Description: High-frequency noise superimposed on high-amplitude slow activity with possible superimposed electrode pops.

Method for reducing or eliminating the artifact: Reprep and repaste the electrode to decrease the impedance.

Description: Obscuration of the background EEG and occasionally EOG by myogenic (muscle) artifact.

Method for reducing or eliminating the artifact: Ask the patient to relax; opening the jaw slightly can dramatically reduce EMG artifact. Rereferencing electrodes can also decrease artifact.

Description: A representation of the EKG in the EEG channels secondary to volume conduction of the EKG waveform. The artifact in the EEG channels should be time locked to the EKG.

Method for reducing or eliminating the artifact: Re-reference the EEG channels to A1 + A2.

Description: The vibration caused by leg movements or snoring can result in high-frequency artifacts in other channels. One can see a manifestation of the snore registering in the chin EMG channel.

Method for reducing or eliminating the artifact: This artifact is very difficult to reduce but should be recognized as a normal physiologic occurrence.

Description: Very sharp, spikelike deflection originating from a mechanically or electrically unstable electrode. The deflections
should have no electrical field and should be isolated to a single electrode. The deflection may however be seen in multiple channels if that electrode is used as a component of a channel.

Method for reducing or eliminating the artifact: Reprep and repaste the electrode to decrease the impedance.

Description: A pulse wave may be seen in the chest belt or abdominal belt that has only a slight delay behind the EKG channel. A representation of the pulse wave may be seen in airflow channels, nasal pressure monitors, and in esophageal pressure-monitoring channels.