Another week, another conference. This one was organised by World Rugby and, like the last, which was organised by the Concussion in Sport Group, it was held in Amsterdam. World Rugby’s chief medical officer, Dr Éanna Falvey, explained that the aim was “to evaluate the latest research and focus on where we might need to focus funding to continue to fill the gaps in our collective knowledge”. There was a lot on the agenda: a session on instrumented mouth guards, a workshop on laws and player welfare, and, first thing in the morning, a series of talks on brain health and chronic traumatic encephalopathy.

World Rugby made all three available by live stream. It’s a positive step forward that the proceedings are open, and that anyone interested is encouraged to watch. It’s some of what they saw when they logged on that’s the worry. There were three speakers in the session on brain health. First up was the neuropathologist Dr Rudy Castellani, who is professor of pathology at Northwestern University Feinberg School of Medicine, and the second was Dr Ken Quarrie, a specialist in the epidemiology of rugby injuries and chief scientist at New Zealand Rugby.

Castellani has previously described himself as an “unabashed denier” of some of the research behind CTE. He previously served as an expert witness for the National Hockey League in a class-action lawsuit alleging the league hid the dangers of concussions and long-term issues. At World Rugby’s conference he explained that, among other reservations, he believes there is insufficient evidence to describe CTE as a “neurodegenerative” disease. It is also his opinion that there are “factual inaccuracies” in the recent guidance issued by the US National Institutes of Health, which acknowledges a causal link between CTE and head trauma.

Given that the NIH is the largest public funder of biomedical research in the world, it is something of a fringe position.

Quarrie is also on record talking about his scepticism about CTE, and in particular the clinical outcomes associated with it. In a recent blog he wrote, “Despite there having been strong claims made about what causes CTE, how it develops, and what clinical outcomes it leads to, the reality is that the science of CTE is very young. There really is a lot of doubt about a number of the issues!” They included whether it is really “a primary, progressive neurodegenerative disease”, the “cause(s) of the pathology”, the “prevalence of the pathology”, and “MAJOR questions remain about the relationship between having CTE pathology in the brain and any given clinical outcome”.

Following these there was a third talk, by Dr Gordon Fuller, a specialist in health data science from the University of Sheffield. It was a critique of the recent research published by a team at the University of Glasgow that demonstrated that former rugby players were at higher risk of neurodegenerative disease when compared to the general population. The original paper wasn’t presented, and the team behind it were not represented. Fuller’s big criticism was about the lack of data about confounding factors, mainly alcohol use, but also steroid use and post-retirement depression, among the rugby players.

Taken altogether, the three talks added up to what seemed like 90 minutes of (to borrow Castellani’s phrase) unabashed scepticism about the existing research into the long-term health consequences of repeated head trauma. At various points explicit criticisms were made of the work done by several of the world’s leading experts in the field, including Dr Ann McKee, distinguished professor of neurology and pathology at Boston University, Dr Willie Stewart, consultant neuropathologist at the University of Glasgow, and Chris Nowinski of the Concussion Legacy Foundation. None of the three were there to offer a rebuttal.

World Rugby did invite other speakers, including representatives of the Glasgow University study and the CLF, to participate in the panel event afterwards. Everyone turned them down, one on grounds that World Rugby had provided only seven days’ notice when the rest of the schedule had been published well in advance, another because they didn’t want to share a platform with one of the speakers. Representatives from both the CLF and the University of Glasgow told the Guardian that they would be happy to talk to World Rugby about their research at another session. In their absence the moderator, the sports scientist Ross Tucker, did his best to introduce some balance by encouraging critical questions at the end.

Despite that, the cumulative effect was that anyone watching the session could reasonably have left with the impression that the issues were overblown, the science behind them unclear, and that World Rugby’s handling of it all is just about spot-on. That last point was, in fact, near enough one of the panel’s conclusions (many of the rest could be best summed up with the tired line: more research is needed). In 90 minutes I’m not sure I heard a single remark that challenged World Rugby’s handling of the issues, or called for any changes to be made to the running of the game. The only thing missing was the caption “This is fine”.

Whether you agree with the speakers or not (and given many of these arguments are already settled, most don’t) it’s easy to see why this sort of self-reinforcement is a problem for the sport. If World Rugby wants to “fill the gaps in our collective knowledge” it should start by filling in the obvious gap in the information it is presenting to the rugby community as an up-to-date survey of the latest research. The conference focused on only one side of the debate, the same side, it so happens, that is most reassuring for its organisers. Quarrie spoke, at one point, about how polarised this discussion has become. Events like this one won’t do anything to redress it.