Aliasing in the visual EEG: a potential pitfall of video display technology

Computerized clinical electroencephalographic (EEG) systems are now widely used, with interpretation performed solely on video monitors. The possibility of artifacts from aliasing of EEG data on a computer screen has received little attention. We describe and illustrate several examples. Photographs of the video display were used. Three cases are shown. Two had escaped initial review and one led to transient changes in patient management. Aliasing artifacts are seen frequently with computerized EEG systems; some may be misinterpreted as EEG activity. Even compliance with current guidelines may not prevent all such artifacts.