Abstracts

Rationale: The mesial temporal lobe epilepsy tends to be medically refractory, however, it is considered that the seizure can be inhibited by surgery and thus the diagnosis of focus of the seizure is important. Usually 10-20 international EEG is performed and it is known that it is sometimes hard to obtain interictal discharges from the recording. We investigated how the interictal discharges are shown in 256 channel dense array EEG and compared to them in 10-20 EEG. Methods: There were four patients (2 male, 2 female, age 17-38; mean 30.2 years old) with the mesial temporal lobe epilepsy, who have been free from seizure after surgery. 256ch dEEG were performed before surgery. We picked up five interictal spikes recorded during light sleep each and examine which cannel's amplitude is the highest of all and investigated the distribution of the spikes, which were compared to scalp EEG recording. Results: The channel which has the highest amplitude is located out of scalp in 18 out of 20 spikes. The highest amplitude is about 1.5 times greater than that of 10-20 at average. Mostly it was shown on forehead, zygomatic area and posterior auricle area. The channels on face detected spikes widely, including that in the opposite side of the focus of seizure. Conclusions: On the case of the mesial temporal epilepsy, the channels on forehead, zygomatic area and posterior auricle area showed spikes well. The channels which had maximum negativities were located in that area mostly and it was much greater than that of 10-20 EEG recording. This is suggested that the channels on face can be more useful to detect interictal discharges on the mesial temporal lobe epilepsy.