Health-funded research study show staying active can safeguard mental capabilities. In fact, that benefit extends all the way down to school-age children.
To delve into how exercise impacts cognitive performance, Etnier and her team have designed studies with older adults, college students, and elementary pupils.
With adults, Etnier explores whether exercise can safeguard mental faculties of individuals at genetic risk for Alzheimer’s disease. In her study, 54 adults between ages 50 and 65 exercised three times weekly (walking and strength-training). They also completed cognitive evaluations at the study’s start, at four months, and at eight months. The evaluations included recalling words from a list of 15 words read aloud and a Stroop test, where a participant must say the color of ink a word is written in instead of reading the word itself.
Everyone benefited.
“Overall, the group showed improvement in cognition associated with physical activity. This suggests that even those with a genetic risk will receive the benefit,” Etnier says. “It’s very exciting to see how long-lasting these benefits are — could we, perhaps, delay the effects of Alzheimer’s so that someone will die of other causes?”
Her team is also analyzing participants’ blood samples to examine brain-derived neurotrophic growth factor, a protein that is simultaneously responsible for strengthening synapses in the brain and pruning those the brain no longer uses. If physical activity is increasing production of this protein, the researchers may have identified one of the pathways by which physical activity is affecting cognition.
It’s clear, though, she says, that not all exercise is created equal. There could be a sweet spot — an optimal duration and intensity that evokes the best response. Working with UNCG undergraduates, she found those factors do matter, as does the timing of exercise relative to a mental task.
Participating students reviewed a 15-word list and recited the words after three 30-minute sessions on the treadmill at low, medium, and maximum capacity. They then returned 24 hours later to repeat the same word list. The students repeated the activity as a whole five times. Based on their performance, Etnier found that moderate and maximal exercise offered the greatest short-term benefits, but maximum exertion prompted the best performance the next day.
Etnier found further evidence of the importance of timing when studying children in the second, fourth, and sixth grades. Her team tested students after they exerted their maximum effort to complete a one-mile run (fourth and sixth graders) or an eight-minute run (second graders). Half of the children tested reviewed a 15-word list before the run, and half reviewed the word list after the run. They returned and were tested on their word recall 24 hours later. Those who ran prior to hearing the list remembered more words than those who ran after.
“Historically, there have been teachers who were afraid that if students exert themselves highly that it would hurt their academic performance,” she says. “We found that they actually performed better when they ran just before being asked to memorize the words than when they didn’t.”
These findings, she says, support the inclusion of physical education sessions early within the school day.
ACL Injury — Female Hormones At Fault?
Researchers have known for decades that women are more likely than men to suffer injury to the anterior cruciate ligament (ACL) — the ligament responsible for stabilizing the knee during jumping, landing, pivoting, and changing speeds. But the reasons behind this difference are still fuzzy.
Dr. Sandra Shultz has been at the forefront of these investigations since the late 1990s, looking specifically at how hormones might affect knee laxity in women.
“We’ve learned that laxity varies greatly among men and women,” Shultz says. “Women naturally have greater laxity than men. That’s important because research shows that greater laxity increases the risk of injury.”
Laxity refers to the amount of existing ligament looseness. With knees, laxity impacts stability. People with greater laxity tend to land more stiffly, and the knee collapses inward. Injuries occur when the force of impact on the knee overwhelms what the ACL can handle — often, the ligament just isn’t strong enough.
Shultz is investigating the potential for hormones to influence that laxity. Past research has shown that more injuries occur during the first half of a woman’s menstrual cycle compared to the second. Shultz’s team hypothesized that the reason might lie in fluctuations in estrogen, progesterone, testosterone, and possibly relaxin, the hormone most responsible for ligament laxity during pregnancy.
To test these changes, the team gathered blood samples from female undergraduate students, measuring their knee laxity on the same days the samples were drawn. They then identified the days of minimum and maximum laxity in each female’s cycle. On those days, subjects were asked to perform a landing maneuver while the researchers measured their lower extremity movement patterns. As expected, on days of maximum laxity, subjects exhibited movement patterns that are associated with a higher risk for injury.
The researchers assessed each subject’s hormone levels and other blood markers on days of minimum and maximum laxity. What they found? Not only do hormone changes correlate with changes in observed laxity, they also correlate with changes in collagen metabolism — in a way that can alter the makeup and structural integrity of soft tissue. These changes most likely contribute to a structurally weaker ligament and render the knee less mechanically stable at certain times of the month.
Dr. Randy Schmitz, Shultz’s colleague, is also adding to what researchers know about ACL injury and recovery. He’s following women who’ve had surgery for ACL injury to observe how their knee cartilage changes in the six months post-operation. He wants to know whether those early changes can predict how the subjects will walk over time. Such knowledge could impact rehabilitation. Figuring out better ways to treat or possibly prevent ACL injuries in females is critical, Shultz says, because the impact is lifelong. The majority of ACL injuries happen between ages 14 and 15, and arthritis sets in within 10 years to 15 years. That means injured young women can have arthritic knees — and face a future of knee replacements — by age 30.
Having a greater understanding of the variability of who’s at risk will help Shultz and her team better understand who to target for intervention.
“These injuries add up to missed time in sports and activities and an increase in potential long-term complications,”Shultz says. “Ultimately, we want to understand what factors increase knee laxity, and then determine if laxity can be changed or not through prevention and strengthening, since some evidence suggests that more muscle mass around the knee is associated with less knee joint laxity.”
Taken together — and individually — the ongoing work inside labs led by Rhea, Etnier, Shultz, and Schmitz continues to move the needle in the right direction for what we know about healthy movement and how the human body and brain can help themselves. Over time, their investigations hold great promise for combatting and, potentially, preventing and conquering some of the most common causes of impaired motion that both men and women face.
To read the article at its original location: http://research.uncg.edu/wp-content/uploads/2015/12/onlinefall2015.pdf
