A comparison of egocentric and allocentric spatial memory in a patient with selective hippocampal damage

The spatial memory of a single patient (YR) was investigated. This patient, who had relatively selective bilateral hippocampal damage, showed the patt ern of impaired recall but preserved item recognition on standardised memor y tests that has been suggested by Aggleton and Shaw [Aggleton JP, Shaw C. Amnesia and recognition memory: a reanalysis of psychometric data. Neuropsy chologia 1996;34:51-62] to be a consequence of Papez circuit lesions. YR wa s tested on three recall tests and one recognition test for visuospatial in formation. The initial recall test assessed visuospatial memory over very s hort unfilled delays and YR was not significantly impaired. This test was t hen modified to test recall of allocentric and egocentric spatial informati on separately after filled delays of between 5 and 60 s. YR was found to be more impaired at recalling allocentric than egocentric information after a 60 s interval with a tendency for the impairment to increase up to this de lay. Recognition of allocentric spatial information was also assessed after delays of 5 and 60 s. YR was impaired after the 60 s delay. The results su ggest that the human hippocampus has a greater involvement in allocentric t han egocentric spatial memory, and that this most likely concerns the conso lidation of allocentric information into long-term memory rather than the i nitial encoding of allocentric spatial information. The findings also sugge st that YR's item recognition/free recall deficit pattern reflects a proble m retrieving or storing certain kinds of associative information. (C) 2000 Published by Elsevier Science Ltd. All rights reserved.