Posterior cortical atrophy (PCA) tends to affect people at an earlier age than typical Alzheimer’s disease, with individuals often being in their mid-fifties or early sixties at the time of their first symptoms. However, it can also affect older people. The first signs are often subtle symptoms which may be difficult for the person experiencing them to explain. Individuals with early visual complaints are typically referred to opticians and eye specialists before referral to a neurologist. However, as mentioned earlier, other selective problems with spelling, numeracy and learned motor skills have also been reported. Even once an appropriate referral has been made, it may take some time before the diagnosis is made formally. Understandably, patients may feel frustrated by the time of diagnosis, typically one to three years from the onset of symptoms.
The underlying cause of PCA in the majority of cases is abnormal alterations to brain cells similar to what is seen under the microscope in Alzheimer’s disease. However, a small number of other conditions can result in similar symptoms, at least initially. These include:
There is no diagnostic test for PCA. However, tests such as specialised visual tests (organised by eye-specialists), neuropsychological tests of cognitive skills (e.g. memory, perception, literacy), blood tests, brain scans (magnetic resonance imagery (MRI) or computerised tomography (CT)), lumbar puncture (examination of the fluid circulating around the brain and spinal cord) and EEG (recording of the electrical activities of the brain) may help to exclude potentially treatable causes such as infection, inflammation or brain tumours. The shrinkage of the back part of the brain as a result of brain cell loss may be visible on the brain scan. It may be difficult to come up with one diagnosis in life and a definitive diagnosis can only be made once the brain tissue is examined by the pathologist. PCA is a rare condition but its exact prevalence in the normal population is currently unknown.