Artifact and recording concepts in EEG.

Artifact is present when electrical potentials that are not brain derived are recorded on the EEG and is commonly encountered during interpretation. Many artifacts obscure the tracing, while others reflect physiologic functions that are crucial for routine visual analysis. Both physiologic and nonphysiologic sources of artifact may act as source of confusion with abnormality and lead to misinterpretation. Identifying the mismatch between potentials that are generated by the brain from activity that does not conform to a realistic head model is the foundation for recognizing artifact. Electroencephalographers are challenged with the task of correct interpretations among the many artifacts that could potentially be misleading, resulting in an incorrect diagnosis and treatment that may adversely impact patient care. Despite advances in digital EEG, artifact identification, recognition, and elimination are essential for correct interpretation of the EEG. The authors discuss recording concepts for interpreting EEG that contains artifact.