Practice Guidance: Guidance on the Verification of Hearing Devices Using Probe Microphone Measurements
British Society of Audiology. (2018).
United Kingdom: British Academy of Audiology; British Society of Audiology, 1-12.
This guideline updates the British Society of Audiology (BSA) 2007 document "Guidance on the use of real ear measurement to verify the fitting of digital signal processing hearing aids". The current BSA guidance provides detailed, step-by-step directions for conducting device fitting verification via probe microphone measurements. The following summary highlights broad recommendations to consider. See the BSA's full text document for all of the recommended steps for conducting device verification measurements.
British Society of Audiology
For children or adults who use hearing aid devices, verification using probe microphone measurements should be used to<ul> <li>determine whether a device matches prescription targets, </li> <li>adjust the device to improve prescription target matches, and </li> <li>verify digital features (e.g., directionality, noise reduction, frequency lowering). </li></ul>In-situ or real ear measurements are recommended as the most direct method of verifying a hearing device. For populations where real ear measurements are not possible, such as babies, young children, or individuals with complex needs, real-ear-to-coupler difference measurement is a recommended alternative. Additional hearing aid verification measures to consider include frequency lowering, aided Speech Intelligibility Index, and Goodness of Fit. See the BSA full text for detailed description for conducting and interpreting probe microphone measurements.
When preparing to conduct probe microphone verification, the equipment should be set up with appropriate software settings and calibrated annually according to manufacturer’s guidance. Pre-recorded, calibrated, and modulated speech signals should be used as the stimulus. The audiologist should arrange the test environment to avoid reflective surfaces and ambient noises.
When conducting probe microphone verification, “the clinician should explain the procedure to the patient and/or carer in appropriate terms and obtain informed consent from them.” (p. 10).
Before conducting real ear or coupler-based measurements, the audiologist should perform an ear examination using otoscopy to account for any outer or middle ear differences. Additionally, tympanometry is recommended prior to real-ear-to-coupler difference testing to check that the ear canal volume and middle ear status of the ears do not differ significantly.
