Common first signs and symptoms of PCA include difficulties with seeing what and where things are (for example, when driving or reading). These include:

• problems with reading
• issues with recognising objects and people
• difficulty with coordination
• issues with judging distances
• light sensitivity

The symptoms of PCA usually begin before the age of 65 and and people are often in their mid-50s or early 60s when they first experience symptoms. However, PCA can also affect older people and it can take a long time for people to receive the correct diagnosis.

Causes of PCA

Posterior cortical atrophy (PCA) means ‘back of the brain shrinkage’ and it refers to the progressive loss of brain cells, particularly in brain regions that process visual and sensory information, such as the occipital and parietal lobes. The changes in the brain that cause PCA can be caused by different disease processes. In the majority of cases PCA is caused by changes to brain cells similar to those that occur in Alzheimer’s disease.

However, the initial symptoms of PCA are very different from those of Alzheimer’s disease. This is because of the different areas of the brain that are affected. In Alzheimer’s disease, the memory areas of the brain are particularly affected, whereas in the early stages of PCA the skills controlled by the rear of the brain (such as vision) are more affected.

People living with PCA typically experience a progressive decline in vision and/or literacy skills (including spelling, writing and arithmetic) in the early stages. Significant changes in memory and language abilities are less common in the early stages.

There are a small number of underlying diseases, as well as Alzheimer’s disease, that can cause PCA. These include:

• Lewy body dementia (LBD) – people may experience visual hallucinations, and may become stiffer and slower in their movements, in a similar way to people living with Parkinson’s disease. People may also experience changes in memory and concentration (or thinking) and sleep issues.

• Corticobasal Syndrome (CBS) – people may have difficulty using one side of their body or experience jerky, awkward or slow movements. See the PSP Association website for further information and support.
• Prion diseases (e.g. Creutzfeldt-Jakob disease (CJD)) – very rare conditions in which people may experience a very rapid decline in their cognition. See the CJD support network for further information and support.

Very little is known about why PCA affects some people and not others, nor how many people there are living with PCA. Research is leading to improved understanding and the Dementia Research Centre (DRC) has many ongoing PCA studies.

Diagnosis and testing

The first signs of PCA are often very subtle and may be difficult for the person experiencing them to describe. People living with PCA usually first experience difficulties with vision. Quite understandably, this leads them to consult an optician. However, the visual problems in PCA are due to changes in the brain rather than the eyes, and so an optician will not usually get to the root of the problem. In PCA the problem is that the affected part of the brain is unable to interpret the information sent to it by the healthy eyes. Problems with spelling, numeracy and learned motor skills have also been reported as early indicators of PCA.

Even once an appropriate referral has been made to a specialist – usually a neurologist, psychiatrist or neuro-ophthalmologist – it may take some time before the diagnosis is made formally. It can typically take 1 to 3 years from the onset of symptoms. As a result, many people living with PCA feel frustrated by the time of diagnosis.

There is no single diagnostic test for PCA. The tests listed below may help to exclude potentially treatable causes such as infection, inflammation or brain tumours:

• specialised visual tests (organised by eye specialists)
• tests of cognitive skills (including memory, visual perception, literacy)
• blood tests
• brain scans may reveal shrinkage of the back part of the brain as a result of brain cell loss (for example, magnetic resonance imagery (MRI) or computerised tomography (CT))
• lumbar puncture
• Electroencephalogram (EEG)

It is important that opticians, ophthalmologists, GPs and others across the healthcare sector are better informed about PCA and better equipped to recognise the symptoms. Rare Dementia Support is working to improve understanding of PCA and other rare dementias and there are some useful resources available on our educational resources page. We have also created a short animated film, called Do I see what you see, narrated by people living with PCA and their partners.

By increasing awareness and understanding of PCA, we hope to ensure that healthcare professionals and communities are better equipped to support people affected by a diagnosis of PCA. Help us by sharing your stories and contacting us at contact@raredementiasupport.org.

See more information about getting or refining a diagnosis.

I have been diagnosed with PCA– what next?

When given a diagnosis of PCA, people naturally ask what will happen next. What challenges might they face and when? What support might be available?

On this page we have provided information on some of the early symptoms commonly associated with PCA as well as available support.

While we try our best to provide general guidance on how abilities may change during the course of PCA, it is important to bear in mind that not everyone will have the same symptoms or progress at the same rate. The experience of PCA will vary according to factors including age, general health and the disease underlying the PCA diagnosis.

See the RDS website page on support after a diagnosis for further information.

Symptoms of PCA

For more detailed information on the symptoms listed here, and suggested strategies to adapt to living with them, please see the RDS website managing and adapting page .

