Stroke Recovery Theories Challenged By New Studies Looking at Brain Lesions, Bionic Arms

Stroke survivors left weakened or partially paralyzed may be able to regain more arm and hand movement than their doctors realize, say experts at The Ohio State University Wexner Medical Center who have just published two new studies evaluating stroke outcomes.

One study analyzed the correlation between long-term arm impairment after stroke and the size of brain lesions caused by patients’ strokes – a visual measure often used by doctors to determine rehabilitation therapy type and duration. The other study compared the efficacy of a portable robotics-assisted therapy program with a traditional program to improve arm function in patients who had experienced a stroke as long as six years ago.

“These studies were looking at two entirely different aspects of a stroke, yet they both suggest that stroke patients can indeed regain function years and years after the initial event,” said Stephen Page, PhD, OTR/L, author of both studies and associate professor of Health and Rehabilitation Sciences in Ohio State’s College of Medicine. “Unfortunately, we know that this is not a message that many patients and especially their clinicians may be getting, so the patients may not be reaching their true potential for recovery.”

Size doesn’t matter
Clinicians frequently tell patients that the bigger the size of the area of their brains affected by their strokes, the worse that their outcomes will be. However, in a lead article in the Archives of Physical Medicine and Rehabilitation, Page’s research team found that there was no relationship between the size of stroke lesions and recovery of arm function in 139 stroke survivors. On average, study participants had experienced a stroke five years earlier.

“Historically, lesion size been thought to influence recovery, but we didn’t find that to be the case when looking at regaining arm and hand movement,” said Page, who also runs Ohio State’s B.R.A.I.N Lab, a research group dedicated to developing approaches to restore function after disabling injuries and diseases. “This has important implications because we know clinicians look closely at lesion volume and may make decisions about the type and duration of therapy, and that some may communicate likelihood for recovery to patients based on this size. Many people think the window for therapy is roughly six months, but we think it’s much longer.”

Page agrees that the first six months after a stroke may represent important healing time for the brain, but that “retraining” it with occupational therapy can potentially be helpful at any time after the stroke. He says that his findings support other theories that the health of remaining brain tissue influences recovery much more than lesion size.

Although there are many studies that have identified a relationship between stroke lesion size and overall neurological function, Page’s study is the first to specifically look at lesion size and upper extremity outcomes.

Robotic arm as good as traditional therapy
In the second study, Page’s team demonstrated that stroke survivors using a portable robotic-assisted arm to perform repetitive task training showed as much motor recovery as patients who performed similar tasks in a therapist-guided outpatient setting.

“Our results are exciting not just because we showed robotics-assisted therapy can offer equal benefit. We showed that both groups got better, even among patients who had suffered strokes as long as eight years ago,” noted Page.

For the study, which was published in the June 2013 issue of Clinical Rehabilitation, patients performed repetitive exercises that focused on everyday tasks while supervised by a therapist in an outpatient setting. Half of the group was randomly assigned to use the robotic arm, a portable device that is worn over the arm like a brace. When a person tries to move a weakened arm, the device senses the electrical impulses and helps the person carry out the movement. A second group performed the same tasks without the device for the same amount of time and in the same environment. The group training with the robotic arm performed tasks as well as their counterparts.

“Therapy can be tiring, expensive, and resource-intensive. This study is important because it shows us that in patients with moderate arm impairment, similar benefits can be derived from using a robotic device to aid with arm therapy as with manually based rehabilitative approaches,” said Page. “Study participants who trained with the robotic arm also reported feeling stronger and more positive about the rehabilitation process.”

Most of the estimated 80 million stroke survivors worldwide will continue to have upper body weakness for months after a stroke, preventing them from accomplishing everyday tasks like lifting a laundry basket or drinking from a cup. Page says that more research in stroke outcomes and rehabilitation is needed, and that he hopes families and healthcare practitioners dealing with stroke will keep the door to recovery open wider and longer.

“Loss of upper extremity movement remains one of the most common and devastating stroke-induced impairments. And the fact is that more stroke survivors are expected yet studies and pathways to optimize rehabilitative therapy for these millions are not always emphasized. In particular, we know active rehabilitation programs help people regain function, but we still don’t know who will benefit the most from these types of therapy,” said Page. “Both of these studies give us insights about patients who will respond best – and most importantly, that we have to give these patients every chance possible to get better, because they can keep getting better.”

Pitt/UPMC Team Describes Technology that Lets Spinal Cord-Injured Man Control Robot Arm with Thoughts

Researchers at the University of Pittsburgh School of Medicine and UPMC describe in PLoS ONE how an electrode array sitting on top of the brain enabled a 30-year-old paralyzed man to control the movement of a character on a computer screen in three dimensions with just his thoughts. It also enabled him to move a robot arm to touch a friend’s hand for the first time in the seven years since he was injured in a motorcycle accident.

