Many strange visual symptoms appear to be a strong indicator of Alzheimer’s disease: ScienceAlert
The rare condition posterior cortical atrophy (PCA) involves strange and disturbing problems with vision and spatial awareness — including difficulty judging distances, seeing movement, and recognizing objects — and a new study highlights its close relationship with Alzheimer’s disease in more detail than ever before.
PCa and Alzheimer’s disease have long been linked to each other, because they share many of the same pathological changes in the brain. However, the rarity of PCA has made it difficult for researchers to fully evaluate it in relation to Alzheimer’s disease.
To address this, an international team of researchers analyzed data from 1,092 people with PCa, and found that it was a very strong predictor of Alzheimer’s disease: in 94 percent of cases, Alzheimer’s-related brain changes were observed that were most likely contributing to PCa. .
“We need more awareness about PCa so doctors can detect it,” says neuropsychologist Marian Chaplow of the University of California, San Francisco (UCSF).
“Most patients see their ophthalmologist when they start experiencing visual symptoms and may be referred to an ophthalmologist who may also fail to recognize PCa. We need better tools in clinical settings to identify these patients earlier and offer them treatment.”
One positive effect this study could have is to screen people with PCa symptoms as soon as possible. The average age of onset is 59 years – several years younger than Alzheimer’s disease – and the average time between the onset of symptoms and the first diagnostic visit is 3.8 years.
The study noted many similarities between PCa and Alzheimer’s disease in terms of amyloid and tau levels in the brain, with accumulation of these proteins long associated with the onset of dementia.
However, there were also some differences, which could give researchers clues about the best treatment courses.
“Patients with PCa have more tau pathology in the posterior parts of the brain, involved in processing visual-spatial information, compared with those with other presentations of Alzheimer’s disease,” says neuropsychologist Reno La Joye of the University of California, San Francisco. . “This may make them more suitable for anti-tau therapies.”
The researchers in this new study hope that their work will lead to a greater understanding of how Alzheimer’s disease arises, and how both Alzheimer’s disease and PCa begin to take over the brain.
With this research covering people in 16 different countries, it is the most comprehensive review of PCa to date – and given its close links to Alzheimer’s disease, it gives us a different perspective on dementia than we get otherwise.
“From a scientific standpoint, we really need to understand why Alzheimer’s disease specifically targets visual areas rather than memory areas of the brain,” says neurologist Jill Rabinovici of the University of California, San Francisco.
“Our study found that 60 percent of patients with PCa were women – better understanding why they are at higher risk is an important area for future research.”
The research was published in Lancet Neurology.