Alzheimer's May Begin With Weird Vision Problems

Scientists have discovered an early-warning sign for Alzheimer's disease that they hope may support earlier and more effective treatment.

About 5.8 million Americans live with Alzheimer's, the U.S. Centers for Disease Control and Prevention says. The progressive disease is the most common form of dementia and is associated with memory loss and cognitive decline in regions of the brain involved in memory, thought and language.

Alzheimer's is thought to be caused by an abnormal buildup of proteins in and around the cells in our brains, but exactly what triggers this process is still unclear. Today, there is no known cure for Alzheimer's. However, medications have been developed that may offer relief to patients and slow down the development of symptoms, particularly if the disease is detected early.

In a study published in The Lancet: Neurology journal, a team of University of California, San Francisco, (UCSF) researchers uncovered the early symptom, which may occur in up to 1 in 10 Alzheimer's cases: weird vision. Specifically, a condition called posterior cortical atrophy (PCA), which affects our ability to judge distances, distinguish between moving and stationary objects, and complete tasks like writing and retrieving dropped objects, despite having normal results in an eye examination.

In its study, the team investigated 1,000 patients from 16 countries who had experienced PCA and found that 94 percent of them also had some sort of Alzheimer's disease biomarker. By contrast, previous studies have shown that just 70 percent of patients with memory loss—a symptom often associated with Alzheimer's—show biomarkers for the disease.

The study highlights the importance of raising awareness of this condition among clinicians and patients.

"We need more awareness of PCA so that it can be flagged by clinicians," Marianne Chapleau, the study's co-first author and a researcher at the UCSF Department of Neurology, said in a statement.

"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. We need better tools in clinical settings to identify these patients early on and get them treatment," Chapleau said.

More research into the mechanisms behind PCA will also be essential, not only for advancing patient care but also for understanding the processes that drive Alzheimer's.

"It's critical that doctors learn to recognize the syndrome so patients can receive the correct diagnosis, counseling and care," the study's lead author, Gil Rabinovici, said in a statement.

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