Intracranial electroencephalography（i EEG）provides the best precision in estimating the location and boundary of an epileptogenic zone. Analysis of i EEG in the routine EEG frequency range（0.5-70 Hz） remains the basis in clinical practice. Low-voltage fast activity is the most commonly reported ictal onset pattern in neocortical epilepsy, and low-frequency high-amplitude repetitive spiking is the most commonly reported ictal onset pattern in mesial temporal lobe epilepsy. Recent studies using wideband EEG recording have demonstrated that examining higher（80-1000 Hz） and lower（0.016-0.5 Hz） EEG frequencies can provide additional diagnostic information and help to improve the surgical outcome. In addition,novel computational techniques of i EEG signal analysis have provided new insights into the epileptic network.Here, we review some of these recent advances. Although these sophisticated and advanced techniques of i EEG analysis show promise in localizing the epileptogenic zone,their utility needs to be further validated in larger studies.
In the present study we explored the different patterns of volumetric atrophy in hippocampal subregions of patients with left and right mesial temporal lobe epilepsy with hippocampal sclerosis(TLE-HS). Meanwhile, the memory impairment patterns in Chinese-speaking TLE-HS patients and potential influencing factors were also determined. TLE-HS patients(21 left and 17 right) and 21 healthy controls were recruited to complete T2-weighted imaging and verbal/nonverbal memory assessment. The results showed that both left and right TLE-HS patients had overall reduced hippocampal subregion volumes on the sclerotic side, and cornu ammonis sectors(CA1) exhibited maximum atrophy. The verbal memory of left TLE-HS patients was significantly impaired(P \ 0.001) and was not associated with the volumes of the left hippocampal subregions. Verbal or nonverbal memory impairment was not found in the patients with right TLE-HS. These results suggested that the atrophy of hippocampal subregion volumes cannot account for the verbal memory impairment, which might be related to the functional network.
Caihong JiLujia ZhuCong ChenShuang WangLeilei ZhengHong Li
