Francesca Cormack

The Development of Intellectual Abilities in Pediatric Temporal Lobe Epilepsy

Summary:u2002 Purpose: The aim of this study was to examine the impact of clinical variables, particularly age at onset of epilepsy, on intellectual function in a group of children with temporal lobe epilepsy (TLE).

Long-term intellectual outcome after temporal lobe surgery in childhood

Objective: Temporal lobe resection is an established treatment for medication-resistant temporal lobe epilepsy, which in recent years has increasingly been performed in children. However, little is known about the long-term outcome in these children. The aim of this study was to characterize intellectual and psychosocial functioning of children after temporal lobe resection as they progress into late adolescence and adulthood. Methods: We report the long-term follow-up of 42 children who underwent temporal lobe surgery after an average postoperative period of 9 years. Longitudinal change in IQ was documented, psychosocial outcome including quality of life was assessed, and preoperative and postoperative T1-weighted MRI brain scans were evaluated quantitatively. A well-matched nonsurgical comparison group of 11 children with similar clinical characteristics was also assessed. Results: At follow-up, 86% of the surgical group were seizure-free, and 57% were no longer taking antiepileptic medication. A significant increase in IQ was found in the surgical group after an extended follow-up period of >5 years. This IQ change was not found in the nonsurgical comparison group. IQ increases were associated with cessation of antiepileptic medication and changes in MRI-derived gray matter volume. The surgical group also reported better psychosocial outcome including quality of life, which was more strongly associated with seizure freedom rather than surgery per se. Conclusions: Surgery for temporal lobe epilepsy performed in childhood results in excellent long-term seizure control and favorable cognitive outcome along with positive effects on brain development. Classification of evidence: This study provides Class III evidence that temporal lobectomy in children with temporal lobe epilepsy is associated with improved long-term intellectual outcomes compared with those undergoing standard medical treatment.

Temporal lobe surgery in childhood and neuroanatomical predictors of long-term declarative memory outcome

See Berg (doi:10.1093/brain/awu320) for a scientific commentary on this article. In a long-term follow-up study of children who underwent temporal lobe surgery for treatment of epilepsy, Skirrow et al. identify no significant pre-to-post-surgery memory losses, but instead robust improvements in memory functions supported by the unoperated temporal lobe. The integrity of remaining temporal lobe structures places constraints on long-term memory outcomes.

A meta-analysis of cognitive outcome following coronary artery bypass graft surgery

Coronary artery bypass graft (CABG) surgery is an established treatment for complex coronary artery disease. There is a widely held belief that cognitive decline presents post-operatively. A consensus statement of core neuropsychological tests was published in 1995 with the intention of guiding investigation into this issue. We conducted a meta-analysis evaluating the evidence for cognitive decline post-CABG surgery. Twenty-eight published studies, accumulating data from up to 2043 patients undergoing CABG surgery, were included. Results were examined at very early (<2 weeks), early (3 months) and late (6-12 months) time periods post-operatively. Two of the four tests suggested an initial very early decrease in psychomotor speed that was not present at subsequent testing. Rather, the omnibus data indicated subtle improvement in function relative to pre-operative baseline testing. Our findings suggest improvement in cognitive function in the first year following CABG surgery. This is contrary to the more negative interpretation of results of some individual publications included in our review, which may reflect poor outcomes in a few patients and/or methodological issues.

Memory in paediatric temporal lobe epilepsy: effects of lesion type and side.

This study investigated the role of underlying pathology on memory function of children with temporal lobe epilepsy (TLE). Memory was assessed in 44 children with TLE resulting from hippocampal sclerosis (HS) or dysembryoplastic neuroepithelial tumours (DNT), and 22 control children. Delayed story and paired associate recall performance was significantly more impaired in children with HS compared to those with DNT, irrespective of the affected side. Semantic memory was impaired in both HS groups, and also in the left DNT group. These results suggest a role for type, and to a lesser extent, side of pathology in the memory profile of children with TLE.

Fixing hearts and protecting minds: a review of the multiple, interacting factors influencing cognitive function after coronary artery bypass graft surgery.

