Toronto Scientists Are Trying to Diagnose CTE in Living People

Chronic traumatic encephalopathy has followed hockey rinks, football fields, and military families for two decades, and it has always come with the same cruel catch. The only way to confirm it is to examine the brain after death.

Researchers at the Centre for Addiction and Mental Health in Toronto are trying to diagnose CTE in a living person for the first time, CTV News reported. The team, led by brain health imaging centre director Neil Vasdev, is testing a radioactive tracer designed to light up the specific form of tau protein that marks the disease on a PET scan. Early results are encouraging, though Vasdev has stressed that the work is at the start of a long validation road and too early to rely on.

Key takeaways

CTE is a degenerative brain disease linked to repeated head impacts, and today it can only be confirmed after death.

A CAMH team is testing a tracer called OXD-2314 that binds to the form of tau protein found in CTE so a PET scanner can see it.

A 2025 first-in-human study in four healthy volunteers found the tracer safe, and early scans now show a signal where CTE would be expected.

Researchers say the tracer still has to be validated in a wider group before anyone can rely on it.

You can act on the cause now by taking every suspected concussion seriously and following Canada's step-by-step return to sport.

What do repeated head impacts do to the brain?

CTE is linked to repeated head impacts, the kind absorbed over years of contact sports or military service, and researchers are now also studying brain injury caused by intimate partner violence. Over time, a toxic form of a protein called tau builds up in the brain, and people can develop memory problems, mood changes, depression, and erratic behaviour.

Those symptoms overlap with so many other conditions that a firm answer has been impossible during life. Doctors can only rule other causes out one by one, which Vasdev told CTV leaves people circling the health care system, hitting dead end after dead end. Head injury is also one of the risk factors for later memory loss that our guide to the dementia risks you can change covers.

How does a brain scan find what only an autopsy could see?

The challenge here is one of precision. Tau comes in six different forms, Vasdev explained, and the form involved in CTE differs from the one found in Alzheimer's disease, which is why scans built for Alzheimer's miss it. The team's approach is to take a drug that binds to CTE-type tau and make it slightly radioactive, so that a brain scan can show where it collects in a living person.

According to National Geographic's reporting on the project, the team screened more than 150 molecules before landing on the tracer, called OXD-2314. A 2025 study in four healthy volunteers found it entered the brain without adverse effects, and Vasdev says the team is now seeing a signal in living people right where CTE would be expected. The next step is a wider pool of participants, across ages, sexes, and causes of injury.

What would a living diagnosis change for families?

Being able to diagnose CTE in life would give people with the suspected disease a proper care pathway and a way to join treatment trials, both of which are out of reach without a confirmed answer. For families, Vasdev told CTV, a diagnosis can explain the mental health changes and erratic behaviour they watched in someone they love.

A living diagnosis would also open the door to the bigger goal. Vasdev has said that if CTE can be detected in life, researchers can start working on stopping it, much as tau-targeting research is reshaping Alzheimer's care, including a new Alzheimer's drug going after a different target. Veterans have volunteered for scans precisely because their histories of head trauma left them wondering what is happening inside their own heads.

What do Canada's concussion guidelines ask you to do?

You cannot get a CTE scan yet, but you can manage the thing that causes the damage. Canada's concussion guidelines for sport call for anyone with a suspected concussion to stop playing right away and get a medical assessment, and the evidence points to repeated and poorly managed impacts as the real problem.

Remove the player immediately. Anyone with a suspected concussion should stop the game or practice that day, even if they say they feel fine.

Get a medical assessment. A doctor or nurse practitioner should confirm whether it is a concussion and guide the next steps.

Return step by step. Follow the gradual return-to-school and return-to-sport plan, and wait for medical clearance before any contact.

Learn your sport's protocol. Parents and coaches should know their league's concussion rules before the season starts.

Book a visit for lingering symptoms. Headaches, fogginess, or mood changes that linger after a head injury deserve attention now, and a simple memory check can be part of that visit.

Frequently asked questions

Can a scan show this kind of brain damage while someone is alive?

Doctors cannot yet diagnose CTE in a living person with certainty, since confirmation still comes only from examining brain tissue after death. Teams like the one at CAMH are testing tracers that would show the disease on a PET scan, and early signals are promising, though researchers say they still need much more testing.

What are the early signs of brain damage from repeated hits?

Possible signs include memory problems, trouble concentrating, mood changes, depression, impulsive or erratic behaviour, and headaches that keep returning. These symptoms have many other possible causes, so anyone with a history of head impacts who notices them should see a doctor for a proper assessment.

How long does concussion recovery usually take?

Most people who get a concussion in sport recover completely within about four weeks, according to Canada's concussion guidelines. Symptoms that last longer deserve a follow-up with a doctor, and a return to contact sport should wait for written medical clearance.

Your next step

Post-concussion symptoms and worries about past head injuries are worth getting assessed properly. The Medimap Health Hub has more on brain health and healthy aging, and you can find a family doctor near you and stop wondering alone.

Disclaimer: This article is for general information only and is not medical advice. It does not replace a conversation with a doctor or other qualified health professional who knows your history. If you think you are having a medical emergency, call 911 or go to the nearest emergency department.