Scalp EEG Could Record Both Ictal Direct Current Shift and High-Frequency Oscillation Together Even With a Time Constant of 2 Seconds. - Murai T; Hitomi T; Matsuhashi M; Matsumoto R; Kawamura Y; Kanda M; Takahashi R; Ikeda A (Journal of clinical neurophysiology : official publication of the American Electroencephalographic Society, 2020)