Otologic symptoms and hearing thresholds among a cohort of call center operators in Lagos

Background: The call center operation jobs are becoming a global phenomenon. The use of headphones for 7 to 9 h daily with varying noise level exposure is quite common among call center operators. This can cause structural and/or functional changes in the auditory system. Researchers have arrived at different conclusions regarding the risks associated with prolonged headphone usage. This study aimed to evaluate the risk of hearing changes and the range of otologic symptoms among call center operators in Lagos State, Nigeria. Methods: This is a prospective cross-sectional study carried out on 90 call center operators (customer service staff) and 90 administrative staff (controls) aged 18 to 40 years working in two call centers affiliated to different private establishments in Lagos State. Their biographic data, work information, and otologic/non-otologic symptoms developed with the commencement of the job were obtained with a self-administered structured questionnaire. After otoscopic examination, diagnostic pure tone audiometry (PTA) was carried out before and after the work shift. Results: The most commonly reported symptoms among the call center operators were headache, tinnitus, and vertigo. Symptoms were noted as early as 3 months into the job in 20 (24.7%) call center operators. The pre-shift and post-shift mean PTA of the call center operators were normal bilaterally and comparable to the controls. There was an elevation of low frequency (500 Hz) mean PTA of> 30 dB in both the call center operators and the controls. The mean PTA average for the call center operators' pre-shift and post-shift were 25.4 +/- 8.2 and 25.6 +/- 8.1 in the right ear, 24.8 +/- 8.5 and 24.7 +/- 8.9 in the left ear, 25.9 +/- 7.8 and 24.7 +/- 7.8 right and left ears for the control. There were no statistically significant differences between the call center operators' pre-shift and the controls' hearing thresholds, and the pre-shift and post-shift hearing thresholds of the call center operators at all frequencies and in both ears. Conclusion: Otologic and non-otologic symptoms arise from prolonged headphones usage among call center operators. No hearing damage or headphone noise-induced hearing loss was recorded in the call center operators in this study.