Diagnóstico de disfonia vocal em professores de um minicípio do interior do Rio Grande do Sul por espectroscopia de absorção molecular no infravermelho com transformada de Fourier.

Abstract

INTRODUCTION: Voice, pointed as an essential component in communication between people, conveys feelings, messages and words. For the teacher, the voice is an essential tool to carry out its activity, since it requires a constant relation of emission-reception between teacherstudent. Therefore, the prevention and promotion of vocal health becomes a focus of attention, since it fights future vocal problems including dysphonia. PURPOSE: To evaluate the potentialities of FT-IR to diagnose the disposition of vocal dysphonia and stress in education professionals. Abstract of article I: Application of salivary infrared spectroscopy and chemometrics to predict vocal changes and stress: a study model with education professionals. Objective: To identify the potentialities of salivary infrared spectroscopy to evaluate the degree of perceived stress, as well as the grade G of GRBAS scale. Method: A total of 47 profissionals from four educational institutions were evaluated (at beginning and after a minimum of 3 h of work) by Perceived Stress Scale (PSS), GRBAS scale, vocal anmnesis questionnaire, and submeted to passive salivar collecting. PSS index was modeled with spectral data (Attenuated Total Reflection, 4000-650 cm-1) by partial least square (PLS) regression and the grade G of GRBAS scale by PLS lonely or associated with discriminant analysis (PLS-DA). Results: G score range from 0 to 2, and the PSS index from 11 to 29 with positive association between both in the range 0-1 and negative associaition in the range 1-2. PLS models presented good performance (R2 > 0.999) concerning to reference values for both PSS index (RMSEP = 0.1416; RSD = 0.70%) and G score (RMSEP = 0.0101; RSD = 1.69%). Alternatively, G score can also be predicted by the PLS-DA algorithm with similar performance. Conclusion: Salivary infrared spectroscopy has the potential to quantify the G of GRBAS in mild disphonies (0 < G < 2) and the associated and perceived stress index at last month, and can be applied to characterize such parameters in substitution to reference methods (PSS questionnaire and GRBAS scale). Abstract of the article II: A new non-invasive approach based on salivary infrared spectroscopy and chemometrics for the evaluation of maximum phonation times.Objective: To evaluate the potential of salivary infrared spectroscopy in association with chemometrics to predict the maximum phonation times (MPTs) /A/, /I/, /U/, /S/, /Z/. Methods: A total of 47 subjects (mean age of 40 years, 89,4% females) from four educational institutions were evaluated by vocal anamnesis at the beginning and after a minimum of 3 h of work. MPTs e saliva were collected at these times. Saliva samples were analysed by Attenuated Total Reflection and the data (spectra + MPTs) were correlated and modeled by chemometrics using partial least squares (PLS) regression. Results: All the means of the final MPTs were smaller than the respective initial means final after the work shift (p ≤ 0,03, more evident in males). MPTs /S/, /Z/ presented a greater association between final and initial evaluations (R = 0.80628 and 0.82662, respectively). The correlation between the first derivative salivary spectra and the respective MPTs by PLS regression allowed the elaboration of chemometric models with high predictive quality (R2 > 0.999; RMSEP < 0.30 s; 0.5% < RSD <1.7%) for all MPTs. Conclusions: Salivary FTIR arises as a new approach to streamline and make more objective the determination of MPTs /A/, /I/, /U/, /S/, /Z/. This condition makes possible the correction of biases and systematic errors in the evaluations of such parameters during vocal anamnesis.