Vision problems could be key to early diagnosis of Alzheimer's disease, study shows

A new study suggests that Alzheimer's disease possibly begins to manifest in some patients as a disease that causes vision problems and is often overlooked. But more awareness could lead to an early Alzheimer's diagnosis.

The study published by the Lancet, found that 94% of patients diagnosed with Posterior Cortical Atrophy, or PCA, a neurodegenerative condition that impairs one's vision and mainly affects the occipital and parietal cortex, also had Alzheimer's. One of the researchers, Marianne Chapleau, shared the findings of the study on X.

"These data indicate posterior cortical atrophy typically presents as a pure, young-onset dementia syndrome that is highly specific for underlying Alzheimer’s disease pathology," states the study.

Researchers state PCA is categorized by the decline in visual processing skills and deterioration of regions in the back of a patient's brain.

“From a clinical point of view, posterior cortical atrophy is probably the second most common clinical presentation of Alzheimer’s disease after memory loss, yet it is under-recognized, and patients can go undiagnosed or misdiagnosed for years,” Dr. Gil Rabinovici, neurologist and senior author of this study, told Medical News Today.

Rabinovici, who is also the director of the Alzheimer’s Disease Research Center at the University of California — San Francisco, said the disease can progress to the point of "functional blindness."

The study concluded the syndrome presents itself more in women and PCA begins to manifest around the age of 59 on average, but normally occurs in folks between 50 to 65 years old.

The study's researchers state more awareness of PCA is needed for early detection and treatment.

Study: Risk factors for early onset dementia, dementia before the age of 65, identified

Weird vision problems: Symptoms of Posterior Cortical Atrophy

Symptoms can vary from patient to patient.

"The most common symptoms are consistent with damage to the posterior cortex of the brain, an area responsible for processing visual information," writes the Alzheimer's Association.

According to the University of San Francisco's Memory and Aging Center, there is no test that can be used to diagnose PCA.

Both to the Alzheimer's Association and UCSF state the following are possible symptoms:

• Issues with vision
• Struggle to recognize people, places, or objects
• Difficulty reading lines of text
• Unable to judge distances correctly
• Struggles to tell the difference between moving and stationary objects
• Inability to tell if there is more than one object
• Increased sensitivity to light or shiny things
• Difficulty seeing in low light
• Can't identify left from right
• Anxiety
• Confusion
• Behavioral changes

The Alzheimer's Association also states there are no established diagnostic criteria for PCA, and it is often unrecognized in patients. Some studies state that about 5% of Alzheimer's patients have PCA, but that percentage can be as high as 15% because the condition is often overlooked.

According to the association, researchers have already started working on creating a standard definition and diagnostic criteria.

What is Alzheimer's?

Alzheimer's disease accounts for around 60% to 80% of all dementia cases, making it the most common cause of dementia, according to the Alzheimer's Association.

It states the disease is caused by microscopic changes in the brain that prevent it from functioning like it normally would and it eventually kills brain cells. The changes start to occur long before a patients start to experience memory loss.

"Scientists believe Alzheimer's disease prevents parts of a cell's factory from running well," states the association. "They are not sure where the trouble starts. But just like a real factory, backups and breakdowns in one system cause problems in other areas."