title: Visual memory after epilepsy surgery in children: a standardized regression-based analysis of group and individual outcomes.
abstract: Visual memory is vulnerable to epilepsy surgery in adults, but studies in children suggest no change or small improvements. We investigated visual memory after epilepsy surgery, both group-wise and in individual children, using two techniques to assess change: 1) repeated measures analysis of variance (ANOVA) and 2) an empirically based technique for detecting cognitive change [standardized regression-based (SRB) analysis]. A prospective cohort consisting of 21 children completed comprehensive assessments of memory both before surgery (T0) and 6 (T1), 12 (T2), and 24 months (T3) after surgery. For each patient, two age- and gender-matched controls were assessed with the same tests at the same intervals. Repeated measures ANOVA replicated the results of previous studies reporting no change or minor improvements after surgery. However, group analysis of SRB results eliminated virtually all improvements, indicating that the ANOVA results were confounded by practice effects. Standardized regression-based group results showed that in fact patients scored lower after surgery than would be predicted based on their presurgical performance. Analysis of individual SRB results showed that per visual memory measure, an average of 18% of patients obtained a significantly negative SRB score, whereas, on average, only 2% obtained a significantly positive SRB score. At T3, the number of significantly negative SRB scores outweighed the number of significantly positive SRB scores in 62% of patients. There were no clear associations of clinical variables (including side and site of surgery and postsurgical seizure freedom) with memory outcome. The present analysis revealed that given their individual presurgical functioning, many children obtained disappointing results on some visual memory tests after epilepsy surgery. Comparison of the SRB analysis with ANOVA results emphasizes the importance of empirically based techniques for detecting cognitive effects of epilepsy surgery in childhood.
authors.affiliation: Sector of Neuropsychology for Children and Adolescents, Hp KG 01.327.1, Brain Center Rudolf Magnus, University Medical Center Utrecht, P.O. Box 85090, 3508 AB Utrecht, The Netherlands; Bio Research Center for Children, Wekeromseweg 8, 6816 VS Arnhem, The Netherlands. Electronic address: meekes.joost@gmail.com.
authors.forename: Joost
authors.initials: J
authors.lastname: Meekes
authors.affiliation: Sector of Neuropsychology for Children and Adolescents, Hp KG 01.327.1, Brain Center Rudolf Magnus, University Medical Center Utrecht, P.O. Box 85090, 3508 AB Utrecht, The Netherlands; Bio Research Center for Children, Wekeromseweg 8, 6816 VS Arnhem, The Netherlands. Electronic address: o.b.braams@umcutrecht.nl.
authors.forename: Olga B
authors.initials: OB
authors.lastname: Braams
authors.affiliation: Department of Child Neurology, Hp KC 03.063.0, Brain Center Rudolf Magnus, University Medical Center Utrecht, P.O. Box 85090, 3508 AB Utrecht, The Netherlands. Electronic address: k.braun@umcutrecht.nl.
authors.forename: Kees P J
authors.initials: KP
authors.lastname: Braun
authors.affiliation: Sector of Neuropsychology for Children and Adolescents, Hp KG 01.327.1, Brain Center Rudolf Magnus, University Medical Center Utrecht, P.O. Box 85090, 3508 AB Utrecht, The Netherlands; Bio Research Center for Children, Wekeromseweg 8, 6816 VS Arnhem, The Netherlands. Electronic address: a.jennekens@umcutrecht.nl.
authors.forename: Aag
authors.initials: A
authors.lastname: Jennekens-Schinkel
authors.affiliation: Department of Neurosurgery, Hp G 03.124, Brain Center Rudolf Magnus, University Medical Center Utrecht, P.O. Box 85500, 3508 GA Utrecht, The Netherlands. Electronic address: p.v.rijen@umcutrecht.nl.
authors.forename: Peter C
authors.initials: PC
authors.lastname: van Rijen
authors.affiliation: SEIN, Epilepsy Institute of the Netherlands Foundation, Location Meer en Bosch, P.O. Box 540, 2103 SW Heemstede, The Netherlands. Electronic address: walpherts@sein.nl.
authors.forename: Willem C J
authors.initials: WC
authors.lastname: Alpherts
authors.affiliation: Department of Behavioural Sciences, Kempenhaeghe Expertise Centre for Epileptology, Sleep Medicine and Neurocognition, P.O. Box 61, 5590 AB Heeze, The Netherlands; Donders Institute for Brain, Cognition and Behaviour, Radboud University, P.O. Box 9104, 6500 HE Nijmegen, The Netherlands. Electronic address: HendriksM@kempenhaeghe.nl.
authors.forename: Marc P H
authors.initials: MP
authors.lastname: Hendriks
authors.affiliation: Bio Research Center for Children, Wekeromseweg 8, 6816 VS Arnhem, The Netherlands; Department of Child Neurology, Hp KC 03.063.0, Brain Center Rudolf Magnus, University Medical Center Utrecht, P.O. Box 85090, 3508 AB Utrecht, The Netherlands. Electronic address: OnnovanNieuwenhuizen@umcutrecht.nl.
authors.forename: Onno
authors.initials: O
authors.lastname: van Nieuwenhuizen
mesh_terms: D000293:Adolescent; D000704:Analysis of Variance; D002648:Child; D002675:Child, Preschool; D004827:Epilepsy / Q000150:complications / Q000601:surgery*; D005260:Female; D006801:Humans; D007206:Individuality; D008137:Longitudinal Studies; D008297:Male; D008569:Memory Disorders / Q000209:etiology / Q000601:surgery*; D011939:Mental Recall / Q000502:physiology*; D009483:Neuropsychological Tests; D010775:Photic Stimulation; D011446:Prospective Studies; D012044:Regression Analysis; D016896:Treatment Outcome; D055815:Young Adult
keywords: Child; Epilepsy surgery; SRB analysis; Temporal/extratemporal resection; Visual memory