Real Ear Measurement (REM) Equipment
Probe-microphone systems used to measure what a hearing aid actually delivers at the eardrum and verify it matches the prescription target.
What it is
About Real Ear Measurement (REM) Equipment
Real ear measurement (REM) is the clinical gold-standard method for verifying hearing aid fittings. A thin probe tube microphone is placed in the patient's ear canal alongside the hearing aid; the REM system then presents calibrated sound and measures the actual sound pressure level at the eardrum — both with and without the hearing aid. The difference (real ear insertion gain, REIG) is compared against the prescriptive target (DSL v5 or NAL-NL2). Without REM, a hearing aid fitted only using manufacturer software data can under- or over-amplify by up to 20 dB in individual patients due to ear canal size and shape variation. Leading REM systems include the Otometrics AURICAL and Interacoustics Affinity. In the UK, NICE guidelines and NHS England Hearing Loss Pathway recommend REM as best practice. Clinical audiologists are responsible for probe tube placement, calibration of the reference microphone, running speech passages at different intensities, and interpreting the output curves to make fitting adjustments.
What you can do with it
Capabilities
Place a probe tube microphone at the correct depth in a patient's ear canal for real ear measurement.
Calibrate the reference microphone and loudspeaker level before running a REM session.
Run live speech mapping and compare hearing aid output to the NAL-NL2 prescriptive target curves.
Identify where a hearing aid is under-amplifying in the high frequencies and adjust gain to bring output onto target.
Document REM results as part of the fitting record and print a verification report for the patient notes.
How to learn it
Learning Resources
Otometrics provides free REM training videos and webinars at otometrics.com
Interacoustics offers free online REM certification modules at interacoustics.com/academy
British Academy of Audiology (BAA) real ear measurement position statement and training resources at baaudiology.org
Harvey Dillon's Hearing Aids (2nd ed) is the standard reference text for prescriptive fitting and REM methodology.
Pro Tip
Position the probe tube 5–6 mm from the eardrum for accurate measurement — too shallow gives artificially low high-frequency readings that lead to under-fitting.
Skills that use this tool
Roles that use this tool