New insights into dementia in Parkinson’s

The research used detailed brain imaging to explore the brain changes linked to thinking and memory changes in Parkinson’s. This study aimed to understand more about why some people develop dementia by examining the brains of people with Parkinson’s with dementia, people with Parkinson’s but no dementia, and healthy controls.

What is Parkinson’s dementia? 

Dementia is when someone experiences a decline in their thinking and memory. In Parkinson’s this can occur at different stages of the condition. For some, movement symptoms appear first, followed by cognitive decline – this is known as Parkinson’s dementia (PDD). For others, cognitive changes may appear before movement symptoms, a condition called dementia with Lewy bodies (DLB). Together, these conditions fall under the umbrella term Lewy body dementia (LBD).

Read more about thinking and memory changes in Parkinson’s on our health content pages. 

What did the researchers find? 

The research involved 131 participants, including:

• 46 people with Parkinson’s but no dementia
• 62 people with Parkinson’s and dementia (either PDD or DLB)
• 23 healthy controls

Using detailed MRI scans, the researchers investigated different regions of the brain and how they interact with each other.

The team found differences in how the brain responds to information in people with dementia. Whereas for people with Parkinson's and no dementia, changes tended to be in physiological and cellular processing. They also found cells that were particularly vulnerable to changes in those with dementia.

The results also suggest that changes in the brain causing movement symptoms are separate to those involved with thinking and memory changes, known as cognitive decline. Symptoms are not simply stages of the progression of the condition.

Professor Rimona Weil, one of the lead researchers involved in the study, described the findings as a “roadmap to understanding cognitive decline in Parkinson’s.” 

You can read the full scientific paper in the journal of Nature Communications.

Why this matters

Dr Katherine Fletcher, our Research Communications Lead, explains why:

"It‘s always great to see results from research we’ve funded and this research is an important step towards understanding the complex relationship between Parkinson’s and dementia. By identifying the unique brain changes linked to cognitive decline, it could help researchers develop more personalised treatments in the future.

"Ultimately, the goal is to better predict who is at risk of developing dementia, diagnose it earlier, and find ways to slow or even prevent cognitive decline.

"While more work is needed, this study provides crucial evidence that could pave the way to improved care and outcomes for people with Parkinson’s."