The Hearing Protection

Is the in situ measurement of hearing aids reliable ?

  • In audiology, in situ audiometry, also known as “built-in audiometry,” refers to the use of hearing aids to directly conduct pure tone audiometry on the user’s ear. At this point, the hearing aid serves as an audiometer, and the optometrist plays a sound with a fixed frequency and loudness using optometrist software. The test procedure is the same as with a traditional audiometer. The test is performed using the “rising five times and falling ten times” method. The subjects avoid the sight and respond to the signal sound.
  • The test should be performed in a relatively quiet environment, such as a store fitting room. To prevent low-frequency acoustic signal leakage, it is better to use closed ear mold or earplug.
  • Due to the particularity of the testing tools and the influence of the surrounding environment, the in situ audiometry has the following limitations compared with the conventional standard audiometer:
  • In situ audiometry is conducted with hearing aids as a tool. The test frequency range is limited due to the influence of hearing aid bandwidth, and usually only the frequency range of 250—6000Hz can be measured ,at the same time, the maximum output of each frequency is lower than that of the audiometer, which affects the judgment of severe and extremely severe hearing loss. To determine the nature of hearing loss, in situ audiometry can only test the air conduction threshold, whereas an audiometer can test the air conduction threshold, bone conduction threshold, and discomfort threshold. The standard pure tone audiometry test is typically performed in a sound insulation room that meets national standards, with a calibrated audiometer. The test results obtained in accordance with such standards are relatively accurate. In situ audiometry is susceptible to noise and has a low level of accuracy.
  • In situ audiometry cannot replace traditional audiometer audiometry. For the assessment of the nature and extent of hearing loss, it is recommended to use a multi-functional standard audiometer for testing. In situ audiometry can be used for supplementary hearing verification when debugging hearing aids. The combination of the two, along with reference debugging, may make hearing aid debugging easier and smoother.


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