Early symptoms

The first symptoms of PCA often include difficulties with seeing what and where things are (such as when driving or reading) and with certain everyday tasks. However, although PCA is typically known as ‘the visual dementia’, sometimes language symptoms can be the earliest thing people notice. For example, the tip of the tongue phenomenon (difficulty retrieving vocabulary) or mixing up certain sounds, for example b and p. 

Vision may be affected in the following ways:

• problems with reading (for example, difficulty following lines of text, words jumbling up, or with certain text formats and sizes)
• difficulties with coordination and spatial awareness (such as picking up objects, dressing, selecting the correct numbers on a telephone)
• visual problems (including perceiving objects amongst clutter, double vision, difficulty focusing)
• issues with judging distances and speeds (for example with moving traffic, walking onto escalators, descending stairs)
• issues with recognising faces (including TV characters, friends, relatives)
• light sensitivity and unusual colour experiences (such as washes of colour when driving at night)

PCA can affect people in different ways and vision is not always the first, or only, area of difficulty for people living with PCA.

Literacy, numeracy and certain coordination skills may also be affected and cause difficulties with the following tasks:

• recalling the exact spelling of words
• handwriting
• remembering the shape or name of particular letters or numbers
• mental arithmetic
• dealing with money and small change
• making gestures (such as waving or giving thumbs up)
• using particular tools, kitchenware or implements (for example scissors, cutlery, glasses)
• getting dressed

The pattern of symptoms that someone has depends on how and where the brain is affected.

Mid to later-stage symptoms

In the mid-stages, people living with PCA may retain understanding of the purpose of everyday activities, but they may need significant help as their visual impairment progresses. Repetitive speaking is also consistent with more intermediate stages of PCA. This may also overlap with people perseverating. 

They might have difficulty with:

• cooking, dressing and using appliances
• reading labels (on food products, for example)
• handling money and change
• telling the time
• walking and/or sitting down
• distinguishing between moving and static objects (such as when watching TV)
• navigating familiar and unfamiliar environments (including the home and/or outdoors)
• recognising familiar faces
• eating with cutlery, and physical tasks requiring hand eye coordination
• finding words to express oneself
• following and engaging in group conversations
• memory and word finding (although many people retain considerable awareness of their situation)
• difficulty sensing the position of different body parts

As PCA progresses, vision can become severely impaired. The world may be viewed in a distorted way (for example, as pieces of a puzzle or as if through a fractured mirror). The person may notice small details but struggle to understand the relationship between objects in a given space.

This can lead to:

• requiring help with most or all everyday tasks (including personal care owing to difficulties with visual and spatial awareness)
• difficulty executing spatial commands and actions (such as ‘turn round’ or ‘step forwards’)
• requiring support or supervision when walking (difficulty in detecting the edges of pavements, paths, and steps; a tendency to shuffle, stoop or lean)

At this stage, many people with PCA are registered as blind, which means that they need help with most visually-guided activities.

Some people may have problems with other senses, including:

• increased sensitivity to pain and temperature (especially in the head, hands and feet)
• changes in the sense of hearing (such as becoming more sensitive to certain sounds)
• sense of imbalance or instability
• experiencing little jerky movements

It can help to speak to others in similar situations who may be able to offer support and helpful advice. Our PCA Support Group meetings are open to anyone affected by PCA, including those living with a diagnosis, carers, family and friends. You can find out about upcoming meetings on our meetings page.

Stages of PCA

People affected by a rare dementia frequently enquire about likely timescales for the disease that they, or the person they care for, are living with. Understandably, some people naturally want more information than others. Some people might want to have as much information as possible soon after the diagnosis, others might prefer to live with and adapt to the symptoms that are currently present, without necessarily accessing detailed information about potential future symptoms they may experience. There is no right or wrong way to approach the quest for information, and it is important for us to be aware that the amount and level of information that we might want, will likely be different to other people around us.

The experience of PCA differs from one person to the next, which makes it difficult to predict what will happen.

There are limited longitudinal studies of PCA which have been largely designed to evaluate changes in thinking abilities or brain structure over several years. While people with young-onset Alzheimer’s disease (the most common cause of PCA) may have a tendency towards faster disease progression than those with later-onset Alzheimer’s disease, some people with PCA have a protracted course extending over more than a decade. 

Together with people living with PCA and their carers, we have developed a document to help guide those affected by PCA, based on the established ‘7 stages of Alzheimer’s disease’ framework. This document should act as a guide only as people’s experiences vary, and people do not necessarily go through the stages in this order. View and download The Stages of Posterior Cortical Atrophy document.