VentiMask: The Effect of Semi-Occluded Vocal Tract Exercises With a Ventilation Mask in Adults With Inconsistent Velopharyngeal Dysfunction Due to Cleft Palate

Purpose: Treating mild passive speech errors in adults with a structurally competent velopharyngeal mechanism is challenging. Task-specific interventions that mimic speech conditions may hold potential. This study investigated the effect of semi-occluded vocal tract (SOVT) exercises, namely, water resistance tube phonation with a ventilation mask, to improve speech and health-related quality of life (HRQoL) in adults with inconsistent velopharyngeal dysfunction (VPD) and mild passive speech errors due to cleft palate. Method: Two male adults (19 and 36 years old) with inconsistent VPD and mild passive speech errors participated in a single-case study to evaluate the effects of a sham intervention (SOVT with a ventilation mask without phonation) versus an active speech intervention (SOVT with a ventilation mask with phonation). The study consisted of five consecutive phases: (1) baseline, (2) sham, (3) withdrawal, (4) active intervention, and (5) maintenance. The active intervention was administered over 2 weeks (five sessions per week, 1 hr per session). Outcomes included (a) perceptual ratings of speech, (b) instrumental nasalance scores, and (c) patient-reported HRQoL. Results: Both participants demonstrated stable baselines across all speech and HRQoL measures during the pre-intervention and sham phases, indicating no effect of the sham intervention. Marked improvements were observed following the active intervention. In both cases, speech understandability and acceptability improved to within normal limits, and passive speech errors were reduced. Additionally, both participants reported clinically meaningful improvements in HRQoL, with sustained benefits observed at the 4-week follow-up. Conclusions: This study provides preliminary evidence that water resistance tube phonation with a ventilation mask is a promising, task-specific intervention for adults with cleft palate who present with inconsistent VPD and mild passive speech errors. Future studies should examine the efficacy of this intervention in larger, randomized controlled trials; explore the role of prior surgical history in treatment responsiveness; and assess long-term outcomes using direct aerodynamic measures.