How Personalized Interactions with Robots Could Help Stroke Victims

^{Israeli President Reuven Rivlin interacts with a robot on Oct. 22 as Dr. Shelly Levy-Tzedek smiles and looks on. Credit: Dani Machlis/BGU}

Personalizing interactions between humans and robots could help rehabilitate stroke victims by boosting patient use of tailored physical therapy programs, researchers have found.

A new study by researchers at the Ben-Gurion University of the Negev (BGU) in Israel has made a first step in developing an interactive movement protocol that fits an individual’s preferences, with the potential to make physical therapy more customized and effective.

“I think of it as a robotic revolution in rehabilitation,” said Dr. Shelly Levy-Tzedek, lead author of the report, published in Restorative Neurology and Neuroscience this month, and head of the Cognition, Aging, and Rehabilitation Lab in BGU's Department of Physical Therapy. “The goal is to have a rehabilitation protocol that includes the robot as a partner and as a coach so that people can do their exercises at home.”

The findings were presented to Israeli President Reuven Rivlin this week during a visit to the BGU campus.

The study used a “mirror game”, usually played in improvisational theater, in which an individual mimics the movement of the robot or vice versa. “People report that when they play the mirror game they feel a sense of togetherness and closeness. We’re the first to my knowledge to play the mirror game between a human and a robot,” Levy-Tzedek said.

The robotic arm was fitted with an Xbox Kinect camera to track the user’s arm. In the game, the user first led the robot, and then the roles were reversed, and finally the pair was instructed to move together.

The study found that the movement of the robot “primes” the human movement. In other words, the participants tended to mimic the robot behavior. “Priming seems to be a byproduct of the interaction, but it actually could be used as a feature that we plan for patients. If we want the patient to move in certain ways, we could accordingly program the robot to move in certain ways,” Levy-Tzedek said.

Researchers also found that participants were evenly split in their preference for either leading or following. This demonstrates a need for robotic physical therapy routines to be responsive to what a patient is most likely to find appealing and satisfying, Levy-Tzedek noted.

“Just like we have personalized medicine, which is tailored to the particular person, it’s the same with human-robotic interactions. It’s not just one size fits all,” Levy-Tzedek said. “Some people are more competitive and like to lead, others less so. You can’t assume that one type of interaction would fit everyone.”

Researchers also found that participants enjoyed tracing smoother, recognizable movements like the infinity sign or circles than jerkier, robotic ones like dribbling a ball or zig zags.

Levy-Tzedek doesn’t envision robotic therapists replacing their human counterparts anytime soon. A robotic coach could, however, be invaluable in encouraging exercises at home and bridging the time between meetings with physical therapists.

“In that gap is where we come into the picture,” Levy-Tzedek said. “This was a first step in that direction of using rehabilitation in a gamified environment.”

Engaging patients in gamified physical therapy routines is important, she said, because patients can often be reluctant to undertake the routines outside of scheduled appointments. “The rehabilitation process can be boring, painful, frustrating, and patients aren’t always motivated enough to do that.”

Almost 800,000 people in the US have a stroke every year, according to the American Stroke Association, or 1 every 40 seconds. Although Levy-Tzedek and her team are first focusing on that demographic, a robotic coach to encourage physically therapeutic routines could have benefits for a much broader user base. There is a “wide variety of conditions” that these findings could apply to, according to Levy-Tzedek, and not necessarily individuals who have a physical disorder.

“It turns out you can be an active couch potato. You can go to the gym three times a week and still suffer from disorders associated with sitting for long periods of time,” she added.

Sedentary behavior such as long hours sat at a desk or at home in front of the TV is associated with an increased risk of cardio-metabolic disease, all-cause mortality and a variety of physiological and psychological problems, according to the International Journal of Behavioral Nutrition and Physical Activity. Encouraging physical routines in the home could help combat that, Levy-Tzedek said.

Over recent years the cost of robotics has dropped dramatically, she said, anticipating that as soon as a decade from now most patients would be able to afford this technology.