A new study from University College London (UCL) has found that differences in brain protein distribution and inflammation may help explain why some people with Alzheimer’s disease first experience vision problems rather than memory loss.
The study focused on a rare form of the disease called posterior cortical atrophy (PCA), which affects how the brain processes visual information.
Unlike typical Alzheimer’s, which mainly causes memory issues, PCA leads to trouble reading, recognizing objects, and finding one’s way around.
It also tends to affect people at a younger age, often in their 50s or 60s. Experts estimate that about one in 10 Alzheimer’s cases are visual-led, rather than memory-led.
In this study, published in Neuropathology and Applied Neurobiology and funded by the Alzheimer’s Society, researchers examined donated brain tissue from 26 people with PCA and 27 people with typical Alzheimer’s. These brain donations were made to the Queen Square Brain Bank at UCL.
The team looked at key markers in the brain, including amyloid and tau proteins (which are closely linked to Alzheimer’s disease) and microglia, a type of immune cell in the brain that helps clear out damaged cells.
They discovered that people with PCA had more widespread buildup of amyloid and tau proteins in the parietal region—the back part of the brain responsible for processing vision. In addition, they found high microglial activity in both the parietal and temporal regions of PCA brains. These areas are also commonly affected in typical Alzheimer’s disease.
In contrast, in people with memory-led Alzheimer’s, the temporal region (important for memory) had the most tau buildup but the lowest level of microglial activity. This suggests that where proteins build up and where inflammation occurs in the brain can influence the type of symptoms a person develops.
Dr. Zeinab Abdi, the study’s lead author from the UCL Queen Square Institute of Neurology, explained: “These findings suggest there is a link between the location of inflammation and protein buildup in the brain, which may explain why some people develop memory symptoms while others experience problems with vision.”
The research could lead to more tailored treatments in the future by recognizing that Alzheimer’s affects different people in different ways. Dr. Abdi hopes this will encourage more studies into how brain inflammation and protein accumulation relate to the symptoms of Alzheimer’s.
Dr. Richard Oakley from the Alzheimer’s Society emphasized the importance of this research: “Dementia is the UK’s biggest killer, and understanding how rarer forms of Alzheimer’s work is crucial if we want to improve diagnosis and treatment. This study takes us a step closer.”
By studying these unusual forms of Alzheimer’s disease, researchers hope to develop personalized care and more effective treatments that address the specific needs of each patient.
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