ABSTRACT
BACKGROUND: The aim of the study was to assess the noise exposure and risk of noise-induced hearing loss (NIHL) among users of communication headsets (CHs) or headphones. MATERIAL AND METHODS: Noise measurements and questionnaire surveys were carried out in 74 workers (aged: 31.8±7.3 years), including military aviation personnel (N = 12), transcribers (N = 18) and call center operators (N = 44). Sound pressure levels (SPLs) emitted by CHs (or headphones) were determined using the microphone in the real ear (MIRE) technique and artificial ear techniques according to PN-EN ISO 11904-1:2008 and CSA Z107.56-13, respectively. The risk of NIHL was evaluated in accordance with PN-ISO 1999:2000. RESULTS: The diffused-field-related A-weighted equivalent-continuous SPLs measured under CHs (or headphones) using the MIRE and artificial ear techniques reached values of 67-86 dB (10-90th percentile) and 68-89 dB (10-90th percentile), respectively. The study subjects used these devices 1.5-8 h (10-90th percentile) per day. Exposure to such noise levels for 40 years of employment causes the risk of hearing impairment (mean hearing threshold level for 2, 3 and 4 kHz > 25 dB) up to 10-12% (MIRE technique) or 19-22% (artificial ear technique). Individual daily noise exposure levels in study group varied 71-85 dB (10-90th percentile). A number of workers complained of problems with understanding speech in noisy environment (28.4%) and hearing whisper (16.2%) and experienced post-work temporary hearing symptoms (16.2-25.7%) as well. CONCLUSIONS: The users of CHs and headphones should be included in the hearing conservation program. Further studies are also needed among employees of other industries. Med Pr. 2019;70(1):27-52.
Subject(s)
Hearing Loss, Noise-Induced/etiology , Noise, Occupational/adverse effects , Occupational Exposure/analysis , Adult , Audiometry , Aviation , Female , Hearing Loss, Noise-Induced/epidemiology , Humans , Male , Military Personnel , RiskABSTRACT
INTRODUCTION: The overall objective of the study was to assess noise exposure and audiometric hearing threshold levels (HTLs) in call center operators. MATERIALS AND METHODS: Standard pure-tone audiometry and extended high-frequency audiometry were performed in 78 participants, aged 19 to 44 years (mean ± standard deviation: 28.1 ± 6.3 years), employed up to 12 years (2.7 ± 2.9 years) at one call center. All participants were also inquired about their communication headset usage habits, hearing-related symptoms, and risk factors for noise-induced hearing loss (NIHL). Noise exposure under headsets was evaluated using the microphone in a real ear technique as specified by ISO 11904-1:2002. The background noise prevailing in offices was also measured according to ISO 9612:2009. RESULTS AND DISCUSSION: A personal daily noise exposure level calculated by combining headset and nonheadset work activities ranged from 68 to 79 dBA (74.7 ± 2.5 dBA). Majority (92.3%) of study participants had normal hearing in both ears (mean HTL in the frequency range of 0.25-8 kHz ≤20 dB HL). However, their HTLs in the frequency range of 0.25 to 8 kHz were worse than the expected median values for equivalent highly screened otologically normal population, whereas above 8 kHz were comparable (9-11.2 kHz) or better (12.5 kHz). High-frequency hearing loss (mean HTLs at 3, 4, and 6 kHz >20 dB HL) and speech-frequency hearing loss (mean HTLs at 0.5, 1, 2, and 4 kHz >20 dB HL) were noted in 8.3% and 6.4% of ears, respectively. High-frequency notches were found in 15.4% of analyzed audiograms. Moreover, some of call center operators reported hearing-related symptoms. CONCLUSIONS: Further studies are needed before firm conclusions concerning the risk of NIHL in this professional group can be drawn.
