Physiological Effects of Voice Therapy for Aged Vocal Fold Atrophy Revealed by EMG Study

Abstract

ObjectivesAge-related voice changes are characterized as breathy, weak and strained, and a deterioration in vocal function in the elderly has been putatively linked to a reduced intensity of speech. They contribute to undesirable voice changes known as presbyphonia. These changes are caused by histological alterations in the lamina propria of the vocal fold mucosa and atrophy of the thyroarytenoid muscle, as well as by decreased respiratory support. There are several clinical studies on presbylarynx dysphonia showing the effectiveness of voice therapy. However, physiological changes of the presbylarynx following voice therapy have not been verified. The purpose of this prospective study was to demonstrate the clinical effectiveness of voice therapy for rehabilitating presbylarynx dysphonia, using vocal function assessments and thyroarytenoid muscular activity detection on laryngeal electromyography (LEMG). Methods10 patients who were diagnosed with aged vocal fold atrophy from ages 60 to 87 years (mean age: 72 years) underwent approximately 12 weeks of voice therapy, mainly using forward-focused voice and vocal resistance training. Stroboscopic examination, aerodynamic assessment, acoustic analysis, Voice Handicap Index (VHI)-10, and LEMG were performed pre– and post–voice therapy. Vocal fold vibratory amplitude (VFVA) was measured by image analysis from the stroboscopic examinations. Turns analysis during steady phonation on LEMG was also assessed. ResultsMaximum phonation time, subglottic pressure, jitter, shimmer, VFVA, and VHI-10 significantly improved after voice therapy. The number of turns per second on LEMG also significantly increased. ConclusionOur data suggest that voice therapy may improve vocal function and thyroarytenoid muscle activity in patients with aged vocal fold atrophy.