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Inside the brain of a suspected CTE patient, 3D scans show impact of repeated head knocks

Gordi Kirkbank-Ellis’s sporting life was littered with heavy knocks to the head.

Some big hits, but also “lots of little concussions too”. Some when he was playing rugby as a child.

The effect of these head knocks over his decades-long career isn’t immediately obvious.

That is, until you see what’s happening to the 54-year-old’s brain.

3D MRI scans like this give a glimpse into damage from repeated blows to the head.

This is a 3D MRI of the brain of a man the same age as Kirkbank-Ellis.

In a typical brain like this, these deep valleys, known as sulci, are tightly packed.

Kirkbank-Ellis’s scan reveals these valleys have widened and filled with fluid.

His brain is slowly shrinking.

This central thin membrane appears to have divided.

The suspected cause is Chronic Traumatic Encephalopathy or CTE.

It’s a type of dementia caused in part by repeated head injuries, like head knocks in football. It can lead to short-term memory loss, mood changes, impulsivity, and rage.

It’s not known how many people have CTE because it can only be diagnosed after death, but some experts say thousands of Australians could be affected.

An emerging field of CTE research is now looking at how to detect it while people are alive, but there are concerns in the scientific community about a controversial way it’s being used to diagnose patients like Kirkbank-Ellis.

When he was four years old, Kirkbank-Ellis remembers he was asked to make a choice: his father told him he could play football or do chores on the family farm in New Zealand. Without hesitating, he chose football.

It was the start of more than three decades of contact sport for Kirkbank-Ellis, competing in rugby, karate, rugby league, and 10 years of boxing.

Kirkbank-Ellis pictured holding the ball in his school rugby photo at age 8. He had already been playing rugby for 4 years by this time. (Supplied: Gordi Kirkbank-Ellis)
Kirkbank-Ellis’s sporting career included a decade as a boxer.(Supplied: Gordi Kirkbank-Ellis)

He now lives near Wollongong and works as a personal trainer. It was during a session in 2020 that he realised something was wrong.

“A client of mine said, ‘Do you not remember that we talked about this yesterday?’ and I had no memory of it. He said we’d had this entire conversation, and I was repeating myself and should get checked.”

Kirkbank-Ellis went to see Dr Rowena Mobbs, a neurologist who specialises in cognitive issues such as dementia, stroke, concussion, and migraine.

He described feeling a change in his mood, being irritable for no reason for years and struggling with his short-term memory.

After several scans and lengthy testing, Dr Mobbs concluded that Kirkbank-Ellis was showing signs of probable CTE.

A controversial diagnosis

CTE is a degenerative brain disease associated with repetitive head impacts. Dr Mobbs says she currently sees over 100 patients like Kirkbank-Ellis, many who played contact sports like football or boxing for years, served in the military, or were victims of domestic violence. Some are showing signs of dementia in their 30s.

Head impacts can include concussions, but bumps, blows or jolts to the head without symptoms, known as sub-concussions, are also a driving force behind CTE. Some contact sports players can experience hundreds, even thousands, of head hits in their lifetimes.

CTE can only be definitively diagnosed after death by examining brain tissue under a microscope, so to determine if someone has suspected CTE while they are alive, Dr. Mobbs uses research criteria recently developed by the US National Institutes of Health, the world’s largest biomedical research agency.

Rowena Mobbs is a neurologist who specialises in cognitive issues such as dementia, stroke, concussion, and migraine.(ABC News: Michael Nudl)

She combines this with her observations and opinion, and further tests, to diagnose people with “probable” traumatic encephalopathy syndrome or TES — the clinical disorder linked to CTE.

But the criteria are meant for research, not diagnosis in a doctor’s office, which has other experts concerned.

While Dr Mobbs can see how her approach might be seen as pioneering, she says it’s built on time-honoured principles to detect and manage dementia, and it allows her to start commonly used dementia and mood-stabilising medication while giving patients and their loved ones immense relief, knowing there is a reason for their behaviour.

“I make no apologies for caring in the best way possible for my patients,” Dr Mobbs said.

A picture of CTE

As part of forming a probable diagnosis, Dr Mobbs looks for specific signs and clues on tests and imaging scans.

In Kirkbank-Ellis’s case, one of those scans was an MRI that revealed to Dr Mobbs his brain appeared abnormal for his age. She noticed volume changes and wider, black areas close to the deep valleys of the brain.

“We all can have shrinkage of the brain as we get older, especially into our 60s, 70s and beyond, but he is a very young person to have what I would deem to be some loss of volume of the brain,” she said.

