University team tests robotic arm exoskeleton at St. Luke’s for stroke recovery

A robotic arm exoskeleton being tested in Spokane is reaching to advance recovery for stroke patients.

Developed at University of Idaho, a two-joint device is in trial use for one arm at Providence St. Luke’s Rehabilitation Medical Center. It is designed to mimic the movement and abilities of the human elbow and forearm and help stroke survivors regain mobility.

But the UI team is working up to a bilateral device, with multijoint robotic exoskeletons extending from shoulder through fingertips for both arms – offering tools to assess impairments, help a patient move a weak limb and support therapy motions with a game interface.

“We’re building it up in phases – starting with a two-joint robot – and we’re expanding now to a five-joint robot that we’re still perfecting the controllers on,” said Joel Perry, UI associate professor in mechanical engineering. He’s also co-director of UI’s assistive robotics lab.

“Then we’ll be building up toward a nine-, 13- and hopefully up to a 15-joint robot per arm. The big part of this project is it’s bilateral and will allow us to do assessments on both arms. That is really important, because there is such a variety of effects after a stroke.

“It makes it harder to compare anyone to normal, so the ability to assess a left arm and a right arm on the same patient can give you a little closer to normal for that person.”

A National Science Foundation grant funded the UI’s project. Starting summer 2015, the project was dubbed BLUE SABINO, for BiLateral Upper-Limb Exoskeleton for Simultaneous Assessment of Biomechanics and Neuromuscular Output.

UI faculty and about two dozen engineering students have assisted the project, along with a Whitworth University professor and two of his students.

“The ultimate hope is that we get all 15 joints of the bilateral system together so it’s able to support full reaching grasp assessment, and along the way, learn new things about how impairment plays out in different people, so we can start gathering a database that better supports targeted therapy,” Perry said.

“The ultimate aim is to improve the quality of life for people with neurological deficits and maximize the quality of recovery outcomes in a minimum amount of time.”

Doug Weeks, St. Luke’s clinical research senior manager, said the robotic bilateral device has wide potential. From birth to end of life, the brain has the capability to change and regain prior function with practice, he added.

“The most common type of stroke, about nine in every 10 strokes, is an ischemic stroke that typically affects one hemisphere of the brain that is responsible for controlling arm activities on the opposite side,” Weeks said.

“What the bilateral robotic device will allow is for each person to act as their own control. We can provide tests to see what the ranges of motion are, the amount of strength, the precision of movement in the unaffected limb after an ischemic stroke, and then be able to compare that to the affected side.

“It has a level of precision that’s going to be higher than what could be generated if we have, for example, a therapist who is performing tests on both limbs to find out the degree of deficits.”

Additionally, occupational therapists routinely set up repeated tasks for stroke patients in rehabilitation. But the number of targeted tasks can increase in less time with assistance from the robotic arms, Weeks said. An option to use a connected computer game for a patient to practice a pattern also provides an incentive, he said.

“Intentional practice is something that we are wanting the patient after a stroke to engage in, so those neurons that were damaged because of the stroke can begin to regenerate, create new pathways – so that arm function, hand function and finger function are something that can be brought back,” Weeks added.

“This robotic device is really a game changer in terms of being able to offer not only evaluation in a stroke patient to see what their capabilities are, and where they might have deficits, but also the ability to provide (patient) practice.”

COVID restrictions delayed testing the early model, but three patients have tried the two-joint device mainly for feedback to UI developers.

“Right now, it’s for one arm, and it just happens to be the left arm,” Weeks said.

Perry said the device with motorized joints can provide motion assistance, but with enough rotation and degrees of freedom that a patient can move. It also measures motion.

“We’re trying to make the device feel like it’s not there,” Perry said.

“The device moves out of your way as you move, so it can record mobility and record function, but because it has the motors, it has the ability to provide assistance, or resistance, or gravity support to the arm. It can put you in a different state to be able to do an assessment specific to a given user.”

It also has sensors and the ability to record signals from muscles and brain activity, Perry said.

Rene Maura, a UI mechanical engineering doctoral student, supported developing advanced control systems, safety systems, electrical design and some game software. Chris Bitikofer, UI mechanical engineer graduate research assistant, also did recent technology work.

Richard Stevens, Whitworth robotics engineering and physics professor, spent a sabbatical year working with the UI team and supports the project in Spokane. He said recent Whitworth students Ryan Grady and Laura Stricker helped develop the game, which allows a patient to move and match a hand-held object to what’s seen on a screen.

Overall, Weeks said the device can potentially support many patients, including after traumatic brain injuries.

“This device will be unique,” Weeks said. “A few others are FDA-approved and on the market but they only collect data from one limb at a time.”

He said most devices also don’t record signals from the muscles and brain as the patient is moving for assessments. “We at Providence St. Luke’s are happy to be part of this collaboration. We are invested because we know what the great potential is for our patients.”