French neurologist reveals how close Johnny Sexton came to retiring in 2015

It's not exactly size of the concussion, it's the frequency.

The accepted medical stance on concussion is that a player becomes more and more susceptible to brain injury with every concussive blow to the head they receive. Put simply, a player with four confirmed concussions is more in danger of picking up another than a player concussed three times. In 2014, Johnny Sexton was concussed four times in nine months. Ahead of Saturday's Six Nations game between Ireland and France, Rugbyrama has reopened the concussion debate surrounding Ireland's No.10. The French rugby website interviews neurologist Jean-François Chermann, who advised Sexton to sit out 12 weeks of rugby, in December 2014, after he had sustained those four concussions in close succession. Chermann reveals that he told Sexton he should consider requiring if he sustained another concussion within three months of his February 2015 return. Chermann states:

"After this period of rest and recovery in stages, everything went well and he was not concussion again... At the time, I told him he should be more worried if was concussed again within the three months of his return. If so, he should consider ending his rugby career."

Fortunately for Sexton, there were no concussions suffered in 2015. However, here have been two close calls [Wasps and Wales] in the last month. Somewhat lost amid the frantic circumstances of Ireland's team announcement, on Thursday, was Sexton's admission that a blow to the head, not shoulder, had caused him some discomfort against Wales. He said:

"I'm okay now, I just got a bang on top of the head and it just compressed my neck a little bit.But I'm fit to go and really looking forward to it. "I'll be fine. I probably felt the way front-rowers feel every day, but as a soft out-half I just didn't hide it as well."

At Stade de France today, Sexton was the most vocal of all the players during and after the captain's run. Ireland captain Rory Best explained:

"Johnny has a big role in terms of the fact he runs the game for us anyway. So from that side of things he has enough to do anyway. "If Johnny knows one of the players personally and someone asked him about it, he's always giving of his time and information. But the pressure's on each player, we can't rely on Johnny because he's played in France, to help us with the profiles, we've got to know all of that ourselves. "He just talked through a few of the plays, things around gameplan. At this stage of the week it's important that it's player-driven."

Sexton has already admitted that this week is very "personal" to him. He is aware of the doubts the French public and media have of his fortitude. In the last two years, Sexton has proved those doubters wrong. On Saturday, it is time to do it all over again.