title: Comparison of concentric needle versus hooked-wire electrodes in the canine larynx.
abstract: BACKGROUND
  The use of a specific electrode type in laryngeal electromyography has not been standardized. Laryngeal electromyography is usually performed with hooked-wire electrodes or concentric needle electrodes. Hooked-wire electrodes have the advantage of allowing laryngeal movement with ease and comfort, whereas the concentric needle electrodes have benefits from a technical aspect and may be advanced, withdrawn, or redirected during attempts to appropriately place the electrode.
  
  
  OBJECTIVE
  This study examines whether hooked-wire electrodes permit more stable recordings than standard concentric needle electrodes at rest and after large-scale movements of the larynx and surrounding structures. A histologic comparison of tissue injury resulting from placement and removal of the two electrode types is also made by evaluation of the vocal folds.
  
  
  METHODS
  Electrodes were percutaneously placed into the thyroarytenoid muscles of 10 adult canines. Amplitude of electromyographic activity was measured and compared during vagal stimulation before and after large-scale laryngeal movements. Signal consistency over time was examined. Animals were killed and vocal fold injury was graded and compared histologically.
  
  
  RESULTS
  Waveform morphology did not consistently differ between electrode types. The variability of electromyographic amplitude was greater for the hooked-wire electrode (p < 0.05), whereas the mean amplitude measures before and after large-scale laryngeal movements did not differ (p > 0.05). Inflammatory responses and hematoma formation were also similar.
  
  
  CONCLUSIONS
  Waveform morphology of electromyographic signals registered from both electrode types show similar complex action potentials. There is no difference between the hooked-wire electrode and the concentric needle electrode in terms of electrode stability or vocal fold injury in the thyroarytenoid muscle after large-scale laryngeal movements.
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, University of Iowa College of Medicine, Iowa City, USA.
authors.forename: D M
authors.initials: DM
authors.lastname: Jaffe
authors.forename: N P
authors.initials: NP
authors.lastname: Solomon
authors.forename: R A
authors.initials: RA
authors.lastname: Robinson
authors.forename: H T
authors.initials: HT
authors.lastname: Hoffman
authors.forename: E S
authors.initials: ES
authors.lastname: Luschei
mesh_terms: D000200:Action Potentials / Q000502:physiology; D000704:Analysis of Variance; D000818:Animals; D004285:Dogs; D004558:Electric Stimulation; D004567:Electrodes, Implanted / Q000592:standards; D004576:Electromyography / Q000295:instrumentation* / Q000379:methods; D004867:Equipment Design; D005260:Female; D006406:Hematoma / Q000473:pathology; D007818:Laryngeal Diseases / Q000473:pathology; D007821:Laryngeal Muscles / Q000293:injuries / Q000473:pathology / Q000502:physiology; D007827:Laryngitis / Q000473:pathology; D007830:Larynx / Q000293:injuries / Q000473:pathology / Q000502:physiology*; D008297:Male; D009068:Movement; D009339:Needles / Q000592:standards; D012146:Rest; D012815:Signal Processing, Computer-Assisted; D013193:Stainless Steel; D014630:Vagus Nerve / Q000502:physiology; D014827:Vocal Cords / Q000293:injuries / Q000473:pathology
chemical_list: D013193:Stainless Steel