Spirits were high in Bathurst as old foes Dubbo Senior College and Orange High rolled into town in June last year to take on the locals for the Astley Cup.

Dating back to 1923, and the oldest annual tri-school sporting competition in the state, few events on the Cup's schedule had been more eagerly anticipated than Bathurst High's rugby league clash against Dubbo, and eyes were on the school's talented 16-year-old, Tyler Horton.

A keen golfer, and with a fearsome reputation for smacking the seamers around the region's cricket fields, Tyler had used his speed and skill on the rugby pitch over the previous eight seasons to stake a strong claim on the five-eighth position of Bathurst's rugby league team, despite being one of the smallest players on the field.

After an uneventful first half, the ball landed in Tyler's hands and he took off. As a sharp-eyed Dubbo player pounced, the left side of Tyler's head connected with his much larger rival's shoulder, whipping his neck back from the impact.

Shaking off the tackle, Tyler moved behind and played on.

"I remember it pretty clearly," he says. "It was a hard hit, but I didn't feel a huge contact to my head."

Minutes after returning the ball to play, dizziness started to wash over the young player and he began to lose sensation in his right leg. Stumbling to the sideline, where sister Emily and father David were watching, he crumpled to the ground.

"He was feeling very unbalanced, he was reaching out with his hands because he couldn't feel where the ground was," recalls his mother, Paula Horton, who arrived at Carrington Park to find her son having a seizure on the ground in front of her. What no one, including Tyler, knew at the time was that a catastrophic chain reaction had begun to unfold inside his brain, one which was rapidly causing his body to shut down.

Also watching from the sidelines, emergency department nurse Tatiana Muller didn't like the look of the scene unfolding in front of her and leapt over the crowd barrier, placing the now unconscious Tyler into the recovery position.

By the time Tyler and his mother had arrived by ambulance at Bathurst Base Hospital, doctors had arranged for an emergency helicopter to airlift him to Sydney's Westmead Hospital, where he was immediately rushed into surgery. "When the ambos arrived, they had this calmness about them that I was grasping on to," Paula Horton recalls. "I didn't want to lose it completely because that wasn't going to help Tyler. You want to be functioning and you want to be sane so you know exactly what's going on."

Placing Tyler into an induced coma, the neurosurgeons in Sydney removed a palm-sized piece of his skull. After four hours clearing clots and controlling bleeding, they walked out of the theatre to update his exhausted family waiting outside. The operation had been a success and Tyler was going to survive.

Just two days after Tyler's injury, 13-year-old Macarthur Saints player Jarrod Fletcher was rushed to the nearby Westmead Children's Hospital and placed on life support after receiving a similar knock during a rugby league game at Campbelltown. He, too, was allowed to stay on the field and play on after being hit in the head, and had subsequently collapsed. As with Tyler, doctors were able to save Jarrod Fletcher's brain, allowing him to return to his western Sydney home after recovering from the emergency treatment.

Half a year after the accident that made headlines around the country and renewed calls for a national concussion commissioner, little evidence remains of the drama that unfolded that day for the Horton family. A large, question mark-shaped scar, starting at the top of Tyler's forehead and curling around his skull, ending in front of his left ear, is the only visible reminder of where doctors punched 70 staples into his head to put it back together after surgery.

A week after being admitted to hospital, Tyler's family drove him back to Bathurst. By the following Monday he was back on the golf course. "One of the most surreal aspects of it was how little recovery there was," says Paula Horton. "We were bracing for much more, but it's almost like it never happened. I guess that's the nature of that type of injury - it can go either way."

While Tyler Horton's injury has had little obvious impact on his life, debate remains about the long-term risks to the thousands of young Australians who suffer similar head blows every year.

Researchers, both in Australia and overseas, are becoming increasingly concerned about possible links between concussion, Alzheimer's disease and other neurological conditions later in life.

Those looking closely at the head injuries young Australians are receiving on the nation's sports fields also suspect that many more are receiving potentially devastating blows than the official figures suggest.

