Study charts exercise for stroke patients’ brains

A new study has found that stroke patients’ brains show strong cortical motor activity when observing others performing physical tasks — a finding that offers new insight into stroke rehabilitation.

Using functional magnetic resonance imaging (fMRI), a team of researchers from USC monitored the brains of 24 individuals — 12 who had suffered strokes and 12 age-matched people who had not — as they watched others performing actions made using the arm and hand that would be difficult for a person who can no longer use their arm due to stroke — actions such as lifting a pencil or flipping a card.

The researchers found that while the typical brain responded to the visual stimulus with activity in cortical motor regions that are generally activated when we watch others perform actions, in the stroke-affected brain, activity was strongest in these regions of the damaged hemisphere and strongest when stroke patients viewed actions they would have the most difficulty performing.

Activating regions near the damaged portion of the brain is like exercising it, building strength that can help it recover to a degree.

“Watching others perform physical tasks leads to activations in motor areas of the damaged hemisphere of the brain after stroke, which is exactly what we’re trying to do in therapy,” said Kathleen Garrison, lead author of a paper on the research. “If we can help drive plasticity in these brain regions, we may be able to help individuals with stroke recover more of the ability to move their arm and hand.”

Garrison, who completed the research while studying at USC and is currently a postdoctoral researcher at the Yale University School of Medicine, worked with Lisa Aziz-Zadeh of the USC Brain and Creativity Institute, based at the USC Dornsife College of Letters, Arts and Sciences, and the Division of Occupational Science and Occupational Therapy; Carolee Winstein, director of the Motor Behavior and Neurorehabilitation Laboratory in the Division of Biokinesiology and Physical Therapy; and former USC doctoral student Sook-Lei Liew and postdoctoral researcher Savio Wong.

Their research was posted online ahead of publication by the journal Stroke on June 6.

Using action-observation in stroke rehabilitation has shown promise in early studies, and this study is among the first to explain why it may be effective.

“It’s like you’re priming the pump,” Winstein said. “You’re getting these circuits engaged through the action-observation before they even attempt to move.”

The process is a kind of virtual exercise program for the brain that prepares you for the real exercise that includes the brain and body.

The study also offers support for expanding action-observation as a therapeutic technique, particularly for individuals who have been screened using fMRI and have shown a strong response to it.

“We could make videos of what patients will be doing in therapy and then have them watch it as homework,” Aziz-Zadeh said. “In some cases, it could pave the way for them to do better.”

New model of how brain functions are organized may revolutionize stroke rehab

A new model of brain lateralization for movement could dramatically improve the future of rehabilitation for stroke patients, according to Penn State researcher Robert Sainburg, who proposed and confirmed the model through novel virtual reality and brain lesion experiments.

Since the 1860s, neuroscientists have known that the human brain is organized into two hemispheres, each of which is responsible for different functions. Known as neural lateralization, this functional division has significant implications for the control of movement and is familiar in the phenomenon of handedness.

Understanding the connections between neural lateralization and motor control is crucial to many applications, including the rehabilitation of stroke patients. While most people intuitively understand handedness, the neural foundations underlying motor asymmetry have until recently remained elusive, according to Sainburg, professor of kinesiology and neurology and participant in the neuroscience and physiology graduate programs at the University’s Huck Institutes of the Life Sciences.

Research by Sainburg and his colleagues in the Center for Motor Control and published in the journal Brain has revealed a new model of motor lateralization that accounts for the neural foundations of handedness. The discovery could fundamentally change the way post-stroke rehabilitation is designed.

"Each hemisphere of the brain is specialized for different aspects of motor control, and thus each arm is ‘dominant’ for different features of movement," said Sainburg. "The dominant arm is used for applying specific force sequences — such as when slicing a loaf of bread with a knife — and the other arm is used for impeding forces to maintain stable posture, such as holding the loaf of bread. Together these specialized control mechanisms are seamlessly integrated into every day activities.

"Our research has shown that this integration breaks down in neural disorders such as stroke, which produces different motor deficits depending on whether the right or left hemisphere has been damaged," Sainburg continued. "Traditionally, physical rehabilitation professionals have used the same protocols to practice movements of the paretic arm, regardless of the hemisphere that has been damaged. Our research shows that each arm should be treated for different control deficits, and it also indicates that therapists should directly retrain patients in how to use the two arms together in order to recover function."

