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Abstract

The term “volume conduction” refers to the complex effects of measuring electrical potentials a distance from their source generators. Near-field potentials refer to those recorded in relative close proximity to the detector, whereas far-field potentials refer to those recorded at a considerable distance, as is most commonly the case in evoked potentials. A relative straightforward model of volume conduction can be worked through to assist in better understanding how volume conduction effects can impact the shape of a recorded neuronal potential. In fact, all motor and sensory nerve conduction waveforms are substantially impacted by volume conductive effects. The recording setup of sensory studies (i.e., whether they are bipolar or referential) also impacts the size and morphology of the recorded signals. In addition, the compound motor action potential actually represents a composite of both near- and far-field activity. The morphology of both spontaneous discharges and the motor unit potentials themselves evaluated during needle EMG are, in part, caused by the complex effects of volume conduction.

Key Words

Bipolar far-field fibrillation potential near-field positive sharp wave source generator referential volume conduction 

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Suggested Reading

  1. Dumitru D, Delisa JA. AAEM Minimonograph #10: Volume Conduction. Muscle Nerve 1991;14: 605–624.PubMedCrossRefGoogle Scholar
  2. Frith RW, Benstead TJ, Daube JR. Stationary waves recorded at the shoulder after median nerve stimulation. Neurology 1986;36: 1458–1464.PubMedGoogle Scholar
  3. Kimura J, Kimura A, Ishida T, et al. What determines the latency and amplitude of stationary peaks in far-field recordings? Ann Neurol 1986;19(5): 479–486.PubMedCrossRefGoogle Scholar
  4. Kincaid JC, Brashear A, Markand ON. The influence of the reference electrode on CMAP configuration. Muscle Nerve 1993;16(4): 392–396.PubMedCrossRefGoogle Scholar
  5. Lagerlund TD. Volume conduction. In: Daube J, ed. Clinical Neurophysiology. Oxford University Press, New York, NY, 2002, pp. 28–36.Google Scholar

Copyright information

© Humana Press Inc. 2007

Authors and Affiliations

  • Seward B. Rutkove
    • 1
  1. 1.Department of Neurology, Beth Israel Deaconess Medical CenterHarvard Medical SchoolBoston

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