MultiCare researcher’s invention improves quality of life for survivors of stroke and other medical conditions

Once every second — on average that’s how often we take a step while walking. Many of us are concerned with the accumulation of those steps — striving for 10,000 a day, perhaps — rather than the mechanics of each one, but not David Embrey, PT, PhD.

Embrey, a retired pediatric physical therapist at MultiCare and founder of the Research and Movement Laboratory at Mary Bridge Good Samaritan Children’s Therapy Unit, had an epiphany back in 2004 that led to the development of the Gait MyoElectric Stimulator (GMES). This medical device is designed to help the millions of people with conditions that affect their ability to walk, for example, those who have suffered a stroke, live with cerebral palsy or have peripheral artery disease.

The evolution of an idea into a product takes patience — 18 years’ worth and counting — but now Embrey is closer than ever to sharing his life-changing invention with the people who need it. He and MultiCare are collaborating with the Innovation Institute to make the GMES widely available to patients.

The vision of a lifetime

The day inspiration came knocking, Embrey was sitting in front of his computer examining the electromyography results of children walking. Electromyography is a diagnostic test that shows how well muscles fire during a specific action.

As he performed a tedious measuring task on his screen, Embrey began to think about an upcoming meeting with a colleague later that afternoon. For months, Embrey and his colleague had been trying to come up with a new research idea that could potentially benefit children with cerebral palsy. It was a mission that was personal for Embrey.

“My brother has cerebral palsy,” says Embrey. “He was the inspiration for my career as a pediatric physical therapist and it was his experience with mobility issues that drove my research interests as well.”

As Embrey sat in front of his computer that day — the impending meeting with his colleague and their lack of viable ideas looming large in his mind — he grew frustrated. He threw his hands in the air, looked up at the ceiling and said, “I’m supposed to see something, but I just don’t. I’m just not smart enough!”

But then his moment of despair transformed into one of insight.

“I looked back at my computer screen, and there the invention was in its entirety,” Embrey says. “I call it my divine vision.”

Partnership, a prototype and the road to development

To help turn his vision into reality, Embrey collaborated with two partners: Jeff Stonestreet, a retired electrical engineer from Boeing; and Gad Alon, PT, PhD, associate professor emeritus at the University of Maryland.

Together, the three of them created a prototype of the GMES, an electrical stimulation system that helps control muscle contraction and joint movement and improve stability while walking. Designed to be worn on the leg, undetectable beneath one’s clothes, the GMES achieves its aim by delivering a slight electrical pulse to the shin and calf muscles.

“What’s unique about the GMES is that it reads the body. It sends electrical impulses so that the correct muscles contract and relax at exactly the right time,” says Embrey. “So, for example, if you’re in a crosswalk and you see a car coming, you’re likely to step faster. The GMES will read the body’s intention and speed up or slow down the stepping process as necessary.”

The electrical impulse itself is mild. Embrey equates it to a light tingling or pulsating sensation that most people lose awareness of after they’ve worn the GMES for a short time.

“The user gets to control the intensity of the electrical impulse,” Embrey says, “and the system doesn’t just run constantly. It automatically turns itself on or off depending on whether a person is moving”

Putting it to the test

Embrey and his collaborators studied the use of the GMES in three groups of people. One of those groups included stroke survivors experiencing hemiplegia, paralysis on one side of the body. One of the most common side effects of a stroke, hemiplegia can make it difficult for a person to walk and maintain balance.

The other two studies focused on children with cerebral palsy and adults with peripheral artery disease, a condition that can cause debilitating cramping in the legs.

Participants in all three studies wore the GMES for six to eight hours a day over the course of eight to 12 weeks, and the results were impressive: The GMES improved walking speed, walking endurance, muscle strength, quality of life and ability to function for all groups.

“There was one study participant in his 40s who had suffered a stroke and could barely walk,” says Embrey. “The GMES improved his walking ability to the point he could drive again and even return to work. It made a dramatic difference in his life.”

Something else that makes the GMES unique? Studies show that is has carryover effects. This means that for eight to 12 weeks after participants stopped wearing the GMES, the improvements to their walking ability remained.

“We think the reason is the length of time patients were wearing the device each day,” Embrey says. “Every single step they took in that 6-to-8-hour window was timed properly, supporting the brain’s ability to re-learn how to coordinate walking.”

Throughout the research and development process, support from the MultiCare Institute for Research & Innovation (MIRI) proved essential to Embrey and his team.

“David’s project is the perfect example of how we help MultiCare employees translate their creativity into innovations that positively impact patient care,” says Anne Reedy, vice president of research at MultiCare. “With support in areas such as research protocol design, grant applications, data collection and analysis and the dissemination of findings, they can research what they care about and play a role in improving health care for those in the community and beyond.”

Overcoming the market hurdle

Over the course of 18 years, Embrey and his team conducted multiple research studies showing the GMES was safe, comfortable and effective. They received two patents, developed multiple prototypes and earned two President’s Awards from MultiCare. However, one big hurdle remained: commercializing it so it could be available for patients at an affordable price.

“Getting a product like this to market requires time, expertise and funding I just didn’t have — investment in the millions, marketing prowess, legal and regulatory knowledge, and so much more,” says Embrey.

By 2021, development of the GMES had stalled and Embrey was ready to retire. It seemed the project would go nowhere.

But once again, disappointment and frustration gave way to hope. This time via telephone call. The Innovation Institute, an organization that works with health care professionals and communities to evaluate ideas and bring them to market, called Embrey. Already in partnership with MultiCare, the Innovation Institute saw value in the GMES and wanted to help Embrey realize his dream.

Now Embrey, MultiCare and the team at the Innovation Institute are close to releasing a new prototype, and they are working toward completing the necessary steps to receive clearance from the U.S. Food and Drug Administration, a requirement for all medical devices.

“This hasn’t been an experience marked by instant gratification, but I’ve appreciated being able to celebrate small successes along the way,” Embrey says. “Plus, it’s really exciting to be at this stage with the Innovation Institute and actively working toward getting the GMES to patients.”