Marlene Escher Boger

A influência do espectro de ruído na prevalência de Perda Auditiva Induzida por Ruído em trabalhadores

A Perda Auditiva Induzida por Ruido (PAIR) e uma doenca insidiosa cumulativa, que cresce ao longo dos anos de exposicao ao ruido associado ao ambiente de trabalho. OBJETIVO: Avaliar a influencia do espectro de ruido na prevalencia de PAIR em trabalhadores. MATERIAL E METODO: Trata-se de estudo de coorte historica com corte transversal realizado em industrias metalurgicas, madeireiras e marmorarias, com niveis de ruido acima de 85dB, nas quais avaliou-se o limiar auditivo para as frequencias de 250Hz a 8.000Hz. Na avaliacao ambiental verificou-se a distribuicao da intensidade sonora em filtro de frequencia de oitava. RESULTADOS: Foram realizadas 192 avaliacoes do limiar auditivo precedidas de anamnese ocupacional. Em relacao a PAIR observou-se que 49,0% dos resultados audiometricos apresentam entalhe em frequencias agudas no audiograma. Foram verificadas as medias e o desvio padrao das frequencias a partir de 3.000Hz em todos os trabalhadores, e observa-se que as maiores medias encontram-se na frequencia de 6.000Hz. Nao foi observada associacao entre as bandas de frequencia com niveis intensos de ruido e a frequencia da lesao auditiva. CONCLUSAO: A intensidade do ruido parece ser o principal fator de risco para perda auditiva, independentemente da banda de frequencia.

The noise spectrum influence on Noise-Induced Hearing Loss prevalence in workers

UNLABELLED Noise Induced Hearing Loss (NIHL) is an insidious and cumulative disease that worsens over the years with work-related noise exposure. AIM To evaluate the noise spectrum influence on NIHL prevalence in workers. MATERIALS AND METHODS This a cross-sectional historical cohort carried out in steel mills, lumber mills and marble shops, with noise levels above 85dB, in which we evaluated the auditory thresholds for frequencies from 250Hz to 8,000Hz. To evaluate the work environment, we observed the entire setting, aiming at checking sound intensities in an eighth frequency filter. RESULTS We carried out 192 hearing threshold evaluations after an occupational anamnesis. Concerning NIHL, we noticed that 49% of the audiometry results presented hearing deterioration in the acute frequencies. We studied the mean values and standard deviations for frequencies over 3,000Hz, in all workers, and we observed that the highest average values were in the frequency of 6,000Hz. We did not notice any association among frequency bands carrying intense noise levels and the hearing damage frequency. CONCLUSION Noise intensity seems to be the main risk factor for loss hearing, regardless of frequency range.

Study of the noise spectrum on high frequency thresholds in workers exposed to noise

UNLABELLED Noise level can be quantified and qualified based on sound characteristics such as intensity, type of spectrum, duration and distribution of the noise exposure during ones working hours. OBJECTIVE To assess noise spectrum and the audiometric configuration of workers. MATERIALS AND METHODS Contemporary cross-sectional cohort carried out in the Federal District - Brazil. We did an environmental analysis (spectral analysis) of the noise in companies from different industries, with audiological assessment of 347 workers. RESULTS The spectral analysis revealed peaks at different frequencies for each industry investigated (8 kHz-metallurgical, 4 kHz-stone Works and 2 kHz-wood works). We noticed that the frequencies of 14 kHz and 16 kHz had significant differences between the various industries, with a greater prevalence of the metallurgical. CONCLUSION The use of noise pressure measuring device, coupled to a frequency analyzer and high frequency audiometric assessment yielded an early detection of hearing damage, helping better organize preventive measures.

Analysis of Hearing and Tinnitus in Workers Exposed to Occupational Noise.

INTRODUCTION Noise is one of the harmful agents to health that is present in the various branches of economic activity. Hearing loss and tinnitus are among the most frequently reported complaints by workers exposed to occupational noise. OBJECTIVE To analyze the hearing and tinnitus in normal-hearing workers exposed to occupational noise. METHODS This is a cross-sectional analytical trial in metallurgical industries, in which we evaluated normal-hearing workers through anamnesis, audiometry and otoacoustic emissions. RESULTS It was observed high prevalence of failure of otoacoustic emissions (40%) and tinnitus (66.6%). Both in the amplitude and in the signal-to-noise ratio, the higher is the frequency of the sound, the worse the results. Despite having audiometry within normal limits, the results indicate that workers are suffering the effects of exposure and reveals association between failure of otoacoustic emissions and tinnitus in this population (X2 = 6,732). CONCLUSION It is concluded that failures in DPOAE and tinnitus are predictors of hearing damage in normal-hearing workers.

Otoacoustic Emission in Noise-Exposed Normal Hearing Workers

Objective: Otoacoustic emission test is useful in monitoring hearing changes and cochlear damage by noise still not detectable in pure-tone audiometry.The aim was to evaluate amplitude of the signal and signal/noise ratio of distortion product otoacoustic emissions (DPOAE) in normal hearing workers exposed to different noise doses. Method: This is a cohort prospective study performed in metalworking industries, in 3 groups of normal hearing workers, GI not exposed (n = 50), GII sporadically exposed (n = 50), and GIII often exposed to occupational noise (n = 50). DPOAE were performed after 14 hours of hearing rest. “Pass-fail” criterion was employed for analyses. Results: Six hundred eight workers underwent hearing thresholds, and 150 of them matched the inclusion criteria and had DPOAE recorded. DPOAE alterations in amplitude of signal and signal to noise ratio were found in groups II and III bilaterally, and the higher the frequency tested the lower were the results in GII and GIII (P < .05). The greater the exposure to noise dose the lower the results (P < .05). GI showed better results according to pass and fail criterion and higher amplitude of the signal and signal/noise ratio than GII and GIII (P < .05). Conclusion: DPOAE results are worse in the exposed groups according to occupational noise dose. It is important to search for undetectable hearing changes in all workers exposed to occupational noise even sporadically, and to encourage the use of hearing protectors, in order to prevent possible irreversible damage.