Abstract

Eye and head movements produce large voltages which obscure the electrical activity of the brain, interfering with diagnostic procedures. In the system and method of the present invention electrical response to such movement artifact is detected by a set of electrodes and transmitted to amplifiers, analog-to-digital converters and an on-line to a digital computer. The computer monitors each of the 19 channels corresponding to the 19 electrodes on the subject's head and a pair of electrodes located diagonally above and below one eye (trans-orbital) to detect artifacts associated with eye movement. Each channel of brain waves and artifact signals, converted into digital information, are compared with a threshold selected digital value set by the operator either by using standard values, by empirically eliciting sample artifacts, or by a standard deviation determination. The computer, after determining that there exists a movement artifact, i.e., an artifact in excess of the digital threshold value, either blanks out the brain wave data for that period or magnetically "marks" the appropriate channel(s) of the multi-channel recording at the time corresponding to the artifact distortion, which may be in all or only some channels.