Kinesiology

Concussion more severe in children

The benefits of sports far outweigh the drawbacks for children and teens … as long as they avoid any trauma to the head. A study now underway in the Department of Kinesiology at the Université de Montréal shows that the consequences of concussion in children can be observed up to 32 weeks after the event. “Until very recently, it was generally believed that children recovered more easily and more quickly from concussion than adults because their brains are more plastic. However, there are more and more indicators that lead us to believe that they may in fact be more vulnerable,” says Dave Ellemberg, a professor in the Department of Kinesiology. 

He has launched the first study designed to measure the short- and long-term effects of concussion caused by sports in children and teens. Previous studies on neuronal plasticity have shown that children recover better than adults from brain surgery, but epilepsy causes great damage to the young brain. “We need to see whether it’s the same thing with concussion,” says Ellemberg.  “If sequelae are present at the time when the child needs all of his or her resources for learning, the child will be doubly affected. We also need to establish protocols for resuming sports that reflect these data.”

Surprisingly, we know virtually nothing about what happens in the brain when concussion occurs. “Animal studies suggest that there are impacts on neurotransmitters, on the axonal structures and in blood flow to the brain, but a great deal remains to be learned about this,” says the researcher. All we know is that the apparent symptoms are pretty much the same no matter how severe the event: dizziness, vomiting, loss of balance, headache and fainting.

An incident that occurred early on in the research contributed an unexpected indicator in terms of the severity of concussion in children. An eight-year-old girl who played soccer, chosen as part of the control group, suffered a concussion one week after taking written tests for cognitive ability and evoked potential (neuronal responses measured by electroencephalography - EEG). The researcher was able to compare the data. “Twenty-four hours after the concussion, delta waves were 2.5 times higher than before. Delta waves are associated with a state of fatigue and low vigilance. Beta and gamma waves, which are associated with attention and information processing, were lower.”

Seven weeks later, delta waves had returned to their normal level, but even after 32 weeks, the beta and gamma waves had not. Neuropsychological tests on paper showed a reduced speed of cognitive skills after the incident, a reduction that resolved after six weeks. “We don’t know whether it’s the same thing with the other children or whether the effects may vary with age,” says Ellemberg. His project is designed to take similar measurements in 100 to 150 children and teens between the ages of seven and 20.

Despite the risk of concussion in team sports, Ellemberg still believes that the benefits of sport for children’s cerebral functions outweigh the disadvantages.  “After 30 minutes of physical activity, measurements taken in my lab show improved attention and quicker response in young children compared to 30 minutes of inactivity,” he reports. Concurrently with the concussion study, the professor is pursuing other work on the short- and long-term effects of sports on memory and attention. “We want to find out whether these gains are sustained after a 12-week program of directed physical activity.”