Hearing loss hazard for call center workers

Noise-induced hearing loss is the second most common occupational disease, reducing the quality of life for millions of people who suffer from it

Loud machinery, equipment or vehicles have always been considered the main culprits for noise-induced hearing loss, but these are - to a great extent - controlled by rules, regulations and careful monitoring.

For years it was believed that being a call centre operator was a low-risk occupation, but personal injury claims by call centre workers are increasing. These include repetitive strain injury, eyesight and posture problems, transient balance disorder, tinnitus and noise-induced hearing loss.

One of the main causes of hearing damage in a call centre is acoustic shock, which occurs when a sudden and unexpected burst of high-frequency noise is transmitted through the operator’s headset.

Dr Setsuo Maeda, a Professor of Human Vibration at Kinki University, Osaka, Japan, has conducted research to compare the use of conventional headsets with bone-conducting devices - and to evaluate whether newly available bone-conducting devices reduce the risk of temporary or permanent hearing loss.

The testing took six days, using a Head and Torso Simulator (HATS), supplied by Brüel & Kjær. In parallel with the actual workers making calls, the incoming call signal from the telephone was divided between two headsets. A PULSE data acquisition system, a monaural headset and a Personal Noise Dose Meter Type 4448 were also used. “The call centre where we carried out the tests is small and noticeably quieter than the large, international call centres that employ hundreds of people,” says Dr Maeda. In fact, the largest call centre in Okinawa employs 3,000 people, making these workplaces potentially much louder than the test call centre. “My conclusion is that hearing damage could occur at levels above 90 dB(A),” says Dr Maeda. Dr Maeda has also conducted laboratory experiments using HATS and PULSE to compare normal headphones, with bone-conducting headsets, using white noise and found: “bone conducting devices help to prevent hearing loss.” This has also been confirmed by studies carried out at the University of Southampton in the United Kingdom.

The full case study is available on Brüel & Kjær’s website.