Treatment of vocal fold bowing using neuromuscular electrical stimulation

Objective: 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. Design: Prospective interventional clinical case series with a 3-month follow-up. Setting: Outpatient speech and hearing clinic in an academic medical center. Patients: Convenience sample of 7 patients diagnosed by an otolaryngologist as having chronic dysphonia for at least 3 months due to bilateral vocal fold bowing. Intervention: A novel voice therapy program incorporating exercise principles and sustained phonations of increasing length, volume, and pitch paired with concurrent transcutaneous neuromuscular electrical stimulation. Main Outcome Measures: Change in maximum phonation time, highest attainable pitch, glottal closure, supraglottic compression, and Voice Handicap Index. Results: 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). VoiceHandicapIndex trendedtowardsignificance (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. Conclusions: 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.