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.