Abstract
A 2-dimensional conducting-paper analogue and a 3-dimensional field-theory model are used to investigate the influence of electrode spacing and size on the waveshape and frequency spectrum of the signal detected by bipolar surface electrodes, when an action potential propagates in a muscle fibre below the skin surfce. The spatial selectivity of bipolar electrodes, and its possible enhancement by linear filtering techniques, are then discussed. Finally, predicted e.m.g power spectra are compared with some practical measurements on biceps brachii muscle in normal subjects.
Sommaire
Un modèle analogique à deux dimensions en papier conducteur et un modèle théorique à trois dimensions sont utilisés pour étudier l'influence de l'espacement et de la taille des électrodes sur la forme d'onde et le spectre de fréquences du signal détecté par les électrodes de surface bipolaires lorsqu'un potential d.action se propage dans une fibre musculaire sous la surface de la peau. La sélectivité spatiale des électrodes bipolaires et son amélioration possible grâce à des techniques de filtrage linéaire sont ensuite discutées. Enfin, l'article compare les spectres de puissance d'e.m.g. prédits avec certaines mesures pratiques du muscle brachial du biceps chez des sujets normaux.
Zusammenfassung
Mit Hilfe eines 2-dimensionalen Litpapier-Analogmodells und eines 3-dimensionalen Feldtheoriemodells wird der Einfluß der Elektrodenabstände und-größe auf die Wellenform und das Frequenzspektrum des von bipolaren Oberflächenelektroden festgestellten Signals untersucht, wenn sich in einer Muskelfaser unter der Hautoberfläche ein Aktionspotential ausbreitet. Danach wird auf die Raumselektivität bipolarer Elektroden und ihre eventuelle Verbesserung durch lineare Filtrierverfahren eingegangen. Schließlich werden noch vorausgesagte e.m.g.-Kraftspektren mit einigen praktischen Messungen verglichen, die bei normalen Versuchapersonen am Bicepsbrachiimuskel vorgenommen wurden.
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Lynn, P.A., Bettles, N.D., Hughes, A.D. et al. Influence of electrode geometry on bipolar recordings of the surface electromyogram. Med. Biol. Eng. Comput. 16, 651–660 (1978). https://doi.org/10.1007/BF02442444
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DOI: https://doi.org/10.1007/BF02442444