How bad does my hearing have to be to fail an audiometry test?

Q:

How bad does my hearing have to be to fail an audiometry test?

A:

For audiometry tests, failure is not measured in terms of "how bad" your hearing loss is but "if" you have suffered any loss at all.

The goal of a hearing test is not to punish employees or search for a reason to fire someone but to protect health and identify problems before serious hearing damage is done. The U.S. Occupational Safety and Health Administration (OSHA) requires workplace audiometric testing for employees who are exposed to potentially hazardous levels of noise in the workplace. The primary purpose of this mandatory workplace audiometric testing is to protect and preserve your hearing. This goal is accomplished by first establishing your baseline hearing level through audiometric testing. An audiometer is used to conduct this hearing test with the results recorded on a graph called an audiogram. In subsequent years, your hearing test results will be compared to your initial baseline audiogram to determine if you have suffered hearing loss. Should these comparisons indicate a deterioration in your hearing, your employer is required to refer you for further examination to determine the cause.

Outside of your workplace's hearing conservation program, a screening hearing test is sometimes used to determine quickly whether an individual should be referred to a specialist for further examination. Hearing tests conducted on school children are an example of this type of audiometric screening. Results from the screening process are sometimes referred to as "pass" or "fail." Those who pass the screening test show no signs of hearing impairment while those who fail are referred for further testing. Again, this determination is not based on a specific level of hearing loss but whether the individual shows any signs of hearing impairment.

An audiogram is the graphical presentation of the results of your audiometry test. The audiogram displays two measures of your hearing, frequency, and intensity. For each ear, a point will be graphed indicating the softest sound you can hear at each designated frequency. This point is referred to as your hearing threshold.

Frequency is the pitch of a sound and is measured in Hertz (Hz). Audiometric testing may evaluate a range of pitches from a low of 250 Hz to a high of 8000 Hz. Most speech falls between the frequencies of 250 to 6000 Hz. Vowel sounds are often lower in frequency. The consonant sounds "f," "s," and "th" are high-frequency sounds. The measure of intensity (how soft or loud a sound is) is reported in decibels (dB). Intensity levels for testing may range from 0 dB to 120 dB. For comparison, OSHA guidelines require audiometric testing for workplaces where dB levels regularly exceed 85 dB. This decibel level is what you might expect to hear from inside your car when driving in city traffic.

Hearing loss is described in degrees that correspond to the severity of the loss. The range of hearing loss is measured in decibels of hearing loss (dB HL) and reported on a scale from normal to profound. If your hearing is normal, this means that the softest sound you can hear—your hearing threshold—may range from -10 to 25 decibels although some tests may employ a slightly narrower range. Profound hearing loss, where only very loud or no sound can be heard, begins at 90 dB HL.

OSHA's guidelines require that you be referred for follow-up action whenever your annual hearing test results indicate a standard threshold shift (STS) when compared to your baseline or previous year's test results. The guidelines define a standard threshold shift as a change in hearing averaging 10 dB or more at the 2000 Hz, 3000 Hz, and 4000 Hz levels in either ear. Thus, if your hearing threshold indicates a hearing deterioration of 10 dB (a 10 dB HL) at any of the three designated frequencies, you would be referred for follow-up care.

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Written by Shauna Krahn
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Shauna Krahn is the manager of medical services at SureHire Occupational Testing, a leading expert in the occupational health and wellness testing industry. SureHire is revolutionizing the occupational testing industry through its proprietary Fitness-to-Work assessments, drug testing adulteration protocols, automated tracking systems, standardized national training and certification system, and industry leading online technologies.   Full Bio