New research on concussions in sports recommends body checking ban in hockey for children, most adolescents

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Few Canadians have probably heard of the Concussion in Sports Group (CSIG) or paid much attention to its international conference, held every four years or so. But just about anyone who plays hockey, soccer, baseball or a host of other sports is affected by the CISG’s work, which establishes global guidelines for the diagnosis and treatment of concussions.

The conference brings together more than 600 scientists, doctors and academics to update the CISG’s protocols. The latest “consensus statement” was published Wednesday in the British Journal of Sports Medicine, and it’s based on decisions from the October, 2022 conference in Amsterdam.

The statement contains a variety of recommendations and changes to existing guidelines. Among them is new advice for the early treatment of concussions, including that light activity within the first 48 hours of injury, instead of total rest, can speed recovery. The document also calls for the elimination of body checking in hockey for children and most adolescents. And it says that mouth guards have proven so effective in reducing concussions that they should be mandatory in youth hockey and other contact sports.

When it comes to the larger issue of long-term health consequences of concussions, the CISG has run into controversy.

Past conference statements have played down links between repeated hits to the head and neurological conditions such as chronic traumatic encephalopathy, or CTE, a degenerative brain disease. Despite numerous studies that have shown a connection, the CISG has said previously that the research had been inconsistent and that no “cause-and-effect relationship had been established.”

In its latest statement, the CISG acknowledged that there was “increasing societal concern about possible problems with later-in-life brain health in former athletes such as mental health problems, cognitive impairment and neurological diseases.” But it concluded that its review of the research has shown that amateur and professional athletes were no more likely to develop mental health problems or die by suicide in later life than the general population. Amateur athletes also had no greater risk of future cognitive impairment, the group said.

The statement did say that the CISG’s examination of 28 studies found that professional football and soccer players had greater mortality rates from neurological conditions such as Parkinson’s disease, Alzheimer’s and amyotrophic lateral sclerosis, or ALS. However, it added that all of the studies had significant limitations.

The researchers “cannot control for many factors that we know in the general population are associated with neurological diseases,” said Grant Iverson, a Harvard University neurologist who lead the statement’s findings on long-term effects. “For example, they often can’t control for something like a stroke, they can’t control for something like heart failure, or hypertension. They also, of course, cannot control for genetics, or family history of neurological diseases.”

He said more research was needed, and the CISG has recommended the creation of an interdisciplinary working group to guide future studies.

Critics argue that the CISG’s criteria for the research it reviews is far too narrow.

During a CISG press briefing this week, Bob Cantu, a neurologist from Boston University, acknowledged that only a faction of the research on CTE had been examined by the group.

The CISG considers only cohort studies, which compare different groups, whereas most of the work on CTE has involved case series research, which typically tracks a single group. “Hundreds and hundreds and hundreds of these case series were not allowed to be used in the systematic review,” Cantu said. However, he agreed with Iverson that many of the case series studies had limitations.

Cantu said the literature reviewed by the CISG showed that CTE was found in just 1 per cent of the general population, but was more common in the brain banks of former professional athletes who had high exposure to repetitive head injuries. The group’s statement concluded that it was “reasonable to consider extensive exposure to repetitive head impacts, such as that experienced by some professional athletes, as potentially associated with the development of the specific neuropathology described as CTE.”

Critics say the CISG has been cautious about the long-term impact of concussions because of its financial ties to major sports organizations that have a vested interest in playing down the risks of hard-hitting sports. These include the International Olympic Committee, as well as the global governing bodies for soccer, hockey, rugby and motor sports.

The CIGS’s statements “have promoted sports-friendly viewpoints that could be construed to pronounce concussions and repeated subconcussive impacts more benign, recoverable, transient and reversible injuries than we consider reasonable,” a group of 17 clinicians and researchers wrote in a paper published in the Journal of Law, Medicine and Ethics in 2021.

During the briefing this week, the conference’s co-leaders acknowledged the concerns and said the CISG had modified its methodology and included a medical ethicist on its scientific committee.

“We’ve evolved the process and we’ve been inclusive,” said Kathryn Schneider, an associate professor at the University of Calgary who co-led the 2022 conference. She added that the statement included a methodology paper that outlined the conference processes. “We’ve tried to be as transparent as we can be.”