Peer Review #1 of "Cognitive performance in distinct groups of children undergoing epilepsy surgery—a single-centre experience (v0.1)"

Abstract

Background. We aimed first to describe trends in cognitive performance over time in a large patient cohort (n= 203) from a single tertiary centre for paediatric epilepsy surgery over the period of 16 years divided in two (developing-pre-2011 vs. established-post-2011). Secondly, we tried to identify subgroups of epilepsy surgery candidates with distinctive epilepsy-related characteristics that associate with their pre-and post-surgical cognitive performance. Thirdly, we analysed variables affecting presurgical and post-surgical IQ/DQ and their change(post-vs. pre-surgical). Methods. We analysed IQ/DQ data obtained using standardized neuropsychological tests before epilepsy surgery and one year post-surgically, along with details of patient's epilepsy, epilepsy surgery and outcomes in terms of freedom from seizures. Using regression analysis, we described the trend in post-operative IQ/DQ. Cognitive outcomes and the associated epilepsy-and epilepsy surgery-related variables were compared between periods before and after 2011. Using multivariate analysis we analysed the effect of individual variables on pre-and post-operative IQ/DQ and its change. Results. Epilepsy surgery tends to improve post-surgical IQ/DQ, most significantly in patients with lower pre-surgical IQ/DQ, and post-surgical IQ/DQ strongly correlates with pre-surgical IQ/DQ (Rho=0.888, p<0.001). We found no significant difference in pre-, post-surgical IQ/DQ and IQ/DQ change between the periods of pre-2011 and post-2011 (p=0.7, p=0.469, p=0.796, respectively). Patients with temporal or extratemporal epilepsy differed in their pre-surgical IQ/DQ (p=0.001)and in IQ/DQ change (p=0.002) from those with hemispheric epilepsy, with no significant difference in post-surgical IQ/DQ (p=0.888). Groups of patients with different underlying histopathology showed significantly different pre-and post-surgical IQ/DQ (p<0.001and p<0.001respectively) but not IQ/DQ change (p=0.345).Variables associated with severe epilepsy showed effect on cognitive performance in multivariate model. Discussion. Post-surgical IQ/DQ strongly correlates with pre-surgical IQ/DQ and greatest IQ/DQ gain occurs in patients with lower pre-surgical IQ/DQ scores. Cognitive performance was not affected by changes in paediatric epilepsy surgery practice. Pre-and post-operative cognitive performances, as well