Visuospatial learning and memory in children pre- and posttemporal lobe resection: Patterns of localization and lateralization.

In children with epilepsy, the impact of surgery including or sparing the mesial temporal lobes (TLs) on visuospatial memory has not been thoroughly investigated, and a clear pattern of hemispheric lateralization has not been observed. The primary aim of this study was to examine visuospatial learning and memory outcomes in children with epilepsy prior to and one year after surgical excision, to determine whether outcomes differed as a function of the localization and lateralization of surgical excisions. Forty-six children who underwent unilateral TL surgery with sparing of the mesial structures (TL group, N = 21, 16 left) or including mesial structures (TL + M group, N = 25 children, 12 left) were retrospectively recruited. Outcomes on the Children's Memory Scale (CMS) Dot Locations subtest (learning, immediate, and delayed recall scores) were examined prior to and following epilepsy surgery. Results revealed significantly reduced visuospatial memory (delayed recall) in the TL + M compared with the TL group after surgery. Despite this significant postoperative difference, there was no significant change in learning, immediate, or delayed recall scores in either group. However, inspection of individual change scores showed that fewer children in the TL + M group improved in delayed recall after surgery (7.2%) compared with children in the TL group (30%) whereas a similar proportion of children in the TL + M (30.4%) and TL (23.3%) groups showed a decline. There were no significant differences in learning or memory scores as a function of seizure laterality before or after surgery and no differences in change over time. Seizure outcome, age at surgery, age at seizure onset, and percentage life with epilepsy were not related to visuospatial learning or memory outcomes; however, greater number of antiepileptic drugs (AEDs) following surgery was related to poorer visuospatial memory (delayed recall) in the TL + M group. In summary, the results show that visuospatial learning and memory performance do not seem to show a significant decline following TL resections in childhood, regardless of whether or not surgery includes the mesial TL and involves the left or right hemisphere. However, although mesial TL excisions might not result in a deficit in visuospatial memory, they may hinder progressions made after surgery. Further research is needed to examine how resection of the mesial TL (alone or in combination with lateral TL structures) affects visuospatial memory outcomes in children, as well as to investigate the degree to which other treatment factors, such as medication, may affect visual memory outcomes.