The effect of surface electrical stimulation on hyolaryngeal movement in normal individuals at rest and during swallowing

• Published in: Journal of applied physiology (1985) 2006-12, Vol.101 (6), p.1657-1663
• Main Authors: Humbert, Ianessa A, Poletto, Christopher J, Saxon, Keith G, Kearney, Pamela R, Crujido, Lisa, Wright-Harp, Wilhelmina, Payne, Joan, Jeffries, Neal, Sonies, Barbara C, Ludlow, Christy L
• Format: Article
• Language: English
• Subjects: Adult; Biological and medical sciences; Deglutition - physiology; Deglutition Disorders - diagnostic imaging; Deglutition Disorders - physiopathology; Deglutition Disorders - therapy; Effects; Electric Stimulation - methods; Electric Stimulation Therapy - methods; Female; Fundamental and applied biological sciences. Psychology; Humans; Hyoid Bone - diagnostic imaging; Hyoid Bone - physiology; Larynx - diagnostic imaging; Larynx - physiology; Male; Medical equipment; Middle Aged; Movement - physiology; Muscular system; Neck; Neck Muscles - diagnostic imaging; Neck Muscles - innervation; Neck Muscles - physiology; Radiography; Reference Values; Rest - physiology; Therapy
• ISSN: 8750-7587; 1522-1601
• DOI: 10.1152/japplphysiol.00348.2006

1 Laryngeal and Speech Section, National Institutes of Neurological Disorders and Stroke, Bethesda, Maryland; 2 Department of Communication Sciences and Disorders, Howard University, Washington, District of Columbia; 3 Office of the Clinical Director, National Institutes of Neurological Disorders and Stroke, Bethesda, Maryland; and 4 Department of Rehabilitation of the Clinical Center, National Institutes of Health, Bethesda, Maryland Submitted 23 March 2006 ; accepted in final form 18 July 2006 Surface electrical stimulation is currently used in therapy for swallowing problems, although little is known about its physiological effects on neck muscles or swallowing. Previously, when one surface electrode placement was used in dysphagic patients at rest, it lowered the hyolaryngeal complex. Here we examined the effects of nine other placements in normal volunteers to determine 1 ) whether movements induced by surface stimulation using other placements differ, and 2 ) whether lowering the hyolaryngeal complex by surface electrical stimulation interfered with swallowing in healthy adults. Ten bipolar surface electrode placements overlying the submental and laryngeal regions were tested. Maximum tolerated stimulation levels were applied at rest while participants held their mouths closed. Videofluoroscopic recordings were used to measure hyoid bone and subglottic air column (laryngeal) movements from resting position and while swallowing 5 ml of liquid barium, with and without stimulation. Videofluoroscopic recordings of swallows were rated blind to condition using the National Institutes of Health-Swallowing Safety Scale. Significant ( P < 0.0001) laryngeal and hyoid descent occurred with stimulation at rest. During swallowing, significant ( P 0.01) reductions in both the larynx and hyoid bone peak elevation occurred during stimulated swallows. The stimulated swallows were also judged less safe than nonstimulated swallows using the National Institutes of Health-Swallowing Safety Scale ( P = 0.0275). Because surface electrical stimulation reduced hyolaryngeal elevation during swallowing in normal volunteers, our findings suggest that surface electrical stimulation will reduce elevation during swallowing therapy for dysphagia. dysphagia; videofluoroscopy; neuromuscular stimulation; neck muscles Address for reprint requests and other correspondence: C. L. Ludlow, Laryngeal and Speech Section, National Institutes of Neurological Disorders and Stroke, 10 Center Dri