Can patients without early, prominent visual deficits still be diagnosed of posterior cortical atrophy?

Early and progressive disabling visual impairment is a core feature for the diagnosis of posterior cortical atrophy (PCA). However, some individuals that fulfil criteria over time might initially present with an onset of prominent posterior dysfunction other than visuoperceptual.

The clinical profile of five patients with a predominantly 'non-visual' posterior presentation (PCA2) was investigated and compared with sixteen individuals with visually predominant PCA (PCA1) and eighteen with typical amnestic Alzheimer disease (tAD).

PCA2 patients showed significantly better performance than PCA1 in one visuospatial task and were free of Balint's syndrome and visual agnosia. Compared to tAD, PCA2 showed trends towards significantly lower performance in visuoperceptual tasks, more severe apraxia and more symptoms of Gerstmann's syndrome.

Our sample of PCA2 patients did not present with clinically prominent visual symptoms but did show visual dysfunction on formal neuropsychological assessment (less pronounced than in PCA1 but more than in tAD) in addition to other posterior deficits. Broadening the definition of PCA to encompass individuals presenting with prominent 'non-visual' posterior dysfunction should be potentially considered in clinical and research contexts.