If it's hard enough to recognise concussion, it's more difficult to identify when there isn't one
The problem with concussion is that the more we know, the less we know.
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When even the medical profession admit there is a limit to their ability to fully grapple with concussion - we know this because so many doctors have wildly deviating opinions on the issue - how can players, referees and spectators?
When an MRI scan or CT scan cannot sometimes be sufficient to properly diagnose a concussion, sport cannot conceivably hope to ensure that potential cases are dealt with adequately.
With medical science unable to correctly and accurately identify concussion, it stands to reason that unqualified humans are even more incapable of doing so - which is why referee Nigel Owens has been pilloried from many quarters for suggesting a head injury occurred to French scrum-half Antoine Dupont last Saturday.
The referee's difficulty is that he knew he was helpless to influence matters due to rugby's current protocols.
In such a cauldron, with nearly 80,000 fans baying and players seeking advantage for their side, the risks in attempting to establish in such circumstances whether or not there may or may not be a concussion is fraught with fallibility.
And when a team spot the chance to potentially manipulate the situation for their own advantage, as it is alleged France did at the weekend, then it is clear that the whole process is unworkable.
The difficulty in Saturday's instance is that, according to fourth official Thomas Charabas, Owens immediately indicated the necessity for a Head Injury Assessment after being alerted by his assistant Paul Williams, who had seen the player fall injured.
Charabas explained how he then initiated the HIA protocol but, almost instantaneously, Dupont indicated his knee had been damaged and the French staff concurred.
The independent match doctor, Mr Gilles Garet, insisted to Charabas that the HIA protocol must continue and the fourth official came onto the field to communicate this information to Owens, by this stage surrounded by irate Irish players.
"Owens did not take the decision," said Charabas. "It's the match doctor who is the ultimate decision maker in such circumstances. Never at any moment has the French staff, including Jean-Baptiste Ellisalde (an assistant French coach) who was in the technical area, asked for any HIA."
While all this is happening in such a short space of time, extensive replays have alerted viewers to the possibility that there may be something more suspicious going on. That France indicate they may re-introduce their starting scrum-half - an expert place-kicker who would have been allowed to take the side's 78th-minute penalty which may have won the game - heightens those suspicions.
However, presuming that the fourth official is correct in asserting that nobody from the French side was involved in initiating the HIA, what can Les Bleus be accused of?
At the very most, they have simply acceded to instructions from match officials and, not for the first time in the history of professional sport, sought to maximise the potential advantage of the ruling.
What remains unclear is quite why they didn't go the whole hog and allow Maxime Machenaud to take the penalty that was missed by his colleague.
Previously he would have been disbarred from doing so, but the ongoing change in the ever-changing protocols would have allowed him to do so.
Ironically, France's manipulation of the HIA protocols against Wales last season had prompted the change which confirms something we do know about concussion - it is impossible for rugby to keep pace with the perils of its unknown consequences.
Everyone in the sport - players, coaches, administrators - is utterly fearful of an NFL-like deluge of medical tragedies and multi-million lawsuits down the line.
Which is why, for example, a referee will never dispute the assessment of a doctor regardless of the pictures being painted in front of him.
If it is hard enough to recognise concussion - symptoms may not emerge for hours or days - it is even harder to identify when there isn't one.
This is what allowed France to exploit the situation in Paris last Saturday and why the referee was hopelessly hamstrung as, despite the persistent questioning which revealed his own doubts, there was no possible way he could have acted otherwise.
Automatically removing injured players - whether suffered to the head or otherwise - has been suggested as a draconian step, and perhaps some day that is a place where the sport may arrive at.
For now, the Six Nations have already established a review but it is difficult to know exactly what they can precisely uncover.
Our money is, as has already happened this season, the unwitting blame being shovelled in the direction of the match officials. It's always easier to blame the ref.
We would hope that they scratch a little deeper.
As we have mentioned, both the role of fourth official and the newly-unveiled position of independent match doctor were filled by French people.
This should not happen. If the sport can pay to ferry neutral referees, TMOS and citing officers around the continent, then it should be in a position to do the same for neutral doctors.
And if the ref can be wired to a Television Match Official and his selection of replays, then why not also a Television Medical Official?
If investigators discover flaws in the already imperfect HIA process, the sport will have damned itself yet again in this area. Unveiling nothing will smack of a whitewash.