Chronic intermittent stimulation of the thyroarytenoid muscle maintains dynamic control of glottal adduction.
Patients with laryngeal motor control disorders need improved dynamic glottal closure for speech and swallowing. To evaluate the functional outcome of intermittent chronic thyroarytenoid muscle stimulation in an animal model, 6 canines were implanted with bilateral Medtronic Xtrel systems containing Peterson-type electrodes in the inferior and superior portions of the thyroarytenoid muscle. Stimulation was on one side only at 60 Hz, for 5 s on and 5 s off, over 8 h, 5 days per week, up to 8 months. Monthly videorecordings were done under anesthesia to measure the voltage threshold for detectable movement on each side, and vocal fold displacement and velocity during maximal stimulation of each side. Movement thresholds were lower in the inferior portion of the thyroarytenoid muscle (P </= 0.0005). Movement velocity was greater on the stimulated than on the nonstimulated side after 3 to 8 months (P = 0.039). No differences in the percentage distribution of different myosin heavy chain types were found between the stimulated and nonstimulated muscle samples. Sustained dynamic glottal adduction with no alteration in thyroarytenoid muscle function or fiber type was achieved with intermittent stimulation over 8 months. The results suggest that chronic intermittent thyroarytenoid stimulation has good potential for improving airway protection in dysphagia.
Ludlow
C L
CL
Laryngeal and Speech Section, Medical Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Building 10, Room 5D38, 10 Center Drive, MSC 1416, Bethesda, Maryland, 20892-1416, USA. ludlowc@ninds.nih.gov
Bielamowicz
S
S
Daniels Rosenberg
M
M
Ambalavanar
R
R
Rossini
K
K
Gillespie
M
M
Hampshire
V
V
Testerman
R
R
Erickson
D
D
Carraro
U
U
D000818:Animals; D001696:Biomechanical Phenomena; D004285:Dogs; D004558:Electric Stimulation; D004567:Electrodes, Implanted; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D005931:Glottis / Q000000981:diagnostic imaging / Q000378:metabolism / Q000502:physiology*; D007821:Laryngeal Muscles / Q000000981:diagnostic imaging / Q000378:metabolism / Q000502:physiology*; D008297:Male; D018995:Myosin Heavy Chains / Q000378:metabolism; D013686:Telemetry; D013997:Time Factors; D014057:Tomography, X-Ray Computed; D014827:Vocal Cords / Q000502:physiology
D018995:Myosin Heavy Chains