It is one of the most testing questions facing football - and one that has been made all the more poignant by the recent deaths of two of Norwich City's all-time greats.
The link between heading a football and ex-professionals developing dementia in later life is one that has been speculated about for some time, but one around which research has been relatively limited.
But now, researchers at the University of East Anglia (UEA) are readying themselves to launch a major £1m study into the connection, backed by another of the Canaries' greatest players.
Former City striker Iwan Roberts, who scored 96 times in 206 appearances for the club between 1997 and 2004, has become one of the first former pros to sign up to the research, which will see him take part in a series of tests every six months to assess his brain and look for early signs of dementia.
Mr Roberts, 51, who has been researching the connection himself for a documentary being broadcast on television in his native Wales, said the study was particularly important for players like himself who relied on heading heavily in their game.
He said: "I was obviously a centre forward that was strong in the air so when I was asked to get involved in the study I did so without hesitation. I am 51 now and can be quite forgetful - I'm not great with people's names, I often mislay my wallet and my keys and while that could just be to do with my age I would always want to know.
"I was really quite nervous when I took the tests the first time, I was worried somebody would tell me there wasn't something quite right with me, but I would always want to know if there's anything I should be concerned about in the foreseeable future."
Mr Roberts added that he did not see the research as "a blame game" - rather a quest for knowledge - and urged organisations like the Professional Footballer's Association (PFA) to back it.
He said: "All families of people who have lost people - like Duncan Forbes - want is answers, a bit of help and not for these things to be brushed under the carpet.
"Some of the scientists I have already spoken to are 100pc certain there is a connection and the sooner we can find out about whether you are developing the illness the sooner you can get help. The tests are not difficult to access, do not take a lot of effort and are well worth 10 minutes of your time.
"I played more than 600 games in my career but it's so much more than just matches. When I was still developing my game at Watford the coaches would take me and the other centre forwards at the end of training and head the ball into empty goals over and over and over again."
The study is being co-ordinated by leader researcher Michael Grey, who was inspired after meeting Dawn Astle, the daughter of former footballer Jeff Astle, whose death in 2002 was judged to be an industrial injury as a result of his profession.
He said: "The research that has already been done in Glasgow was brilliant but it is too big a problem not to look at in even more depth. It is something that has been coming for a long time.
"I am from Canada and I got quite a few concussions while playing ice hockey, while my sisters had the same playing football and we are all concerned about dementia. What we will really be looking at is the rate of decline and if it is increased.
"In defence of the past, people did not know anything about this but we want to make sure people know more in the future and that they can be signposted to the right places for help."
For more information about the study visit scoresproject.org
Recent club deaths
In recent months, Norwich City supporters were saddened by the loss of two of the club's greatest ever players - who both died dementia-related deaths.
In October, former club captain Duncan Forbes died at the age of 78, in the Heartsease care home he spent his later years.
Mr Forbes, who made 357 appearances for the club between 1968 and 1980, had been receiving treatment for Alzheimer's since 2007 and fought a long battle with the illness.
Last month, Martin Peters, the only World Cup winner ever to represent Norwich City, died at the age of 76.
Mr Peters, who was part of the England squad that lifted the World Cup in 1966, made more than 200 appearances for City between 1975 and 1980, before also going on to play for non-league Gorleston.
Like his former team-mate Mr Forbes, the two-time player of the year also faced a fight with Alzheimer's.
How you can get involved
The UEA is looking for both men and woman to take part in the study - but particularly former professional footballers.
All participants must be aged above 50, but Dr Grey said the study was not restricted to people that had played the game professionally, and that he would welcome players of all levels of the sport.
He said he was also keen to hear from active non-footballers, to draw parallels with other sporting activities.
Once people have signed up to take part, they will be required to take four short tests every six months, which can be participated in from home.
He added that the age was set at 50 due to staffing restrictions and that the study may be opened up to younger participants in due course.
Those who do not meet to age criteria but still wish to help can do so through financial contributions.
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