Damage found after late AFLW player Jacinda Barclay donates brain for concussion research

AFLW player Jacinda Barclay, who died last year, has become the first contact sportswoman in Australia to have her brain donated to the Australian Sports Brain Bank, where researchers have uncovered neurological damage that they described as a “ticking time bomb”.

Barclay, who died in Chidlow, WA, last October aged 29 after a short but intense period of mental illness, was found by brain bank researchers to have degradation to her cerebral white matter.

Microdamage of this kind has been observed in American footballers, and is understood to be the consequence of repetitive head injury from contact sports. White matter changes and repeated head injury have also been linked to the development of mental illness and an increased risk of suicidal ideation.

Barclay’s groundbreaking donation has been hailed as “a defining moment towards balancing gender equity in sports concussion research”. Previously, donations to the brain bank have been from male contact sport athletes, including high profile Australian rules footballers Danny Frawley and Shane Tuck. Both were found to have severe cases of chronic traumatic encephalopathy (CTE), a neurodegenerative disease attributed to their playing careers.

Barclay was a multi-talented sportswoman. She was drafted to the AFLW’s Greater Western Sydney in 2016 and played 23 games for the club over four seasons. She previously represented Australia in baseball, playing at five World Cups, and was also an American football quarterback in the short-lived LFL Australia, and later in the United States.

Jacinda Barclay played four seasons of AFLW with GWS Giants. Photograph: Matt King/Getty Images

Researchers at the brain bank said the findings on Barclay’s brain have opened up new areas of inquiry in sports concussion research.

The white matter changes found in Barclay’s brain are unusual in someone so young, and she did not have any other conditions, such as heart disease or diabetes, that might otherwise explain them.

There was no finding of CTE, which is understood to be a consequence of repeated head trauma, marked by deposits of a protein called tau in the brain’s delicate blood vessels. CTE often manifests in life as behavioural changes, memory loss and other cognitive impairment, mood swings and mental health issues including depression and anxiety. It is unable to be definitively diagnosed except postmortem, by autopsy.

While a long-term career in contact sport is becoming widely accepted as a substantial risk factor for the development of CTE, less well understood is how white matter changes in the brain from non-concussive or sub-concussive blows may be affecting both elite and younger, amateur or early-career sportspeople.

Barclay did not have a substantial clinical history of concussion, and her brain did not show evidence of her having sustained a concussion in the weeks before she died.

Instead, the researchers found that her cerebral white matter had thickened and hardened.

“The vessels in the white matter had changes that you often see in elderly people, but not in someone of Jacinda’s age who is in peak physical health,” said Michael Buckland, the executive director of the Australian Sports Brain Bank and the neuropathologist who examined Barclay’s brain.

“An elite athlete shouldn’t have those changes. There was some evidence of white matter injury around those altered vessels. I hadn’t noticed that before in other subjects, but we haven’t had many athlete donors as young as Jacinda before.”

Buckland compared the findings in the white matter of Barclay’s brain to those of other cases he had examined, and found the damage to Barclay’s white matter was more pronounced, even though she was younger than them.

“It is well established in the medical literature that concussion causes white matter injury,” said Alan Pearce, Associate Professor at La Trobe University and Research Manager at Australian Sports Brain Bank (Victoria). “But changes to the white matter of the brain have also been observed in contact sports players after as little as one season.”

One study, conducted in 2016, found significant changes in the white matter of players as a consequence of sub-concussive blows over a single season of gridiron – players who were under 14 and had never before been diagnosed with concussion.

How white matter damage is linked to the development of CTE is not clear, said Pearce, but it indicates microdamage in the brain more broadly, and with further exposure to hard knocks, the risk of developing CTE is increased – a “ticking time bomb”, Pearce said.

The Giants run out under No 34 in memory of Jacinda Barclay in February this year. Photograph: Mark Kolbe/Getty Images

To date, research has shown links between white matter changes and mental health issues, and with both concussive and sub-concussive injuries. “The limitation is that those two areas of research haven’t coalesced. How does the white matter damage from repeated concussion and head injury affect mental illness?” said Pearce.

“We know there’s more going on than just accumulation of tau in people with traumatic brain injuries,” said Buckland. “Tau’s the marker we can find for CTE, but we know there’s white matter damage and blood vessel damage too.”

The bout of mental illness Barclay experienced in 2020 that culminated in her death was described by her family as completely out of character.

Barclay’s family is yet to receive the report from the Western Australian coroner into her death, but told Guardian Australia they wanted to make the brain bank’s findings public to raise awareness about the importance of the facility’s work and to highlight the paucity of research into women in this area.

“Jacinda loved sport and was a fearless advocate for women and women’s equality in sport,” the family said. “She always wanted to help people, and her donation to the brain bank means she can continue to help people and be a shining light for other women in the games that meant so much to her.”

Pearce and Buckland also emphasised the necessity of gender equity in sports concussion research.

“We really need to understand if there are differences between men and women’s brains,” said Pearce. “Research is totally biased towards men in this area – it’s really important that we’re balancing the ledger here and not just talking about men all the time. But we also need to ensure that scientific research doesn’t just reinforce harmful social stereotypes too.”

“Women play just as hard as men, but we’re just so much further behind in our understanding of the effects,” said Buckland. “Very few women have come through the studies, even in the US. Hopefully Jacinda’s donation will encourage other women to pledge.”