In preparing to test their model, Sainburg and his team selected study participants from the New Mexico Veterans Administration Hospital and Penn State Milton S. Hershey Medical Center based on specific criteria in order to accurately distinguish the motor control mechanisms specific to each brain hemisphere. Participants were then asked to perform a series of tasks on a virtual reality interface, programmed and designed by Sainburg, which allowed the researchers to record detailed 3D position and motion data. The data for all the participants’ hand trajectories and final positions were then aggregated to compare the effects of left versus right hemisphere damage on different aspects of control.

"Our results indicated that while both groups of patients showed similar clinical impairment in the contralesional arm, this was produced by different motor control deficits," Sainburg said. "Right hemisphere damaged patients were able to make straight movements that were directed toward the targets, but were unable to stabilize their arms in the targets at the end of motion. In contrast, left hemisphere damaged patients were unable to make straight and efficient movements, but had no difficulty stabilizing their arms at the end of motion. These results confirmed that each hemisphere contributes unique control to its contralesional arm, verifying why our arms seem different when we use them for the same tasks."

Results mirror those of Sainburg’s prior studies of motor deficits in unilateral stroke patients, focused on the ipsilesional arm, which formed the basis for his model of lateralization.

"Because both arms in stroke patients show motor deficits that are specific to the hemisphere that was damaged, we have concluded that the left arm is not simply controlled with the right hemisphere and vice versa," Sainburg said. "This is a revolutionarily new perspective on sensorimotor control: each hemisphere contributes different control mechanisms to the coordination of both arms, regardless of which arm is considered dominant."

Sainburg and his colleagues are currently designing follow-up studies that will aid the development of new rehabilitation protocols addressing the specific motor deficits associated with each hemisphere.

New therapy device enables stroke victims to recover further

Scientists from Nanyang Technological University (NTU) have developed a new stroke rehabilitation device which greatly improves recovery in stroke patients.

Thanks to this invention, stroke patients who had undergone conventional rehabilitation for a year or more and had hit a plateau in their recovery, managed to make significant progress in their ability to carry out everyday tasks.

Some of these long-term stroke sufferers have recovered up to 70 per cent of motor function clinical scores in just a month during the trial.

The new stroke therapy system, known as Synergistic Physio-Neuro Platform (SynPhNe), is currently undergoing thorough clinical investigations and more feasibility trials at local hospitals.

In use for 150 therapy hours, it has not had any side effects so far. Patients who tried SynPhNe also said they experienced little fatigue while using this easy-to-use system.

Developed by Dr John Heng, a senior research fellow at NTU’s School of Mechanical and Aerospace Engineering and his PhD student, Mr Banerji Subhasis, this system gives hope to frustrated patients who want to see more progress after completing conventional rehabilitation therapies.

The NTU research team of four has published over 11 scientific papers since 2008 on the principles of the system, its effectiveness and ease of use.

“While current rehabilitation systems do benefit many patients, there are also other patients who still have difficulties performing everyday activities like holding a fork or drinking from a cup, despite the usual rehab sessions,” said Dr Heng.

“SynPhNe works by giving real-time feedback to the patients on what is happening in their mind and in their muscles. Patients using SynPhNe know where their problems lie and can slowly work towards overcoming each problem, instead of feeling frustrated and going through a painful, expensive and prolonged trial-and-error process when their improvements are not visible.”

How it works

SynPhNe consists of patented computer software connected to a specially designed headset with neural sensors and a sensor arm glove. The device is designed to be worn easily by stroke patients who usually have control of only one arm.

These sensors provide feedback on the stress, attention, and relaxation levels of the mind and which muscles are being activated or inhibited by the patient. The software contains instructional videos for limb movements which the patient can mimic to improve his/her performance of various tasks.

Sensor information is displayed in real time via the computer screen so that the patient is aware of what is happening in his mind and body while undergoing the rehabilitation exercises.

