Objective To compare the effects of different surgical approaches for selective amygdalohippocampectomy in patients with pharmacoresistant mesial temporal lobe epilepsy with regard to the neuropsychological outcome and to replicate an earlier study employing a matched-pair design.
Method 47 patients were randomised to subtemporal versus transsylvian approaches. Memory, language, attentional and executive functions were assessed before and 1 year after surgery. Multivariate analyses of variance (MANOVAs) with presurgical and postsurgical assessments as within-subject variables and approach and side of surgery as between-subject factors were calculated. Additionally, the frequencies of individual performance changes based on reliable change indices were analysed.
Results Seizure freedom International League Against Epilepsy (ILAE) 1a, was achieved in 62% of all patients without group difference. MANOVAs revealed no significant effects of approach on cognition. Tested separately for each parameter, verbal recognition memory declined irrespective of approach. Post hoc tests revealed that on group level, the subtemporal approach was associated with a worse outcome for verbal learning and delayed free recall as well as for semantic fluency. Accordingly, on individual level, more patients in the subtemporal group declined in verbal learning. Left side of surgery was associated with decline in naming regardless of approach.
Conclusion The main analysis did not confirm the effects of approach on memory outcome seen in our previous study. Post hoc testing, however, showed greater memory losses with the subtemporal approach. Previous findings were replicated for semantic fluency. The discrepant results are discussed on the background of the different study designs.
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Contributors VLV has performed the statistical analyses, interpretation of the data and wrote the first draft of the article. CH supervised the whole process of analysis and writing of the manuscript. All co-authors made substantial contributions to the conception and design of the study, the treatment and recruitment of the patients and the acquisition of the data. All co-authors revised the manuscript critically, approved the final version and are accountable for all aspects of this work. VLV, J-AW and CH are responsible for the neuropsychological aspects, CEE for the presurgical work-up and JS, MvL, AG and DD for the neurosurgical aspects.
Funding Patients’ follow-up was funded as part A1 of the Transregional Collaborative Research Consortium SFB-TR3 “Mesial temporal lobe epilepsies” of the Deutsche Forschungsgemeinschaft (DFG).
Disclaimer The funding sources had no role in the design of the study, interpretation of the results or in the writing of the manuscript.
Competing interests CEE is consultant for Desitin and Novartis and received honoraria for talks from Pfizer and Eisai. CH reports personal fees from GlaxoSmith Kline, UCB Pharma, Pfizer, Desitin Pharma, EISAI, Viamed GmbH, assurance companies, courts and occupational insurance associations and grants from German Research Foundation.
Patient consent Obtained.
Ethics approval All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards. The randomised study was reviewed and approved by the reviewers of the German Research Council (Deutsche Forschungsgemeinschaft, DFG) and the local ethics committee at the University of Bonn Medical Center.
Provenance and peer review Not commissioned; externally peer reviewed.
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