Posterior cortical atrophy (PCA)

• If you have posterior cortical atrophy, tissue in your brain atrophies (shrinks) as cells are lost.

• PCA can affect your visual processing, spelling, writing and arithmetic.

• People often experience the first symptoms of posterior cortical atrophy in their mid-50s or early 60s. However, it can also affect older people.

About posterior cortical atrophy

Posterior cortical atrophy (PCA) involves the loss and dysfunction of brain cells, particularly at the posterior (back) of the brain.

If you have PCA, the tissue in the outer layer of your brain will shrink as you lose cells.

This loss of brain tissue can lead to problems with vision, spelling, writing and arithmetic.

People often start experiencing PCA symptoms in their 50s or 60s. It can also affect older people.

Causes of posterior cortical atrophy

In most cases, the underlying cause of posterior cortical atrophy is Alzheimer’s disease. But other conditions can show similar symptoms. These include Lewy body disease, corticobasal degeneration and Creutzfeldt-Jakob disease.

Signs and symptoms of posterior cortical atrophy

In its early stages, posterior cortical atrophy can affect people in different ways. It might affect both sides of your brain equally, or only one part of your brain first, or more significantly.

The first symptoms may be trouble with literacy, numeracy and movement, like:

• remembering how to spell words
• handwriting or typing
• remembering the shape or name of letters or numbers
• mental arithmetic
• dealing with money and small change
• making gestures like waving or giving a thumbs up
• using reading glasses, tools and implements, like cutlery or scissors
• (this is partly related to difficulties with visual perception).

You might also develop problems related to the way your brain deals with visual information, like:

• recognising objects in pictures (particularly if the objects are incomplete or taken from unusual angles)
• recognising faces, including those of friends, relatives or television characters
• understanding where and how far away things are, like reaching out to pick something up but missing it
• judging speed or distance, like when walking downstairs or driving
• Seeing objects as moving when they’re still
• missing lines of text when you’re reading
• reading particular words, because letters seem to move around
• reading larger print, like headlines
• objects appearing to have an unusual colour
• increased sensitivity to bright light or shiny surfaces
• double vision
• feeling as though your eyes are jerking around
• getting dressed and undressed.

The visual problems caused by PCA aren’t a problem with your eyes, but with the way your brain interprets signals from your eyes. 

Posterior cortical atrophy and Alzheimer’s disease

Many experts believe posterior cortical atrophy is a form of Alzheimer’s disease. This is because the brain changes observed in both types of dementia can be similar. However, the symptoms for each type are different.

Alzheimer’s disease affects most areas of the brain and is commonly associated with deterioration in memory, language and perception.

In posterior cortical atrophy, changes tend to be at the back of the brain, affecting only the skills which that part of the brain supports. So if you have posterior cortical atrophy, you will tend to have well-preserved memory, but instead have problems with visual processing and literacy skills such as spelling, writing and arithmetic.

Diagnosing posterior cortical atrophy

There is no single test that can tell you if you have PCA. Instead, specialists will use tests to rule out other causes, like an infection or brain tumour. These tests might include:

• visual tests by eye specialist
• a full assessment of your thinking and reasoning abilities
• blood tests
• brain imaging
• a lumbar puncture to examine the fluid around the brain and spinal cord
• other medical tests.

Even after you get the right tests, it may take some time before you get a formal diagnosis of posterior cortical atrophy.

A definitive diagnosis of PCA can only be made post-mortem, once the brain tissue is examined by a pathologist.

Progression of posterior cortical atrophy

PCA is a degenerative condition, which means your symptoms will become stronger over time.

As it progresses, you will likely have more trouble with finding the right words, day-to-day memory and with your thinking skills generally.

In the later stages, you may develop jerking movements in your limbs and, possibly seizures.

Treatment and management of posterior cortical atrophy

There is no medication to treat posterior cortical atrophy specifically, and there’s no known cure yet.

Your doctor may prescribe medications used to treat Alzheimer’s disease. They can treat the symptoms of PCA, and they may slow its progression.

Psychological therapies or antidepressant medication may be used to improve low mood, depression, irritability, frustration and loss of self-confidence.

Visual aids can help you with visual impairment. You can try talking clocks or watches, mobile phones with simplified displays, cooking aids such as sensors that beep when a cup is almost full and audio books.

Occupational therapy can help people find ways to adapt to changes in abilities and maintain independence and wellbeing.

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