At the elite level, the major football codes in Australia - rugby league, rugby union and Australian rules - have all made significant changes to their concussion protocols based on the consensus reached at the International Conference on Concussion in Sport in Zurich in 2012. New rules help officials identify likely incidents of concussion and hefty fines are in place for clubs that fail to remove concussed players from play or return them to the field with insufficient rest. In 2014, four National Rugby League (NRL) clubs - Penrith, Canterbury, North Queensland and Wests Tigers - were slapped with $20,000 fines for breaching the governing body's guidelines.

A recent landmark $US765 million ($982 million) settlement between the American National Football League (NFL) and more than 4500 former players who had sued over concussion-related brain injuries sustained during their careers has also cast a spotlight on the increasing number of concussions occurring in rugby league. The NRL's own figures show that concussion is relatively common at the elite level, with, on average, five to seven reported per team per season.

Over the past three years, the Australian Football League (AFL) has also recorded a significant increase in the number of concussions requiring players to miss games, although it attributes it to a growing awareness of the dangers among doctors, coaches and players, who are becoming more likely to report it and treat it as a serious health risk.

While awareness may be growing at the higher echelons of our football codes, experts worry that extra vigilance is not filtering down fast enough to the community level, where the number of concussions is growing rapidly.

A 2013 study of sport-related concussion in Victoria found a 60 per cent increase in hospital admissions since 2002-03, with team ball sports - particularly the football codes - topping the list of sports with the highest numbers of brain injuries. On a per-capita basis, motor sports and equestrian events had the highest rates of hospitalisation, while the greatest increase over the nine years of the study had been for roller sports (such as skateboarding, roller blading and roller derby).

The same study also estimated that the vast majority of concussions were likely going unreported and untreated by doctors, with the actual number likely to be six to 10 times higher than the official figures.

Professor Caroline Finch, one of the report's authors and a director of the Australian Centre for Research into Injury in Sport and Its Prevention, says no one really knows how many players are being concussed on the nation's ovals and sports grounds every week due to a lack of data. "The short- and long-term consequences of concussion mean that potentially years of productive life are lost, and there are substantial economic costs for individuals, families and society," she warns.

With no routine monitoring or reporting in Australia, she has called for a national registry of concussions, warning that the void in the national debate created by the lack of data is increasing the level of concern and potential misinformation about links to one of the most extreme forms of sport-related brain injury: chronic traumatic encephalopathy, or CTE.

The previously little-known degenerative condition was launched into the headlines in October last year when a post-mortem of former Kansas City Chiefs footballer Jovan Belcher's brain revealed that he had probably been suffering from the condition shortly before shooting dead his girlfriend and then himself in December 2012. CTE, which until recently could only be diagnosed post-mortem, has been linked to aggression, confusion and depression among those who have suffered repeated head trauma.

After years of disputing evidence that its players were more likely to suffer brain damage than the general population, the NFL revealed in court documents in September that it expects up to one in three former players will develop dementia, Alzheimer's, or other neurological disorders like Parkinson's Disease.

In a study reported in 2012 in the medical journal Brain, autopsies of 85 donated brains, mostly from former US professional athletes, revealed that the majority had suffered extensive injury in which brain tissue had become clogged with a protein linked to CTE. All had endured multiple blows to the head during their professional sporting careers.

Finch and her colleagues argue that Australia's high-participation football codes could be associated with an even greater concussion risk than the American game as a result of differences in protective equipment worn and the speeds of the game. They also worry that rule changes introduced to make games faster and more enjoyable for fans, as well as the increased prevalence of bigger, stronger and faster athletes, are adding to the risks.

It's not a subject the NRL seems particularly eager to discuss. Attempts to contact the organisation for comment on this article went unanswered.

But biomechanist Dr Andrew McIntosh is sceptical. Having recently concluded a review of concussion research, policy and practice in Australia over the past 20 years, he says we need to be careful before applying the American findings to Australian sports.

"If a third of all professional football players are going to develop symptoms as a result of concussion, where is the epidemic of demented players from 20 years ago?" he asks.

While more substantial protective headgear has been suggested as an option for Australian football codes, McIntosh says hard-shell helmets like those used in gridiron, while reducing the number of major skull fractures, have had little impact in reducing the number of concussions.

