Hearing Protection Devices and Speech

 

The following is an excerpt of an inquiry from a Workplace INTEGRA client to our Director of Audiology, George Cook, Au. D., CCC-A.  Edits were made to conceal the client’s identity and employee name.

Dr. Cook,

I have a situation in the XXXX location of our company and need your professional opinion.

Attached is an employee’s hearing record. This employee states that he cannot wear hearing protection on the job due to the fact he feels unsafe. He states he cannot hear other employees speaking to him while wearing hearing protection.

My questions are:

  •  After reviewing this employees hearing record, can you please tell me if it is possible that he cannot hear other employees while wearing hearing protection, earplugs, or muffs?
  • If the answer is yes to question number one, can you please suggest if there is a hearing protector that can help the employee hear other employees?

Thanks,

I have reviewed (employee) hearing tests.  I would believe wearing hearing protection may interfere with his understanding other employees at times.  He has a mild hearing loss in the speech range in the right ear and low normal hearing in the speech range of his left ear.  Additional attenuation from hearing protection would cause additional hearing difficulty.  However, this type hearing loss can sometimes be fitted with musician hearing protectors.  The difference between standard hearing protectors and musician’s protectors is the amount of attenuation in the high frequencies.  Standard hearing protectors will attenuate more in the high frequencies than in the lower frequencies.  Musician’s protectors provide a relatively flat (+/-5dB) attenuation across frequencies.  The purpose of these protectors is to attenuate sound without distorting the signal or music.  Flat attenuating hearing protectors have been successful in fitting employees with an already existing mild loss in the speech range.  There are several manufactures of musician’s hearing protectors. One of the more common names is Etymotics, with models ER9m ER15, and ER25, with increasing levels of attenuation.  Westone provides a custom molded musician’s protector and EAR has a light insert musician’s protector.  You might search the Internet for ‘musician’s hearing protectors’ and come up with a few more providers.

In addition, there are manufacturers of amplified hearing muffs.  These muffs will amplify up to 82dB SPL and protect with levels above that.  EAR/Peltor manufactures a gunfire muff, Tactical VI or Tactical VII, which will limit background noise to 82dBA.  This muff has been recommended successfully for employees with mild speech frequency loss working in intermittent noise levels needing to hear speech. The muffs cost between $140 and $170 so I would try the insert plugs first.  Once you introduce a new protector, everyone wants it.  They can be difficult to wear as they will amplify background noise in quiet as well as speech.  But if nothing else works, they deserve a try.  Both Bilsom and Peltor manufacture amplified muffs.  Sperian also manufactures an amplified muff, the Impact and Impact Sport models.

The Cadillac muff of this type is the Sensear.  They are designed to allow speech communication in the presence of background noise.  They are in the $400 range.  I tried on a pair recently at the NHCA Conference in Phoenix, AZ and they work well.  

As a precautionary note, this employee’s hearing has shown significant change in the right ear over the past few years.  The low frequency change is not characteristic of noise exposure.  He should be referred to an ear specialist for diagnosis and possible treatment.

His medical health history and medications need to be reviewed by his physician.  This employee must not work in noise without protection.  He has demonstrated hearing change and must protect his hearing from any contribution from noise on or off the job.

Regards,

George Cook, Au. D., CCC-A