Application of intraoperative direct electrical stimulation in epilepsy surgery involving eloquent areas

Objective To report the experience on application of intraoperatvie direct electrical stimulation(DES) and continuous electrocorticography (ECoG) monitoring in surgical treatment of lesional epilepsy involving eloquent areas.Methods 49 consecutive epilepsy patients with structural lesions adjacent to eloquent areas from our institute between April 2007 and July 2012 were included.The patients were processed one-stage surgery with combined application of intraoperative DES and continuous ECoG monitoring.Results 48 patients successfully identified the eloquent area.One week after surgery,12 patients suffered worsened neurological dysfunction.At 6 months follow-up,3 patients had persistent worsened neurological dysfunction.Following up 1.5-6.0 years (mean 40.0 ± 14.4 months) in 47 patients,34 patients with Engels class Ⅰ,6 with class Ⅱ,3 with class Ⅲ,1 with class Ⅳ,and the total effective rate(patients in Engle's class Ⅰ and Ⅱ)was 81.6％.Conclusion Combined application of intraoperative DES and continuous ECoG monitoring can identify the eloquent area precisely,safely and reliably,and also can assist to localize epileptogenic foci.This technique can achieve good seizure outcome meanwhile decreasing incidence of neurological dysfunction for lesional epilepsy involving eloquent areas. Key words: Epilepsy surgery;  Eloquent areas;  Direct electrical stimulation;  Electrocorticography