Abstracts

Rationale: Localization of eloquent brain area is a particular concern prior to resective surgery for children with intractable epilepsy because resection of cognitive area lead to decline of cognitive function. We can estimate memory and language dominance from result of neuropsychological test in subset of epilepsy children. However, we still don’t know whether cognitive network co-exist in epileptogenic network in developing brain. Our question in this study is “Can neuropsychological test define the margin of resectable epileptogenic zone in developing brain?” We hypothesize that neuropsychological test cannot define the accurate margin of resectable epileptogenic zone, but might be a cardinal element to decide the strategy for epilepsy surgery in developing brain.Methods: We retrospectively reviewed 71children with intractable epilepsy who underwent intracranial video EEG at SickKids from 2009 to 2014. We defined the estimated dominant hemisphere for language prior to epilepsy surgery by 1)preoperative verbal memory performance and 2)lateralization of epileptic hemisphere indicated with EEG and MEG. Results of pre/post neuropsychological test(VIQ,PIQ) were compered to age at seizure onset, seizure duration and estimated dominant hemisphere.Results: We analyzed 39children. 12children had abnormal development. Mean age at seizure onset was 6.1years. Mean duration of seizure was 5.5years. Mean period of postoperative neuropsychological test was mean 1.1years. Mean VIQ significantly declined after resective surgery(pre;83.4,post;77.5,p<0.001). While, mean PIQ did not change(pre;81.3,post;81.4).A regression analysis revealed a significant positive correlation between duration of seizure and post/pre change of VIQ(r=0.33,p=0.035) and post/pre change of PIQ(r=0.39,p=0.015). Mean VIQ significantly declined after surgery with age of seizure onset ≧5years (n=22,pre;86.4,post;78.8,p=0.002), while did not change <5years(n=17,pre;79.6, post;75.8). 25children were categorized with surgery in estimated dominant hemisphere, and 14children were categorized with surgery in estimated non-dominant hemisphere. Mean VIQ significantly declined after surgery with estimated dominant hemisphere(pre;79.7,post;73.6,p=0.002), while did not change after surgery with estimated non-dominant hemisphere(pre;90.1,post;84.6). There were significant difference between pre and post VIQ with age of seizure onset ≧5years in estimated dominant hemisphere(n=16,pre;83.6,post;75.3,p=0.001), and age of seizure onset <5years in estimated non-dominant hemisphere(n=8,pre;87.4, post;81.9,p=0.046).Conclusions: VIQ declined after resective surgery in children with intractable epilepsy. Short duration of seizure related with postoperative decline of cognitive function. Decline of VIQ was related with resective surgery in estimated dominant hemisphere with age of seizure onset ≧5years and resective surgery in estimated non-dominant hemisphere with age of seizure onset <5years. Neuropsychological test could be a cardinal element to decide the strategy for epilepsy surgery in developing brain.