In fact,concussion is diagnosed only by observing overt symptoms such as dizziness and confusion,nausea and unsteadiness. Complicating matters,the condition varies wildly between individuals and incidents. Symptoms can manifest instantaneously – or appear hours later. And they can linger for months – or disappear within minutes.

Chronic Traumatic Encephalopathy (CTE) is a degenerative brain disease found in people with a long history of head trauma – not so much a handful of big concussions but rather hundreds (or thousands) of smaller impacts over a number of years.

CTE often manifests as a kind of dementia but can only be diagnosed post-mortem.

The Concussion Legacy Foundation,the advocacy arm of the ground-breaking concussion research group at Boston University,makes a distinction between bigger hits and “subconcussive impacts” (of the kind sustained when NFL players routinely bang their helmets into one another). The foundation uses the analogy of a car driving down a poorly maintained road. Sure,big potholes might burst a tyre or crack an axle but smaller potholes do immense harm,too:drive over those little bumps a dozen times a day,every day of the year,for more than a decade,and the wear and tear can be catastrophic.

It makes sense,then,that CTE was first diagnosed in 1928 in boxers,under the descriptordementia pugilistica (also known as “punch drunk syndrome” and later “slug nutty”) but it roared back into the public consciousness in 2005,when pathologist Bennet Omalu found CTE in the brain of an American footballer,former Pittsburgh Steeler Mike Webster. This discovery was subsequently made into a movie starring Will Smith as Dr Omalu (although a recent investigation by theWashington Post, “From Scientist to Salesman”,calls into question some of Omalu’s claims).

CTE often manifests as a kind of dementia but can only be diagnosed post-mortem. Once a person who has pledged their brain dies,they are sent to a mortuary where their brain is removed and weighed then fixed in formalin to preserve the tissue. Researchers scrutinise photos of the brain for bleeding,bruising and patterns of atrophy,where the sulci (valleys) and gyri (bumps) of the brain have become deep or shallow,narrow or wide.

They then slice the brain vertically at three-millimetre intervals along what’s called the coronal plane,photograph each slice and place portions the size of a postage stamp into microscope slides. The slides are washed in various stains that react to proteins and – in the search for CTE – scientists look specifically for the dark brown build-up of a protein known as Tau. “Tau normally helps a healthy neuron,” says concussion expert and neuroscientist Dr Alan Pearce. “But if an accumulation of it clumps,it can strangulate a neuron or nerve cell. Found in specific places,it becomes evidence of a degenerated brain.”

Has CTE been found in Australian athletes?

Yes,it has. The first diagnosed case was former rugby union player Barry “Tizza” Taylor,who died in 2014,aged 77. His brain was sent to the Global Brain Bank at Boston University and displayed all the hallmarks of severe CTE. Soon after,the local arm of the brain bank was launched as a collaboration between Sydney University and Royal Prince Alfred Hospital,and dozens of retired athletes pledged to donate their brains upon death,including the likes of former Wallaby and now journalist Peter FitzSimons.

In 2019,rugby league was rocked when the brains of former NRL players Steve Folkes and Peter Moscatt were examined and both found to have the neurodegenerative condition. That same year,however,the first donated brain of a former Australian rules player,WAFL rover Ross Grlusich,was examined and,despite Grlusich suffering numerous concussions throughout his career and ultimately dying of dementia,no evidence of CTE was found. As one researcher has noted:“Not all smokers get lung cancer.”

In February 2020,CTE was officially diagnosed in a former AFL player – the legendary player and coach Graham “Polly” Farmer,who died in late 2019 after battling dementia for a number of years. Next,it was found in the brain of Saints champion Danny Frawley,whose battles with mental health were well known.

Most recently,it was revealed that former Richmond midfielder Shane Tuck – who ended his life in 2020 at 38,while dealing with mental health issues – suffered from severe CTE,with one neuropathologist describing his case as “the worst case I’ve seen so far”. Tuck’s diagnosis is particularly stark,as the 173-game Tiger veteran had no reported history of serious concussions.

What long-term problems can head knocks cause?

