Effects of Mechanical Vibration Stimulation of the Larynx on Voice Production.

ABSTRACT

INTRODUCTION: Combining mechanical vibration stimulation with resistance training to improve neuromuscular performance is a method that has gained popularity in the field of sports sciences. PURPOSE: To evaluate the immediate and mid-term effects of mechanical vibration stimulation (G-Life NL3000) of the larynx associated to vocal exercises. METHOD: Fourteen professional voice users divided into Experimental Group - Seven participants who performed a 20-minute exercise protocol with humming applying mechanical vibration stimulation (G-Life NL3000) of the larynx once a day for 30 days; Control Group - Seven participants who performed only the 20-minute exercise protocol with humming. For comparison purposes, the evaluation was carried out pre-stimulation, immediately after simulation (post) and 30 days after stimulation (late-post). RESULTS: The Experimental Group showed a statistically significant progress in the post-immediate evaluation and in the post-treatment evaluation for maximum phonation time (*P = < 0.001), Jitter (*P = 0.008), Shimmer (*P = 0.005), noise-to-harmonics ratio (*P = 0.005). In the GRBASI scale, the Experimental Group showed significant results in the post-treatment evaluation for Grade (*P = 0.005), Roughness (*P = 0.008), Breathiness (*P = 0.018) and Instability (*P = 0.018). A self-perception voice questionnaire showed better voice quality (*P= 0.031) and easier phonation (*P = 0.005) in the Experimental Group. CONCLUSION: Mechanical vibration stimulation of the larynx associated to humming produced positive changes in the vocal pattern and significantly improvement in short and mid-term vocal quality for participants in this study.