Rule changes, not headgear, are the way to reduce rugby players' risk of brain injury, says a New Zealand expert in the wake of a league player's death.

Bay of Plenty's Tere Livingstone died on June 15, after suffering a brain injury during a weekend game.

The Pāpāmoa Bulldogs rugby league player was critically injured on June 10, during a shield competition match at Mitchell Park, Tauranga.

Despite surgery, he died five days later at Waikato Hospital.

It would be impossible to completely remove the risk of head injury in rugby, says rehabilitation medical director Dr Richard Seemann, of ABI Rehabilitation which supports people with traumatic brain injuries.

'The evidence for protective headgear stopping brain injury is non-existent," says Dr Seemann.

'I understand that mouth guards may reduce the risk. Primarily, risk will be mitigated by rules that reduce the chances of direct head impacts, but this is a contact sport, and the risk will never be zero.”

Policy disallowing body checking in child or adolescent ice hockey reduced the rate of concussion in games by 58 per cent.

And there are strict post-concussion procedures in rugby, says Dr Seemann, which 'if they are followed, should protect players from second impact syndrome and the long-lasting effects of repeated frequent concussion”.

An investigation into how Tere Livingstone was injured is underway. He's pictured with his partner, Chloe and young son Nikora. Photo: Supplied.

Deaths from head injuries incurred by rugby players are rare.

'We certainly see plenty of concussion level – mild traumatic brain injuries – that come to our concussion teams in Auckland, Whangārei and Wellington. Severe ones are rare. In the general population, the ratio of mild to severe TBI is about 20 to 1."

But, depending on the type of contact, head injuries could prove fatal, Dr Seemann says.

'If the force is severe enough, that can result in small blood vessels around and in the brain being injured, with intra-cranial bleeding, and that is primarily the event that causes the severe outcomes, with disability and death.”

The circumstances around Livingstone's injury cannot be revealed while New Zealand Rugby League investigates the incident, says chief executive Greg Peters.

Tere was critically injured during a game for the Coastline District Rugby League Werohia Shield, and emergency services attended at the field.

In 2014, a 17-year-old Northland rugby player, Jordan Kemp, died after suffering a head injury during a tackle. Despite neurosurgery for an acute brain bleed, he was pronounced dead two days after the incident.

And there's a 'rare phenomenon” called second impact syndrome which is a key reason for standing players down for up to several weeks after concussion, says Dr Seemann.

It involves 'sudden severe brain swelling, often fatal, after repeated concussion, usually within a few days, but I have never been involved with a case”.

Former All Black Carl Hayman attributed his early onset dementia to head injuries received during games. Photo: Shane Wenzlick/Stuff.

The question of rugby bodies' liability over head injuries is also a contentious issue, with a high profile UK case involving 400 rugby, league and football players taking legal action against sports governing bodies on claims they suffered brain injuries during their careers.

The class action includes former internationals such as England's Steve Thompson and former All Black prop Carl Hayman, who attributed his early onset dementia to head knocks during his rugby career.

The lawsuit argues that sports authorities such as World Rugby, the English Rugby Football Union and the Welsh Rugby Union 'were negligent in failing to take reasonable action in order to protect players from permanent injury caused by repetitive concussive and sub-concussive blows”.

While New Zealand rugby officials will no doubt be closely following the case, it's a different situation, says Dr Seemann.

'The legal cases relate to another issue, chronic traumatic encephalopathy (CTE), which is caused by repeated head impacts, with many minor concussions occurring over years of play.”

Former All Blacks flanker Josh Kronfeld recently pledged to donate his brain to progress CTE research around contact sports.

Research is necessary to establish exactly what CTE entails, says Dr Seemann.

'Some younger players seem to develop significant personality changes, and older ones develop a dementing illness. It is not clear that the underlying cause is the head impacts, or aspects of professional sport lifestyle.”

While the Rugby Union has protocols in place, there is always a tension between playing and staying safe, says Dr Seemann.

'They are very aware of the issues related to CTE now, and it will be interesting to see if that results in changes in the way that professional rugby players are managed.”.

Annemarie Quill/Stuff