Robotic Device Aids in Stroke Recovery

By Anna Lynn Spitzer

Irvine, Calif., July 17, 2007 --Unite a robotic engineer, a stroke neurologist, an occupational therapist and a computer scientist in the pursuit of better stroke rehabilitation, and what do you get?

Meet HoWARD.

A computerized robot that helps improve stroke patients’ hand mobility, HoWARD – Hand-Wrist Assisting Robotic Device – is the brainchild of Calit2 academic affiliate Steven Cramer, M.D., associate professor of neurology; former UCI postdoctoral fellow Craig Takahashi, who’s currently assistant professor of engineering at Santa Ana College ; Lucy Der-Yechiaian, UCI Medical Center occupational therapist; and Vu Le, College of Medicine neuro-imaging programmer.

Steven Cramer
Cramer and three
colleagues collaborated
on the robot.

Cramer, who researches the brain’s repair mechanisms after stroke or spinal cord injury, had investigated many approaches to rehabilitation. Everything pointed to the benefit of repetition in rebuilding motor skills.

“It’s clear that an important part of making things move better is practice. It’s like learning to play the piano,” he says.

Four Expert Viewpoints

Soon after arriving at UCI in 2002, Cramer met Takahashi, who expressed interest in his idea of a rehabilitative hand robot. Cramer then recruited Der-Yechiaian and Le for their respective proficiencies.

“We wanted to build a solid program from an engineering point of view, that improved the hand in a way that only a stroke neurologist would know, in a manner relevant to how an OT helps people, where the robot interfaces with a virtual reality-type program,” Cramer says.

Having a four-person team was advantageous, Takahashi says. “This research is multidisciplinary in nature, so it required collaboration. Each team member brought his/her expertise to the table.”

He relied on neurological input from Cramer and therapy guidance from Der-Yechiaian as he built the prototype, then Le wrote the software interface and computer games.

“The human hand is quite intricate and no two people move their hands the same way,” Takahashi explains. “The challenge was designing a device that could accommodate many different hands… within a limited budget.”

The result: a pneumatically actuated, three-degrees-of-freedom (wrist, thumb and four fingers movement) device. Using interactive video games, it helps stroke patients relearn the grasping and releasing movements crucial for daily living tasks.

Fun, Games and Hard Work

During therapy, with the right hand strapped into HoWARD, the patient is instructed to repeatedly open or close the hand, and attempt other tasks shown on a computer screen. To keep it interesting, Le programmed several unique games and exercises. Patients are cued to grab an object as it travels by, or squeeze a lime or drop ‘gems’ into corresponding geometric shapes.

HoWARD, robotic device to aid stroke victims
HoWARD delivers sensory feedback from each task to the brain's motor output center, helping to rebuild motor skills.

Patients must attempt each task alone, but after three seconds, HoWARD uses air-driven pistons to help.

“When you move your hand, your brain is listening,” Cramer explains. “When HoWARD helps complete a task, that shapes the movement and delivers sensory feedback into the brain’s motor output center.

“It’s important that the patient initiates the movement,” he adds. Whatever they can’t complete, HoWARD reminds their brain how it feels to go the rest of the way.”

Currently, a therapist augments the treatment by using real objects in some exercises to encourage tactile stimulation. Cramer says the team is working to automate that task and integrate it into HoWARD’s repertoire.

A Promising Future

Results from the first clinical trial were encouraging.

Thirteen stroke patients with similar baseline skills were divided into two groups; each received 20 hours of therapy over three weeks. Group A, in the first half of the sessions, attempted to complete the tasks without assistance. HoWARD helped out during the second half; Group B used HoWARD the entire time.

Motor skills in both groups increased steadily. Group B boasted significantly greater improvements than Group A, further confirming HoWARD’s effectiveness.

And one month after therapy ended, all patients showed slight declines in their abilities, indicating the significance of continuity.

Cramer is pleased. “We weren’t looking for numbers to jump off the scale,” he says. “We wanted a functional tie-in – to demonstrate that if they can improve by 30 percent, maybe they can go shopping (by themselves).”

Mapping Brain Results

The study’s tangible results were confirmed by changes in the sensorimotor cortex of the brain. Functional MRIs administered to the participants revealed an increase in cortical representation for the practiced tasks, while non-rehearsed tasks did not result in any brain changes.

Cramer has obtained an NIH grant for HoWARD’s next clinical study, which is underway.

And one day, he would like to see HoWARD go wireless for tele-rehabilitation applications. “I think robotic therapy with intelligent communication in the home is the wave of the future,” he says. “Instead of therapists treating one patient at a time, they could have a bank of monitors in front of them and treat 10 patients at a time. There’s no reason that couldn’t happen.”