Real Ear Measurement Explained: How Your Hearing Aid Is Checked in Your Ear
by Crystal Hearing Solutions
Real ear measurement (REM) is a check of your hearing aid, not of your hearing. While you wear the hearing aid, a thin, soft tube rests in your ear canal close to the eardrum, and a small microphone connected to it measures the sound there. Your audiologist sees how much sound the hearing aid delivers at each pitch, compares it with a target worked out from your hearing test, and adjusts the hearing aid until the two match closely.
Quick Answer: What a Real Ear Measurement Test Does
It measures the sound your hearing aid actually produces inside your ear canal, since the same setting gives a different result in every ear. Your audiologist compares it with a prescription target worked out from your audiogram, then fine-tunes the hearing aid until soft, average and loud speech reach your eardrum at the right levels. It is painless and done as part of a hearing aid fitting.
What the Measurement Shows
Audiologists also call it probe microphone measurement. Two small microphones do the work. One sits just outside your ear and checks the test sound from a loudspeaker in front of you. The other measures the sound at the tip of the probe tube, close to your eardrum. From your audiogram, the equipment works out your target with a recognised prescription formula, such as NAL-NL2 or DSL v5.0. The screen then shows your target and what your hearing aid delivers, as lines from low pitches to high.
A complete measurement checks four things:
| What is measured | What it checks | If it is off, you may notice |
|---|---|---|
| Soft speech | Quiet voices are loud enough to hear | Soft voices and voices from another room are missed |
| Average speech | Everyday conversation is clear | Words sound muffled, or sharp and tinny |
| Loud speech | Loud voices stay loud but comfortable | Busy places feel harsh and tiring |
| Maximum output | The hearing aid’s loudest sound stays below your discomfort level | Sudden sounds, like a pressure cooker whistle, startle or hurt |
Why Every Ear Needs Its Own Check
Every ear canal has its own size and shape, and that changes the sound reaching the eardrum, pitch by pitch. A smaller ear canal leaves less space between the hearing aid and the eardrum, so the same setting produces more sound in it. The fit matters too: an open dome lets low-pitched sound leak in and out, while a closed dome or a custom ear mould keeps more of it in.
When a hearing aid is programmed, the manufacturer’s fitting software makes a first setting from your audiogram. It is a starting point, worked out for an average ear. Real ear measurement then tests that setting in your own ear, so your fitting is checked against your prescription target instead of being taken on trust. Professional guidelines for audiologists, including those of the American Academy of Audiology and the British Society of Audiology, recommend this check for hearing aid fittings.
The difference shows most in the high pitches, which carry consonants such as “s”, “f” and “th”, the sounds that make speech clear. With too little sound there, you hear that someone is talking but miss the words. With too much, voices turn sharp or tinny.
What Happens During a Hearing Aid Real Ear Measurement
It is done at your fitting, with the hearing aids you will wear. Step by step:
- Step 1, a look in your ear: the audiologist checks each ear canal with a small light, to make sure the tube can be placed safely. If anything needs medical attention, such as signs of an infection, you will be asked to see an ENT specialist first.
- Step 2, your targets: your latest audiogram is entered, and the equipment works out your prescription targets.
- Step 3, the probe tube: a thin, soft tube is placed in your ear canal, its tip close to the eardrum without touching it.
- Step 4, the hearing aid goes in: it is placed alongside the tube, carefully, so the tube stays where it is.
- Step 5, the test sounds: you sit facing a small loudspeaker while it plays speech-like sounds at soft, average and loud volumes. Stay still and quiet, because talking or chewing can move the tube.
- Step 6, adjust and measure again: the audiologist adjusts the settings and repeats the measurement until the line for your hearing aid sits close to your target, from low pitches to high.
- Step 7, loud sounds: a short, loud test sound checks that the hearing aid’s maximum output stays below the level you find uncomfortable.
The other ear has the same check. For each ear, the measuring adds up to a few minutes, plus the time spent adjusting in between. Finally, you listen to voices and everyday sounds, and the audiologist fine-tunes for comfort. Someone new to hearing aids may start a little below the target and be brought up to it over the following weeks, as the brain gets used to sound again.
Who Benefits Most from Real Ear Measurement
Every fitting gains from being measured, but it matters most for:
- First-time wearers: they have nothing to compare the sound with.
- Children: their ear canals are small, and young children cannot tell you what they hear.
- High-pitch hearing loss: the most common pattern with age and with noise exposure, in the pitches where ear canals differ most.
- Severe or profound hearing loss: powerful hearing aids need their loudest output checked. Our guide to the degrees of hearing loss explains these grades.
- Open domes and past ear surgery: an open fit lets sound escape, and an ear canal reshaped by surgery behaves very differently from an average one.
- Hearing aids that never felt right: the measurement shows whether the sound matches the target, a clear place to start.
What to Ask Your Audiologist
You do not need to read the graphs yourself. Just ask:
- Will my hearing aids be checked with real ear measurement? Ask when you book, so time is set aside for it.
- Is my hearing test recent enough? Your target comes from your audiogram. If your hearing may have changed, a fresh pure tone audiometry test comes first. If your hearing has dropped suddenly, in one ear or both, see an ENT specialist the same day: that is urgent.
- Can you show me the screen? Ask to see your target and the measured line, and where they differ.
- Have you checked loud sounds? The maximum output should be measured too.
- Will you measure again if the settings or the dome change? Each change alters the sound in your ear.
How It Fits with Programming and Your Trial
Real ear measurement is one step in getting a hearing aid right. The steps, in order:
- Your hearing test: your audiogram sets the targets. Our guide explains how the different hearing tests work.
- Programming: hearing aid programming gives the hearing aid its first setting from your audiogram.
- Measurement: real ear measurement checks that setting in your ear and corrects it.
- Your trial: you wear the hearing aids at home, at work and at family functions, and note what is still hard. A hearing aid trial is a fairer test of a hearing aid when it starts from a measured setting.
- Fine-tuning: the audiologist adjusts for what you noticed, and measures again after a big change.
At Crystal Hearing Solutions, Real Ear Measurement (REM) is available for fittings at every clinic, and all our audiologists are RCI-certified. Our free 7-day trial lets you judge your hearing aids in your own routine. Ask for REM when you book your fitting. You can read more, and book, on our page for real ear measurement in Mumbai.
Frequently Asked Questions
No. A hearing test, such as pure tone audiometry, measures how well you hear. A real ear measurement test measures what your hearing aid delivers inside your ear. The hearing test comes first, because its results set the targets your hearing aid is checked against.
No. A thin, soft tube rests in your ear canal without touching the eardrum, and you simply sit still and listen. Most people feel very little, perhaps a slight tickle.
Only a few minutes of measuring for each ear. Adjusting the hearing aid and measuring again adds to that, so plan for it as part of your fitting appointment.
Yes, when the tube is placed correctly and you keep still. It measures the sound in your own ear canal instead of estimating it from an average ear, which is why audiology guidelines recommend it for checking a fitting.
It is still worth having. A hearing aid can feel comfortable and yet give too little of the high pitches that make speech clear. The measurement shows whether it matches your target, so you get its full benefit.
Ask for REM When You Book
Choosing your first hearing aids, or replacing old ones? Talk to us about a fitting checked with Real Ear Measurement (REM) at any of our 11 clinics across Mumbai, Thane and Navi Mumbai. Our phone and WhatsApp are answered 9am to 9pm, every day, by audiologists and clinical experts.