Hearing Aid Fitting: Why Real-Ear Measurements Are the Only Reliable Method

What Real-Ear Measurements Actually Do

You’ve bought a hearing aid. You paid for it. You waited weeks for the appointment. But when you put it in, the world still sounds muffled, too quiet, or strangely echoey. Why? Because most hearing aids are not fitted to your ear. They’re fitted to an average. And your ear isn’t average.

Real-ear measurement (REM) is the only way to know for sure what’s happening inside your ear canal when your hearing aid is turned on. It’s not a guess. It’s not a simulation. It’s a direct, physical measurement of sound pressure levels-right where your eardrum sits. A tiny probe microphone, thinner than a strand of hair, is placed inside your ear, just 5 millimeters from your eardrum. Then, while you sit quietly, the hearing aid plays speech sounds at different volumes. The probe picks up exactly how much amplification is delivered at each frequency-250 Hz to 8000 Hz-and compares it to your personal prescription targets like NAL-NL2 or DSL v5.0.

This isn’t optional. It’s science. A 2021 study in the International Journal of Audiology found that ear canal shape can change how much sound reaches your eardrum by up to 20 decibels between people. That’s the difference between hearing someone clearly and missing half the conversation. If your hearing aid is calibrated using a test box (a standardized 2cc coupler), you’re relying on data from a fake ear. Real-ear measurement uses your ear.

Why Manufacturer Settings Aren’t Enough

Most hearing aids come with a default setting called a “first fit.” It’s based on your audiogram and a generic model of the human ear. Companies like Oticon, Phonak, and Widex use algorithms to estimate how much amplification you need. But here’s the problem: those algorithms assume your ear canal behaves like the average ear. It doesn’t.

According to MarkeTrak data from 2021, first-fit algorithms get the gain right only 52% of the time. That means nearly half the time, your hearing aid is either too loud or too soft in key speech frequencies. You might hear vowels fine but miss consonants like “s,” “t,” or “k”-the sounds that give speech its clarity. That’s why so many people say, “I can hear people talking, but I can’t understand them.”

REM fixes this. When verified with real-ear measurements, hearing aids hit their target gain 92% of the time, compared to just over half with manufacturer defaults. A 2019 study in the Journal of the American Academy of Audiology showed patients who had REM during fitting understood speech in noisy environments 35% better than those who didn’t. That’s not a small gain. That’s the difference between avoiding social situations and joining them.

The REM Process: What Happens During Your Appointment

During your fitting, your audiologist will start with a quick check of your ear canal using an otoscope. This isn’t just for show. About 0.9% of people have minor perforations or wax blockages that can interfere with measurements. If something’s wrong, they’ll fix it before moving on.

Then comes the probe tube. It’s inserted gently into your ear, alongside the hearing aid. You’ll feel a slight tickle-some people say it’s like a feather brushing the inside of their ear. It’s not painful, but it’s unusual. Most people get used to it in seconds.

The audiologist will play speech sounds at three levels: soft (50 dB), normal (65 dB), and loud (80 dB). You’ll hear phrases like “The cat sat on the mat” or “She bought a red hat.” The probe records how your hearing aid responds at each frequency. The software overlays your target curve-the ideal amplification based on your hearing loss-and shows you exactly where the aid is falling short or going too far.

If the output is too low at 3000 Hz, where speech clarity lives, the audiologist adjusts the high-frequency gain. If it’s too loud at low frequencies, causing booming or feedback, they reduce bass. All of this happens in real time. You’ll see the changes on a screen. You’ll hear them immediately. And you’ll know, with certainty, that the settings match what your ear needs-not what the factory assumed.

What Happens Without REM

Many people skip REM because they’re told it’s “not necessary,” or because the provider doesn’t have the equipment. That’s common in retail hearing aid stores and with over-the-counter (OTC) devices. But the results speak for themselves.

