- A stroke can impair a person’s movement, sensory abilities, speech, and other functions.
- Scientists in Germany say a brain-robot apparatus may be able to help a person with paralysis after a stroke regain some mobility.
- The device was used in research in which study participants used the brain-robot interface to move their hands.
People who experience paralysis after a stroke might have new options for controlling their hands or limbs via their brain, according to a new study published today in the Journal of Neuroscience.
Researchers, led by Fatemeh Khademi, PhD, a data scientist at the Institute for Neuromodulation and Neurotechnology at the University Hospital and the University of Tuebingen in Germany, studied a brain-robot apparatus to control the movements of a hand in stroke patients with paralysis.
The scientists measured brain and muscle activity in healthy participants as well as people who’ve had a stroke using electroencephalogram (EEG) and electromyography (EMG).
At the same time, the participants controlled a brain-robot interface for their hands. Researchers asked the participants to think about moving their hands to operate the apparatus.
Researchers then observed that electrical activity between the hand and muscle parts of the brain increased, indicating enhanced communication between the two regions.
“We work with patients who cannot open their hands at all. Our brain-robot interface allows them to control the robot-assisted opening of their hand by imagining the movement. This apparatus is a training tool,” said Dr. Alireza Gharabaghi, lead study author and director of the Institute for Neuromodulation and Neurotechnology at the University Hospital Tuebingen. “Patients are expected after weeks or months of training to develop the ability to open their hand again.”
The researchers placed participants in the study in one of two groups.
One group consisted of 27 healthy right-handed participants, ages 19 to 37, without a history of psychiatric or neurological disorders. They were asked to complete a motor task. Fifteen participants received proprioceptive or physical feedback – the apparatus moved. The other 12 received visual feedback – they saw a color change on a screen when they achieved and sustained a predefined brain state. This group could master motor control of the apparatus, whether they received physical or visual feedback.
The second group included 8 right-handed participants who previously had a stroke and had paralysis in their hands. They ranged in age from 34 to 68, received 20 sessions within four weeks, and received only physical feedback.
At the end of the study, the stroke participants showed a small but significant improvement in the arm, wrist, and hand motor function.
The researchers concluded that motor function was possible in both groups through the brain-robotic connection. This approach could help neurorehabilitation in stroke patients with paralysis of the hand and possibly other limbs.
“Controlling a robotic arm with thoughts alone is a brain-machine interface. Essentially, the electrical activity within different brain regions changes with every thought, sensation, and movement,” explained Dr. Adi Iyer, a neurosurgeon at the Pacific Neuroscience Institute at Providence Saint John’s Health Center in Santa Monica, California.
“New technology (electrodes) can detect subtle fluctuations in brain waves and a computer can process that information and translate the signal into a movement for a computer cursor, mechanical arm, and even a full-body robotic avatar,” Iyer told Healthline.
A stroke occurs when blood flow to the brain is cut off, often from blood clots and ruptured blood vessels.
“A stroke is when a part of the brain is damaged from not getting enough oxygen. The damage is often permanent, and some people are severely disabled. Suppose brain-machine interfaces such as the one in the study can be used to rewire the brain after a stroke. In that case, patients could recover much more quickly and completely,” said Iyer.
The effects of a stroke can be different depending on where the stroke occurs but include a decrease in functioning in:
- Movement and sensation
- Speech and language
- Eating and swallowing
- Cognitive (thinking, reasoning, judgment, and memory) ability
- Perception and orientation to surroundings
- Self-care ability
- Bowel and bladder control
- Emotional control
- Sexual ability
Paralysis commonly occurs after a stroke, often on one side of the body, according to the Christopher & Dana Reeve Foundation. Paralysis occurs on the opposite side of the body from the stroke. For example, if the right brain stroke, the left side of the body is affected.
About one-third of stroke survivors recover with no or minor impairments. Another 40 percent have moderate to severe impairment and 10 percent will need treatment in a long-care facility. About 15 percent die shortly after the stroke.
A stroke can affect brain activity.
“For people with stroke, certain parts of the brain are damaged and unable to send the signal to muscles, causing weakness or paralysis, said Dr. Deepak Gulati, the medical director for the Telestroke Program and an assistant professor of neurology at the Ohio State University College of Medicine.
“In the rehabilitation phase, multiple studies have shown that brain regions surrounding the damaged tissue or regions from the normal side start creating signals that improve weakness or paralysis,” Gulati told Healthline. “These normal brain areas try to take over the function that the damaged tissue served before the stroke. These signals can be further enhanced by stimulation or picked up by implantable devices in the brain and subsequently communicated to a robotic arm.”
“New brain signals and pathways generated after stroke is called brain plasticity or rewiring of the brain,” he added. “Different techniques studied stimulate these normal brain regions, which can help recover from paralysis or neurological deficits suffered during a stroke.”
Treatment for a stroke should be given within hours of the start of symptoms, according to the
- Numbness or weakness in the face, arm, or leg, especially when it occurs on one side of the body
- Confusion, trouble speaking, difficulty understanding speech
- Trouble seeing in one or both eyes
- Trouble walking, dizziness, loss of balance, or lack of coordination
Signs of a stroke usually occur suddenly. If someone is having a stroke, you should call 9-1-1 so medical professionals can start lifesaving treatments.