The aim of the data collected from participants such as Gardner will provide an objective diagnosis of concussion and, as importantly, lead to a definitive understanding of when it is safe to return to sport following a concussion.
Neary's work is an extension of the ground-breaking research carried out in the New Zealand Rugby Health project, led by the AUT's Professor Patria Hume. The findings of increased osteoarthritis and decreased brain function in retired rugby players came as no surprise to Hume given the contact nature of the sport but the finding of increased cardiovascular health issues were unexpected.
The findings of the NZ Rugby Health Project were published in online journal Sports Medicine in 2016. Due to public and scientific demand, the project went global, with studies now being carried out in the United Kingdom, Australia, Canada, USA and New Zealand under the leadership of New Zealanders Hume and Dr Doug King, and Dr Karen Hind in the UK.
Neary's work, Hume says, will add a significant piece to the concussion jigsaw puzzle.
It was ice hockey that drew Neary to the world of head injuries. One of his graduate students was looking at head injuries in hockey players and wanted some equipment to measure recovery. Neary had the infrared imaging that shone an optical light into the head to measure blood oxygen levels.
"On one wavelength it gives you an indication as to how much oxygen is bound to haemoglobin. At another wavelength it will show you how much haemoglobin is all by itself without oxygen. Every time you're thinking, neurons are firing and have to use oxygen and that requires increased blood supply to the brain."
Neary realised his picture was incomplete and he needed to measure that blood flow using a snappily named ultrasound tool called a Transcranial Doppler.
"We started looking at the physiology of the brain [post-concussion] but our research showed the heart was also affected," Neary said.
"It was a mushy heart, or sick-heart syndrome. In a normal contraction, the heart muscle snaps, in a concussion it's like this," he says using his hands to demonstrate a slower, sloppier contraction.
Much of the research around concussion has concentrated almost exclusively on brain function but Neary believes the heart – or blood flow – plays a pivotal role, particularly in rehabbing concussion. His research shows that concussion changes the timing of the heart, and heart-rate variability is reduced.
For years, popular theory has been complete rest accelerates concussion recovery. Neary's discovery of the connection between the cardio system and concussion, however, leads him to believe recovery should work hand-in-hand with jump-starting the heart. In this respect he has become an advocate for exercise during recovery, essentially to increase blood flow.
Neary talks about concussion upsetting the autonomic system, the one that takes care of your internal workings, like breathing, without you needing to think about it.
"Once we ascertain the level of disruption, we can start to work on what we can use to rehabilitate that faster," he says.
An increased awareness of the dangers of concussion has led to more urgency in the scientific and sports communities to find answers around head injuries and, in particular, when it is safe to return to the sport.
While there are many aspects to concussion that remain a mystery - "we could both get hit in the head in the same place with the same force and come away with two totally different concussions," Neary says - understanding when it is safe for players to return is a priority.
It might be too late for those long retired like Gardner, but the data collected from him could be vital for the next generation of players.
•Neary is in New Zealand for three weeks and will be delivering a public lecture on Thursday, March 14, 6pm at the AUT Millennium, "Do you have a woodpecker brain? The perils of concussion".
TESTING FOR CONCUSSION
Breath hold: Participants hold their breath for 20 seconds then breathe normally for 40s. Brains hate variation in carbon dioxide levels. Holding your breath allows researchers to measure the increased blood flow to the brain.
Where's Wally?: Participants close their eyes for 20 seconds and are given 40s to find Wally. This is repeated five times. This is an effective way of measuring cognition.
Squat standing: A simple test, alternating squatting and standing every 5-10s for five minutes. This increases the heart rate and will increase blood flow to the brain. Blood flow is reduced in concussed patients.
