Effect of three semi‐occluded vocal tract therapy programmes on the phonation of patients with dysphonia : lip trill, water‐resistance therapy and straw phonation

Abstract

BACKGROUND : To date, the immediate effects of a semi‐occluded vocal tract (SOVT) configuration have been thoroughly demonstrated. However, it is not yet sufficiently confirmed whether a therapy programme (i.e. longer than one session) using SOVT exercises leads to an enhanced phonation and improved voice quality. AIMS : The aim of this study was to investigate the effect of three SOVT therapy programmes: lip trill, water‐resistance therapy (WRT) and straw phonation, on the vocal quality, vocal capacities, psychosocial impact and vocal tract discomfort of patients with dysphonia. METHODS AND PROCEDURES : A blocked‐randomized sham‐controlled trial was used. Thirty‐five patients with dysphonia (mean age = 21 years; 33 women, two men) were assigned to either a lip trill group, a WRT group, a straw phonation group or a control group using blocked randomization. The lip trill, WRT and straw phonation groups practised their respective SOVT exercise across 3 weeks, whereas the control group received a sham treatment across the same time span. A multidimensional voice assessment consisting of both objective (multiparametric indices: Dysphonia Severity Index (DSI), Acoustic Voice Quality Index (AVQI)) and subjective (subject's self‐report, auditory–perceptual evaluation) vocal outcomes was performed by a blinded assessor pre‐ and post‐therapy. OUTCOMES AND RESULTS : Lip trill and straw phonation therapy led to a significant improvement in DSI. Auditory–perceptual grade and roughness significantly decreased after straw phonation. Lip trill and WRT both led to a significant decrease in Voice Handicap Index. Subjects reported a better self‐perceived vocal quality and a more comfortable voice production after WRT. No changes were found after the sham treatment in the control group. CONCLUSIONS AND IMPLICATIONS : Results suggest that SOVT therapy programmes including lip trill or straw phonation can improve the objective vocal quality in patients with dysphonia. Auditory–perceptual improvements were found after straw phonation therapy, whereas psychosocial improvements were found after lip trill and WRT. Patients seem to experience more comfort and a better self‐perceived vocal quality after WRT. This study supports the use of the three SOVT therapy programmes in clinical practice. They all had a positive impact on one or more outcomes of the multidimensional voice assessment. Strikingly, vocal quality outcomes were not in line with the subject's opinion. Larger‐scale investigation is needed to support these preliminary findings.