A number of scientific papers have found a correlation –as distinct from a causal relationship – between multiple concussions (three or more) and a greater chance of cognitive impairment later in life,increasing the risk of everything from anxiety to epilepsy,Parkinson’s disease and the nervous system disease ALS,also known as Lou Gehrig’s disease. People who sustain even mild traumatic brain injuries often experience underlying neurological problems at an accelerated rate,notes Dr Mark Cook,chair of medicine at the University of Melbourne and director of neurology at St Vincent’s Hospital.

“The most famous example of repeated brain injury causing problems down the track was Muhammad Ali. Nothing was obviously wrong right away but down the track everything was wrong,” Cook says. “I like boxing and I like football and I like ice-hockey,but if you injure your brain repeatedly,it’s hardly surprising that it could lead to seizures and cognitive decline. To excuse the pun,it’s a no brainer.”

There has only been one longitudinal study of head knocks in Australian athletes,by David Maddocks,who tracked concussions in AFL players at three clubs in 1989. A quarter of a century later,in 2014,University of Melbourne masters student Hannah Blaine (with help from Maddocks and supervision from Professor Michael Saling) re-tested players at one of the clubs. “We found that concussion didn’t have an impact on their cognitive or psychosocial functioning,” Blaine says. “One guy had reported 20 concussions. He actually performed the best across the sample. Particularly on things like learning and memory.”

They presented the findings at the fifth International Neuropsychological Society and Australasian Society for the Study of Brain Impairment conference in Sydney in 2015. But their message – that this cohort of footballers were unaffected by concussion later in life – was unwelcome.

Concussion is a notoriously difficult condition to study,and occasionally throws up results such as that discovered by Blaine,yet it should in no way dispel any urgency to address the issue,given the raft of young players retiring after enduring concussions too severe or too frequent. The list grows every AFL season,to more than a dozen in the past few years,including the likes of Koby Stevens,Kade Kolodjashnij and Liam Picken. Others remain in limbo after a string of hits,including Patrick McCartin,25,the number one pick from the 2014 draft,who said in an interview in 2019,“I’m a shell of a person that I was,really. I’m completely different.” (McCartin is currently playing for the Sydney Swans reserves in the hopes of resurrecting his career after more than three years out of game.)

NRL,too,has been affected. Newcastle winger James McManus was forced out of the game after enduring a series of head knocks,while former Rooster Eloni Vunakece admitted a string of head knocks played a part in his decision to quit the sport. Sydney Roosters co-captain Jake Friend – a three-time premiership winner – is the latest to retire,after receiving three concussions in six months,following more than 20 concussions throughout his career.)

“They can’t find their cars,they can’t find their car keys – along with erratic behaviour,and their wives about to leave them.”

And rugby union has not gone untouched,with former Wallaby players Toby Smith and Anthony Fainga’a leaving the game for fear of what might happen should they suffer another concussion.

Then there are retired players of yesteryear in each code who are suffering debilitating cognitive issues including memory loss and mood swings,confusion and seizures. Many have already pledged to donate their brains to the Australian Sports Brain Bank. Player agent Peter Jess has been in touch with athletes from several sports,and says there is a consistency to the issues they report.

“Depression. Anxiety. They can’t find their cars,they can’t find their car keys – along with erratic behaviour,and their wives about to leave them,” says Jess. “That’s the elephant in the room – a lot of these guys are on wife two and three. And they’ll tell you,‘That guy over there is not the guy I married. He’s short-tempered. He’s angry. He can’t hold down a job.’ It’s a really sad situation.”

So what happens on the field now when a player is hit?

All codes have different protocols but they all use the diagnostic SCAT-5 (Sport Concussion Assessment Tool,Fifth Edition). First,a club doctor approaches the player and asks questions such as “Who are you playing on?“,“What’s the score?” and “What day is it?” These are known as “the Maddocks questions” because they were devised by David Maddocks of the University of Melbourne in 1995 after his seminal paper,Neuropsychological recovery after concussion in Australian rules footballers.

