Research suggests that children’s IQ is not reduced by concussion

The findings – from emergency room visits at children’s hospitals in Canada and the United States – show that IQ and intelligence are not affected in a clinically meaningful way by pediatric concussions.

The study compares 566 children with concussions to 300 children with orthopedic injuries. The children range in age from eight to sixteen years and were recruited from two cohort studies. The Canadian cohort includes data collected from five children’s hospital emergency departments, including Alberta Children’s Hospital in Calgary, along with those in Vancouver, Edmonton, Ottawa and Montreal (CHU Sainte-Justine). In Canadian hospitals, patients completed IQ tests three months after injury.

The US cohort was conducted at two children’s hospitals in Ohio, where patients completed IQ tests three to 18 days after injury.

“There is clearly a lot of concern about the effects of concussion on children, and one of the biggest questions is whether or not it affects a child’s overall intellectual functioning,” says Dr. Keith Yeates, PhD, a professor at the University of Calgary. Psychology and senior author of the Pediatrics paper. Yeates is a renowned expert on the effects of brain disorders in children, including concussion and traumatic brain injury.

“The data on this is mixed and opinions within the medical community vary,” says Yeates. “It is difficult to collect large enough samples to confirm a negative finding. The absence of a difference in IQ after a concussion is more difficult to prove than the presence of a difference.”

Combining the Canadian and American cohorts yielded the Pediatrics studied an abundant sample and it allowed Yeates and his co-authors – from universities in Edmonton, Montreal, Vancouver, Ottawa, Atlanta, Utah and Ohio, along with Mount Royal University in Calgary – to study patients with a wide range of demographic characteristics to test and clinical characteristics.

“We looked at the patient’s socio-economic status, gender, severity of injuries, history of concussion and whether there was loss of consciousness at the time of injury,” says Yeates. “None of these factors made a difference. Across the board, concussion was not associated with lower IQ.”

The children with concussion were compared to children with orthopedic injuries other than concussion to control for other factors that might influence IQ, such as demographic background and the experience of trauma and pain. This allowed the researchers to determine whether the children’s IQs were different than expected, minus the concussion.

The study’s findings are important to share with parents, says Dr. Ashley Ware, PhD, professor at Georgia State University and lead author of the paper. While the Pediatrics research was underway, Ware was a Killam Postdoctoral Fellow at UCalgary, where Yeates was her supervisor.

“Understandably, there is a lot of fear among parents when it comes to their children’s concussions,” says Ware. “These new findings offer really good news, and we need to get the message across to parents.”

Dr. The paper’s co-author Stephen Freedman, PhD, professor of pediatrics and emergency medicine at the Cumming School of Medicine, agrees. “It’s something doctors can tell children who have suffered a concussion, and their parents, to help reduce their fears and concerns,” says Freedman. “It is certainly reassuring to know that concussions do not lead to changes in IQ or intelligence.”

Another power of the Pediatrics research is that includes the two cohort studies, one testing patients within days of their concussion and the other after three months.

“That makes our claim even stronger,” says Ware. “We can show that even in the first days and weeks after a concussion, when children show symptoms such as pain and slow processing speed, their IQ is not affected. Then it’s the same story three months later, when most children have recovered.” This study allows us to say that we consistently do not expect IQ to decline from the time children are symptomatic to the time they have recovered.”

She adds: “It’s a nice ‘rest in peace’ message for the parents.”