A systematic study of topographical memory and posterior cerebral artery infarctions

Abstract

Objective: To estimate the prevalence of topographical memory impairment following posterior cerebral artery infarctions (PCAI) and define its anatomical correlations.

Methods: We recruited 15 patients (mean duration of 4 months postinfarct). We administered 2 sets of experimental tests to assess topographical memory: one set included 5 computerized tasks (CompT) and the other set consisted of one ecological topographical orientation test (EcolT) that included 4 tasks (i.e., map drawing, picture recognition and ordering, backward path). Fifteen healthy participants served as controls. Patients and controls underwent a volumetric T1 MRI brain scan. Brain lesions in patients were segmented, normalized, and correlated with performance.

Results: Topographical memory impairments were evidenced in patients with PCAI using both group and individual analyses (50%), with more severe outcomes in patients with PCAI in the right hemisphere. CompT and EcolT were highly correlated, but the ecological test was more sensitive in revealing topographical memory impairments. Voxel-based lesion-symptom mapping demonstrated that 2 regions located in the cuneus and the calcarine sulcus correlated significantly with behavioral performance.

Conclusions: Topographical memory disorders following PCAI are reported in 50% of the patient population. Our results demonstrate the importance of developing and using dedicated batteries of topographical memory tests, in particular real-life tests, to identify such deficits.