Why some people stay sharp despite brain disease and what it could mean for dementia

Not everyone who develops changes in the brain goes on to develop dementia.

That’s the focus of new research from UNSW Sydney, which is shedding light on why some people remain mentally sharp well into older age, even when their brains show signs of damage linked to conditions like Alzheimer’s disease or stroke.

The answer lies in something researchers call cognitive resilience. It describes the brain’s ability to keep thinking, remembering and functioning despite ageing, injury or disease.

What is cognitive resilience?

For years, dementia has often been seen as a direct result of changes in the brain.

But researchers are now finding that it’s not that simple.

Some people have significant brain disease but show few or no symptoms. Others experience decline more quickly. The difference may come down to how resilient the brain is.

“Dementia is not an inevitable consequence of brain pathology,” said Henry Brodaty, Co-Director of the Centre for Healthy Brain Ageing.

“Some individuals show remarkable cognitive resilience, maintaining cognitive abilities despite a substantial burden of disease in the brain.”

A shift in how we understand dementia

In the past, doctors could only confirm the extent of brain disease after someone had died.

Now, advances in brain imaging and blood tests are changing that.

Researchers can study changes in the brain in real time, tracking conditions like Alzheimer’s disease, Lewy body disease and vascular disease while people are still living, and seeing how these changes relate to memory and thinking over time.

This is helping shift the focus from simply identifying disease to understanding how the brain copes with it.

It’s not just about biology

The research also highlights something important for everyday life.

Cognitive resilience is not only shaped by what happens in the brain. It is also influenced by factors like education, health, lifestyle and access to care across a person’s lifetime.

That means things like managing blood pressure, staying mentally and socially active, and maintaining overall health could all play a role in protecting the brain.

Lead author Alice Powell said improving vascular health, including heart health and circulation, may be particularly important.

“Optimising vascular health across the lifespan may offer particularly powerful cognitive benefits,” she said.

What this could mean for the future

The findings are part of a growing shift in dementia research.

Instead of focusing only on treating disease after it appears, there is increasing attention on prevention and on helping people maintain their cognitive function for as long as possible.

By combining cognitive testing with brain scans and blood-based markers, researchers hope to better understand who is more resilient and why.

Over time, that could lead to new approaches that help slow or even prevent cognitive decline.

A more hopeful message

For older Australians and their families, the message is a meaningful one.

Changes in the brain do not always lead to dementia. While there are no guarantees, there are factors that may help protect cognitive health over time.

Understanding resilience, and how to support it, could become one of the most important parts of ageing well.