A TEST OF SPATIAL MEMORY AND ITS CLINICAL UTILITY IN THE PRESURGICAL INVESTIGATION OF TEMPORAL-LOBE EPILEPSY PATIENTS

Deficits in memory for figurative detail, spatial composition and the spatial location of objects in a scene have been reported postoperativ ely in right temporal lobectomy patients. The aim of this study was to examine whether these deficits can be used as a sign of lateralised d ysfunction in pre-surgical temporal lobe epilepsy (TLE) patients. Sixt y-nine patients with lateralised TLE (27 right, 42 left) were assessed on a battery of neuropsychological tests, including tests of general intellectual functioning and psychomotor speed and standardised memory tests involving the learning and recall of verbal and non-verbal mate rial. A new task, the ''Aspects of Spatial Memory Test'' (AoSMT), base d on the experimental tasks developed by Pigott and Milner[39] was als o administered. The RTLE and LTLE groups did not differ in their overa ll level of intellectual function or on measures of cognitive and moto r speed. On the AoSMT the LTLE group recognised significantly more fig urative detail changes than the RTLE group. In addition, the RTLE grou p took significantly longer than the LTLE group to identify changes in orientation, figurative detail and filled/unfilled spaces. Poor score s on the AoSMT were significantly correlated with quantitative MRI mea sures of right hippocampal pathology. The clinical and theoretical imp lications of these findings are discussed. (C) 1998 Elsevier Science L td. All rights reserved.