title: Functional electrical stimulation of laryngeal adductor muscle restores mobility of vocal fold and improves voice sounds in cats with unilateral laryngeal paralysis.
abstract: Functional electrical stimulation (FES) has been proposed as a potential treatment for restoring motor functions of denervated motor systems. We investigated whether FES of paralyzed laryngeal adductor muscles could restore adduction to the vocal folds. In addition, we studied the effect of stimulated vocal fold adduction on the intensity and overall quality of voice production. We recorded movement of the vocal fold, electromyographic activity of muscles recruited for vocalization, and sound production in unanesthetized decerebrate cats during FES of the paralyzed thyroarytenoid (TA) muscle. FES of the paralyzed TA muscle induced adduction of the vocal fold. Appropriate stimulus parameters for induction was 1.5-3.0 mA intensity pulses delivered at a frequency of 30-50 pulses per second (pps). FES of the paralyzed TA muscle prolonged phonation time and increased intensity of voice sounds during vocalization induced by electrical stimulation (0.2 ms, 20-50 microA, 50 pps) of the periaqueductal gray (PAG). The quality of voice sounds evaluated by sound spectrography was shown to improve during vocalization with FES. We conclude that FES of the paralyzed laryngeal adductor muscle was effective in restoring adduction of the vocal fold and improving voice sounds impaired by unilateral laryngeal paralysis.
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Asahikawa Medical College, Midorigaoka Higashi 2-1-1-1, Asahikawa 078-8510, Japan. katada@asahikawa-med.ac.jp
authors.forename: Akihiro
authors.initials: A
authors.lastname: Katada
authors.forename: Satoshi
authors.initials: S
authors.lastname: Nonaka
authors.forename: Masaaki
authors.initials: M
authors.lastname: Adachi
authors.forename: Isamu
authors.initials: I
authors.lastname: Kunibe
authors.forename: Takuya
authors.initials: T
authors.lastname: Arakawa
authors.forename: Masanobu
authors.initials: M
authors.lastname: Imada
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Hayashi
authors.forename: David L
authors.initials: DL
authors.lastname: Zealear
authors.forename: Yasuaki
authors.initials: Y
authors.lastname: Harabuchi
mesh_terms: D000818:Animals; D002415:Cats; D003655:Decerebrate State; D003714:Denervation; D004558:Electric Stimulation; D004576:Electromyography; D005260:Female; D007821:Laryngeal Muscles / Q000502:physiology*; D007830:Larynx / Q000502:physiology*; D008297:Male; D010487:Periaqueductal Gray / Q000502:physiology; D014826:Vocal Cord Paralysis / Q000628:therapy*; D014827:Vocal Cords / Q000502:physiology*; D014828:Vocalization, Animal / Q000502:physiology*