Blurred Vision and Hallucinations: The First Signs of a Rare Form of Alzheimer’s

By | March 25th, 2024

Clinicians have found that a rare, difficult to diagnose form of dementia called posterior cortical atrophy which can strike vision before affecting memory is usually a form of early-onset Alzheimer’s disease. New research might make it easier for people to receive a diagnosis and early treatment.

One day, when Deb Jobe looked inside her closet, she noticed a giant black hole that wasn’t there before. When she called over her husband, he became worried — the “hole” was actually a black weighing scale. Around the same time Jobe, who was in her early 50s, was also having trouble thinking and remembering things at work. After a series of doctors’ appointments, she eventually learned the cause: She had a rare form of dementia called posterior cortical atrophy.

Though Jobe was accurately diagnosed with PCA, others might find that the process is a several-year journey full of dead ends. PCA’s initial symptoms don’t always involve dementia’s telltale memory problems. Instead blurred vision, visual hallucinations, and difficulty reading tend to appear early on, sending people on a wild goose chase to the eye doctor. They might only see a neurologist when their cognition starts to decline. 

Complicating the diagnostic process is PCA’s early onset — most people start developing symptoms before age 65, well before most doctors would think to consider a form of dementia. (Studies show that people with early-onset forms of dementia might struggle to get a timely, accurate diagnosis for this reason.) 

But diagnosing PCA may be about to get just a little easier: A new study published by researchers this year in Lancet Neurology paves the way for better clinical guidelines for diagnosing the condition. 

The newly published research also confirms that many cases of PCA are a form of early-onset Alzheimer’s, according to study co-author Yolande Pijnenburg. 

“Most memory clinics do not have the right tools to detect PCA at the early stages because neurologists tend to focus on memory tests and only ask in general terms if a person has problems seeing, reading, or writing,” Pijnenburg of the Amsterdam University Medical Center told Alzforum

What did the researchers find?

The researchers studied 1,092 people across 36 research centers in 16 different countries across North America, South America, Europe, Asia, and Australia. They looked at people diagnosed with PCA who underwent a PET scan, lumbar puncture, or brain autopsy. Half of the people within the study had at least one copy of the APOE4 gene which increases the risk of developing Alzheimer’s disease. 

The most common symptoms that people with PCA experienced related to their perception and visuospatial abilities. These were the most common symptoms:

  • Three in five people had trouble copying a drawing
  • Half had problems with depth perception
  • Half had problems with simple math
  • Half had problems seeing more than one object at the same time. For example, they might notice a glass of wine on a table but not the rest of the plates and cutlery.

On average, even though most of the people in the study developed symptoms at age 59 but it took four years for them to receive a diagnosis. In that time, many of the people with PCA developed more cognitive symptoms and memory problems. 

An early, accurate diagnosis, a better outcome for patients

“We hope this paper will raise awareness of PCA so eye-care specialists and neurologists will know to recognize and identify it early,” senior author on the study, Gil Rabinovici told Alzforum.

Recognizing these symptoms early could mean an early referral to the right specialist and help people with PCA get an early diagnosis sooner. Some of the patients with PCA might get diagnosed in time to try Leqembi, which may be able to help slow the disease progression or participate in other clinical trials testing new treatments to slow the disease.

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3 thoughts on “Blurred Vision and Hallucinations: The First Signs of a Rare Form of Alzheimer’s

  1. My father had this.
    He had it for about 8 years – 80 to his death at 88. He was diagnosed with Benson’s syndrome – another name for PCS.

  2. My husband has PCA and now Lewy body dementia too. He had autoimmune encephalitis about 9 years before so we had brain scans that showed the atrophy in the posterior lobes of his brain.

    I often wonder if the two are connected the encephalitis started at around 60 PCA not diagnosed until 9 years later but signs started 4 years before diagnosis and were not investigated immediately as sone of his issues seemed to follow on the cognitive damage caused by the encephalitis. I wonder how much the two are connected

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