Real-Ear Measurements (REMs)

When it comes to hearing aids, there is only one guaranteed way to get the volume right, and that is by measuring the volume provided by your hearing aid—deep inside your own ear. Each person has a unique hearing profile and ear canal resonance, and a unique preference for sound.

What are REMs?

Real-ear measurements (REMs) are used to verify the “correct” hearing aid volume is provided, while factoring in your unique hearing profile and ear canal resonance. This should be considered the starting point. From there, you may work with your audiologist to make additional tweaks based on your own sound preferences.

Why are REMs performed?

REMs are used to verify hearing aid performance. They take a snapshot of the sound coming out of your hearing aid while it sits in the ear canal. Audiologists or hearing healthcare providers place a probe microphone (thin, pliable tube connected to a microphone) in the ear canal and then set the hearing aid over the top of the probe microphone. Once in place, sound is presented through a loudspeaker and the output of the hearing aid is measured. Results are displayed either as a graph or table and help your hearing healthcare provider understand the volume of sound your hearing aid is providing for each pitch.

Verifying your prescription

During a new hearing aid fitting, your hearing healthcare provider will select a prescriptive formula. These prescriptions are calculated from a number of factors including your hearing loss and help your hearing healthcare provider set up the correct amplification for different types and volumes of sounds.

When hearing aids amplify sound, they can provide different amounts of volume depending on your hearing loss, the frequency, and the type of sound coming into the hearing aid. REMs allow your hearing healthcare provider to confirm your hearing aids are applying the right volume for different sounds according to the prescription. Speech, or speech-like sound, is the best signal to use during prescription verification and should be presented at soft, average, and loud intensities.

Verifying hearing aid features

Your hearing aids are equipped with many features to improve your listening experience. REMs help your hearing healthcare provider ensure the features are doing exactly what they should be doing. Through REMs, we can measure the performance of features like noise reduction, directional microphones, and telecoils.

The benefits of REMs

REMs can help an audiologist or hearing healthcare provider confirm appropriate amplification settings and ensure features in the hearing aid are functioning as they should. REMs are an important tool for fitting hearing aids and diagnosing hearing aid malfunction.

• Provide maximum benefit - The more sound you hear, the better you’ll do with your hearing aids. If your hearing aids are fit right to your prescription, you’ll hear as much sound as possible, without over-amplification.
• Minimize loudness discomfort - During a routine REMs test, your provider should verify that loud speech is not too loud. They may play a series of loud sounds to establish that your hearing aid is not over-amplifying. These loud sounds should be no louder than your loudest comfortable sounds that were (hopefully) measured during your hearing test.
• Hear just enough soft sound - Soft sound is tricky. You want to hear the world around you, but you don’t want the refrigerator buzzing in your ear from the living room. REMs are a great way to get the soft sounds just right.
• Check for hearing aid malfunction - Your hearing aid should perform the same way at every annual checkup. If the REMs test shows reduced volume versus previous tests, there is likely a hardware malfunction or wax or moisture issue affecting your hearing aid.
• Verify features - Through REMs, we can measure the performance of features like noise reduction, directional microphones, and telecoils.
• Keep your hearing aids in tune - If your provider measures a significant change in your hearing, they should run REMs again, to make objective, data-driven adjustments to your hearing aids.
• Check headroom - Your hearing aid should last at least 3-5 years, so the provider should check that the hearing aid doesn’t need to be at maximum volume on day 1. If your hearing changes, your provider will need to turn up the volume.
• Double-check the manufacturer - When your hearing aid is configured on the manufacturer’s software, the provider will tell the software about your hearing loss and hearing aid configuration options (like venting and speaker strength). The software will guess how loud to set the hearing aid, and it may be in the right ballpark, but REMs are the primary method of double-checking them.

How REMs are performed

REMs require a probe tube (thin, pliable silicone tube), a microphone at the level of the ear, a loudspeaker, and a quiet room. Your audiologist or hearing care provider will examine your ear canal to ensure it is free of ear wax and/or any other debris. The probe tube is then placed in your ear canal as close to the eardrum as possible with the hearing aid placed over the probe tube. You might feel a tickle or feel a bit of pressure during the probe tube placement. This is normal as the skin in the ear canal is more sensitive closer to the eardrum but the probe tube is very soft and will not damage your ear.

You will likely be facing a loudspeaker once all the pieces are in place. Your hearing healthcare provider will turn on the loudspeaker and play different sounds and measure the sound in your ear canal through the probe tube. Sometimes your hearing aid will be turned on and sometimes it will be turned off, depending on the type of measurement. The sound from the loudspeaker might be speech or some type of speech-like noise and will vary in volume. As a listener, you will just sit quietly during the measurements. You will not need to respond during the measurements.

Want to see how it’s done? Dr. Cliff, AuD has a great 9 minute YouTube video packed with information and demonstration.

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What to expect and look out for

As beneficial as REMs are, they are only useful when your hearing healthcare provider understands how to read the results. It is possible for your provider to complete the procedure but not understand how the results impact the hearing aid fitting or feature validation. As a client, there are some key things you can look for to feel confident in your provider.

During a new hearing aid fitting, be on the alert for the following:

• You should be in a quiet room.
• Your hearing healthcare provider is making adjustments (changing volume settings on the computer software that will directly upload to your hearing aids).
• Your provider should be testing at several different volumes of sound from the loudspeaker. This means you should be sitting through the same version of sound several times with levels ranging from soft (50-55 dBSPL), average (60-65 dBSPL) and loud (70-75 dBSPL).
• You should see prescriptive target markers for your hearing loss and the results of the measurement on the screen in front of you (or near you, depending on the setup).
• At some point, your hearing healthcare provider should do a maximum power output (MPO) measurement. You will hear a 3 second series of tones that are quite loud. This measurement will let your provider measure the loudest your hearing aids will ever get. If the results are over your uncomfortable listening level (UCL), your provider can reduce the maximum volume on your hearing aids so you don’t feel discomfort when loud sounds, like sirens or alarms, are nearby.
• This process should take 10-20 minutes but may be longer depending on how many adjustments are needed to correctly fit your hearing aids to prescriptive targets.

During feature validation, be on the alert for the following:

• Your hearing healthcare provider will activate different features on your devices (and might deactivate some at the same time). This is done through computer software and digitally loaded to your hearing aids.
• You might be asked to move if your provider is testing directional microphone function.
• Most of the time you will listen to noise, not speech.

Finding a provider who performs REMs

Some providers will discuss REMs on their website but not all will. Use our Pro Finder to find audiologists who routinely perform REMs during their new hearing aid fittings. If you’re wondering if your current audiologist or hearing healthcare provider offers REMs, it’s worth asking before your new hearing aid fitting.