Distinct brain changes may help explain why some people with Parkinson’s develop Parkinson’s dementia while others do not.
Researchers used detailed MRI scans to compare people with Parkinson’s and dementia, people with Parkinson’s but no dementia, and healthy controls.
The findings suggest the brain changes linked to movement symptoms may be separate from those tied to memory and thinking problems, known as cognitive decline.
Parkinson’s UK part-funded the study. Professor Rimona Weil, one of the lead researchers, described the findings as a “roadmap to understanding cognitive decline in Parkinson’s”.
The study involved 131 participants, including 46 people with Parkinson’s but no dementia, 62 people with Parkinson’s and dementia, and 23 healthy controls.
Among those with dementia were people with Parkinson’s disease dementia, where movement symptoms come first and problems with thinking and memory develop later, and dementia with Lewy bodies, where cognitive symptoms can appear before movement problems.
Together, these conditions fall under the umbrella term Lewy body dementia.
The scans showed differences in how the brain responds to information in people with dementia. In people with Parkinson’s but no dementia, changes tended to be in physiological and cellular processing.
Researchers also identified cells that appeared to be particularly vulnerable in those with dementia, offering further clues about why some people develop cognitive symptoms and others do not.
The results also suggest that brain changes causing movement symptoms are separate from those involved in cognitive decline, rather than simply being stages in the progression of the condition.
Dr Katherine Fletcher, research communications lead at Parkinson’s UK, said: “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.”
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