title: Influence of asymmetric recurrent laryngeal nerve stimulation on vibration, acoustics, and aerodynamics.
abstract: OBJECTIVE
  Evaluate the influence of asymmetric recurrent laryngeal nerve (RLN) stimulation on the vibratory phase, acoustics and aerodynamics of phonation.
  
  
  METHODS
  Basic science study using an in vivo canine model.
  
  
  METHODS
  The RLNs were symmetrically and asymmetrically stimulated over eight graded levels to test a range of vocal fold activation conditions from subtle paresis to paralysis. Vibratory phase, fundamental frequency (F0 ), subglottal pressure, and airflow were noted at phonation onset. The evaluations were repeated for three levels of symmetric superior laryngeal nerve (SLN) stimulation.
  
  
  RESULTS
  Asymmetric laryngeal adductor activation from asymmetric left-right RLN stimulation led to a consistent pattern of vibratory phase asymmetry, with the more activated vocal fold leading in the opening phase of the glottal cycle and in mucosal wave amplitude. Vibratory amplitude asymmetry was also observed, with more lateral excursion of the glottis of the less activated side. Onset fundamental frequency was higher with asymmetric activation because the two RLNs were synergistic in decreasing F0 , glottal width, and strain. Phonation onset pressure increased and airflow decreased with symmetric RLN activation.
  
  
  CONCLUSIONS
  Asymmetric laryngeal activation from RLN paresis and paralysis has consistent effects on vocal fold vibration, acoustics, and aerodynamics. This information may be useful in diagnosis and management of vocal fold paresis.
  
  
  METHODS
  N/A.
authors.affiliation: Laryngeal Physiology Laboratory, Department of Head and Neck Surgery, UCLA School of Medicine, Los Angeles, California, U.S.A.
authors.forename: Dinesh K
authors.initials: DK
authors.lastname: Chhetri
authors.forename: Juergen
authors.initials: J
authors.lastname: Neubauer
authors.forename: Elazar
authors.initials: E
authors.lastname: Sofer
mesh_terms: D000162:Acoustics; D000818:Animals; D004285:Dogs; D004558:Electric Stimulation / Q000379:methods*; D005931:Glottis / Q000502:physiology; D023421:Models, Animal; D010699:Phonation / Q000502:physiology*; D012009:Recurrent Laryngeal Nerve / Q000502:physiology*; D012680:Sensitivity and Specificity; D014732:Vibration; D014741:Video Recording
keywords: Recurrent laryngeal nerve; acoustics; high speed video; laryngeal asymmetry; phonation; vibration