Propagated insertional activity: A model of positive sharp wave generation

Daniel Dumitru, Carlos T.J. Martinez

Research output: Contribution to journalArticlepeer-review

10 Scopus citations


In this study we utilized a dual monopolar needle recording technique to assess propagated electromyographic insertional activity from the same single muscle fiber in order to characterize different categories of insertional activity. A total of six combinations of insertional activity were identified. Only two fundamental types of single muscle-fiber insertional discharge configurations were generated: biphasic initially-negative and monophasic positive. The propagated waveforms corresponding to these two insertional discharges were primarily triphasic initially-positive and, only rarely, monophasic positive. The monophasic positive insertional activity generated at the inserting electrode site is postulated to arise from a depolarization zone adjacent to a needle-induced peri-electrode membrane crush. The monophasic positive discharge was utilized as a model for positive sharp wave generation. It is postulated that the majority of positive sharp waves are initiated at the inserting electrode adjacent to a needle-induced zone of muscle membrane crush in contrast to the previous supposition that positive sharp waves are blocked fibrillation potentials.

Original languageEnglish (US)
Pages (from-to)457-462
Number of pages6
JournalMuscle and Nerve
Issue number4
StatePublished - Oct 2006


  • Insertional activity
  • Needle electromyography
  • Positive sharp wave
  • Single muscle fiber
  • Volume conduction

ASJC Scopus subject areas

  • Clinical Neurology
  • Physiology (medical)
  • Cellular and Molecular Neuroscience
  • Physiology


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