Posterior cortical atrophy (PCA) is an early-onset dementia syndrome in which cortical degeneration leads to perceptual dysfunction. It is most commonly, although not exclusively, caused by Alzheimer's disease (AD). Unlike 'typical' amnestic AD, the histopathological burden (amyloid plaques and neurofibrillary tangles) is in the parietal and occipital lobes (Levine et al. 1993; Tang-Wai et al. 2004), causing brain shrinkage (atrophy) in these regions (Figure 1) and corresponding deficits in visuospatial and visuoperceptual processing (Lehmann et al. 2011), whilst episodic memory and insight are relatively preserved (Tang-Wai et al. 2004).PCA is often referred to as the visual variant of AD or biparietal AD.