Abstract: To investigate the value of preoperative standard electroencephalography (EEG) location for patients with intractable epilepsy. Methods: Thirty patients suffering from intractable epilepsy received common EEG examination first, and after hospitalizatoin, standard EEG examination. According to different conditions of patients, reduction or stop of medicine, depriving sleep inducement, and sphenoid electric pole were deployed for 90 to 120 minutes. The results of standard EEG in the consciousness and in the sleep, especially in the NREM and REM term were obtained. Results: Compared with common EEG, standard EEG method significantly increased the positivity rate of epileptic wave(43% vs 87%). Local epileptic electric activity was much more increased in NREM and REM term than in consciousness. Original focus in EEG was unanimous with surgery position in 16 cases. Conclusion: Local abnormal electric activity in sleep cycle and EEG changes derived from epileptic focus hemisphere are of great value in epileptogenic focus location.

Key words: Epilepsy, refractory, Brain mapping, Location