Dr Heng said that while multi-model associative learning is known to be useful in the development of babies and in education, it is the first time that their research team is adapting it for stroke therapy. Tested on 10 patients so far, it has shown to be very effective in accelerating the recovery in stroke patients.

In associative learning, a patient will find out the link between cause and effect, or intent and physical result. The patient learns what he/she wants to do and what is actually happening with their limbs. This helps the patient to self-correct movements to match intended actions.

“For example, if a patient wants to move his wrist, but his wrist is not moving, SynPhNe will be able to show him that his mind had sent out a signal, his muscles have received it, but because supporting and opposing muscles are clenched, he will need to relax the opposing muscle in order to move his wrist,” Mr Subhasis explained.

“Another common problem is that the patient may feel stressed while undergoing therapy, which affects his muscle control. So by showing the stress level on the screen, SynPhNe will teach the patient how to control his breathing and posture to regain his balance and composure so that he can continue with the exercises.

“In short, SynPhNe makes patients aware of what is happening with their bodies so they learn how to relax their mind and muscles. This helps them to re-learn simple actions like holding a pen or a cup which may be arduous tasks for stroke victims.”

Ramping up patient trials

Patient trials are still on-going and 10 patients have undergone the trial for 12 sessions, each lasting 90 minutes. Over a four-week period, they have all shown some improvement on the clinical scales. It was found that patients with hand control and hand weakness problems improved the most, in several cases, up to 70 per cent.

The scientists started the patient trials in October 2012 at Tan Tock Seng Hospital and are embarking on another similar trial at the National University Hospital. Talks are underway to start another trial at Singapore General Hospital and in India.

SynPhNe, which took over five years to develop, have also won successive grants from the National Medical Research Council, the National Research Foundation’s Proof-of-Concept grant and Singapore-MIT Alliance for Research and Technology (SMART)’s Innovation Grant.

Start-up to look into commercialisation

Apart from conducting further trials involving 50 more patients, the next step for the scientists is to form a start-up company to turn the SynPhNe prototype into a portable stroke therapy kit for home use. This kit is expected to be cheaper than most robotic rehabilitation systems in the market which may cost over tens of thousands of dollars.

“This reduction in cost will allow for perhaps a rental or subsidy scheme for patients who wish to practise in the convenience of their own home instead of having to go to rehabilitation centres. It has the added advantage of providing constant updates of instructional videos and exercises to match the patient’s improvement and can even send their reports to their therapists via the device’s Wi-Fi capabilities,” Prof Heng added.

The idea to develop SynPhNe was inspired by the mind-and-body-as-one philosophy preached in traditional practices such as Taichi, Aikido and Yoga, and the health benefits they bring.

Mr Subhasis, a martial arts and yoga practitioner for more than 30 years had sought to bring this health benefit to people through modern yet simple, affordable technology. In the latest study, the patients who synergised their minds and bodies best (based on the brain and muscles signals recorded by SynPhNe) made the most dramatic improvements.

 “Training the patients to self-regulate their mind and body increases their confidence to make positive changes in their lives. It also helps therapists better customize rehabilitation routines based on the individual patient’s capabilities and perceptions,” Mr Subhasis added.

The Singapore-MIT Alliance (SMART) and Technology Transfer Office at NTU (NIEO) are assisting the research group with the commercialisation process.

Worldwide patent for a Spanish stroke rehabilitation robot

Robotherapist 3D, a robot which aids stroke patients’ recovery, is to be brought to market by its worldwide patent holder, a spin-off company from the Miguel Hernández University of Elche (Alicante, Spain). It is the first robot to enable patients to start doing exercises while supine, allowing them to begin shortly after the stroke and expediting recovery.

The company, a leader in this field in Spain, already has two robots: Robotherapist 2D and Robotherapist 3D. For the latter, it has a worldwide patent. Both are actuated by pneumatic technology and have been designed to improve arm movement in stroke patients.

According to the researcher, Robotherapist 2D is a planar robot which allows movement in two dimensions and includes sensors to determine the patient’s condition and a sound feedback system. “With this robot, certain tasks are carried out. The patient’s arm is moved parallel to the table: to the right, to the left and in a straight line. They are exercises to improve coordination,” he says.