Depending on the quality of the player’s answers – and red flags such as stumbling and disorientation – the player rests for 10 minutes. They are checked for obvious physical symptoms such as double vision,vomiting,convulsions – or headache,fatigue,nervousness.

A cognitive screening then tests memory and recall. The doctor might read aloud a series of words –finger,penny,blanket,lemon,insect – and ask the player to repeat the string of words,in any order. The doctor does the same with digits,the list of numbers growing progressively harder to remember. They also perform a balance examination (walking a line on the floor,heel to toe,nine metres long). All of this contributes to a subjective read on their state of mind. If they are deemed to have been concussed,they are removed from play.

Someone who has been concussed many times will probably need to rest even longer again.

Exactly when they are fit to return to play again varies by individual. Every concussion is unique,says Dr Robert Cantu,co-founder of the CTE Centre at Boston University,senior adviser to the NFL Head,Neck and Spine Committee and the world’s foremost expert in “return to play” procedures.

Someone who has suffered another concussion only recently,for instance,might need longer to recover than someone concussed for the first time. Someone who has been concussedmany times will probably need to rest even longer again. “And most importantly,” says Cantu,“someone who’s had a previous concussion whose symptoms have lasted weeks or months should certainly be given more time off than someone whose previous concussion cleared up in a matter of minutes.”

An understanding of what happened in the incident is important,too. Was the collision horrific,where you would expect or predict concussion? Or was the blow fairly inconsequential or innocuous? The latter is actually more troubling because it took such little impact to cause harm. “If the hit seemed minor,you’re going to be more cautious putting that person back into play because obviously that person is going to be exposed to other such minor hits.”

What’s the risk in returning early?

There are a few dangers to consider. First,if a player hasn’t completely recovered from concussion,their athletic and evasive skills could be compromised. (Symptoms often vanish quickly but other subtle changes in the brain are more persistent.) Professor Michael Saling was one of the co-authors of the first Australian studies into concussion in 1989,which found persistent impairment in speed of information processing,reaction time and decision making. “We could see that the cerebral effects of concussion were quite long-lasting,and the cycle of recovery could extend over a two-week or three-week period.”

Second,if a player who has not fully recovered from concussion sustains a follow-up head trauma,their symptoms can be exacerbated. “It can be debilitating,” says Cantu. “Someone who might have been days from overcoming their concussion may end up with a concussion that is prolonged weeks,or months,or more.”

Third,if a player sustains one of these hits while not fully recovered,they may be more susceptible to cognitive decline later in life. Associate Professor Sandy Shultz of Monash University and the Alfred Centre has been studying this idea of a “window of vulnerability” since 2010. His work involves experimenting with “pre-clinical models”,meaning rats,which wear tiny 3D-printed helmets and are then concussed with a mechanical device. When these rats were struck again – while biological imbalances from the first concussion were still in play – they experienced progressive and persisting long-term brain damage,as well as learning and memory deficits,sensorimotor abnormalities,depression and anxiety.

But what this means for footballers is unclear. “Because how do you study that in people?” asks Shultz. (You can’t take a statistically significant group of healthy young athletes,hit them over the head,then hit them again at varying intervals during their recovery,just to see what happens.) The data from rodents suggests the timing of subsequent hits is important,says Shultz,“but whether that applies in humans,we just don’t know.”

Until recently,roughly four out of five players who suffered a concussion while playing AFL still lined up to play the next weekend. That might sound an alarming number,but perhaps not when considering the research of Dr Nathan Gibbs,a former NRL player,club doctor for the Sydney Swans for nearly two decades and now head doctor for the Wallabies. During one 12-year stretch at the Swans,Gibbs compiled his own research with surprising results. In the aftermath of 140 concussions,every single Swan played the following week. And their immediate performance – based on a mark out of 20 given by the coach – was unaffected. “They playedwell,” Gibbs says. “The outcomes were good.”

