More former players have entered the legal process against the game’s authorities for negligence.
Former Welsh under-20 center Adam Hughes, 30, is the youngest to claim permanent brain damage.
Neil Spence, the England Under-21s, is also among those involved while four former England and Wales players remain anonymous.
A lawsuit is being prepared against the Rugby Football Union (RFU), the Welsh Rugby Union (WRU) and World Rugby.
It means that nine players are now in preparation for the action – although the law firm representing the organization says more than 100 players have come forward.
These additional players will now be tested for early depression and their details will be added to the application which could include the existing nine when ready.
A letter of appeal, outlining the intention to sue, was handed over to the governing bodies on Thursday.
All members of the group of nine, including England’s World Cup-winning hook Steve Thompson, were recently diagnosed with early signs of dementia.
Former players say constant blows to the head are to blame.
Spence says that forgetting to pick up his children from nursery was the first time he realized he had a mental health problem.
“Eight years ago when my children were young, I should have been going to raise them,” Spence told BBC Sport.
“I moved past the nursery to a local school where I was coaching rugby and started setting up the session, but I realized I was in the wrong place.
“Not only that, the kids were in half term. They weren’t there. I was supposed to pick up my kids from the nursery which is 1,000 meters down the road. That’s when I realized that something was wrong. “
Meanwhile, the 42 – year – old Thompson played in every game in England when they won the 2003 World Cup, but he says: “I don’t remember any of those games. scary. “
It is the first legal move of its kind in world rugby and, if successful, could change the way the game is played.
Rylands Law, who represents the group, said the risks of concussion injuries were “known and predictable”, and lists 24 alleged failures in World Rugby, the RFU and the WRU.
“We know that key players in the game have been debating the issue of head injuries since the 1970s, and despite this we are, more than 40 years later, with so many players, and at such an early stage. in their lives, finding themselves in this terrible position, “said Richard Boardman of Rylands Law.
“I sincerely hope that World Rugby, RFU and WRU now meet their responsibilities. “
‘The human body is the same all over the world’
At the same time NFL medical experts say they are in constant contact with rugby authorities about how they can reduce decision making in the sport.
NFL chief medical officer Dr. Allen Sills says his sport seeks to “share knowledge in a faster fashion” with World Rugby and other contact sports.
In 2011, the The NFL paid out £ 700m to former players who suffered brain damage.
“We regularly share with each other’s sports organizations around the world,” Sills told the BBC.
“If there are silver lining with the Covid-19 setting, I would say this has further strengthened our communication.”
Sills says there are some differences in methods and training between American football and rugby union, but admits that the internal damage can be similar because “the human body is the same something all over the world ”.
“We talk at least every two weeks with Rugby World Cup, Australian Football, and a number of those other contact sports, and we share what we’ve learned,” he said.
“We share what we find in our research, we share what our rules are changing and we learn from each other and I think we all share the same goals. “
What is CTE & how is it proven?
All players who have come forward so far have been diagnosed by neurologists at King’s College, London, with early-onset depression and possibly Traumatic Encephalopathy (CTE).
CTE is the disease discovered by Dr. Bennet Omalu in American footballer Mike Webster, and the subject of the film Concussion by Will Smith. In 2011, a group of American footballers began class action against the NFL and won a settlement worth around $ 1bn (£ 700m).
CTE can develop when the brain is subjected to many small beats or rapid movements – sometimes called sub-motions – and is associated with symptoms such as memory loss, depression and progressive depression.