(ORDO NEWS) — Together with the Turner National Medical Research Center of Pediatric Traumatology and Orthopedics, HSE researchers studied how the brains of children with arthrogryposis after muscle transplantation control elbow flexion. It turned out that in such patients, more motor neurons are involved, that is, the beginning of a new movement requires more effort from the brain.
Article published in Frontiers in Pediatrics . Arthrogryposis is a congenital anomaly of the musculoskeletal system, in which limbs are deformed, joints and muscles are underdeveloped, and movement is generally limited. Congenital multiple arthrogryposis occurs in one in 10 thousand newborns. The disease does not progress with age and does not impair the child’s cognitive ability.
With arthrogryposis, it is important to restore the ability to flex the elbow so that the person can take care of themselves without assistance. This is achieved by transplanting muscles that can control the elbow bend. During the rehabilitation of such patients, it is necessary to teach their brain to control the limb in a way that was previously inaccessible to it. The brain does not own a pattern of movement that a person did not reproduce in his daily activities.
The study of the brain activity associated with elbow flexion makes it possible to develop the most effective methods for the rehabilitation of patients with arthrogryposis undergoing muscle transplantation. Such studies have rarely been done in children, and their brain activity can be very different from that in adults.
To fill this gap, scientists from the HSE Institute for Cognitive Neurosciences conducted an experiment. Four children with congenital multiple arthrogryposis and five healthy children 5–10 years old were invited to participate in the study. Three of the four children with arthrogryposis have previously undergone muscle transplant surgery to restore elbow flexion. The study also included a group of five healthy adults.
During the experiment, the subject sat at the table and, at the command of the experimenter, brought his hand to his mouth, imitating the process of eating. During this time, his brain activity was recorded using a magnetoencephalography (MEG). In total, the participants were required to make 80 movements – 40 with each hand.
Analysis of the collected data showed that patients with arthrogryposis who had undergone muscle transplants were more likely to experience bilateral activation of the cerebral cortex when moving with one hand. In them, this activity was more dispersed in the cortex compared to healthy children and adults.
“The activity of both sides of the cerebral cortex can be explained by a common difficulty in initiating movement: patients with arthrogryposis need to recruit more motor neurons in this task. At the same time, their movements were less accurate and slower compared to healthy subjects, ”explains one of the authors of the article, a senior researcher at the Institute of Cognitive Neurosciences at the Higher School of Economics Evgeny Blagoveshchensky .
The dynamics of brain activity in patients differed from the dynamics of healthy subjects: movement-induced brain responses had a greater distribution in time compared with the control group. The slower the movement was performed by the patient, the more time-distributed the picture of total activity accompanied him. This is probably due to the involvement of a complex compensatory mechanism in the elbow flexion process.
According to the researchers, since it is the onset of movement that causes the greatest difficulties in children with arthrogryposis after muscle transplantation, possible rehabilitation strategies for such patients may include non-invasive brain stimulation – it will facilitate the onset of movement. The research is carried out under a grant from the Russian Science Foundation , headed by Iiro Jaskelainen , scientific director of the International Laboratory for Social Neurobiology at the Institute of Cognitive Neurosciences.
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