The aim of this study was to evaluate the hearing status of call centre
operators in relation to their noise exposure. Conventional pure-tone
audiometry and extended high-frequency audiometry were performed in 49
workers, aged 22–47 years (mean ± SD: 32.0 ± 6.0 years), working in call
centre from 1.0 to 16.5 years (mean ± SD: 4.7 ± 2.9 years).
Questionnaire inquiry aimed at collecting personal data, the information
on ommunication headset usage habits, self-assessment of hearing ability
and identification of risk factors for noise-induced hearing loss were
also carried out. Sound pressure levels generated by the communication
headset were determined using the artificial ear technique specified in
CSA Z107.56-13 (2013) standard. The background noise prevailing in
offices was also measured according to PN-N-01307 (1994) and PN-EN ISO
Personal daily noise exposure levels in call centre operators varied
from 66 to 86 dB (10–90th percentile). About half of the study subjects
had normal hearing in the standard frequencies (from 250 to 8000 Hz) in
both ears, while only 27.1% in the extended high-frequencies (9–16 kHz).
Moreover, both high-frequency and speech-frequency hearing losses were
observed in less than 10% of audiograms, while the extended
high-frequency threshold shift was noted in 37.1% of analysed ears. The
levels of call centre operators in the frequency of 0.25–11.2 kHz were
higher (worse) than the expected median values for equivalent (due to
age and gender) highly screened population specified in ISO 7029 (2017).
Furthermore, they were also higher than predicted for 500–4000 Hz
according to ISO 1999 (2013) based on the results of noise exposure