A 2022 survey of 1,247 hearing aid users on HealthyHearing.com found that 87% of those who had REM rated their devices as “very effective.” Only 52% of those without REM felt the same. On Reddit’s r/hearingloss, users who bought OTC aids online often report the same complaints: constant whistling, voices sounding robotic, or needing to turn the volume up so high it hurts. One user wrote: “Saved $1,000. Still can’t understand my wife.”

OTC hearing aids are legal now, thanks to the FDA’s 2022 rule. But the FDA also explicitly says these devices “cannot replace the need for professional evaluation and fitting.” Why? Because they lack verification. They can’t measure what’s happening in your unique ear. They’re designed for mild hearing loss and general use-not for people with complex needs.

Even in clinics, if you’re not getting REM, you’re being fitted by guesswork. And guesswork leads to frustration, wasted money, and abandoned hearing aids.

Why Audiologists Won’t Skip This Step

Board-certified audiologists don’t skip REM because they’re trying to make your appointment longer. They do it because they’re required to. The American Speech-Language-Hearing Association (ASHA), the American Academy of Audiology (AAA), and the American Medical Association (AMA) all recognize REM as the gold standard. In fact, 97% of audiologists surveyed by the Hearing Industries Association in 2022 said REM is mandatory for every fitting.

It’s also covered by insurance. The CPT code 92597 was introduced in 2017 specifically for real-ear measurements. Medicare and most private insurers reimburse for it because it’s proven to reduce follow-up visits. A 2021 study by Abrams et al. showed that patients who had REM needed 43% fewer adjustments afterward. That’s less time in the clinic, less money spent, and more confidence in your device from day one.

Even the FDA and the International Organization for Standardization (ISO) agree. As of 2023, ISO 12121:2023 requires REM verification for all hearing aids sold in Europe. In the U.S., the Joint Committee on Infant Hearing says REM is “essential for all pediatric fittings.” If it’s required for babies, it’s required for adults too.

The Future of Hearing Aid Verification

Technology is making REM faster and smarter. New systems from Widex and Phonak now use AI to analyze real-ear data in seconds, cutting fitting time by up to 30%. Instead of manually tweaking gain curves, the software suggests adjustments based on thousands of previous fittings. But here’s the key: even with AI, the probe microphone is still needed. No algorithm can replace the physical measurement of sound in your ear.

Some companies are exploring 3D ear scanning to create digital models of the ear canal. That’s useful for custom shells and earmolds. But as Dr. Pamela Souza said in her 2022 AAA keynote: “No matter how advanced our modeling becomes, we’ll always need to verify what’s actually happening in the real ear.”

Right now, the National Institute on Deafness and Other Communication Disorders is funding $2.4 million in research to make REM more accessible and automated. But the goal isn’t to eliminate it-it’s to make it faster, cheaper, and available everywhere.

What to Ask Before Your Fitting

If you’re scheduled for a hearing aid fitting, don’t assume REM is included. Ask these questions:

• Will you use real-ear measurements to verify my hearing aid settings?
• What prescriptive targets will you use-NAL-NL2 or DSL v5.0?
• Will you show me the results on screen during the fitting?
• Do you have a sound booth that meets ANSI standards?

If the answer to any of these is “no,” consider going elsewhere. This isn’t about upselling. It’s about getting your money’s worth. A hearing aid that doesn’t work properly is just a expensive piece of plastic. One that’s verified with REM is a tool that restores your connection to the world.

Final Thought: Your Ears Are Unique. Your Hearing Aid Should Be Too.

Everyone’s fingerprint is different. Everyone’s ear canal is different. Your hearing loss is unique. So why would you settle for a one-size-fits-all solution?

Real-ear measurement isn’t a luxury. It’s the baseline for professional hearing care. It’s the difference between hoping your hearing aid works and knowing it works. If you’ve struggled with hearing aids before, it’s not you. It’s the fitting. And it’s fixable.

Don’t accept guesswork. Demand verification. Your ears-and your conversations-are worth it.