Rafaella Cristina Oliveira

Effect of classroom acoustics on the speech intelligibility of students

PURPOSE To analyze the acoustic parameters of classrooms and the relationship among equivalent sound pressure level (Leq), reverberation time (T₃₀), the Speech Transmission Index (STI), and the performance of students in speech intelligibility testing. METHODS A cross-sectional descriptive study, which analyzed the acoustic performance of 18 classrooms in 9 public schools in Belo Horizonte, Minas Gerais, Brazil, was conducted. The following acoustic parameters were measured: Leq, T₃₀, and the STI. In the schools evaluated, a speech intelligibility test was performed on 273 students, 45.4% of whom were boys, with an average age of 9.4 years. The results of the speech intelligibility test were compared to the values of the acoustic parameters with the help of Students t-test. RESULTS The Leq, T₃₀, and STI tests were conducted in empty and furnished classrooms. Children showed better results in speech intelligibility tests conducted in classrooms with less noise, a lower T₃₀, and greater STI values. The majority of classrooms did not meet the recommended regulatory standards for good acoustic performance. CONCLUSION Acoustic parameters have a direct effect on the speech intelligibility of students. Noise contributes to a decrease in their understanding of information presented orally, which can lead to negative consequences in their education and their social integration as future professionals.

The impact of noise exposure on workers in Mobile Support Units

PURPOSE To investigate the presence of auditory and nonauditory symptoms in professionals working in ambulances. METHODS This was a descriptive cross-sectional study with a convenience sample. Thirty-six professionals working in mobile support units, including drivers and nursing technicians from two private urgency and emergency services in the city of Belo Horizonte, Minas Gerais, Brazil, participated in the study. A questionnaire containing 17 multiple-choice questions was applied to the participants with questions regarding life history and occupation, family history of hearing loss, use of medications, and presence of auditory and nonauditory symptoms, among others. The professionals answered the questionnaire individually, in their workplaces, and received help from the researcher to understand the content of questions, if needed. Data were statistically analyzed using the Statistical Package for the Social Sciences (SPSS) software, version 16.0. RESULTS The most reported auditory symptoms were tinnitus, intolerance to intense sounds, and ear plenitude. The most reported nonauditory symptoms were irritability, headache, talking difficulties in noisy environments, and sleep alterations. A difference (p≤0.05) was observed when the relation between self-perception of drivers and nursing technicians on hearing acuity, presence of tinnitus, irritability, and communication difficulty was analyzed. CONCLUSION Auditory and nonauditory symptoms are frequent in workers from mobile support units. An association between the workers symptoms and the performed function was also observed. The results indicate a need of developing preventive actions regarding general health, which are aimed at the preservation of hearing health and quality of life of these professionals.

A mass-spring model of the auditory system in otosclerosis

INTRODUCTION: This paper aims to describe a model to simulate otosclerosis using a mass-spring model and to correlate the results with the clinical and audiological data on the disease. METHODS: A mass-spring model was used to represent the behavior of the auditory system simulating otosclerosis. The model consisted of six masses (air volume in the external auditory canal; tympanic membrane; malleus; incus; stapes, and cochlear fluid), springs and dashpots simulating the supporting ligaments and muscles. The parameters to simulate the disease were obtained from the literature; stapedial annular ligament stiffness was increased by 10-fold and to 100-fold and stapes mass increased by 5-fold. RESULTS: There was a decrease in stapes displacement in the lower frequencies when the stiffness of the stapedial annular ligament was increased. It was also found a reduction in stapes displacement in the higher frequencies with increased stapes mass. CONCLUSION:The increased stiffness of the stapedial annular ligament can be an indication of early stage disease, whereas increased bone growth suggests disease progression. The results of the simulation are in agreement with the clinical and audiological disease and support the need for further study of the stapedial annular ligament to find ways to evaluate its functioning and thus enable early detection of hearing losses caused by changes in that structure.