Abstracts

Rationale: The selection of suitable candidates for resective surgery is a complex process informed by a number of interacting clinical and pathological features (Lee, 2010). Among these are patient demographics, seizure semiology, video-EEG monitoring, structural neuroimaging, functional neuroimaging and neuropsychological assessment (Keary, et al., 2007; Baxendale, Thompson, Harkness, & Duncan, 2006). Neuropsychological assessment is undertaken to provide a comprehensive understanding of the patient’s preoperative cognitive profile, to determine whether the pattern and level of cognitive function as indicated on psychometric testing is concordant with the seizure focus as demonstrated on all other forms of investigation (Wilson, et al., 2015). Where the pattern of cognitive function is discordant with previous investigations, surgery may be excluded on the basis of risk to the patient for suboptimal outcomes following surgery, both with regard to general cognition and recovery, as well as anticipated seizure freedom (Baxendale & Thompson, 2005). Despite the clear clinical significance of neuropsychological assessment in the surgical decision-making process, there exists a heterogeneity in clinical practice with regard to the classification of concordant cognitive profiles, as well as the selection of psychometric tests for this purpose (Wilson, et al., 2015; Vogt, et al., 2017; Keary, et al., 2007; Bowden, Simpson, & Cook, 2015). While a number of guidelines have been put forward, and most notably by the International League Against Epilepsy (ILAE) Neuropsychology Task Force (Wilson, et al., 2015), precise test batteries are not specified or uniformly practiced; the selection of psychometric tests vary by epilepsy center (Vogt, et al., 2017; Keary et al., 2007). This disparity in clinical approach has implications not only for the patient, but also for the discipline of neuropsychology as an evidence-based practice (Bowden, 2017). The current research focuses on the role of neuropsychology in the preoperative assessment of patients for epilepsy surgery, with a view to clarifying current practice within the field with respect to identifying suitable candidates for surgery, in terms of the lateralization and localization of seizure focus as indicated on psychometric testing. Methods: A systematic review and meta-analysis was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Information sourcesA search of the electronic databases Medline, EMBASE and PsycINFO was conducted for all journal articles published between January 2000 and December 2017 (the date of last search was 20 March 2018).Population. Adults, who have undergone resective surgery for epilepsy, with preoperative neuropsychological assessment. Intervention. Preoperative neuropsychological assessment for the lateralization and localization of seizure foci. Comparison. Lateralization indicated on other preoperative measures such as EEG, MEG, fMRI, MRI, as well as postoperative measures such as histology and seizure freedom. Outcome. Seizure lateralization to either the left or right temporal lobes.  Results: The systematic review is still to be completed.  Preliminary data suggest considerable heterogenity in clinical practice with regard to psychometric test selection, and cognitive profiles thought suitable for surgery.  Results of the review and subsequent meta-analyses are due for completion in August 2018. Conclusions: There currently exists considerable heterogeneity in preoperative neuropsychological assessment, with regard to both test selection and the cognitive profiles considered suitable for surgical intervention. Funding: Not applicable