Still,the AFL moved to tighten its concussion protocols in 2020,requiring players to successfully pass the SCAT-5 (the same test used during games to diagnose concussion) a full five days before playing again,instead of merely a day in advance of a game,meaning a player would essentially need to pass the test within a few days of their concussion,or miss the following match. This seemed like a careful step in the right direction,given concerns that a blanket rule simply sidelining every concussed player for a week would be difficult to implement. The persistent fear – in all sports – was that such a rule could force concussion “underground”. That is,if players know that being concussed will rule them out of a game the following week,it might motivate them to conceal their symptoms.

This assertion is not without merit. Players have recently admitted to withholding the truth about their symptoms from club doctors,while retired players have admitted to intentionally performing poorly on their mandatory pre-season baseline cognitive testing,making it easier to pass a concussion test when hit during the season.

And so in 2021,the AFL took their cautious stance on the issue further than any code,bolstering their protocols with a new rule:if a player is medically diagnosed as suffering a concussion,they are now automatically sidelined for 12 days.

Pundits immediately asked,“What if that causes a player to miss a grand final?” and almost immediately received an answer,when AFLW star Chelsea Randall was concussed in the women’s league preliminary final,and ruled out of the 2021 AFLW Grand Final one week later. The Adelaide Crows captain was asked at first whether she would challenge the new protocols,in an attempt to take the field. “I decided not to take any further action because what kind of message would that be sending to our grassroots football?” she told her club media team. “Because concussion is serious,it is scary.”

However,former Saints’ skipper Nick Riewoldt,who played in two losing grand finals and a draw in his 336-game career with St Kilda,told Fox Footy he would consider legal action if faced with the same predicament as Randall. Riewoldt is adamant that the fallout from concussion be taken seriously,yet concedes the drive to win a premiership is powerful. “If I was in the same situation,imagine September,still playing in your 30s,captain,all of those things. I’m taking it as far as I can take it. I’m going to the Supreme Court,I’m going for an injunction,” Riewoldt told Fox Footy. “I understand the severity of concussion and we heard Chelsea,but there’s a very clear parameter. If I feel OK to play,I’m taking it as far as I possibly can to play.”

Although Riewoldt’s comments were criticised,they reflected the sentiments of a number of players who fear missing a grand final through an ill-timed concussion. The AFL have admitted they are open to discussing the prospect of a pre-grand final bye beyond 2021 that might give players concussed in a preliminary final the recovery time to play in a grand final.

Are retired players likely to sue for compensation?

A class action in the US brought by retired gridiron players against the NFL,and settled in 2013,has resulted in more than $US600 million in claims so far,and could balloon well beyond that amount. Naturally,people have considered similar lawsuits in Australian sport.

A handful of former AFL players – including John Platten,John Barnes and Shaun Smith – have investigated pursuing a class action lawsuit,proposed by Adelaide lawyer Greg Griffin. Two Sydney law firms,Bannister Law and Cahill Lawyers,are investigating similar suits for former NRL players suffering “reasonably preventable brain injuries”.

These actions would allege that the NRL and AFL – as the sole controller of rules,medical panels,protocols and sanctions – allowed their games to be needlessly violent in various ways,such as routinely allowing players back into the cauldron of training or games when they were demonstrably unwell.

However,the suits will face some challenges. First,class action lawsuits are incredibly expensive,and so will require the investment of a litigation funder. Next,to be certified as a class,they will need to show that the players are all facing similar issues as a result of similar harm caused by similar negligence. (That could be tough,given that players come from different eras,and might have even received some of their concussions in state or amateur leagues,in childhood,or even post-career sports like boxing.) They will also need to establish “causation” –proving in court that the maladies they now endure are a direct result of the blows they sustained on the field. And they will need to show a negligent breach of a duty of care,establishing exactly when and what the AFL and NRL knew about concussion,or should have known,along with their failure to act.

The case mooted against the AFL was raised three years ago but no statement of claim has been filed in court.

Smith received a $1.4 million insurance payout from MLC Life Insurance in 2020 after he was found to have suffered “total and permanent disablement” due to head knocks he copped in his 109-game AFL career.

