title: Effects of Functional Electrical Stimulation on Denervated Laryngeal Muscle in a Large Animal Model.
abstract: Bilateral vocal fold paralysis (BVCP) is a life-threatening condition that follows injury to the Recurrent Laryngeal nerve (RLn) and denervation of the intrinsic laryngeal musculature. Functional electrical stimulation (FES) enables restoration and control of a wide variety of motor functions impaired by lower motor neuron lesions. Here we evaluate the effects of FES on the sole arytenoid abductor, the posterior cricoarytenoid (PCA) muscle in a large animal model of RLn injury. Ten horses were instrumented with two quadripolar intramuscular electrodes in the left PCA muscle. Following a 12-week denervation period, the PCA was stimulated using a once-daily training session for 8 weeks in seven animals. Three animals were used as unstimulated controls. Denervation produced a significant increase in rheobase (P < 0.001). Electrical stimulation produced a 30% increase in fiber diameter in comparison with the unstimulated control group (33.9 ± 2.6 µm FES+, 23.6 ± 4.2 µm FES-, P = 0.04). A trend toward a decrease in the proportion of type 1 (slow) fibers and an increase in type 2a (fast) fibers was also observed. Despite these changes, improvement in PCA function at rest was not observed. These data suggest that electrical stimulation using a relatively conservative set of stimulation parameters can reverse the muscle fiber atrophy produced by complete denervation while avoiding a shift to a slow (type 1) fiber type.
authors.affiliation: Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, USA.
authors.forename: Jon
authors.initials: J
authors.lastname: Cheetham
authors.affiliation: Comparative Neuromuscular Disease Laboratory, Royal Veterinary College, London.
authors.forename: Justin D
authors.initials: JD
authors.lastname: Perkins
authors.affiliation: Liverpool John Moores University, Liverpool, UK.
authors.forename: Jonathan C
authors.initials: JC
authors.lastname: Jarvis
authors.affiliation: Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, USA.
authors.forename: Marta
authors.initials: M
authors.lastname: Cercone
authors.affiliation: Med-el, Innsbruck, Austria.
authors.forename: Martin
authors.initials: M
authors.lastname: Maw
authors.affiliation: Department of Biomedical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, USA.
authors.forename: John W
authors.initials: JW
authors.lastname: Hermanson
authors.affiliation: Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, USA.
authors.forename: Lisa M
authors.initials: LM
authors.lastname: Mitchell
authors.affiliation: Comparative Neuromuscular Disease Laboratory, Royal Veterinary College, London.
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Piercy
authors.affiliation: Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, USA.
authors.forename: Norm G
authors.initials: NG
authors.lastname: Ducharme
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D004599:Electric Stimulation Therapy / Q000379:methods; D004567:Electrodes, Implanted; D006736:Horses; D007821:Laryngeal Muscles / Q000294:innervation / Q000473:pathology / Q000502:physiology*; D061226:Recurrent Laryngeal Nerve Injuries / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology / Q000628:therapy; D014057:Tomography, X-Ray Computed; D014826:Vocal Cord Paralysis / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology / Q000628:therapy
keywords: Equine; Functional electrical stimulation; Larynx; Neuroprosthesis; Reanimation