Vocal warm-up and cool-down in teachers: a quasi-experimental controlled study.

Maria Lúcia Vaz Masson,Camila Miranda Loiola-Barreiro,Eliana Maria Gradim Fabbron

doi:10.1590/2317-1782/20182018143

Abstract

To verify the effects of vocal warm-up (VWU) and vocal cool-down (VCD) strategies on teachers. A quasi-experimental exploratory blind-evaluator study with control group that included teachers from a public secondary school. Teachers assigned to the experimental group (EG) performed VW prior to classes and VCD after classes. Teachers in the control group (CG) did not perform VWU and simply got voice rest after classes. Intergroup (EG vs. CG) and intragroup (pre-test versus post-test) comparisons were drawn from an auditory-perceptual evaluation, acoustic analysis, and self-reported discomfort. The mean acoustic and discomfort indicators and the percentage of improvement or worsening of vocal quality were calculated with a statistically significance level of p<0.05. EG and CG did not differ from each other in the intergroup analysis. The intragroup analysis showed that VWU improved voice quality and decreased the degree of body-related discomfort. VCD decreased both the fundamental frequency (f0) and the degree of discomfort, particularly in relation to the voice aspects. Vocal rest did not show any statistical difference. VWU showed positive effects on the auditory-perceptual evaluation and self-reported discomfort (body). VCD impacted f0 and self-reported discomfort (voice). Due to the exploratory nature of the research, the statistical power was not enough to demonstrate a difference in the comparison between EG and CG. However, the results indicate a potential for protecting teachers' voice and may be incorporated into daily work settings. Further controlled studies with random samples and greater numbers of participants should be conducted to confirm these results.

Highlights

Teachers are one of the most prominent professional categories that rely on voice as a work tool
Voice improvement was observed in 75% of teachers, whereas indifference was observed in 25% (p=0.00) with vocal warm-up (VWU); voice worsening (57.1%) and indifference (42.9%) close to the statistical significance (p=0.059) were observed following vocal cool-down (VCD)
The non-randomization of samples, as well as the absence of a homogeneity test between the groups, could potentially induce a selection bias. It allowed for the organization of a protocol of procedures and analyses that may constitute a starting point for new randomized studies with greater statistical power to be conducted, confirming the hypotheses put forward. The results of this exploratory quasi-experimental study conducted with secondary school teachers of a public institution did not show statistically significant difference between the group undertaking vocal warm-up (VWU) before class and vocal cool-down (VCD) after class, compared to the group that did not undertake the first procedure and got vocal rest after class

Summary

Introduction

Teachers are one of the most prominent professional categories that rely on voice as a work tool. Work-related voice disorder (WRVD)(2) is common in teachers and is associated with personal and environmental factors, as well as with factors related to work organization. A literature review indicated an average vocal change prevalence in teachers ranging between 20% and 50%. Higher indexes (63%) have been found for self-reported voice problems[5], followed by vocal change detected by auditory-perceptual assessment (53.6%)(6) and medical diagnosis of “vocal fold pathology” (18.9%)(7), which reveals a reduction of individual perception and evaluations by speech-language therapists and physicians. The female gender, more than seven years in teaching practice, unfavorable work environment, intensive voice use, respiratory disease, hearing loss and common mental disorders were found to be associated with these indexes[7]. High levels of noise, teaching of Physical Education classes, and habitual use of voice at a high intensity were the most consistent indicators[8]

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