Effect of Semi-occluded Vocal Tract Therapy on the Phonation of Children With Vocal Fold Nodules

The goal of this clinical trial is to determine and compare the effects of different voice therapy programs in children with vocal fold nodules. Vocal fold nodules are non-cancerous growths on the vocal folds which cause hoarseness. The main questions this trial aims to answer are: What are the short-term effects of the new voice therapy program 'straw phonation' and a more traditional 'resonant voice therapy' program on (a) the vocal quality, (b) the size of the growths on the vocal folds, and (c) the overall functioning in children with vocal fold nodules? During straw phonation exercises, you make sound through a drinking straw. During resonant voice therapy exercises or 'humming', you make an 'm' sound as you breathe out. What are the long-term effects of these voice therapy programs? Participants will receive a short-term intensive voice therapy program of four days. The researchers will compare the straw phonation group, resonant voice therapy group and control group to see if voice therapy works well in treating children with vocal fold nodules. The researchers hypothesize that straw phonation will have better results than resonant voice therapy. Straw phonation exercises are easier for children because they use an external tool (the straw) and less self-correction is needed.

Background: The main goal of voice therapy in children with vocal fold nodules is to improve their communication, vocal quality and wellbeing. However, in this population, efficacy or effectiveness studies of voice therapy are extremely limited and show methodological shortcomings. There is an urgent need to understand the impact of different semi-occluded vocal tract (SOVT) techniques on the multidimensional facets of voice, as these SOVT exercises are frequently used in clinical practice. The common feature of these exercises is a reduction in the cross-sectional area of the vocal tract while voicing. Results of this project will have an impact on evidence-based voice therapy in children and consequently on reimbursement agreements of the health care system in the future. This fundamental research regarding the impact of SOVT techniques on the voice can also lead to the development and improvement of SOVT techniques. Purposes: The first purpose of this project is to determine and compare the short-term effect of a "non-intuitive" SOVT therapy program (straw phonation) with a more traditional "intuitive" resonant voice therapy program of one week on (a) the vocal quality, (b) the laryngeal anatomy and function, and (c) the psychosocial wellbeing in children (aged between 6 and 12 years) with vocal fold nodules using a randomized sham-controlled trial. The second purpose of this project is to determine and compare the long-term effect of these voice therapy programs on (a) the vocal quality, (b) the laryngeal anatomy and function, and (c) the psychosocial wellbeing of the children. Hypotheses: Giving the promising physics of an SOVT, a positive short-term effect of straw phonation and resonant voice therapy is hypothesized. However, the non-intuitive technique straw phonation is expected to be in favor for a pediatric population. For these exercises, semi-occlusions are created by an external tool and instructions, feedback, and self-corrections can be reduced to a minimum. These factors might lead to faster results, which might in turn reduce feelings of frustration and demotivation by the children. Study design: A longitudinal randomized sham-controlled trial will be used. Patients will be randomly assigned to one of the 2 treatment groups "straw phonation", "resonant voice therapy", or the control group receiving a "sham treatment". Innovativity: This research will be innovative because of (a) the topic and study population (SOVT in children between 6 and 12 years) which is an underexposed domain in literature; (b) the methods investigating multidimensional facets of voice (c) the randomized sham-controlled study design using a large study group, a control group receiving sham treatment, random allocation of participants and blinded assessors and (d) the combination of short-term and long-term outcome. Participants: Inclusion criteria and exclusion criteria are described further in the application. Voice assessment: A standardized and multidimensional voice assessment including both objective and subjective vocal outcomes will be performed to evaluate the participants' voice pre and post-therapy, and at 3 months and 6 months follow-up. The multidimensional voice assessment will consist of the following outcomes: (a) vocal quality, (b) laryngeal anatomy and function, and c) psychosocial wellbeing. Assessments (a) and (c) will be performed in a sound-treated room at Ghent University Hospital by speech-language pathologists experienced in voice diagnostics. Assessments (b) will be performed by experienced otorhinolaryngologist. All assessors will be blinded to group allocation and study evolution. A detailed overview of the outcome characteristics is described further in the application. Voice therapy: The content of the different therapy arms / interventions is described further in the application. Statistical analysis: Linear mixed model analyses (LMM) will be used to determine whether there is a difference in evolution between the groups over time. Post-hoc pairwise comparisons with Bonferroni corrections will uncover specific within and between group differences. Intraclass correlation coefficients models and Cohen's κ will be used to determine inter- ant intrarater reliability.

