Can Posterial Cortical Atrophy indicate Alzheimer’s disease?
Posterial Cortical Atrophy, sometimes called Benson’s disease, is a rare degenerative brain condition that affects the back part of the brain that processes vision, spatial perception, spelling and calculation.
It is well understood that Alzheimer’s affects brain functions such as memory, spatial awareness, speaking and writing, but lesser known are the changes to the brain associated with the condition that may also impact the eyes.
A recent study at the University of California at San Francisco found that PCA is associated with Alzheimer’s disease and can be an early warning sign.
PCA can cause challenges in judging distances, distinguishing between moving and stationary objects, and perceiving more than one object at a time. The condition can also cause difficulty in recognizing people, places and objects, reading frustrations, and problems with driving.
The study found that in 94% of cases, individuals with PCA go on to develop Alzheimer’s disease and it is found in up to 10% of all diagnosed Alzheimer’s cases.
PCA is often misdiagnosed because it produces visual processing symptoms, rather than the typical memory issues associated with the disease. Even with normal eye examinations, the disorder is often missed. Dr. Marianne Chapleau, of UCSF's Department of Neurology, emphasized the need for better diagnostic tools for PCA.
“Most patients see their optometrist when they start experiencing visual symptoms and may be referred to an ophthalmologist who may also fail to recognize PCA. Patients usually first visit a doctor 3.8 years after symptom onset, by which time mild or moderate dementia is often apparent," Chapleau said. "At diagnosis, many patients showed signs of ‘constructional dyspraxia, space perception deficit, and simultanagnosia.’ Additionally, nearly half struggled with basic math calculations and reading. We need better tools in clinical settings to identify these patients early on and get them treatment."
Chapleau’s colleague at UCSF, Dr. Renaud La Joie, also stressed that early detection could enhance Alzheimer’s treatment. Research found that the patients with PCA showed similar levels of amyloid and tau, like those in typical Alzheimer’s cases, indicating they might benefit from new treatments.
UCSF is considering treatments for those with PCA and non-amnestic variants of Alzheimer’s disease. The research concluded that overall better understanding of PCA is important for advancing patient care and understanding the processes that drive Alzheimer's disease.
Additionally, senior author Dr. Gil Rabinovici, director of the UCSF Alzheimer's Disease Research Center, emphasized the need to identify why Alzheimer's targets visual areas in the brain rather than memory areas. He also suggested the higher prevalence of PCA in women as a key area for future research.