The Effects of Amplification on Vocal Dose in Teachers with Dysphonia.

PURPOSE: The purpose of this study was to determine if voice amplification influenced vocal dose in female teachers with dysphonia. MATERIAL AND METHODS: This was an experimental study with comparative intrasubjects in which 15 individuals were compared in two different moments: condition 1 (C1) without voice amplification and condition 2 (C2) with voice amplification. All of them were female, kindergarten and elementary school teachers who presented organic or functional dysphonia. The search was carried out at the school where the teachers work. The professional voice use was considered the teachers' activity for a continuous period of two classes (average recording time of 96 minutes, with no difference in time between C1 and C2). To measure the dose we used the vocal dosimeter composed of a microphone, an accelerometer fixed to the neck, and a portable unit that stores the vocal data. The phonation data (intensity, fundamental frequency, phonation percentage, cycle dose, and distance dose) were analyzed by the equipment software (VoxLog). RESULTS: The use of vocal amplification in teachers promotes a reduction of the fundamental frequency (295.6-267.7 Hz), the voice intensity (96.2-93.3 dB sound pressure level), the cycle doses (489.4-345.2 thousand cycles per second), and distance doses (3,800-2,300 m). CONCLUSION: The vocal amplification allows the teacher to maintain the same phonation time (phonation percentage) but decreases the number of vocal fold oscillations (cycle dose) and the total distance traveled by the vocal fold tissue during phonation (distance dose), reducing the exposure of the vocal folds to voice trauma.

Dose Vocal: uma revisão integrativa da literatura / Vocal dose: an integrative literature review

RESUMO O objetivo da pesquisa foi realizar uma revisão da literatura referente aos tipos de dose vocal e aos resultados destas medidas em diferentes situações comunicativas. Houve levantamento da literatura nacional e internacional, publicada nos idiomas Inglês, Espanhol ou Português, utilizando-se as bases de dados MEDLINE, LILACS, IBECS e ISI (Web of Science), dos últimos 21 anos, cujos artigos estavam disponíveis na íntegra. Quinze estudos contemplaram os critérios propostos. A maioria dos artigos estudou professores, visto que são mais vulneráveis para a ocorrência de disfonia. Os tipos de dose encontrados foram porcentagem de fonação, dose temporal, dose cíclica, dose de distância, dose de energia radiada e dose de energia dissipada. O aumento da dose vocal está associado ao uso excessivo e prolongado da voz na atividade docente, principalmente entre os professores da educação infantil e os de canto. As altas doses vocais correlacionam-se também à presença de disfonia, ao maior nível de ruído ambiental, à grande variação prosódica na fala e à autopercepção de fadiga vocal. Pacientes com disfonia comportamental (nódulos e pólipos) apresentam maiores doses vocais que pacientes com outros quadros disfônicos. Fatores como repouso de voz e uso do amplificador vocal indicam a diminuição da dose da voz.

ABSTRACT This study aimed to perform a literature review about the vocal doses and the behavior of these measurements in different communicative situations. A review on MEDLINE, LILACS, IBECS and ISI Web of Science databases of the literature written in English, Spanish and Portuguese, within the past twenty-one years, of articles which were fully available, was performed. Fifteen studies met the set criteria. The majority of the articles studied teachers, since they belong to a vulnerable group for dysphonia. The doses found were phonation percentage, time dose, cycle dose, distance dose, energy dissipation dose and radiated energy dose. The vocal dose increase is associated with an excessive and prolonged voice use in teaching activity, especially when teaching young children and teaching music. The high vocal doses are also associated with the presence of dysphonia, the background noise, the large prosodic variation in speech and the self-perception of vocal fatigue. Patients with behavioral dysphonia (nodes and polyps) present higher vocal doses than patients with other types of dysphonia. Factors such as voice rest and use of voice amplifiers indicate a decrease of vocal dose.