Posterior Cortical Atrophy: A longitudinal neurocognitive case study.

Abstract

Posterior Cortical Atrophy (PCA) is a neurodegenerative disease that first develops in the occipital-parietal-temporal cortex. While its major pathological cause is the same as that of Alzheimer's disease (e.g. Tang-Wai & colleagues), the development of the cognitive changes over its course is quite different. Here we present a 6-year longitudinal account of the neurocognitive profile of a highly intelligent man (BG), starting from the year of his diagnosis to that of his death. Despite his normal visual acuity and visual fields, BG initially reported reading difficulties. Early in his disease, he had deficits in visual attention, processing speed and recognition. His recognition difficulties first presented as alexia without agraphia, followed by topographical disorientation, prosopagnosia, simultagnosia, and object agnosia. Next, his visuo-constructional, arithmetic skills, and visual memory gradually declined. Relative to his severe visuo-perceptual and recognition difficulties, his abilities to reach for objects remained functional. Serial MRI brains demonstrated progressive left-more-than-right occipital, temporal and parietal atrophy with relative sparing of the hippocampi. Four years following diagnosis, BG could no longer perform any visual tasks and started to develop significant expressive language difficulties. Over the full course of the disease, his motor abilities, verbal recognition and verbal logical memory remained functional, and his practical reasoning normal. BG's case illustrates that the neurodegenerative process involve in PCA can first affect the visuo-cognitive functions typical of the ventral system, extend to all functions dependent on the posterior areas, and eventually to language areas, all while sparing areas responsible for practical and logical verbal reasoning. Meeting abstract presented at VSS 2018