Disproportionate intentional spatial-memory impairments in amnesia

Abstract

Twenty-four amnesics, including patients with Korsakoff's disease, post-encephalitic amnesia and amnesia caused by rupture of an anterior communicating artery aneurysm (ACoAA), were compared with 24 matched control subjects on a task in which words were presented in any one of four positions on a computer screen and subjects were instructed to remember both the words and their locations. The patients were tested after more learning opportunity, exposure to shorter lists, and after shorter delays than were their controls in order to match the word recognition performance of the two groups. Under these conditions, the amnesics' ability to locate recognized words was significantly worse than that of their controls. Although there was a tendency for the ACoAA patients to show more severe spatial memory deficits than Korsakoff patients, there was no clear evidence that aetiology of amnesia was a critical determinant of whether spatial memory was more impaired than word recognition. It was concluded that amnesics show a disproportionately severe memory deficit for spatial information that is intentionally encoded as well as for that which is incidentally encoded.