## Breadcrumb - [Home](/) - [Resources & Support](/resources-support) - [Parkinson's Today Blog](/resources-support/blog) ## Breadcrumb - [Home](/) - [Resources & Support](/resources-support) - [Parkinson's Today Blog](/resources-support/blog) Science News # Brain Inflammation Linked to Dementia Risk in Parkinson's Disease Apr 22, 2025 ![Parkinson's Foundation Science News blogs](/sites/default/files/styles/no_sizing/public/images/science-news-blog-header.png?itok=pp6v6Yh2) Parkinson's disease (PD) is known primarily for its [movement-related symptoms](/understanding-parkinsons/movement-symptoms "Movement Symptoms"), but it can also lead to [dementia](/library/fact-sheets/advanced-thinking-changes "Advanced Thinking Changes & Parkinson’s"), a devastating decline in cognitive abilities. Nearly half of people diagnosed with Parkinson’s develop dementia within 10 years of their Parkinson’s diagnosis. Researchers are now looking closer at what happens in the brain early in the disease to understand why some people with Parkinson’s develop dementia while others don't. ![Man distressed with head in hands](/sites/default/files/styles/380x361/public/images/Dementia%20%281%29.png?itok=Alsc6PzH) A new study, published in *[Brain](https://academic.oup.com/brain/article/147/3/923/7284003)*, focused on two key factors: brain inflammation (also called neuroinflammation) and the buildup of a protein called tau. Neuroinflammation, an immune response within the brain that is largely protective when working correctly, can release harmful chemicals that can damage or kill neurons when overactive, impairing communication between brain cells essential for cognitive processes. Tau protein, when misfolded and accumulated, forms tangles that disrupt how brain cells transport nutrients, preventing them from functioning properly and eventually leading to cell death. Both processes can contribute to the progressive loss of brain cells and synaptic connections and may ultimately lead to the cognitive decline characteristic of dementia. However, it was not known to what degree these factors were linked to dementia risk in people with early-stage Parkinson’s. ### Study Results The study enrolled 31 people recently diagnosed with Parkinson’s (the average time since diagnosis was one year) and 19 people of similar ages that did not have Parkinson’s. Using specialized brain scans (PET scans), researchers examined brain inflammation and tau accumulation in each participant. In addition, levels of body-wide markers of inflammation and tau were evaluated through a blood test. The researchers also evaluated the participants’ potential risk for dementia by assessing visual-motor skills, word recall and results from a genetic test (*MAPT* genotype) that is linked to dementia. Based on these test results, they divided participants into two groups — those at higher risk or lower risk for dementia. The study found that people at higher risk for dementia showed significantly more brain inflammation in several brain regions compared to both those at lower risk and people without PD. This inflammation was also linked to poorer performance on a cognitive test (ACE-III). Additionally, the overall level of neuroinflammation correlated with the amount of body-wide markers of inflammation seen in the blood test. This suggests that a high level of inflammatory markers detected in the blood may be a sign of increased neuroinflammation. Interestingly, while tau protein buildup was observed, it didn't seem to directly relate to cognitive decline. However, the study did find that more brain inflammation was linked to tau accumulation, particularly in the high-risk group. People with Parkinson's scored lower on a cognitive test (ACE-III) compared to those without Parkinson's. Even within the Parkinson's group, those at higher risk for dementia scored lower on the same test than those at lower risk. Interestingly, the group at higher dementia risk had been diagnosed with Parkinson's for a slightly shorter time but showed more severe Parkinson's symptoms. There was no link between higher risk of dementia and age, gender, or the amount of Parkinson's medication someone took. Overall, these findings suggest that brain inflammation is evident in the [early stages of Parkinson's](/understanding-parkinsons/what-is-parkinsons/stages "Stages of Parkinson's") and may be a key factor in determining who develops dementia. On the other