Short-term intensive voice therapy program of one week (3 hours a day for 4 consecutive days): straw phonation and vocal hygiene recommendations

Short-term intensive voice therapy program of one week (3 hours a day for 4 consecutive days): resonant voice therapy and vocal hygiene recommendations

Short-term intensive voice therapy program of one week (3 hours a day for 4 consecutive days): vocal hygiene recommendations

The two experimental groups will receive either straw phonation therapy or resonant voice therapy. The hierarchical structure of the therapy sessions will be equal for the three programs. In each session, vocal rest pauses will be foreseen by playing games, performing drawing assignments, etc. This will make the therapy more pleasant and less intensive. All voice therapy programs will be guided by the same experienced voice therapist. Content: Day 1: counseling (anatomy and physiology of the voice and vocal fold nodules), vocal hygiene recommendations (water intake, avoiding vocal misuse and abuse) Day 2: breathing exercises, vocal hygiene recommendations, straw phonation on vowel and syllable level, pitch variations Day 3: breathing exercises, vocal hygiene recommendations, straw phonation on word and sentence level, pitch variations Day 4: straw phonation in spontaneous speech, combination exercises

The two experimental groups will receive either straw phonation therapy or resonant voice therapy. The hierarchical structure of the therapy sessions will be equal for the three programs. In each session, vocal rest pauses will be foreseen by playing games, performing drawing assignments, etc. This will make the therapy more pleasant and less intensive. All voice therapy programs will be guided by the same experienced voice therapist. Content: Day 1: counseling (anatomy and physiology of the voice and vocal fold nodules), vocal hygiene recommendations (water intake, avoiding vocal misuse and abuse) Day 2: breathing exercises, vocal hygiene recommendations, resonant voice therapy on vowel and syllable level, pitch variations Day 3: breathing exercises, vocal hygiene recommendations, resonant voice therapy on word and sentence level, pitch variations Day 4: resonant voice therapy in spontaneous speech, combination exercises

Participants of the control group will receive a sham treatment, including the exact same games, drawing assignments, etc. as in the experimental groups. However, no SOVT or other active vocal techniques will be practiced. Vocal hygiene guidelines (e.g. avoid screaming, imitating voices, sufficient hydration etc.) will be kept equally in the four groups. All voice therapy programs will be guided by the same experienced voice therapist. Content: Day 1: counseling (anatomy and physiology of the voice and vocal fold nodules), vocal hygiene recommendations (water intake, avoiding vocal misuse and abuse) Day 2: breathing exercises, vocal hygiene recommendations Day 3: breathing exercises, vocal hygiene recommendations Day 4: combination exercises

The dysphonia severity index (DSI) is a multiparametric score to quantify vocal capabilities. It is based on a weighted combination of 4 voice parameters: maximum phonation time (MPT, s), highest frequency (F-high, Hz), lowest intensity (I-low, dB) and jitter (%). The DSI is constructed as 0.13 MPT + 0.0053 F-high - 0.26 I-low - 1.18 jitter +12.4. The index ranges from -5 to +5. A score above +1.6 is considered normal.

The acoustic voice quality index (AVQI) is a multiparametric score to quantify vocal quality. It is based on a weighted combination of 6 voice parameters: smoothed cepstral peak prominence (CPPS), harmonics-to-noise ratio (HNR), shimmer local (SL), shimmer local dB (SLdB), general slope of the spectrum (slope) and tilt of the regression line through the spectrum (tilt). The formula is constructed as 9.072 - 0.245 × CPPs - 0.161 × HNR - 0.470 × SL + 6.158 × SLdB - 0.071 × Slope - 0.170 × Tilt and ranges from 0 to 10. A lower score correlates with a better vocal quality.

The pediatric voice handicap index (pVHI) is a questionnaire to investigate children's voice-related quality of life, completed by the parents. The index ranges from 0 to 92. A higher score correlates with more psychosocial impact of the voice disorder.

The GRBASI-scale (Grade, Roughness, Breathiness, Asthenicity, Strain, Instability) is used for the perceptual evaluation of vocal quality. Each parameter will be scored with 0 (normal), 1 (mild impairment), 2 (moderate impairment) or 3 (severe impairment). The parameter 'grade' correlates with the overall grade of hoarseness.

The size of the vocal fold nodules will be evaluated using a grading scale for pediatric vocal fold nodules, developed by Nuss et al. (2012). Grade 0 corresponds with no present nodule, grade 1 with nodules protruding less than 0.5 mm, grade 2 with nodules protruding 0.5 to 1.0 mm, ang grade 3 with nodules protruding more than 1 mm.

Inclusion Criteria: children aged between 6 and 12 years (primary school) diagnosed with vocal fold nodules by an otorhinolaryngologist and speech-language pathologist experienced in voice diagnostics. Exclusion Criteria: nasal or ear diseases neurological disorders

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