Stroke Rehabilitation Device Converts Thoughts To Electrical Impulses
A unique stroke rehabilitation device which converts an individual’s thoughts to electrical impulses to move upper extremities has been developed by a University of Wisconsin-Madison scientist. Stroke patients using it have seen improvements in motor function and ability to perform daily activities.
Each year, nearly 800,000 people suffer a new or recurrent stroke in the United States, and 50 percent of those have some degree of upper extremity disability,” said Vivek Prabhakaran, M.D., Ph.D. “Rehabilitation sessions with our device allow patients to achieve an additional level of recovery and a higher quality of life.”
Brain Computer Interface
The rehabilitation device was created by Dr. Prabhakaran, along with co-principal investigator Justin Williams, Ph.D., and a multidisciplinary team. They combined two known technologies.
One is a functional electrical stimulation (FES) system, currently used to help stroke patients recover limb function. The other is a brain control interface (BCI), which provides a direct communication pathway between the brain and this peripheral stimulation device.
In this video, released in 2012, a paraplegic woman is shown using a brain control interface to control a robotic arm and take a sip of coffee.
With functional electrical stimulation systems, electrical currents are used to activate nerves in the paralyzed extremities.
By means of a computer and an electrode cap placed on the head, the new BCI-FES device, dubbed the Closed-Loop Neural Activity-Triggered Stroke Rehabilitation Device, interprets electrical impulses from the brain and transmits the information to the FES.
Basically, the stroke patient thinks of moving their finger, and the BCI receives and identifies those signals, transmits them to the FES, and the FES makes the finger move. Through repeated motion making, patients should be able to reconstruct the neural pathways that used to work, under the theory of brain plasticity.
Passive Stroke Rehabilitation Technique
“FES is a passive technique in that the electrical impulses move the patients’ extremities for them,” Dr. Prabhakaran said. “When a patient using our device is asked to imagine or attempt to move his or her hand, the BCI translates that brain activity to a signal that triggers the FES. Our system adds an active component to the rehabilitation by linking brain activity to the peripheral stimulation device, which gives the patients direct control over their movement.”
A small clinical trial has been done of the device, with eight patients having one hand affected by stroke. The same patients served as a control group by using their normal, unaffected hand.
Patients in the study represented a wide range of stroke severity and amount of time elapsed since the stroke occurred.
Even having had regular rehabilitative care, the patients had varying degrees of residual motor deficits in their upper extremities. Each underwent nine to 15 rehabilitation sessions of two to three hours with the new device over a period of three to six weeks.
fMRI is able to show which areas of the brain are activated while the patient performs a task, and DTI reveals the integrity of fibers within the white matter that connects the brain’s functional areas.
Improved Recovery Levels
Patients who suffered a stroke of moderate severity showed the most improvement to motor function following the rehabilitation sessions. Patients diagnosed with mild and severe strokes reported improved ability to complete activities of daily living following rehabilitation.
According to Dr. Prabhakaran, the results captured throughout the rehabilitation process, particularly the ratio of hemispheric involvement of motor areas, related well to the behavioral changes observed in patients.
A comparison of pre-rehabilitation and post-rehabilitation fMRI results revealed reorganization in the regions of the brain responsible for motor function. DTI results over the course of the rehabilitation period revealed a gradual strengthening of the integrity of the fiber tracts.
“Our hope is that this device not only shortens rehabilitation time for stroke patients, but also that it brings a higher level of recovery than is achievable with the current standard of care,” Dr. Prabhakaran said. “We believe brain imaging will be helpful in both planning and tracking a stroke patient’s therapy, as well as learning more about neuroplastic changes during recovery.”