Real ear measurement (REM) is a probe microphone test that measures the actual sound level your hearing aid delivers at your eardrum during fitting. It’s the clinical gold standard for verifying hearing aids work as prescribed for your unique ear anatomy, yet fewer than 40% of Australian hearing aid fittings include it. At The Audiology Place, we use REM on every single fitting, without exception, because without it we’re essentially guessing whether your $4,000 to $12,000 investment is actually working.
The uncomfortable truth is that most hearing aid fittings in Australia rely on manufacturer first-fit formulas—software predictions based on population averages that assume your ear canal is a standard size and shape. It isn’t. Research consistently shows that approximately 20% of hearing aid fittings performed without real ear verification miss the prescribed amplification target by 10 dB or more, particularly in the high frequencies where speech clarity lives. That’s the difference between understanding your grandchild clearly and asking them to repeat themselves constantly.
What Real Ear Measurement Actually Measures
During a REM test, we place a thin silicone probe tube into your ear canal, positioning it a few millimetres from your eardrum. The hearing aid sits in your ear as it normally would, and we play calibrated speech signals through a speaker positioned at ear level. The probe microphone captures what’s actually happening acoustically at the eardrum—not what the hearing aid manufacturer’s software thinks should be happening, but what is happening in your specific ear.
We’re measuring sound pressure level across frequencies, typically from 250 Hz through 4000 Hz, and comparing those measurements against evidence-based prescriptive targets. The two most common formulas we use are NAL-NL2 (developed by Australian researchers at National Acoustic Laboratories) and DSL v5, both derived from decades of research on optimal audibility and speech understanding. Your audiogram tells us what you can’t hear; REM tells us whether the hearing aid is successfully filling in those gaps at the one place that matters—your eardrum.
The acoustic reality inside your ear canal is vastly different from laboratory predictions. Ear canal volume, length, shape, and the depth of hearing aid insertion all affect the actual output. A shorter ear canal will create resonance peaks at different frequencies than a longer one. A tight canal will reflect sound differently than a more open one. Children’s ears behave completely differently from adult ears, which is why REM is absolutely non-negotiable in paediatric fittings, yet somehow still treated as optional in adult audiology.
Why So Few Clinics Actually Use It
The statistics are damning. Multiple studies, including systematic reviews by Aazh and Moore published in the International Journal of Audiology, confirm that only 30-40% of hearing aid fittings globally include real ear verification, despite every professional audiology body—including Audiology Australia—listing it as best practice. In Australia, the figure is similarly dismal. I’ve seen patients who’ve spent five years wearing hearing aids fitted without REM, aids that were delivering 15 dB less gain than needed in the 3000-4000 Hz range, the exact frequencies critical for understanding consonants like ‘s’, ‘f’, and ‘th’.
Why don’t more clinics do it? Three reasons, none of them acceptable. First, it takes time—an extra 15-20 minutes per fitting. For high-volume retail chains focused on throughput, that’s 15-20 minutes they could spend with another customer. Second, it requires proper equipment and clinical skill. Real ear systems cost $15,000-$30,000 and require ongoing calibration. Not every retail store wants that capital investment. Third, and most problematically, REM occasionally reveals that a particular hearing aid model isn’t physically capable of meeting a patient’s prescription. When that happens, ethical practice demands recommending a different device, even if it’s less profitable. I’ll let you guess how often that happens at commission-based retailers.
The research evidence supporting REM is overwhelming. A 2018 study by Valente and colleagues published in the Journal of the American Academy of Audiology found that hearing aids fitted with REM verification resulted in significantly better aided speech recognition scores and higher patient satisfaction ratings than fittings without verification. Anderson’s work on hearing aid outcomes has repeatedly demonstrated that matching prescriptive targets—which is only possible with REM—predicts long-term hearing aid success better than any other single variable.
How We Use REM at Every Fitting
When you come to The Audiology Place for a hearing aid fitting, REM isn’t optional, fast-tracked, or performed only on “complex cases.” It’s embedded in our standard protocol for every patient, every time.
After programming your hearing aids based on your audiogram, we insert the probe tube approximately 5mm past the end of your hearing aid or custom earmould. We verify placement by checking insertion depth against anatomical landmarks, ensuring we’re measuring in the appropriate location. Then we run a series of test signals—usually recorded speech passages at 55, 65, and 75 dB SPL—representing soft, average, and loud conversational speech.
The real ear measurement system displays your actual aided response against the prescriptive target in real time. We’re looking for match within ±5 dB across the speech frequency range, though we pay particular attention to the 1500-4000 Hz region where consonant information lives. If we see deviations, we adjust the hearing aid’s gain and frequency response, then re-measure. This isn’t a one-and-done process; it’s iterative. Sometimes we’ll measure, adjust, and verify three or four times before we achieve appropriate match.
We also measure your unaided response first—your ear’s natural resonance before the hearing aid is introduced. This Real Ear Unaided Response (REUR) gives us baseline information about your ear canal acoustics and helps us identify any anatomical factors that might affect fitting. The difference between what we measure without amplification and what we achieve with the hearing aid fitted is called Real Ear Aided Response (REAR), and that’s what we’re ultimately trying to optimise.
What This Means for Your Hearing Aid Outcome
The practical difference REM makes isn’t subtle. I’ve had patients tell me they thought they were “bad at wearing hearing aids” because they couldn’t adapt to the sound quality, when the reality was their previous fittings were so far off prescription that the aids were effectively delivering random amplification. When we fit them properly with REM verification, suddenly speech becomes clear without being harsh, background noise becomes more manageable, and they actually want to wear the devices.
Proper verification also prevents over-amplification, which is just as problematic as under-amplification. Hearing aids fitted too loud can cause listening fatigue, headaches, and sound quality complaints. They also risk noise-induced threshold shifts if excessive output isn’t properly controlled. REM allows us to verify not just that you’re getting enough amplification, but that you’re not getting too much.
This is particularly important for first-time hearing aid users. Your brain hasn’t heard certain sounds clearly for years, sometimes decades. When we restore audibility through properly verified amplification, there’s an acclimatisation period. But that acclimatisation only happens when the starting point is correct. Starting with incorrect amplification just trains your brain to an inappropriate sound profile, making it harder to adapt when we eventually get it right.
Real ear measurement isn’t innovative or cutting-edge. It’s been the documented gold standard for hearing aid verification since the 1980s. The equipment exists, the research base is unambiguous, and the professional guidelines are clear. The only reason it’s not universal is commercial convenience.
At The Audiology Place, we’ve made a deliberate choice to operate outside the retail model that prioritises volume over verification. We’re not commissioned on sales, we’re not owned by a manufacturer, and we’re not incentivised to rush appointments or skip clinical steps. REM on every fitting isn’t a marketing claim—it’s simply how hearing aid fitting should be done, and we’re not interested in compromising on that standard.
If you’re considering hearing aids, or you’ve been wearing aids that never quite worked properly, the question to ask isn’t whether the clinic uses REM. The question is why wouldn’t they.