Dr Mobbs also saw white matter lesions on Kirkbank-Ellis’s scans. These lesions can develop for different reasons with age, but in footballers, Dr Mobbs says they can be the result of head injury and scarring.

On this type of scan, an FDG PET, Dr Mobbs looks for changes related to metabolism in the brain and uses this imaging to correlate with the shrinkage of the brain. Typically, neurologists are looking for an even, bright yellow appearance.

In Kirkbank-Ellis’s scans, areas of low metabolism are indicated in purple, particularly changes in the temporal lobes — the memory areas — at the front of the brain, as well as patchy areas on the sides.

Dr Mobbs says there are almost no perfect tests for the brain, and, ultimately, it’s down to the instinct and expertise of the clinician to make the call and continually revise it as they continue to see the patient over the years.

Probable, not definite

Dr Michael Buckland is a neuropathologist and the director of the Australian Sports Brain Bank. He recently co-authored a paper diagnosing the late AFLW player Heather Anderson with CTE — the first time the brain disease had been diagnosed in a professional female athlete.

He is among those in the scientific community concerned about diagnosing patients with probable CTE while they are still alive and says people may not understand a diagnosis is probable, not definite.

“?The reason people have been criticised in the past [for diagnosing probable CTE] is that CTE has got a lot of media attention, and there’s a lot of anxiety about it in the community,” said Dr Buckland.

“Nevertheless, there is a flip side,” he added. “These patients need — and there’s a lot of people struggling out there — and want some sort of certainty, and they certainly need care.”

Dr Buckland is the director of the Australian Sports Brain Bank.(ABC News: Ron Foley)

Dr Mobbs says that, in her experience, her patients understand the diagnosis as probable.

“It’s much better to allow that person who’s come to you for care, that opportunity of care of the symptoms and a general understanding of what’s going on,” Dr Mobbs said. “Often they’ve been struggling and floating in life without any label, without any validation of what they’re going through.”

Professor Robert Stern, a neurologist from Boston University, is one of the world’s leading experts on CTE in contact sports and was part of the group that put together the TES criteria. He emphasised that the criteria are for research, and while he doesn’t use it to diagnose people in his clinic, he generally agrees with Dr Mobbs in that it’s up to the clinician to do it appropriately.

However, Professor Stern is concerned that, given the publicity CTE gets, people may become unnecessarily scared and hopeless.

“The big problem in my mind is that people self-diagnose,” he said. “They think because they’ve had changes in their mood and keep hearing about people diagnosed with CTE that they’re doomed, they likely have CTE and might not go to the doctor.”

“I think it’s critical that people be assessed and treated appropriately.”

Dr Mobbs says she interprets a patient’s symptoms and history, along with results from various diagnostic tools and testing, such as MRI, PET and neuropsychology. She then combines this information with her clinical judgement and expert opinion to identify the type of dementia the patient may have. She also rules out other conditions that may imitate dementia symptoms, such as depression, nutritional deficiencies, or side effects from medication.

Dr Mobbs emphasises that there is no definitive test for CTE, which is also the case for Alzheimer’s disease. Instead, a clinical diagnosis is based on expertise, the opinion of the neurologist, the brain injury, and other tests.

“So we get all of that information to create a jigsaw puzzle, which although incomplete and not 100 per cent, can actually give us the picture of CTE,” she said.

The more you’re exposed to, the higher the risk

Part of piecing together this puzzle is understanding the impact of repeated head injuries on the brain on a microscopic level.

Direct head blows, whiplash, or concussions can cause the brain to twist and strike the skull, causing it to elongate and stretch. This can cause damage and stretching of individual brain cells.

Although the exact mechanism is not yet known, these repeated blows to the head cause a protein called tau to accumulate in parts of the brain.

In the brains of people with CTE, there is an abnormal build-up of tau in the depths of the valleys of the brain known as the sulci — the deep crevices or folds on the brain’s surface. Over time, the protein builds up in a characteristic pattern, causing damage to brain cells and leading to dysfunction. Eventually, the tissue starts to die and shrink.

Repeated hits to the head can cause microscopic injuries that contribute to a build-up of tau protein in the brain over time.

A study published last month on deceased American footballers revealed a player’s chance of developing CTE is related to the number of head impacts and the cumulative strength of those hits, not the number of diagnosed concussions. So if two athletes have had similar career lengths, the one who has had more head impacts and been exposed to greater force on the brain over time is more likely to develop the disease. This may be one reason why not everyone who plays contact sports will develop CTE.

