Factors influencing the validity of audiometry Copy

Factors influencing the validity of audiometry

It is essential that accurate, reliable, and valid results are obtained to avoid unnecessary expenses and loss of productivity. Some of the factors that may contribute to inaccurate and invalid results include:

The test must be conducted by a competent person
The earphone placement is specific. If the earphones are incorrectly placed with the wrong earphone on the wrong ear the results will not be accurate. The red earphone must be placed on the right ear and the blue earphone on the left ear
The earphones are calibrated to a specific machine; therefore, the technician must ensure that the correct earphone set is used with the correct audiometer
The stimulus must be presented in descending order while the frequency remains the same. Each frequency is tested completely before moving on to the next frequency
The stimulus must be presented at irregular intervals to prevent the worker from anticipating the stimulus
Avoid presenting the stimulus where the worker can see the presentation on the stimulus as this will give the worker cues to respond
Avoid any distractions such as moving around within view of the worker
The technician must become familiar with the specific audiometer in use
Accurate instructions must be given to the worker prior to testing. The technician must ensure that the worker understands the instructions and is consistent with the instructions given
The ambient noise levels must not exceed 45dB in the testing room; however, it is preferable to use a booth
The equipment must be calibrated according to the legal requirements and must be checked daily prior to use
Various physiological aspects can influence the reliability of the test. These may include a temporary threshold shift, the general health of the worker and symptoms such as tinnitus

Psychological factors

The motivation and attitude of the worker can affect the test results. If the worker feels threatened by the possible results, he/she may respond erratically resulting in a nil/void result. The purpose of the test must be explained including the hearing conservation programme and the benefits of the test
Lack of concentration can result in delays and inaccurate test results. The technician should observe the worker throughout the test to ensure attention
Ensure thorough instructions to all workers to avoid the worker assuming that they are familiar with the test procedure when in fact they are not
Language barriers may also result in invalid test results

Figure 8.6:  A. A screening audiogram on Mr C. – original4 

B. A screening audiogram on Mr C – repeated4

WALKER, JJ MD: American Family Physician Journal.  Audiometry Screening and Interpretation 2013 Jan 1;87(1):41-47 U.S  https://www.aafp.org/afp/2013/0101/p41.html

In audiogram Figure 8.6A above a false low-frequency hearing loss in both ears is evident because of excessive background noise in the test area. When the worker is retested in a quiet area that the hearing levels are within normal limits see Figure 8.6B4.