Use of Full-Band EEG for Noninvasive Ictal Localization

Determination of the epileptogenic zone is typically attempted by ictal video electroencephalographic (EEG) recordings with scalp electrodes, correlated with other noninvasive studies, particularly neuroimaging. However, conventional scalp EEG gives often equivocal information about the location of seizure origin, or it is incongruent with other tests, leading to the requirement for invasive recordings (1–4). The spatial resolution of the conventional scalp EEG can be enhanced with existing, but clinically unexploited, source localization techniques (5). However, there remains an obvious need for better noninvasive detection of seizure-related signals that arise in brain structures (e.g., deep temporal lobe and neocortex) typically involved in seizure initiation. It is evident from our recent work that detection of such signals is greatly improvedwith an extendedEEGbandwidth (6).While conventional EEGhas a limited bandwidth (typically 0.5–70Hz), distorting or ignoring slow EEG events, a full-band EEG (FbEEG) that detects all physiological frequencies can be obtained using a DCcoupled (direct current coupled) amplifier and proper electrode–skin interface. This