Have
You Checked Your Audiometer Today?
by Susan Cooper Megerson, MA CCC-A
Evaluation of the effectiveness of your Hearing Conservation Program depends upon the accuracy of your audiometric testing efforts. In turn, the validity of the audiometric testing results is dependent upon several factors, one of which is the adequate functioning of your equipment. As the OHC performing the audiometric test, you are responsible for proper calibration and appropriate documentation of your audiometer. As discussed in your CAOHC training course, the Occupational Safety and Health Administration (OSHA) and good practice require that three types of audiometer calibration be conducted:
- Functional Check: The operation of the audiometer must be checked daily - prior to audiometric testing. First, the output of the audiometer is checked by conducting an audiometric test for a person with known, stable thresholds or utilizing a "bio-acoustic simulator" device. Next, the tester must listen to the output of the audiometer to make sure it is free from distorted or unwanted sounds. Deviations of 10 dB or greater on the output check or detection of static or unwanted sounds on the listening check require that an acoustical calibration be performed prior to use.
- Acoustical Calibration: The acoustical calibration must be performed at least annually. This is a more objective form of the functional check conducted using an acoustic calibration system. Output deviations of greater than 10 dB or any other unusual variations require that an exhaustive calibration be performed.
- Exhaustive Calibration: An exhaustive calibration must be conducted at least every two years in accordance with specifications of the American National Standards Institute (ANSI). As the name implies, this calibration entails a more in-depth analysis of the audiometer’s function and may include adjustments according to ANSI specifications.
There are many resources available to you should you need assistance or guidance in maintaining your audiometric equipment:
- CAOHC’s HEARING CONSERVATION MANUAL: See Chapter VII for a more detailed description of calibration requirements and recommended protocols. Appendix VII includes samples of various audiometer calibration forms, courtesy of a number of CAOHC Course Directors, which may be useful in your day-to-day documentation.
- Your Course Director or Professional Supervisor: Be sure to review calibration procedures and documentation with your professional supervisor (the audiologist or physician responsible for reviewing audiograms and determining referrals/follow-up). It’s best to identify your "quality control" procedures in advance, so that equipment problems are detected and resolved prior to testing. As we all know, a few minutes spent on prevention is well worth avoiding the costly consequences of following-up on inaccurate results and retesting employees.
- Calibration Service Provider: Ask your professional supervisor or audiometer supplier if acoustic/exhaustive calibration services are available. Many will come to your location and provide the service on-site. If you must ship your audiometer for annual calibration or repair, pack carefully, and don’t forget to include earphones, the response switch and all connecting cords, so that the complete system can be evaluated.