Reducing Motion Artifacts and Interference in Biopotential Recording

The application of engineering principles and techniques to biopotential recording has resulted in a continual improvement both in the type and the quality of recorded signals. Physical placement of electrodes has enabled improved discrimination of the biopotential of interest (such as the ECG) from unwanted biopotentials (such as the EMG). Understanding that the major motion artifact in ECG recording arises from the skin and not the electrode has resulted in techniques that reduce this artifact, such as skin abrasion and mechanical stabilization. However, skin abrasion makes the skin more subject to irritation, so mild gels are required. The development of the floating silver/silver chloride electrode has eliminated motion artifact and noise caused by the electrode. The development of the driven-right-leg circuit has greatly reduced interference due to power lines. Adaptive filters have reduced the difficult-to-eliminate interference due to spark-gap electrosurgical units.