A recent study revealed that approximately 10% of Alzheimer’s cases are accompanied by early visual disturbances, which often indicates the onset of the disease. This condition, known as posterior cortical atrophy (PCA), manifests as sudden challenges in tasks related to vision, such as writing, determining the movement of objects, or effortlessly retrieving dropped items. Even though eye exams appear normal, individuals may struggle with these everyday activities. Marianne Chapleau, one of the study’s co-lead authors from the University of California, San Francisco’s department of neurology, emphasized the need for increased awareness of PCA among clinicians to facilitate early detection.
In a UCSF news release, it was noted that many patients only visit their optometrist once they start experiencing visual symptoms, and even when referred to an ophthalmologist, the condition may still go unrecognized. The need for improved clinical tools to identify these patients early and provide them with treatment was emphasized.
To assess the potential predictive value of PCA for dementia, Chapleau’s team examined data from over 1,000 patients across 36 sites in 16 countries. The research revealed that PCA typically manifests at an average age of 59.
The study also found that patients with PCA often struggled to accurately replicate simple diagrams, experienced difficulty in judging an object’s location, and had challenges in visually perceiving multiple objects simultaneously. Additionally, their mathematical and reading abilities started to decline.
According to the UCSF team, 94% of individuals who experienced Posterior Cortical Atrophy (PCA) eventually developed Alzheimer’s disease, while the remaining 6% developed different forms of dementia, such as Lewy body disease or frontotemporal lobar degeneration.
The researchers emphasized that this statistic is significantly more indicative of dementia compared to conditions like memory loss, where only 70% of individuals with memory impairment go on to develop dementia.
It is worth noting that many individuals with PCA initially do not exhibit cognitive issues. However, the study revealed that approximately four years later, mild or moderate deficits in memory, executive function, behavior, speech, and language became evident.
These findings were recently published in The Lancet Neurology journal.
Renaud La Joie is the lead author of the study and a member of UCSF’s department of neurology and the university’s Memory and Aging Center. He suggests that because PCA typically manifests years prior to actual dementia, it could potentially identify patients who could benefit from newly approved Alzheimer’s medications.
Some of these medications are designed to target tau, a protein that accumulates in the brains of individuals with Alzheimer’s disease.
“Individuals with PCA show greater tau pathology in the posterior areas of the brain, which are involved in visuospatial information processing, in comparison to those with other manifestations of Alzheimer’s. This may indicate that they are more suitable candidates for anti-tau therapies,” he explained.
It’s imperative for physicians to be able to identify the syndrome so that patients can be given the proper diagnosis, guidance, and treatment,” emphasized Dr. Gil Rabinovici, senior author of the study and director of the UCSF Alzheimer’s Disease Research Center.
“From a scientific standpoint, it’s crucial to comprehend why Alzheimer’s is specifically impacting visual rather than memory regions of the brain,” he further commented. “Our study revealed that 60% of individuals with PCA were women—gaining a better understanding of why they seem to be more vulnerable is a key area for future research.
