Motor unit action potentials recorded with concentric electrodes: Physiologic implications

Daniel Dumitru, John C. King, Sanjeev D. Nandedkar

Research output: Contribution to journalArticlepeer-review

24 Scopus citations


Computer simulations of concentric needle electrode recording characteristics assume a hemisphere spatial recording territory for the electrode's core with the cannula shielding electrical activity arising from those muscle fibers located behind the cannula with respect to the electrode's core. It is also believed that the motor unit action potential's (MUAP) duration is generated by the number of muscle fibers within the electrode's hemispherical recording territory. This presumption suggests that rotating the needle will necessarily alter the number of muscle fibers within the hemispherical recording territory and hence lead to an alteration in MUAP duration. Comparisons were performed for different needle orientations with documentation of no statistically significant alteration in MUAP duration. Additionally, referential recording montages with the concentric needle electrode revealed that the electrode's core records MUAPs with durations comparable to those detected by the cannula. These findings strongly suggest that the recording territory of the concentric needle electrode, with respect to MUAP duration, is not a hemisphere but a sphere encompassing most if not all of the MUAP's muscle fibers in a manner similar to that of a monopolar needle. These findings have significant implications regarding presently used MUAP simulation techniques and require a reconceptualization of how the concentric needle electrode records electrical activity within a volume conductor.

Original languageEnglish (US)
Pages (from-to)333-339
Number of pages7
JournalElectroencephalography and Clinical Neurophysiology - Electromyography and Motor Control
Issue number5
StatePublished - Oct 1997


  • Concentric needle electrode
  • Instrumentation
  • Motor unit
  • Motor unit action potential
  • Volume conduction

ASJC Scopus subject areas

  • Neuroscience(all)
  • Clinical Neurology


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