Verifying efficacy of self-inhalation training for velopharyngeal dysfunction -Velopharyngeal closure in healthy adults during different tasks-

Abstract

Objective: Velopharyngeal dysfunction causes not only resonance problems (so called “hypernasality”) but also dysphagia particularly in the elderly. In our previous study, we developed a new inhaling training method to objectively improve velopharyngeal function using measurement of peak inspiratory flow (PIF) rate, which was effective in all patients. In this study, we clarify the degree of velopharyngeal closure to determine the efficacy of our training to improve the closure mechanism. Methods: Three healthy volunteers performed tasks in a magnetic resonance imaging (MRI) gantry in the supine position. To confirm velopharyngeal function, volunteers were first asked to distinguish the difference in the velum position between the production of a nonnasal (sustained phonation /shi:/) and a nasal (sustained phonation /n:/) sound. They were then asked to inhale forcefully through the mouth from an empty 500-ml plastic bottle. For comparison, volunteers performed exhaling forcefully, then inhaling and exhaling softly, through a straw. Each task was performed for 30 seconds, and the MRI images were obtained in sagittal sections. Results: Inhaling forcefully from an empty plastic bottle created the strongest velopharyngeal closure between posterior surface of velum (soft palate) and posterior pharyngeal wall in all volunteers. Conclusion: The results of our MRI study supported our training method. Using inhalation through a PIF meter or from a plastic bottle to create resistance strengthens particularly the levator veli palatini muscle for velopharyngeal closure, which may be useful in patients with other acquired velopharyngeal dysfunctions including physiological aging. Also, anyone, anywhere can train with plastic bottles.