Hearing Check Program

Basics of Audiometric Testing

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Setting up a Hearing Check (Audiometry) Program

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Delivery Model

Audiometric testing programs can be accomplished in several different ways. Making the best choice usually depends on knowing what your company needs and understanding the advantages and disadvantages of the model options and selecting the option that makes the most sense for the employer and employees.

In general, the broadly used models can be categorised as:
 

  • In-house: the employer has dedicated space, equipment, and personnel to conduct the hearing tests on-site.
  • Mobile service provider: a third-party service provider comes to the job site with equipment and personnel to conduct the tests, typically in a mobile van or trailer.
  • Off-site medical/audiology clinic or hospital: workers travel to an off-site facility that offers hearing testing services.
  • Combination: using two or more of the models to complete the baseline, annual, and follow-up tests.

 

The number of workers who are tested annually is usually a factor in which delivery model works best.

Personnel

Audiometric test programs need qualified people to conduct the hearing checks and also a professional, either an audiologist or physician, to provide program oversight and review “problem audiograms.” The term audiometric technician or occupational hearing conservationist (OHC) describes the person giving the tests. There is education and certification available for audiometric technicians.

Professional oversight of the audiometric testing program is required by regulation and can be provided by either an audiologist or physician.

Audiologists or physicians are also permitted by regulation to conduct the hearing checks. So in some programs, both the administration of the testing and the program review may be done by the same person.

Equipment

If you are setting up an in-house audiometric testing program, you will need several pieces of equipment. The typical equipment list includes:


  • Audiometer: A device used to measure the sensitivity of hearing with pure-tones of various frequencies. The audiometer has earphones that must be calibrated to the audiometer. There are different types of audiometers, including manual, microprocessor, and coumputer controlled.
  • Otoscope: A bright light with a magnifying lens that is used to view the outer ear and eardrum. It is helpful to know the condition of the ear canal before doing a hearing test and when inserting hearing protection devices.
  • Bioacoustic simulator: A specialised device that is used to verify the performance of the audiometer. Each day that hearing testing is to be done, the technician places the earphones onto the simulator and a quick check of its hearing thresholds is performed. Changes in thresholds of the bioacoustic simulator can indicate a malfunctioning audiometer.
  • Audiometric database management system: A commercial software program specifically designed to collect, analyze, and store audiometric data and related hearing conservation information. Using an audiometric database management system can help with recordkeeping, generating reports, and trend analysis.
  • How do you use Audiograms?

    Audiograms are used to document existing hearing loss, detect any deterioration of hearing and appropriate rehabilitation. It does not measure the effectiveness of noise control measures or the causes of any hearing damage or injury.

    Recommended procedures for audiometry can be found in AS/NZS 1269.4.

    Some Australian regulations have a general requirement for medical surveillance of people occupationally exposed to hazards, a requirement which has been interpreted to mean that audiometric surveillance is required for people occupationally exposed to noise. Some jurisdictions have specific requirements for provision of regular hearing tests for people whose noise exposure is such that they need to rely on hearing protectors for protection.

Standard Threshold Shift

Example Calculation of Standard Threshold Shift

Standard Threshold Shift

  • An audiogram should be run according to AS/NZS1269.4 Section 8. A significant threshold shift is defined as:

    • (a) a shift in average threshold at 3000, 4000 and 6000 Hz greater than or equal to 5 dB; or
    • (b) a shift in mean threshold greater than or equal to 10 dB at 3000 and 4000 Hz; or
    • (c) a change in mean threshold greater than or equal to 15 dB at 6000 Hz; or
    • (d) a threshold shift greater than or equal to 15 dB at 500, 1000, 1500 or 2000 Hz; or
    • (e) a threshold shift greater than or equal to 20 dB at 8000 Hz.
  • Abnormal Thresholds

    Abnormal Thresholds

    Normal hearing thresholds are in the range of 0 – 25 dB hearing level (HL). Thresholds that are greater than 25 dB HL are said to be outside the normal range and indicate that a hearing loss is present. There are typical patterns of hearing loss, sometimes associated with the cause of the hearing loss. 

    Thresholds that are either outside the normal range of hearing or atypical for a type of hearing loss are considered to be abnormal. 

    When thresholds are abnormal, more attention is needed in order to determine the best approach to managing the hearing loss and worker.

  • Invalid Tests

    There are times when test results are either incomplete, were not done according to the regulatory requirements, or do not represent the actual hearing ability of a worker. Invalid tests cannot be used to meet regulatory requirements and do not serve the purpose of identifying early stages of noise-induced hearing loss. Sometimes the test can be repeated to correct errors, either due to improper testing protocols or equipment malfunction. Other times a worker may need to be referred to an audiologist for more comprehensive testing.

  • Standard Threshold Shift Follow-Up

    Any confirmed threshold shift should lead to action as described in AS/NZS129.4 Section 9. Confirmation leads to a review of all of the relevant factors e.g. noise generation, ototoxic agents, training and fit of HPD's.

    • Hearing protection is required for all workers with noise exposure at 85 dBA TWA and higher. Workers who had not been using HPDs before the threshold shift must be fitted with an HPD, trained on the use and care of the HPD, and required to use them.
    • Worker who had been using an HPD may need greater attenuation to reduce the exposure to 85 dB TWA. If so, alternative hearing protectors with more attenuation must be provided. Workers should be refitted and retrained on HPDs.
    • If additional testing is needed, or if there is a reason to suspect that the HPDs are causing a medical problem, the worker should be referred for an audiological or medical evaluation.
    • The worker must be informed of the need for a medical examination if it appears there is a medical condition that is not related to the use of HPDs.

Resources to Learn About Audiometric Testing

Noise, SafeWork Australia

See “Codes and Guides”

This page also includes links to State and Territory Regulators for specific local requirements

Audiometric testing and assessment of audiograms should be carried out by competent persons in accordance with the procedures in AS/NZS 1269.4:2005 - Occupational noise management - Auditory assessment. Available from
SAI Global

  • IMPORTANT NOTE: This information is based on selected current national requirements. Other State or local requirements may be different. Always consult User Instructions and follow local laws and regulations. This website contains an overview of general information and should not be relied upon to make specific decisions. Reading this information does not certify proficiency in safety and health. Information is current as of the date of publication, and requirements can change in the future. This information should not be relied upon in isolation, as the content is often accompanied by additional and/or clarifying information. All applicable laws and regulations must be followed.

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