Neurofax

For extracranial EEG recording, disc electrodes were placed over the scalp according to the international 10–20 EEG system. Moreover, T1/T2 electrodes[11 (link)] and periorbital electrodes (supraorbital lateral: SOL, infraorbital lateral: IOL, and infraorbital medial: IOM)[10 ] were placed [Figure 1a]. The MA electrodes were placed on the MA angles on both sides and the CH electrode was placed on the CH at the midline of the mandible [Figures 1a and b]. CH and MA electrodes are farther from the mesial temporal lobe compared to other extracranial electrodes [Figures 1a and b]. He underwent simultaneous recordings of extra- and intracranial EEG as part of a presurgical evaluation, as described previously.[2 (link),7 (link)-9 (link)] EEG recordings were collected using a digital EEG recorder (Neurofax: Nihon Kohden, Tokyo, Japan).

Twenty-nine of the 32 patients underwent routine EEG recording preoperatively and on POD1. Follow-up EEG was performed in 3 patients who developed CHS. Routine EEG recordings were obtained from an 18-channel digital EEG machine (Neurofax; Nihon-Kohden, Tokyo, Japan) with electrode placement according to the International EEG 10-20 system. The EEG recordings were performed for at least 30 min for each patient at rest.

Digital scalp EEG (Neurofax; Nihon-Kohden, Tokyo, Japan) was recorded with the international 10–20 system electrode placement and additional T1/T2 electrodes. The EEG recordings were performed for at least 1 h for all patients. Continuous EEG monitoring (more than 6 h) was performed in 15 patients. PDs and RDA were identified using standardized critical care EEG terminology of the American Clinical Neurophysiology Society (Hirsch et al., 2013 (link)). The PDs were subcategorized as lateralized, bilateral independent and generalized PDs. The RDA was subcategorized as lateralized, bilateral independent and generalized RDA. The EEG seizures were identified as frequency change and apparent spatiotemporal evolution pattern of epileptiform discharges with a frequency of >25 times per 10 s epoch. Brief rhythmic epileptiform discharges were identified as repetitive epileptiform discharges occurring two or three times per second, lasting only a few seconds. Single spike or sharp waves were not evaluated in this study. Two experienced, board-certified experts of EEG and clinical neurophysiology (S.O., H.O.) independently reviewed the recordings of EEG, unaware of the patients’ clinical data including ASL.