Short-Term Effects of Semi-Occluded Vocal Tract Therapy on the Phonation of Children With Vocal Fold Nodules: A Randomized Controlled Trial

Abstract

PURPOSE: The aim was to determine and compare the short-term effects of two intensive semi-occluded vocal tract (SOVT) programs, "straw phonation" (SP) and "resonant voice therapy" (RVT), on the phonation of children with vocal fold nodules. METHOD: A pretest-posttest randomized controlled study design was used. Thirty children aged 6-12 years were randomly assigned to the SP group (n = 11), RVT group (n = 11), or control group receiving indirect treatment (n = 8) for their voice problems. All participants received 11 hr of group voice therapy over four consecutive days. A multidimensional voice assessment consisting of both objective (dysphonia severity index and acoustic voice quality index) and subjective (pediatric voice handicap index and perceptual rating of overall severity) measures was performed pre- and posttherapy. Voice therapy effectiveness was evaluated using group-level analyses (linear mixed models) and individual-level analyses to investigate what proportion of participants changed to a clinically relevant degree. RESULTS: Group-level analyses found no significant Time × Group interactions, indicating that the evolution over time did not differ among the three groups. Within-group effects of time showed a significant and equal improvement in dysphonia severity index in the SP and RVT groups and a significant improvement in perceptual rating of overall severity in the SP group. For dysphonia severity index, individual-level analyses showed that 36% and 45% of participants improved to a clinically relevant degree in the SP and RVT groups, respectively. For acoustic voice quality index, 38% improved to a clinically relevant degree in the SP group. CONCLUSIONS: Results suggest that short-term intensive SOVT programs may have a positive effect on voice quality and vocal capacities of children with vocal fold nodules. Participants seem to benefit more from a SP program than a RVT program.