Computerized visual field defects in posterior cortical atrophy

Abstract

Background and objective: Posterior cortical atrophy (PCA) is a progressive neurodegenerative syndrome that presents with cortical visual dysfunction and relatively preserved memory. Although higher cortical visual syndromes are well known in PCA, visual field defects detected by computerized visual field (CVF) perimetry have not been systematically described. The objective of this study was to describe CVF defects measured by threshold perimetry in PCA.

Methods: This was a retrospective case series of patients meeting proposed PCA diagnostic criteria seen in the Neuro-ophthalmology and Neurobehavior Clinics at the University of Colorado during 2002 to 2006. History, examination, neuroimaging, autopsy, and CVF studies were analyzed.

Results: Nine of 11 patients who met the criteria for PCA and had CVF testing were included. Seven of the 9 patients had homonymous hemianopia or quadrantanopia, and 2 had bilateral constriction. All patients progressed to dementia. Criteria were met for probable Alzheimer disease (AD) in 7, definite AD in 1, and definite dementia with Lewy bodies associated with AD pathology in 1. Seven of 9 patients had early and prominent complaints of difficulty driving.

Conclusions: CVF defects were characterized by homonymous visual field defects or bilateral constriction. Eight of 9 patients progressed to probable or definite AD, but the CVF defects were distinctly different from those in typical AD. This observation probably reflects a posterior shift of cortical pathology to the primary and early secondary visual cortices in PCA. CVF testing should be considered in older patients with unexplained visual complaints, particularly when associated with difficulty driving, which may indicate the possibility of PCA and prompt early neurobehavioral evaluation.