“It’s a dose relationship,” said Dr Mobbs. “Just like asbestos, just like radiation, and the more you’re exposed to, the higher the risk.”

‘We help each other’

There is no known cure for CTE, but for Dr Mobbs’s patients with a suspected diagnosis, some have found access to medication and support groups have provided relief.

Enrique “Topo” Rodríguez represented Argentina and Australia in rugby in the 1970s and 1980s. He said that when he played rugby that players weren’t aware of what concussion was, and “if you left the field, you were considered weak”.

The 71-year-old was diagnosed with probable CTE by Dr Mobbs this year. He says he’s had bipolar disorder and depression for a long time, but the last five years have been particularly challenging, with his short-term memory deteriorating and communication becoming a struggle.

Rodríguez says the community support group founded by Dr Mobbs at Macquarie University Hospital in Sydney, Concussion Connect, has been beneficial.

“I started going last year, and it helps,” said Rodríguez. “I’m now in contact with people I get on with, and we help each other in different ways, especially when we’re down.”

Last year, Dr Mobbs said she saw a patient with suspected CTE every week. Now, she estimates it’s one or two people at her clinic per day.

“We have seen generation after generation celebrating big hits and tough tackles in football in this country,” Dr Mobbs said.

“This is a chronic public health emergency — a huge cost that could’ve been prevented.”

The future of contact sports

The recommendations from a Senate inquiry into concussions and repeated head trauma in contact sports are due to be handed down next week.

The inquiry heard from a range of medical and legal groups and individuals who called for urgent action on concussion and head injury in sport, with submissions recommending more funding, research and education, and consistent guidelines.

Experts have suggested changes to the way children engage with contact sports in Australia. (flickr/Mike Hauser/ccby2.0)

A number of experts have called for changes to how children engage with contact sports in Australia.

Suggestions include delaying children’s exposure to contact sports and modifying training and gameplay to avoid direct contact where possible.

“Naturally, there will be a lag time in preventing CTE from the interventions we make today, perhaps 20 years from now, but the ethical obligation is for us to act now and improve the outcomes of kids in sport today,” Dr Mobbs said.

In Australia, Rugby Australia, the NRL and AFL, as well as leagues overseas, have introduced rules aimed at preventing and managing head injuries with symptoms, like concussions. Professor Robert Stern says more needs to be done about repetitive head knocks that don’t have symptoms.

“Concussions are something leagues, and the owners can do something about because they’re measurable: you can count them, improve the management of them or diagnosis of them,” Professor Stern said.

“It’s important to do something to reduce concussions, but when it comes to long-term consequences, I think focusing on concussions takes away from the much, much more important issue.”

Spokespeople for the NRL, AFL and Rugby Australia have responded by saying they take player safety and long-term welfare seriously, have extensive track records of implementing policies and procedures to reduce and manage head injuries, and that there is no greater priority than the health and safety of their athletes at all levels.

Gordi Kirkbank-Ellis says he has no regrets but wouldn’t play such high-contact sports if he could have his time again.(Supplied: Gordi Kirkbank-Ellis)

Kirkbank-Ellis says that while he’s worried about dementia in the future, taking medication has “made a big difference”.

“I’m way more switched on than I’ve been for a while, and it’s kind of mood changing too, so I feel a lot better about myself,” Kirkbank-Ellis said.

“Now that I have the information about where I could be heading, I can do something about it.”

Kirkbank-Ellis has no regrets about his choices but says he wouldn’t play such high-contact sports if he could have his time again.

“Like my dad would say, ‘Mate, there’s no point crying over spilt milk because the milk has been spilled’,” he said. “But it’s done, and there’s nothing I can do about it.

“There’s no way I would let my son compete in heavy contact sport knowing what I know now — there is no way I would.”

If this story has caused issues for you, please call Lifeline 13 11 14 or Beyond Blue on 1300 22 46 36, or call the 24/7 National Dementia Helpline 1800 100 500 or visit


Read the full statements from the NRL, AFL and Rugby Australia.

Images used in the graphics, ‘Stages of CTE’ and ‘Abnormal tau build-up in a brain with CTE’, were originally published by McKee AC, Stein TD, Huber BR, Crary JF, Bieniek K, Dickson D, et al. . Chronic traumatic encephalopathy (CTE): criteria for neuropathological diagnosis and relationship to repetitive head impacts. Acta Neuropathol. (2023) 145:371–94. doi: 10.1007/s00401-023-02540-w – DOI – PMC – PubMed (CC BY 4.0)



Author: Russell White