The effects of temporal or frontal lobe resection on verbal learning in children

Pediatric temporal lobe resection (TLR) and frontal lobe resection (FLR) for intractable epilepsy are being carried out with increasing frequency. These surgical procedures typically involve the removal of cortical tissue associated with verbal learning skills. Researchers have reported that adults undergoing TLR or FLR may experience declines in various aspects of verbal learning, including immediate and delayed recall, recognition, and learning strategies. Few studies have examined the results of these procedures on verbal learning skills in children, and results have been inconsistent across studies. This study assessed the verbal learning abilities of children with medically-refractory epilepsy before and after TLR or FLR. The California Verbal Learning Test-Children\u27s Version (CVLT-C) was administered to 13 children (9 temporal, 4 frontal; ages 10–16) pre-operatively and approximately 1 year post-operatively. Pre- to post-surgical changes in CVLT-C recall measures and learning characteristics were examined; group performances (temporal vs. frontal) were also compared. For the combined group (temporal + frontal), results revealed a significant decline in delayed free recall scores (t (12) = 2.449, p = .031) following surgery; in addition, the decline in immediate recall scores approached significance (t (12) = 2.006, p =.068). No other significant changes were observed for the sample as a whole. To examine group and individual performance, change scores were computed (post-surgical scores minus pre-surgical scores). Qualitative analysis of the results indicated that the immediate and delayed recall scores of all of the TLR patients either remained stable or decreased after surgery; most also demonstrated declines in recognition (83%) and decreased use of semantic clustering (71%). Fifty percent of the FLR patients exhibited stable immediate recall, delayed recall, and recognition scores, but 50% also evidenced decreased semantic and serial clustering. Correlations were calculated to determine risk factors for verbal learning decline; age at time of surgery was the most influential factor, with older children demonstrating decreased immediate recall and recognition scores, and increased use of serial clustering. Duration since seizure onset and surgery in the non-language-dominant hemisphere were also identified as risk factors for declines. These results offer important information for medical professionals to utilize in the pre-operative counseling of children and their families; furthermore, they may aid school and clinical child psychologists and teachers in the remediation and rehabilitation of children following surgery