Complex visual disturbances may be indicator of posterior cortical atrophy

The authors discuss the cases of five patients with complex visual disturbances in the absence of ocular pathology who were ultimately diagnosed with posterior cortical atrophy (PCA). The initial symptoms of PCA are usually nonspecific visual complaints that prompt a patient to visit an ophthalmologist. However, when ocular pathology is not found, the diagnosis often is delayed until cognitive deficits are detected or further testing is performed.

The patients in this study were between the ages of 50 and 66 years and presented with initial visual disturbances - such as an inability to read or thread a needle and nyctalopia - who progressed to disorders such as prosopagnosia and apraxia.

One to five years after the onset of visual symptoms, they were diagnosed with PCA based on visual cortical complaints, clinical evolution and neuroimaging findings. None of them had a family history of dementia.

MRI and PET scanning aided in their diagnoses. While the MRI scans in this paper display cortical atrophy, the PET images showing hypoperfusion are striking.

All of the patients progressed to global dementia. An autopsy confirmed the diagnosis of Alzheimer disease in one patient. However, memory, insight and judgment were relatively preserved until late in the course, resulting in the failure to recognize PCA earlier.

The authors conclude that PCA should be considered in patients with complex visual symptoms in the absence of ocular pathology. They say that early neurological assessment may avoid diagnostic delay.