Treatment of Vocal Fold Bowing Using Neuromuscular Electrical Stimulation

Abstract

To investigate the clinical effectiveness and safety of a novel behavioral voice therapy program combining structured vocal exercise with adjunctive neuromuscular electrical stimulation for rehabilitating dysphonia secondary to vocal fold bowing. Prospective interventional clinical case series with a 3-month follow-up. Outpatient speech and hearing clinic in an academic medical center. Convenience sample of 7 patients diagnosed by an otolaryngologist as having chronic dysphonia for at least 3 months due to bilateral vocal fold bowing. A novel voice therapy program incorporating exercise principles and sustained phonations of increasing length, volume, and pitch paired with concurrent transcutaneous neuromuscular electrical stimulation. Change in maximum phonation time, highest attainable pitch, glottal closure, supraglottic compression, and Voice Handicap Index. Maximum phonation time for /i/ increased significantly (z = -2.201, P < .03), with a modest effect demonstrated (Hedges g, 0.65; 95% confidence interval, -0.56 to 1.75). Voice Handicap Index trended toward significance (z = -1.787, P < .07). Glottal closure during phonation improved, and supraglottic compression decreased. Improvements were maintained or enhanced at the 3-month follow-up. Analysis of highest attainable pitch data was limited owing to aperiodicity in the baseline evaluations. Behavioral voice therapy with adjunctive neuromuscular electrical stimulation reduced vocal fold bowing, resulting in improved acoustic, laryngeal, and patient-centered outcomes. Maximum phonation time and glottal closure results imply increased vocal fold tension secondary to enhanced thyroarytenoid or cricothyroid muscle function after voice therapy.