Posterior Cortical Atrophy

What is Posterior Cortical Atrophy?

Posterior Cortical Atrophy (PCA) refers to progressive and gradual degeneration of the outer layer of the brain (cortex), particularly in the part of the brain located in the back (posterior) of the head. It is not known whether PCA is a unique disease or a possible variant form of Alzheimer’s disease. In many people with Posterior Cortical Atrophy, the affected part of the brain shows plaques and tangles (common with Alzheimer’s disease) but located in a different area of the brain. In some people with PCA, the brain changes resemble those of other diseases such as Lewy Body Dementia or a form of Creutzfeld-Jakob disease. While most cases of Alzheimer’s disease occur in people aged 65 years or older, the onset of PCA is often between 50 – 65 years of age.

Since there is no standard definition of PCA and no established diagnostic criteria, we do not yet have the exact statistics regarding prevalence. Some studies show that about five per cent of people diagnosed with Alzheimer’s disease have PCA. Since PCA often goes unrecognized, the actual prevalence may be as high as 15 per cent. Researchers and physicians continue working to establish a standard definition and diagnostic criteria for PCA.

Is it genetic? Can it be passed on to family members?

The causes of Posterior Cortical Atrophy (PCA) are unknown, and no obvious genetic changes have been shown to be linked to the condition. It is also not known if the risk factors for Alzheimer’s disease are also risk factors for PCA.

What changes can I expect?

The symptoms of Posterior Cortical Atrophy (PCA) can vary from person to person and can change as the condition progresses. The most common symptoms are consistent with damage to the posterior cortex of the brain, an area responsible for processing visual information. These include gradually development of difficulties with visual tasks such as reading a line of text; judging distances; distinguishing between moving objects and stationary objects; inability to perceive more than one object at a time; disorientation; and difficulty maneuvering, identifying, and using tools or common objects.  Other symptoms can include hallucinations, difficulty performing mathematical calculations or spelling. Anxiety is also reported. In the early stages, most people do not have substantial changes regarding memory, but memory can be affected in later stages.

How is it diagnosed?

PCA is often misdiagnosed because of its rare occurrence and unusual and varied symptoms. Additionally, people may first consult an ophthalmologist who may indicate a normal eye examination. Since the initial problems perceived are eye problems, cortical brain damage may not be considered as a cause.

Currently, there are no standard diagnostic criteria for PCA though researchers are focused on developing it. Physicians rely on a combination of neuropsychological tests, blood tests, brain scans and a neurological examination to diagnose the condition and rule out other potential explanations for symptoms such as strokes or tumours. Some of the distinguishing features of PCA include gradual onset of visual symptoms with preservation of normal eye function and preservation of memory, combined with a relatively younger age of onset between 50- 65 years of age.

There is ongoing discussion regarding whether PCA should be considered a form of Alzheimer’s disease or a separate disease entity.

What kind of treatment is available?

Currently, there is no specific treatment for PCA that can stop or slow its progression. It has been suggested that drugs used to temporarily ease brain dysfunction in Alzheimer’s disease may be helpful in PCA, but this has not yet been proven. Some people with PCA may benefit from treatments that help alleviate symptoms such as depression or anxiety, but the overall benefits and risks of such treatments are not yet established.

Further Information