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NIOSH - National Institute for Occupational Safety and Health
NIOSH Hearing Loss Research Program Review NIOSH Publications on Noise and Hearing The National Academies - Advisors to the Nation on Science, Engineering, and Medicine

What does the HLR Program Do?

In this section ....

Research Goal 1

Research Goal 2

Research Goal 3

Research Goal 4

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R&D Portfolio - Research Goal 2.4:
Develop a hearing protection and communication system

Firefighter Standing
Hearing protection devices present a challenge for communication in noisy environments. In certain work settings such as firefighting and emergency response, engineering noise controls are difficult, if not impossible, to implement. Workers must instead rely on personal hearing protection, such as standard earplugs, to prevent noise-induced hearing loss. Conversely, worker safety depends on the ability to hear and understand the speech of other workers, plus one’s own speech, particularly in a noisy setting. Given the choice between personal safety and hearing loss prevention, many workers opt not to wear HPDs because they think that HPDs impair communications.[55] A survey of health and safety professionals found that 65 percent of those responding thought the workplace would be safer if workers could easily communicate with each other and with supervisors.[56]

The safety of first-responders such as firefighters, police officers is dependent upon their ability to communicate with one another to effect a coordinated plan of action.

EarTalk is a communication device that is incorporated into a HPD that was developed by HLR researchers between 1989 and 1991.[57] EarTalk provides workers with the means to communicate clearly with speech while protecting their hearing. The EarTalk device uses a miniature microphone to detect the speech signal in the ear canal of the talker, electronically processes the sound to restore natural sound quality and transmits the signal to miniature speakers in the ear canal for a listener.[58]

HLR program researchers developed and built several customized applications of the EarTalk system for trials in auto racing, fire fighting, and the military. In 2002, a prototype EarTalk system was tested in high-noise environments at the Voice Communication and Research Evaluation System facility at Wright-Patterson Air Force Base. The tests showed that EarTalk performed as well as current racing communication systems but did not achieve the same level of speech intelligibility as more expensive military communication headsets with noise canceling microphones underneath a noise-reducing muzzle. EarTalk remains as a viable alternative to existing and mostly outdated communication systems, but due to lack of funding and challenges associated with technology transfer of publicly-developed inventions to the private sector, the system’s potential has yet to be fully recognized.

Ear Talk Photos



EarTalk was developed and patented by HLR researchers and allows the user talk and listen through microphones and receivers positioned under the hearing protection device.




In late 2004, a new r2p project was funded by NIOSH to facilitate the technology transfer of EarTalk to industry by providing resources for the manufacturing and marketing of a commercially viable EarTalk system.

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[56] Cameron H [1988]. Audio Mechanical Transducer Communication System. NIOSH Grant R43 OH02313, Cincinnati, Ohio.

[57] U.S. Patent and Trademark Office [1991]. – Ear Based Hearing Protector/Communication System. U.S. Provisional Patent Application Number 5,426,719.

[58] Kardous CA [1998]. Eartalk - Hearing Protector and Communication System in Prasher P., Luxon L., Pyykko I. (eds.), Advances in Noise Research, Volume II: Protection Against Noise. Whurr Publishers, London.


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