Posterior cortical atrophy (PCA), also called Benson's syndrome, is most usually considered to be an atypical variant of Alzheimer's disease.[1] The disease causes atrophy of the back (posterior) part of the cerebral cortex, resulting in the progressive disruption of complex visual processing.[2] PCA was first described by D. Frank Benson in 1988.[3][4]
Despite being caused by the same disease process, the effects of posterior cortical atrophy and typical Alzheimer’s disease upon the behaviour, thought processes and skills of individuals with each condition are very different. Typical Alzheimer’s disease is most commonly associated with deterioration in memory, language, perception and a host of other skills and abilities. By contrast, individuals with posterior cortical atrophy tend to have well preserved memory and language but instead show a progressive, dramatic and relatively selective decline in vision and/or literacy skills such as spelling, writing and arithmetic.
In rare cases,[4] PCA "can also be due to other diseases including dementia with Lewy bodies and Creutzfeldt–Jakob disease."[2]
PCA usually affect people at an earlier age than typical cases of Alzheimer's disease, with initial symptoms often experienced in people in their mid-fifties or early sixties.[2] This was the case with writer Terry Pratchett, who went public in 2007 about being diagnosed with PCA.[5]