“We don’t see kids with symptoms, sometimes, until they are on the bus ride home,” he said during one Q&A session with several colleagues, some of whom told similar stories.

“Because the bus ride is a very demanding vestibular environment, their system compensates at that point. We see kids with ocular symptoms when they are doing their math, later on. So what you see immediately on the field may not be what you get later on.”

Asked if athletes should be removed from play completely, rather than subjected to pitchside assessments, such as those utilised in professional rugby, Dr Collins was clear and concise. “Unequivocally,” he said.

Dr Collins was supported by Dr Barry O’Driscoll, the former Ireland international, who was chairman of the IRFU’s medical committee and a member of World Rugby’s medical and concussion committees for 12 years.

Dr O’Driscoll resigned from his roles with both organisations four years ago, in protest at the decision to introduce what was, at first, a five-minute pitchside assessment of players with suspected concussions.

That has since increased to ten minutes, while a 13-minute period is currently being used in the Aviva Premiership, where pitchside video reviews and new eye-scanning technology are being utilised to aid team doctors.

Dr O’Driscoll remains unimpressed. “It’s stabbing in the dark,” he said of pitchside tests.

“You must not experiment with a young person’s brain like this. It’s no better- off now. You’ve got to have the same rule right across the board: for the children, for the community game, and for the elite.

“If there is any sign or symptom, they have got to come off and not return to play that day. If there is one thing I would say to the GAA, it is this: it is a hornet’s nest, don’t go down there. Rugby dug a hole for themselves and they’re still digging.”

The GAA have turned away from that path.

Last December, the association’s medical, scientific, and welfare committee rejected a proposal, at annual congress, to introduce temporary substitutions that would facilitate similar pitchside assessments.

However, criticisms of rugby’s pitchside protocols were contested last Saturday by the IRFU’s chief medical officer, Dr Rod McLoughlin, who claimed there were misconceptions concerning its use and purpose.

“Any player with suspected concussion is removed from the field of play in rugby,” he explained.

“The ten-minute rule allows you to do an assessment to see if you have any suspicions. It has never been an attempt to make a diagnosis of concussion. It is ... bringing somebody off to see if you have any suspicion. If you have a suspicion, they stay off ... If I run into somebody, no clash of heads, get up and stagger for two or three steps, you are off. You don’t get a single test.”

Dr McLoughlin also emphasised that the use of pitchside assessments was restricted to the professional game. Players in the amateur game are removed from play immediately and, if aged under 20, face a 23-day lay-off.

Dr O’Driscoll dismissed the explanation as “confusing and conflicting and contradictory” and added that World Rugby’s use of pitchside assessments was placing team doctors in an invidious position.

“The player’s brain is vulnerable after signs or symptoms of a concussion, and, if you look at this 13-minute rule, now, that rugby have, and the guidance they are giving to the elite doctors, it is conflicting,” said Dr O’Driscoll. “It is contradictory and it is putting the doctors in a quite impossible situation.

“If you have to take a player off for a test of his brain, something has happened and that means you must keep that player off.”

The Croke park symposium was organised by Bon Secours Health System, UPMC, and the GAA.