How is posterior cortical atrophy different to other forms of dementia?

Posterior Cortical Atrophy (PCA) is a rare form of dementia which may be related to Alzheimer’s disease. Find out how it can affect you…

In a nutshell

Posterior Cortical Atrophy (PCA) was only discovered in 1988 and remains relatively rare and unknown. PCA usually affects people aged between 50-65 and often starts by causing complex visual problems, rather than confusion or memory loss. Scientists aren’t sure if Posterior Cortical Atrophy is a form of Alzheimer’s or a unique disease. Research is ongoing.

Three facts worth knowing

• Posterior Cortical Atrophy is the form of dementia which author Sir Terry Pratchett was diagnosed with, aged 59.
• PCA is often misdiagnosed because it’s so rare. So whilst studies suggest around five percent of people diagnosed with Alzheimer’s disease have PCA, some experts believe it could be as many as 15 per cent.
• Posterior cortical atrophy (PCA), is also known as Benson's syndrome, after Dr Frank Benson who first described it in 1988.

Here’s the science

PCA is a neurodegenerative disease which damages the back (posterior) of the brain known as the occipital lobe. This part of the brain is responsible for vision. The amyloid plaques and neurofibrillary tangles of Alzheimer’s disease are thought to cause the damage, which is why PCA is often considered to be a variant of Alzheimer’s disease.

Did you know?
Researchers are still trying to establish a standard definition and diagnostic criteria for Posterior Cortical Atrophy.

What actually happens?

People who have Posterior Cortical Atrophy (PCA) normally experience changes in vision, they’re often unable to see objects that they know are in front of them, or can see details but not the bigger picture – they’re able to see ‘the tree but not the forest.’ This gradually impacts on daily life, affecting driving, reading, writing, and numeracy (which are controlled by the back part of the brain). Memory loss and confusion only tend to happen later on in the journey – perhaps after a few years.

Good to know

• There is no specific medical treatment for Posterior Cortical Atrophy, but drugs for Alzheimer’s disease can be helpful.
• Since memory remains intact for quite some time, many people with Posterior Cortical Atrophy retain personality and insight, and can talk as fluently and coherently as they always have, which can be some comfort to them and their loved ones.