Noise exposure and hearing status among call center operators.

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.