A uniquely New Zealand study into the devastating dementia-like disease CTE is focussing on the behaviour of sheep in two paddocks in rural New Zealand. 

The study is part of the research being conducted by a team led by Dr. Helen Murray, head of Chronic Traumatic Encephalopathy (CTE) research at the Centre for Brain Research at the University of Auckland. 

CTE, once known as "punch drunk" for its prevalence in boxers, is caused by repeated head impacts. Crucially, the risk comes not just from major concussions—which trigger stand-down protocols—but also from frequent, small sub-concussive blows that often go unnoticed. 

Speaking to Clare de Lore on Newstalk ZB’s Brainstorming podcast, Dr. Murray—a former international ice hockey player—notes that while rugby often dominates the conversation, CTE affects all collision sports, as well as high-risk occupations like the military and police, and victims of domestic violence. 

Speaking to Clare de Lore on Brain Research Powered by Sheep: A Kiwi Approach to CTE, Dr. Murray—a former international ice hockey player—notes that while rugby often dominates the conversation, CTE affects all collision sports, as well as high-risk occupations like the military and police, and victims of domestic violence. 

A definitive diagnosis of CTE is currently only possible post-mortem. The disease’s devastating impact has been tragically demonstrated by the deaths of rugby players Shane Christie and Billy Guyton, both of whom took their own lives after battling the disease. 

Geoff Cooper, whose father died of CTE after 57 years of local rugby, is following Dr. Murray’s work closely, having witnessed CTE decline firsthand. 

“This thing starts with these subtle things like “how do I spell something” but quickly it becomes issues of .. recollection or losing your words, losing your vocabulary and then later on losing your relationships, control and agency,” he told Brainstorming. 

Dr. Murray is focused on finding reliable biomarkers to identify CTE risk, which would allow individuals to mitigate danger or retire from high-risk activities. She has turned to a surprising surrogate for her research: sheep. 

Sheep brains share a similar folded structure to human brains and post-mortem examinations show CTE is found at the bottom of the folds. In a study she calls "the most Kiwi thing ever," Dr. Murray is comparing two groups of rams: intact rams that naturally head-butt during mating season, and a control group of castrated rams that exhibit little to no such behavior. 

“We can’t do this with living people. We can’t put people in a room and knock some on the head and not knock others so we’re using rams. We’re trying to understand the steps along the way to get to that disease (CTE) - what is happening after repeated head knocks earlier in their life that’s contributing to this disease and getting worse over time,” Dr Murray told Clare de Lore. 

Though the research is in its early stages, it is already yielding results. MRI scans and blood samples show changes in the rams' brains similar to those observed in humans. By correlating these impacts with post-mortem findings, the team is developing a profile for early detection. 

Despite the known risks in, for example, boxing, Dr. Murray advocates for a balanced approach rather than banning the sports. 

“We need to work productively with athletes so going in and saying “this is terrible” is not going to help us have that conversation. So I go in with my athlete’s hat and say “tell me how you train, why you do what you do” and then we try to find a balance that will help you protect yourself long term,” she explains. 

The global objective is to identify reliable biomarkers within the next five years. In the interim, the focus remains on harm reduction strategies, such as delaying the start of contact sports for children and adjusting season lengths to try to ensure sufficient brain recovery. 

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