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- Uniting the hemispheres: Russian scientists are working on rehabilitation of stroke patients
Uniting the hemispheres: Russian scientists are working on rehabilitation of stroke patients
A team from the Skolkovo Institute's Neurocenter and doctors from the Federal Center for Brain and Neurotechnology (FCMN FMBA of Russia) are investigating disruptions in the interactions between the cerebral hemispheres of stroke patients a few seconds before the start of body movement. Analyzing brain activity in motion can help doctors in the rehabilitation process. Details can be found in the Izvestia article.
An acute problem
Stroke is an acute violation of human cerebral circulation, in most cases resulting in disability for the rest of life. There are hundreds of thousands of stroke patients in the country: in 2023, there were 418,927 stroke patients in Russia (Rosstat data, there are no results from last year).
In order to reduce the incidence and find new ways to restore neural networks, scientists from Skoltech and the Federal Research Center of the Russian Academy of Medical Sciences are conducting joint scientific work. The study is being conducted with the financial support of the Russian Science Foundation (grant No. 21-75-30024 "Development of invasive and non-invasive corticospinal and peripheral interfaces using biomarker monitoring for neurorehabilitation of motor functions and pain control"). So far, scientific analysis is at the stage of studying neural processes in the violation of interactions between the left and right hemispheres of the brain in a stroke patient. Scientists want to figure out how to restore the brain's ability to imagine future actions during strokes and synchronize it with different brain processes in order to restore mobility to the body and plasticity to the brain, which are lost during illness.
— One of the most common causes of stroke is a violation of blood flow in the middle cerebral artery of the right or left hemisphere. This often leads to the development of unilateral paralysis due to the destruction of neural networks in the motor cortex," says Nikolai Syrov, a senior researcher at Skoltech and one of the study participants.
The prognosis after a stroke largely depends on several factors, scientists say. About 10-15% of patients recover fully, and about 25% have minor effects. About 40% have moderate or severe disability, and about 20% of people die within the first month. Several factors play a role here.
— The first is a type of stroke, ischemic or hemorrhagic. With ischemic stroke, the prognosis is often more favorable. The second is the size and localization of the lesion: damage in the motor areas causes movement disorders, in the speech areas — aphasia, etc. The third is the speed of care: thrombolytic therapy (clot cleavage) is effective only in the first 4.5 hours. Another factor is the patient's age and the presence of concomitant diseases (hypertension, diabetes mellitus, atrial fibrillation)," says Alexander Zakharov, Director of the Research Institute of Neuroscience at the SamSMU Ministry of Health of Russia, PhD, neurologist.
The brain represents
The body "loses" any of its actions twice: first in the cerebral cortex, where the brain "sees" a picture of future action, and only then the person does everything as the brain "saw". When a person prepares to move a foot, leg, arm, or even finger, there is a surge of lateralized readiness potential in the cerebral cortex, an electrical impulse of the brain that precedes the body's readiness to move. These electrical potentials originate in the occipital part of the brain, where the visual centers are located, and then the signal goes to the midbrain and the substantia nigra, responsible for movement and coordination. Lateralized potentials are recorded by scientists using electroencephalography (EEG) and used in the future to assess the mechanisms of the central nervous system.
In order to assess the potential of stroke patients and compare it with the same indicator of a healthy person, Skoltech scientists, together with rehabilitation specialists from the Federal Medical Center, planned and conducted a special study. One of his goals was to study changes in EEG potentials after a stroke and how they can be related to body movement, as one can observe their changes during rehabilitation as the patient regains motor skills. The group of subjects included 21 patients with hemiparesis, a paralysis of one half of the body caused by a stroke. All participants underwent rehabilitation at the Federal Medical Center, and their health was monitored daily for two weeks. The second group of subjects included the same number of healthy volunteers of the same age.
During the experimental session, the subjects watched a light bulb and, as soon as it was lit, pressed a button on a special panel as soon as possible. There were two light bulbs, which was how the scientists recorded the movements of both the healthy and the affected hand. If the strength in the affected hand was not enough to fully press the button, the Skoltech scientists asked the subject to at least tighten the muscles of the arm and attempt to move his hand. The seemingly simple task activated several processes in the patient's brain at once: the process of waiting for a command, the process of responding to a light bulb, then preparing the movement with the right hand, and finally the movement itself and the brain's analysis of feedback. Scientists have determined that when imagining body movement, a signal appeared in the motor cortex of the brain. And when the body was actually moving, about a second of the appearance of the same signal was observed before the actual movement in the hemisphere opposite to the active arm.
— We found out that the mental image of the future movement of the body that appears in the brain is very different in real and imaginary motion. This discovery will make it possible to observe the improvement of the position of the motor systems of the brain even before their manifestation in the movements of the human body and will improve the processes during rehabilitation," says Nikolai Syrov, a senior researcher at Skoltech and one of the study participants.
Stroke has a young face
Stroke is getting younger, doctors and scientists say. According to the V.A. Negovsky Research Institute of General Intensive Care, there were almost 1,000 of them last year, and 700 over the past six months of this year. Stress, nutrition, ecology and a lifestyle that is far from healthy have an effect.
Analysis of brain activity during movement with a healthy arm can also provide interesting and useful data for the diagnosis and rehabilitation of stroke-affected brains. The two hemispheres of the brain work together, and it is obvious that a violation of the function of one will lead to a change in the work of the other. "Our work is one of the few that drew attention to changes in the brain control of an intact hand and how these changes can be used in post—stroke diagnosis," says Nikolai Syrov.
Exactly how the research by Skoltech scientists will help patients recover from stroke will not become clear until rehabilitologists begin to put this discovery into practice.
— One hundred percent recovery is possible only in some cases. It is necessary to take into account the nature of disorders during the course of the disease, the causes of the development of conditions, and the pathogenesis of stroke. To do this, all patients, without exception, need early rehabilitation in the intensive care unit, this is normatively fixed, including in the recommendations of various. More than 80% of patients regain consciousness," says Artem Kuzovlev, Deputy Director and Head of the V.A. Negovsky Research Institute of General Intensive Care, FNCC RR, MD.
The center's patients are being restored thanks to rehabilitation technologies. Extreme cerebral hypothermia allows you to control the temperature of the cerebral cortex and increase the patient's level of consciousness. Another technology, medical xenon anesthesia— makes it possible to enhance and activate the processes of neuroplasticity, that is, the formation of new neural networks in the brain.
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