A new study brings some hope for the millions of people living with stroke-related disability in the United States.
Researchers have concluded it may be possible for stroke survivors to regain some voluntary control by “training” uninjured areas of the brain.
The study reveals how a small number of patients with stroke-related paralysis in one arm used a brain-computer interface to teach their functioning brain regions to compensate for the regions damaged by stroke.
With the help of a device called Ipsihand, which helps to detect and translate brain signals, the patients regained some hand control.
Eric Leuthardt, of the Washington University School of Medicine in Missouri and a co-senior study author, and colleagues recently published their findings in the journal Stroke.
Stroke is a condition whereby blood flow to the brain is restricted. This deprives the brain cells of oxygen, causing them to die.
According to the Centers of Disease Control and Prevention (CDC), around 795,000 people in the U.S. have a stroke each year.
While the majority of adults survive this potentially fatal condition, they are often left with some form of disability, such as paralysis on one side of the body.
Physical therapy may help stroke survivors to regain some control of their affected limbs, but only 10 percent of patients make a near-full recovery.
The new research may open the door to a novel strategy that helps to improve the quality of life for stroke survivors.
Utilizing motor signals
The side of the body that is affected by stroke depends on what side of the brain has been damaged.
If a stroke occurs in the left side of the brain, then a patient may experience paralysis on the right side of the body. A stroke that occurs on the right side of the brain may cause paralysis on the left side the body.
This is because the areas of the brain that are responsible for movement are situated on the opposite side of the body to the limbs that they control.
However, in previous research, Leuthardt and colleagues found that there is a tiny region on each side of the brain that plays a role in body movement on that same side.
The team explains that when a person moves a left hand, electrical signals representing the intention of that movement initially appear in the left side of the brain.
In a matter of milliseconds, the motor regions on the right side of the brain are activated, which translates into movement of the left hand.
With this in mind, the researchers set out to determine whether it is possible to use the electrical signals that represent movement intent to trigger movement on the same side of the body.
“The idea is that if you can couple those motor signals that are associated with moving the same-sided limb with the actual movements of the hand, new connections will be made in your brain that allow the uninjured areas of your brain to take over control of the paralyzed hand,” explained Leuthardt.
Improved motor skills
The researchers tested their theory on 10 patients, all of whom had lost the use of their right or left arm due to having a stroke at least 6 months previously.
At the beginning and end of the 12-week study, as well as every two weeks in between, patients underwent a standard motor skill assessment.
This tested their ability to make arm movements and grip, grasp, and pinch with their hands.
Throughout the study, each patient used the Ipsihand device at home for around 10 minutes to two hours each day, for at least five days per week.
Developed by the University of Washington Researchers, Ipsihand is comprised of a mobile brace that is placed on the hand, a cap consisting of electrodes, and a computer that amplifies the brain signals detected by the electrodes.
The team explains that the device detects the patient’s intention to move their paralyzed hand. In turn, their second and third fingers are bent to meet their thumb, in a “pincer-like” fashion.
At the end of the study, the researchers found that the patients’ motor skill scores had improved by 6.2 on a point scale of 57.
“An increase of six points represents a meaningful improvement in quality of life,” said Leuthardt. “For some people, this represents the difference between being unable to put on their pants by themselves and being able to do so.”
What is more, patients also reported an increase in the ability to use their affected arm as the study went on, as well as an increase in satisfaction of motor skills.
The amount of time spent using the device did not appear to affect patients’ motor skills. Instead, the researchers found that any improvements in motor skills were influenced by how well the device detected and translated brain signals.
“As the technology to pick up brain signals gets better, I’m sure the device will be even more effective at helping stroke patients recover some function,” said co-senior author Dr. Thy Huskey.