Individual players can take legal action too,arguing they were injured during a period in which leagues or clubs knew enough but didn’t act enough. In the NRL,for example,former Newcastle and NSW winger James McManus is suing the Knights over their management of his head knocks,claiming they failed to properly assess or monitor him,and continually exposed him to new danger after suffering concussions. In the AFL,former Adelaide Crow Sam Shaw has done the same – believing the concussions that ultimately forced him out of football were mishandled by Crows medical staff.

A more likely path to restitution would be some kind of fund,established to support any player whose livelihood has been diminished by the debilitating effects of concussion. (Athletes,unlike other employees in Australia,have no workers compensation system to rely on for “no fault” benefits when hurt performing their profession.) The AFL has so far resisted calls to establish a concussion-specific fund (as the NFL have done in America),but instead suggested it will put more money into the AFL Players’ Association Hardship Fund,which supports players who are struggling in the post-playing life.

Are the football codes taking the issue seriously?

Very seriously. It’s worth noting that players such as Frawley and Farmer took to the field in a wildly different era,when little was known about the potential fallout from head knocks. Once the extent of the insidious damage wrought by concussion in the NFL started to emerge in the mid-2000s,local leagues began to act. In 2008 for instance,the AFL codified the way players should be assessed after head knocks,and in 2009 and 2010 – and a handful times more since then – they tweaked the laws of the game to curtail reckless high bumps and dangerous tackles,also moving to disincentivise players from trying to draw high contact free kicks.

Rugby union made strides,too,lowering the legal tackle height worldwide in 2019,which led to an instant 28 per cent drop in concussions. They also introduced the Blue Card system,under which medical staff or referees can remove a player from a game the moment they see any symptoms of concussion. In the junior ranks,rugby created the Size for Age program,in which juniors can be moved between age groups to suit their physical or mental development.

For young rugby league players,there is now a modified rules SafePlay format of the game,along with the TackleSafe program to teach juniors better tackling technique. The NRL,meanwhile,began doling out huge fines to clubs that allow players to remain on the field after a concussion. The Wests Tigers,Canterbury-Bankstown Bulldogs and the Parramatta Eels are among many on the receiving end of $20,000 sanctions.

The codes all continue to invest in scientific research.

Sideline technology has improved,too,allowing medical staff in all codes to replay incidents using the Hawk Eye tablet technology. In 2019,the AFL also began employing independent “spotters” to identify potential concussion events.

Helmets can only go so far in offering protection. AFL and NRL and rugby union players can (and some do) wear soft rubber and foam helmets,but these are more likely to prevent bruises and cuts and potential fractures than concussions. Bear in mind that players can sustain a concussion when no contact is made with the head at all,from the mere whiplash or sheer aggressive force of a hit to the upper body. Yet there is ongoing (and promising) research into new headgear,the Hexlid,that might reduce the risk of concussion.

The codes all continue to invest in scientific research. In women’s football,researchers are looking at why women suffer concussion at a higher rate than men – whether the reason is biological (neck strength is a potential determinant),or due to the semi-professional nature of the league,or the greater willingness of women to report symptoms and ask for help.

The AFL has committed $2.5 million per year over the next decade towards a “substantive longitudinal study of concussion”,which includes the use of “smart” mouthguards,which record and measure linear and rotational head impacts,and should ultimately contribute to a greater understanding of subconcussive hits. This is just one of many studies underway examining the immediate effect of any concussive knock,including everything from blood testing and saliva biomarkers and eye-tracking,in the hope of producing the “holy grail” for concussion in sport:an objective diagnostic tool,that can be used swiftly on the sidelines.

The codes are all also sharing awareness programs in the hope that change will also come from amateur and junior leagues.The AFL released the HeadCheck app to help such teams – who don’t have paid club doctors – to determine if it might be prudent to remove a player from the field and seek treatment. The careful and cautious mantra filtering through sport all around the world – particularly where children are involved – seems to be taking hold:“If in doubt,sit them out.”

Crisis support can be found at Lifeline:(13 11 14 andlifeline.org.au),the Suicide Call Back Service (1300 659 467 andsuicidecallbackservice.org.au) and beyondblue (1300 22 4636 andbeyondblue.org.au)

This explainer,first published in 2019,has been updated to reflect developments.