VISUAL MEMORY DEFICITS AFTER DAMAGE TO THE ANTERIOR COMMISSURE AND RIGHT FORNIX

A 47-year-old right-handed woman suffered an accidental dural perforation in the course of intranasal drainage of a right-sided sphenoid mucocele. Radiological examination revealed a small hematoma involving the anterior commissure, the right foramen of Monro, and the right fornix, resulting in severe anterograde amnesia for visual stimuli. Visual retention disturbances were manifested by a loss of the ability to conjure up new visual images, loss of topographical memory, and the cessation of dreaming. Dissociation was striking between severe deficits on tests exploring anterograde visual memory, revisualization, visuospatial organization, construction abilities, and normal or mildly impaired performance on tests implying verbal material and verbal memory. In agreement with experimental findings, it is postulated that combined damage to the anterior commissure and fornix on the right side could cause severe deficits in visual retention in humans.