Ischemic heart disease is a significant cause of mortality and morbidity in Western populations. Consistent with this, coronary artery bypass graft (CABG) surgery remains one of the most frequently performed major surgeries. Improved survival rates mean that our research focus now extends beyond surgical technique to include quality of postoperative outcome. Postoperative cognitive dysfunction (POCD) has emerged as one of the most challenging and hotly debated issues, with increasing impetus to answer the unresolved question: does fixing the heart come at a cost to the brain?nnCABG surgery is associated with neurological events including stroke in 1.6%1 and delirium in 5.8%2 of patients. Beyond these severe and marked alterations to neurological function, there has been a widely held belief that CABG surgery is associated with POCD, which may presage a decline toward dementia. Research has been influenced by the 1995 Consensus Statement3 into the study of POCD in patients undergoing CABG surgery. Although the methods of investigation set forth by the Consensus Statement achieved widespread acknowledgment, its specific recommendations have not always been followed.4 Despite significant methodological issues, it seems that the balance of interpretation has historically been in favor of CABG surgery as a cause of significant POCD. More recently, however, a review of a series of publications from a well-controlled longitudinal cohort study conducted at Johns Hopkins5 and a meta-analysis6 suggested that cognition is in fact stable or may even show some improvement after CABG surgery in the majority of patients, at least within the first year (Figures 1 and 2). There is little doubt that POCD affects some patients in the short term, but the pathophysiological mechanisms underlying this and the influence on longer-term cognitive function remain uncertain. For research to progress, we require a paradigmatic shift in our focus from …

Early-onset epilepsy, cognition, and behaviour: continuity and challenge.

SIR–Childhood epilepsy, particularly when it begins early in life, is associated with an increased risk of cognitive and behavioural impairment. While poor cognitive outcome is not easily explained by more extensive visible neuropathology, the early years of cognitive development provide a critical foundation for the later emergence of higher-order cognitive skills. This early development can be disrupted by epilepsy, thereby affecting the subsequent developmental trajectory into mid-childhood and beyond. Although much research has been retrospective or crosssectional (examining school-aged children or adults), it has been previously noted that behavioural features indicative of cognitive impairment are present in early childhood, often before formal cognitive testing is undertaken, suggesting that early identification of children at risk is possible. The recent paper of Berg et al. builds on these observations, and offers a thorough prospective assessment of the behavioural, academic, and cognitive status of children with early-onset epilepsy. By making use of a large and well characterized cohort of children who appeared to be otherwise neurologically unremarkable, followed prospectively over 9 years, the researchers address many of the outstanding issues in the literature such as the contribution of seizure load and medication. The authors provide clear evidence that behavioural abnormalities in the preschool years can predict cognitive and academic difficulties in mid-childhood. It is particularly interesting to note that the adaptive behaviour scale used predicts academic performance (e.g. reading comprehension) even when the correlation between behaviour and IQ is controlled for. This suggests that the early assessment used (Vineland Adaptive Behavior Scales) is tapping constructs, such as language, which are not well assessed by IQ but are nevertheless important determinants of performance in children with epilepsy. Such an observation, highlighting continuities in behaviour and development, leads to several interesting research challenges. Firstly, there is the need to examine structural and functional brain developmental in children with epilepsy in more detail. Although the Berg et al. report that the children appeared normal on clinical imaging, this does not preclude subtle changes which may be detected using different imaging methods. Secondly, the study focuses on those children with an IQ higher than 70, who are predominantly in mainstream schooling (albeit with additional educational support). This allows standardized cognitive testing and the sophisticated approach used. However, it is important to note that 13% of the study population from which their sample was taken had an IQ of less than 70, suggestive of severe learning difficulties. Such a percentage is understandably less than that seen in surgical samples, but it nevertheless represents a large number of children whose cognitive development is significantly impaired, and for whom educational and occupational opportunities are likely to be severely limited. There is a need to explore the developmental and neural trajectories of these children. The Berg et al. data suggest that early behavioural problems tend not to resolve spontaneously, but rather herald continuing cognitive and academic difficulties. Therefore, research on interventions, particularly for those children at risk of the most negative outcomes, is needed. For example, it has been suggested that in early-onset symptomatic focal epilepsy, early surgical resection of the epileptogenic cortex may be beneficial. Indeed in the Berg et al. study, remission and not being on an antiepileptic medication at follow-up were both associated with better cognitive outcome, suggesting that seizure-freedom permits adaptive plasticity to compensate to a certain extent for the early burden. Nevertheless, additional cognitive or educational rehabilitation may be helpful to these children. Such interventions will be expected to be most effective for children with early-onset epilepsy when they take place early in childhood, but currently there is no consensus on their timing, nature, and effectiveness. In conclusion, the paper by Berg et al. makes an important contribution to our understanding of the antecedents of academic and cognitive difficulties in children with early-onset epilepsy. However, important unanswered questions remain with regards to both the most cognitively impaired children and the best therapeutic approaches for optimizing cognitive outcome.