title: [Approaches to reduce the retroaction of long-term monitoring of bioelectric events in ergonomic field studies (author's transl)].
abstract: When monitoring bioelectric signals the surface electrodes can cause a retroaction on the subject thereby introducing an error of measurement. There are two types of retroaction: physical and psycho-physiological. A physical retroaction due to the hydration process of the skin occurs if 'wet' electrodes are used for the recording of the skin conductance level (SCL) causing a continuous drift of the SCL and a decrease in sensitivity to SCL changes. Therefore a dry electrode was developed with improved performance: It exhibits less sensitivity to motion, is not subject to polarization, and features better SCL long-term stability. When recording the electrocardiogram or the electromyogram a psychophysiological retroaction occurs due to the annoyance caused by the skin-irritating abrading techniques in order to decrease the skin impedance and reduce the motion artifact. In an attempt to abandon the skin preparation whenever permissible without sacrificing the measurement accuracy a performance estimation procedure was developed. Basing on the information on the signal frequency content, the electrode contact area, the required accuracy of measurement and the amplifier input impedance a decision on the necessity of skin preparation is made. Moreover, the results of a study are reported investigating the reduction of motion artifacts by means of electrode design and appropriate electrode jelly formulation.
mesh_terms: D004562:Electrocardiography; D004566:Electrodes; D004576:Electromyography; D004594:Electrophysiology; D006804:Ergonomics; D006801:Humans; D008991:Monitoring, Physiologic; D012879:Skin Physiological Phenomena
vernacular_title: Rückwirkungsarme Ableitung bioelektrischer Signale bei arbeitswissenschaftlichen Langzeituntersuchungen am Arbeitsplatz.