With brain-computer interface (BCI) technology, the thoughts of Tim Hemmes, who sustained a spinal cord injury that left him unable to move his body below the shoulders, were interpreted by computer algorithms and translated into intended movement of a computer cursor and, later, a robot arm, explained lead investigator Wei Wang, Ph.D., assistant professor, Department of Physical Medicine and Rehabilitation, Pitt School of Medicine.

“When Tim reached out to high-five me with the robotic arm, we knew this technology had the potential to help people who cannot move their own arms achieve greater independence,” said Dr. Wang, reflecting on a memorable scene from September 2011 that was re-told in stories around the world. “It’s very important that we continue this effort to fulfill the promise we saw that day.”

Six weeks before the implantation surgery, the team conducted functional magnetic resonance imaging (fMRI) of Mr. Hemmes’ brain while he watched videos of arm movement. They used that information to place a postage stamp-size electrocortigraphy (ECoG) grid of 28 recording electrodes on the surface of the brain region that fMRI showed controlled right arm and hand movement. Wires from the device were tunneled under the skin of his neck to emerge from his chest where they could be connected to computer cables as necessary.

For 12 days at his home and nine days in the research lab, Mr. Hemmes began the testing protocol by watching a virtual arm move, which triggered neural signals that were sensed by the electrodes. Distinct signal patterns for particular observed movements were used to guide the up and down motion of a ball on a computer screen. Soon after mastering movement of the ball in two dimensions, namely up/down and right/left, he was able to also move it in/out with accuracy on a 3-dimensional display.

“During the learning process, the computer helped Tim hit his target smoothly by restricting how far off course the ball could wander,” Dr. Wang said. “We gradually took off the ‘training wheels,’ as we called it, and he was soon doing the tasks by himself with 100 percent brain control.”

The robot arm was developed by Johns Hopkins University’s Applied Physics Laboratory. Currently, Jan Scheuermann, of Whitehall, Pa., is testing another BCI technology at Pitt/UPMC.

Woman With Quadriplegia Feeds Herself Chocolate Using Mind-Controlled Robot Arm

In a study published in the online version of The Lancet, the researchers described the brain-computer interface (BCI) technology and training programs that allowed Ms. Scheuermann, 53, of Whitehall Borough in Pittsburgh, Pa. to intentionally move an arm, turn and bend a wrist, and close a hand for the first time in nine years.

Less than a year after she told the research team, “I’m going to feed myself chocolate before this is over,” Ms. Scheuermann savored its taste and announced as they applauded her feat, “One small nibble for a woman, one giant bite for BCI.”

“This is a spectacular leap toward greater function and independence for people who are unable to move their own arms,” agreed senior investigator Andrew B. Schwartz, Ph.D., professor, Department of Neurobiology, Pitt School of Medicine. “This technology, which interprets brain signals to guide a robot arm, has enormous potential that we are continuing to explore. Our study has shown us that it is technically feasible to restore ability; the participants have told us that BCI gives them hope for the future.”

In 1996, Ms. Scheuermann was a 36-year-old mother of two young children, running a successful business planning parties with murder-mystery themes and living in California when one day she noticed her legs seemed to drag behind her. Within two years, her legs and arms progressively weakened to the point that she required a wheelchair, as well as an attendant to assist her with dressing, eating, bathing and other day-to-day activities. After returning home to Pittsburgh in 1998 for support from her extended family, she was diagnosed with spinocerebellar degeneration, in which the connections between the brain and muscles slowly, and inexplicably, deteriorate.

Thought-controlled prosthesis is changing the lives of amputees

The world’s first implantable robotic arm controlled by thoughts is being developed by Chalmers researcher Max Ortiz Catalan. The first operations on patients will take place this winter.

“Our technology helps amputees to control an artificial limb, in much the same way as their own biological hand or arm, via the person’s own nerves and remaining muscles. This is a huge benefit for both the individual and to society”, says Max Ortiz Catalan, industrial doctoral student at Chalmers University of Technology in Sweden.

Ever since the 1960s, amputees have been able to use prostheses controlled by electrical impulses in the muscles. Unfortunately, however, the technology for controlling these prostheses has not evolved to any great extent since then. For example, very advanced electric hand prostheses are available, but their functionality is limited because they are difficult to control.

“All movements must by pre-programmed”, says Max Ortiz Catalan. “It’s like having a Ferrari without a steering wheel. Therefore, we have developed a new bidirectional interface with the human body, together with a natural and intuitive control system.”

Today’s standard socket prostheses, which are attached to the body using a socket tightly fitted on the amputated stump, are so uncomfortable and limiting that only 50 percent of arm amputees are willing to use one at all.
This research project is using the world-famous Brånemark titanium implant instead (OPRA Implant System), which anchors the prosthesis directly to the skeleton through what is known as osseointegration.

“Osseointegration is vital to our success. We are now using the technology to gain permanent access to the electrodes that we will attach directly to nerves and muscles”, says Max Ortiz Catalan.

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