Strange vision problems may indicate Alzheimer's disease – UPI.com

In 94% of cases, individuals who exhibit posterior cortical atrophy (PCA) are likely to develop Alzheimer’s disease according to a study. The remaining 6% are prone to other dementias such as Lewy body disease or frontotemporal lobar degeneration. Photo by Adobe Stock/HealthDay News

Unusual visual disturbances could signal the impending onset of Alzheimer’s disease in about 10% of cases during the early stages, a recent study has revealed. The condition known as posterior cortical atrophy (PCA) involves sudden challenges with vision-related tasks such as writing, assessing the movement of objects, and picking up dropped items effortlessly. Individuals may struggle with these everyday activities despite passing an eye exam without issue.

“There is a need for greater awareness of PCA so that healthcare providers can identify and address it,” said Marianne Chapleau, co-lead author of the study and affiliated with the University of California, San Francisco’s department of neurology. “Most patients seek help from optometrists as they begin to experience visual symptoms and may be referred to an ophthalmologist who could also overlook PCA. This emphasizes the necessity for improved tools in clinical settings to detect these patients early and provide them with appropriate treatment.”

To gauge the predictive nature of PCA in relation to dementia, Chapleau’s team conducted an analysis involving over 1,000 patients from 36 sites across 16 countries. PCA tended to manifest at an average age of 59. Patients presenting with PCA often struggled with tasks such as accurately reproducing simple diagrams, discerning an object’s location, and visually perceiving more than one object at a time, as indicated by the research. Additionally, their math and reading abilities started to deteriorate.

The research conducted by the UCSF team discovered that 94% of individuals with PCA went on to develop Alzheimer’s disease. The remaining 6% were diagnosed with other dementias like Lewy body disease or frontotemporal lobar degeneration. This is significantly more predictive of dementia compared to conditions such as memory loss, where only 70% of affected individuals develop dementia, according to the researchers.

While many individuals may initially display no cognitive impairments when affected by PCA, the study revealed that mild or moderate deficits in memory, executive function, behavior, speech, and language typically emerged around four years later.

The findings of the study were published in The Lancet Neurology journal. Renaud La Joie, also from UCSF’s department of neurology and the university’s Memory and Aging Center, served as the first author of the study. He believes that since PCA usually precedes actual dementia by several years, it could identify patients who might benefit from recently approved Alzheimer’s medications.

Some of these medications specifically target tau, a protein that accumulates in the brains of individuals with Alzheimer’s disease. “Patients with PCA exhibit more tau pathology in the posterior parts of the brain, which are involved in the processing of visuospatial information, compared to those with other presentations of Alzheimer’s. This may make them more suitable candidates for anti-tau therapies,” explained La Joie.

Dr. Gil Rabinovici, the senior study author who heads the UCSF Alzheimer’s Disease Research Center, added, “It’s crucial for doctors to learn to recognize the syndrome so that patients can receive the correct diagnosis, counseling, and care.” He further stated, “From a scientific perspective, it is imperative for us to understand why Alzheimer’s specifically affects visual areas of the brain rather than memory areas. Our study revealed that 60% of patients with PCA were women. Gaining a better understanding of why they appear to be more vulnerable is an important area for future research.”