"I think what we have to do is ensure concussion guidelines are implemented at all levels, particularly at the community level, which is far more difficult than in professional sport. At a community level, the management of concussion has to be very simple. If a player has been hit in the head and is demonstrating some symptoms, that person needs to be taken out of the game. They shouldn't return to the game, and they need to see a doctor."

McIntosh has begun work using accelerometers attached to players to better measure and understand the severity of impacts that lead to concussion. But a lack of local research funding has made it difficult to quantify the true size of the concussion problem, with much of the work done on a shoestring budget using PhD students. In contrast, America's NFL has donated $30 million towards medical research into injuries suffered by its players, with CTE, concussion and understanding the potential relationship between traumatic brain injury and Alzheimer's disease a likely focus for study.

At the Australian Institute of Sport's concussion lab, conveniently located next to the boxing rings of the combat sports centre, Professor Gordon Waddington and PhD candidate Lisa Elkington from the University of Canberra ask me to take off my shoes, step onto a sensitive pressure pad, close my eyes and try not to fall over while standing on one leg. After running through a series of questions about general perceptions of wellbeing and number memory tests, they show me a card game on a laptop, measuring how quickly I can respond to a card being turned over. After nearly an hour of testing my balance, and running me through a series of memory and recall tests, it's clear I'm unlikely to become an elite athlete any time soon, but I'm also unlikely to be suffering from concussion.

"The problem with these kinds of tests is that everyone has a different level of normal ability," says Waddington. "To be really effective they require a baseline test: you need to be tested in your off season when you're clear of having a head knock to ensure you've got something to measure against. At the elite level that is now happening ... but not in the junior sports."

During his work with snow-sport athletes who had suffered a concussion, Waddington says many reported losing some of their ability to control movements, even though all their psychological and concussion test scores had come back as normal.

He says the impact on growing brains in young athletes adds an extra level of complexity to the already little-understood long-term consequences of repeated concussions.

One US neurosurgeon has gone so far as to call for a complete ban on all tackle football for players under the age of 14, arguing that younger brains are more easily injured in collisions. "Even returning to physical training too early without getting another knock can itself lead to scar tissue forming in the brain in places where it shouldn't be," he says. "We don't know what long-term impact that is having in neurological conditions that appear to be occurring in athletes who have had too many knocks."

While the data has not yet proven it, Elkington says there is also anecdotal evidence that brains in people under the age of 16 take at least seven to 10 days longer, and sometimes more, to recover from concussion than adults. She says many players and coaches at the community level still don't understand that concussion can occur without a player being knocked out.

At the Melbourne Brain Centre, director Chris Rowe and his colleagues are trying to find answers to some of the questions about the long-term impact of being repeatedly hit in the head.

By scanning the brains of war veterans with a history of traumatic brain injury and post-traumatic stress disorder, they are attempting to study links to Alzheimer's disease and dementia.

Already the cutting-edge scanning equipment housed in Melbourne's Austin Hospital has allowed them to pick up tell-tale build-ups in the brain, known as amyloid plaques, which are understood to contribute to the onset of Alzheimer's disease. With enough funding, they hope to be able to develop a simple blood test that would allow those markers to be detected in high-risk groups, including soldiers and sports people who have had multiple concussions.

"It's early days in this research," says Rowe. "We'd like to extend it to a five-year study where we could follow people and to broaden it to people who have had recent head trauma, like road accident victims ... but we need the funding."

Back in Bathurst, Paula Horton bristles when asked whether she'll let her son return to the rugby league field. "The surgeon said she'd give him 12 months off, but that's a bit too soon for me. He jokes and asks me if I'll come and watch him play the Astley Cup this year, and I tell him if he does I'm moving town."

But having watched her husband, David, come off motorcycles at high speed during his racing days, she doesn't believe in being ruled by fear. She is more concerned about the fact Tyler has just gained his provisional driving licence than what might happen to him on the sporting field.

Tyler, having just been selected for the NSW under-19 indoor cricket squad, is still undecided about whether he'll try to return to rugby league football.

"I definitely want to go back, but I'm unsure how I'll feel once it's footy season again," he says. "For me, playing footy is pretty important, I take it pretty seriously, and I'll definitely go support [Bathurst High] if I don't play. But I will feel a little bit left out because I could be out there playing. I'm just a bit worried that if it happens again, it might not turn out as good this time."