Spectral analysis
The cross-channel grand average of the global EEG, PSD, and rPSD was calculated (Figure 3 A and B and Supplemental Table 2). After FDR correction, absolute PSD in slow rhythms was significantly increased in the TLE groups compared to controls (delta:p HC-NC=0.012,p HC-AC=0.012; theta:p HC-NC=0.019,p HC-AC=0.012). Group differences in rPSD were also detected for delta (p HC-NC=0.003,p HC-AC=0.002) and alpha (p HC-NC=0.002,p HC-AC<0.001). The results revealed that the general EEG activity slowed in drug-resistant TLE. No significant group differences in the absolute and relative PSDs were observed for gamma.
Moreover, group comparisons of PSDs were performed in each channel (Figure 3 C&D and Supplemental Table 3 & 4). As shown in Figure 3, powers in slow rhythm in the TLE groups were significantly increased mainly over the anterior regions, particularly the anterior and middle temporal lobes, compared to controls. The absolute PSD in alpha showed no difference in the group comparison. However, the relative PSD revealed that the percentage of alpha power decreased in both TLE groups over the entire head compared to controls. For gamma frequencies, the rPSD over the central, frontal, and temporal lobes was lower in the TLE groups than in the controls.