hand, accumulation of tau protein in early-stage Parkinson’s does not appear to correlate with dementia risk. ### Highlights - The study enrolled 31 people who were recently diagnosed with Parkinson’s and 19 people of similar ages that did not have Parkinson’s. People with Parkinson’s were grouped into those with high- and low-risk for dementia. - People with Parkinson's scored lower on a cognitive test (ACE-III) compared to those without Parkinson's. - Using specialized brain scans (PET scans) and markers, researchers examined whether participants showed signs of brain inflammation and tau protein accumulation - People at higher risk for dementia showed significantly more brain inflammation in several brain regions compared to those at lower risk and people without PD. - Brain inflammation was also linked to poorer performance on a cognitive test (ACE-III). ### What does this mean? This study indicates that brain inflammation may be an early contributor to dementia in Parkinson’s disease. As a result, neuroinflammation could potentially be a useful biomarker to identify people with Parkinson’s who are at risk for dementia. This opens the door to potential treatments that target brain inflammation, possibly preventing or slowing the progression of dementia in people with Parkinson's disease. There are several anti-inflammatory treatments already licensed to treat other conditions, which could potentially be repurposed to help treat PD-related dementia. However, it could take many years before a treatment strategy to alleviate Parkinson’s-linked dementia becomes widely available. ### What do these findings mean to the people with PD right now? This study further solidifies the link between the brain inflammation people with PD experience and the risk for dementia. [Parkinson’s disease dementia](/library/fact-sheets/advanced-thinking-changes "Advanced Thinking Changes & Parkinson’s") symptoms include potential thinking, memory and behavior changes — these symptoms can be wide-ranging. If you notice symptoms, talk to your movement disorders specialist about dementia concerns. While there is no way to stop the disease’s progression, a doctor can help [manage the symptoms](/events/2023/Lenexa "Managing Changing Symptoms"). [Learn more about dementia](/library/fact-sheets/advanced-thinking-changes "Advanced Thinking Changes & Parkinson’s") ### Learn More The Parkinson’s Foundation believes in empowering the Parkinson’s community through education. Learn more about the topics in this article through our below resources, or by calling our free Helpline at 1-800-4PD-INFO (1-800-473-4636) for answers to your questions. - [Dementia](/understanding-parkinsons/non-movement-symptoms/dementia "Dementia") - [Cognition: A Mind Guide to Parkinson’s Disease](/library/books/cognition "Cognition: A Guide to Thinking Changes in Parkinson's Disease") - [Advanced Parkinson’s](/resources-support/carepartners/advanced "Advanced Parkinson’s") ## Related Materials Fact Sheets ### [ Pain in Parkinson's Disease ](/library/fact-sheets/pain) [Read Now](/library/fact-sheets/pain) Fact Sheets ### [ Occupational Therapy & Parkinson's ](/library/fact-sheets/occupational-therapy) [Read Now](/library/fact-sheets/occupational-therapy) Fact Sheets ### [ Nutrition and PD ](/library/fact-sheets/nutrition) [Read Now](/library/fact-sheets/nutrition) ## Related Blog Posts ![A man and woman checking the man's smart watch.](/sites/default/files/styles/500x360/public/images/sn7-2026.png?h=9105c3fe&itok=oI-mUdym) Science News ### [ Study Finds 5 Subtle Walking Changes That Show Up Before a Parkinson's Diagnosis ](/blog/science-news/walking-changes-before-parkinsons) READ NOW ![Woman working from home with family in the background](/sites/default/files/styles/500x360/public/images/2026-science-news-6-blog-hero.jpg?h=ed9ce7df&itok=FfSOrcf_) Science News ### [ Early-Onset Parkinson’s in Younger Adults Is Rising Worldwide, Global Study Finds ](/blog/science-news/early-onset-parkinsons-rising) READ NOW ![Neurologists looking at brain scans](/sites/default/files/styles/500x360/public/images/sn-5-2026-preview.jpg?h=9105c3fe&itok=XlXeezsl) Science News ### [ Two New Studies Show Adaptive Deep Brain Stimulation May Improve Walking in Parkinson’s ](/blog/science-news/adaptive-deep-brain-stimulation) READ NOW ### PD Health @ Home Join us for new, weekly virtual wellness programs! 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