Little-Known Variant of Alzheimer’s Disease Linked to Vision Problems
Many people are familiar with the idea that Alzheimer’s disease primarily affects memory, but for some patients, the early signs of the disease manifest in the form of vision problems. This little-known variant of Alzheimer’s, known as posterior cortical atrophy (PCA), can make the correct diagnosis difficult, leading to delays in treatment for thousands of people. However, a first-of-its-kind international study has shed light on this different form of Alzheimer’s, providing new insight into its symptoms and potential treatments.
The study, led by researchers at the University of California, San Francisco and published in Lancet Neurology, examined data from 1,092 PCA patients from 16 different countries. It found that, on average, the syndrome begins to affect patients at age 59, about 5-6 years earlier than most affected patients from the most common form of Alzheimer’s. Additionally, approximately 94% of patients with PCA had Alzheimer’s disease, while the remaining 6% were affected by conditions such as Lewy body disease and frontotemporal dementia.
The researchers estimate that PCA may account for up to 10% of all Alzheimer’s cases, making it a significant but little-known variant of the disease. With greater awareness of the syndrome, the authors hope that doctors will be able to diagnose it earlier, potentially allowing for earlier intervention and treatment.
The study also highlighted that PCA is diagnosed on average only four years after the onset of visual symptoms, often when signs of memory loss also begin to appear. This delay in diagnosis is likely due to the fact that patients initially seek help from general practitioners, optometrists, and ophthalmologists before seeing a neurologist, as the first symptoms primarily affect vision.
In terms of symptoms, the study found that the most common early signs of PCA include difficulty reading and driving, as well as problems with judging distances, recognizing multiple objects together, and perceiving distances between objects. Some patients may also experience hallucinations. As the disease progresses, memory decline may become more pronounced.
While there is currently no definitive cure for PCA, treatment aimed at improving visual impairment and managing Alzheimer’s symptoms can help patients. Additionally, early identification of PCA could have important implications for the treatment of Alzheimer’s, potentially making patients candidates for therapies currently used in the United States or in experimental phases.
The study also highlighted that a particularly high number of PCA patients are women, with around 60% of patients being female.
The little knowledge about PCA in the medical community can be attributed to the fact that the syndrome was not well understood and experts did not use the same diagnostic parameters until recently. It wasn’t until 2017 that scientists agreed on a single description of the condition, with a publication in the journal Alzheimer’s & Dementia. The rare form of Alzheimer’s linked to posterior cortical atrophy gained attention when British writer Terry Pratchett, author of the Discworld series, announced in 2007 that he had been diagnosed with the syndrome. His public battle with the disease helped bring greater awareness to this little-known variant of Alzheimer’s.
In conclusion, the study’s findings have the potential to improve the early diagnosis and treatment of PCA, providing hope for patients who may be affected by this little-known form of Alzheimer’s. With greater awareness of the syndrome, more research can be directed towards understanding and treating this variant of the disease, potentially bringing relief to those affected by its unique symptoms.