Emory University | Woodruff Health Sciences Center
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A Step Forward

Helping stroke patients regain push-off

By By Dana Goldman | Photography by Kay Hinton

Story Photo

Assistant Professor Trisha Kesar and research coordinator Steven Eicholtz demonstrate a new biofeedback interface connected to the Motion Analysis Lab treadmill. 

Trisha Kesar has spent her career confounded by a problem. As director of Emory’s Motion Analysis Lab, she has been frustrated watching stroke survivors struggle to recover walking function—and physical therapists struggle to effectively help. “Gait is complicated,” says Kesar, who has a PhD and is assistant professor of rehabilitation medicine and physical therapy at Emory. Often stroke patients struggle to regain push-off in the leg affected by stroke, leading to difficulties in walking at an appropriate speed. Some may compensate for limited push-off in ways that can hurt other parts of their body.

“Until now, we haven’t had a good way of telling patients during training or rehabilitation, ‘This is what I want you to do, and here’s an objective measure of whether you’re doing it or not,’” says Kesar. “If they’re not paying attention or don’t have the cognitive ability or body awareness they had before the stroke, it can be a challenge to help them gain awareness of their own deficits.”

Now Kesar and colleagues, including Professor Steve Wolf, PhD, PT, FAPTA, FAHA, have come up with a possible solution. Using adapted biofeedback software and a projector screen connected to the Motion Analysis Lab’s instrumented, force-sensing treadmill, they’re able to provide real-time quantitative data about push-off to patients as they walk. This is the first known research focused on applying biofeedback for regaining push-off after stroke.

Preliminary studies show that such feedback can help patients increase push-off without negative compensation or consequences. Results of a pilot study appeared in the June 2017 issue of the Journal of NeuroEngineering and Rehabilitation and show that healthy volunteers increased push-off on the targeted leg by 20% to 30%.

For Kesar, push-off has long been a focus of her career. “Push-off is one of the key factors that influences gait in stroke,” says Kesar. Without enough push-off by the affected leg, a series of problems may ensue, including limping, leaning, slow walking, and compensating with the unaffected leg—all of which can lead to musculoskeletal issues, balance challenges, and an increased risk of falling.

Conversely, improving push-off may remedy these challenges. “If I fix push-off, I can fix problems with knee flexion, improve walking speed, and so much else,” says Kesar. “Push-off is one of the few deficits that can help target other impairments, offering upstream effects that benefit other parts of the gait cycle and other joints like the knee.”

With the current biofeedback interface, patients walking on the treadmill hear a beep and see a bar move on a screen when they meet or exceed their push-off goal for each step. In the feasibility study with healthy college-age participants and a subsequent pilot study with stroke survivors, research participants adjusted their movements to increase the occurrence of the beeps. Lab researchers individualized target push-off goals for each participant, measuring push-off in newtons.

“The beauty was that stroke survivors could see every step they took in real time and see how close they were getting to the target the physical therapist had set for them,” says Kesar. “They all wanted to succeed because it’s like playing a game.” Within one session, study participants walked with more push-off and symmetry and were able to maintain those changes for 10-15 minutes after the training period. “It showed proof of concept,” says Kesar.

Kesar says this new intervention is possible because of recent technological advances. “The system gives information about real-time physiological behavior in a way that patients understand and that directs them how to change behavior,” says Kesar. Goals are individualized and adjusted as patients gain skill and strength. If a patient increases push-off in a way that could have a negative impact, such as by leaning, physical therapists can offer redirection. “It’s beautifully simple,” says Kesar. “People want more information. They want to know that they’re doing what we want them to do.”

Atlanta dentist Piara Singh had a stroke in July 2009 and participated in the study. “Being in Dr. Kesar’s study has made me aware of concentrating on foot placement and push-off,” he says. “I think of the biofeedback beep while walking on the treadmill at home.”

Stroke survivor Jeanie Gamble also participated in the study. She says her time on the lab’s treadmill continues to support her rehabilitation efforts. “I was able to learn what I was doing right and what wasn’t as effective,” she says. “I learned what I needed to do.” Gamble now takes long walks a few times a week, focusing during parts of those walks on foot placement and push-off.

The initial studies have been funded by Emory through Kesar’s ongoing research grant and include collaboration with Wolf, former Emory physical therapy neurology resident Katlin Genthe 16DPT, Emory Motion Analysis Lab manager Steven Eicholtz, and Georgia Tech undergraduate researcher Chris Schenck.

Kesar and Genthe are speaking about the research at a biofeedback symposium at the American College of Rehabilitation Medicine conference later this year. Kesar is also applying for grants to extend this research. “It’s hard for patients to stay motivated and push themselves to the right challenge level,” says Kesar. “My goal is to develop a gait-retraining game that is engaging and entertaining. I want to make rehab more fun.”

Future research may also explore how this real-time feedback may work with another of Kesar’s research interests—functional electrical stimulation—or other existing gait treatments.

Eventually, Kesar hopes that biofeedback may be a tool that physical therapists can regularly integrate into their treatment regimens. As technology continues to evolve, Kesar imagines that sensors within shoe insoles could connect to phone apps—and that such technology may someday take the place of her treadmill and projector screen. She also anticipates that others besides stroke survivors may benefit, including patients recovering from traumatic brain injuries and military veterans recovering from physical injuries. It’s just a matter of time, she says, before biofeedback is a tool throughout rehabilitation medicine.

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