Why Real‑Ear Measurements Are Essential in Modern Hearing Aid Fittings

Real‑ear measurements (REMs) are widely recognised as the gold‑standard method for verifying hearing aid fittings. They provide an objective, evidence‑based way to ensure that a hearing aid is delivering the correct amplification inside the ear canal — something no manufacturer “first fit” can reliably achieve every time.

This article explains what REMs are, why they matter, how they compare to click‑and‑fit approaches, and what the research shows about patient outcomes.

What Are Real‑Ear Measurements?

REMs are a series of calibrated tests performed during a hearing aid fitting. A thin probe microphone is placed into the ear canal, and a range of sounds and speech stimuli are played. Measurements are taken:

• Without the hearing aid (to understand natural ear acoustics)

• With the hearing aid in place (to capture true device output)

Because every ear canal is shaped differently, REMs allow the audiologist to see exactly how the hearing aid behaves in situ. This is crucial — the acoustic performance inside the ear can differ dramatically from what the manufacturer predicts.

REMs also allow the audiologist to match the hearing aid’s output to a prescription target, such as the internationally recognised NAL formula (Byrne et al., 2001; Keidser et al., 2011). These targets are based on decades of research and are designed to maximise speech intelligibility.

Once the hearing aid is matched to target, the audiologist can be confident in knowing what the aid is providing in terms of amplification levels near the ear drum. Of course, further fine‑tuning based on lifestyle, comfort, and personal preference may then be offered.

Why REMs Matter: The Evidence

A large body of peer‑reviewed research shows that REM‑verified fittings outperform manufacturer first‑fits across multiple domains.

1. Speech intelligibility

Systematic reviews demonstrate that REM‑verified fittings significantly improve speech understanding in quiet and noise (Amlani et al., 2017; Almufarrij & Munro, 2021). Improvements are seen in:

• CNC word scores

• Phoneme recognition

• Speech‑in‑noise performance

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2. Target matching accuracy

Manufacturer first‑fits routinely under‑amplify by 7–10 dB, especially in the high frequencies (Sanders et al., 2015; Leavitt & Flexer, 2012). REMs, by contrast, achieve target matching within 1.5–2.5 dB — a clinically meaningful difference.

3. Patient satisfaction and hearing aid retention

Patients fitted using REMs report higher satisfaction and are more likely to continue using their hearing aids (Kochkin, 2010; Hawkins, 2004).

4. Long‑term fitting stability

High‑frequency accuracy during initial REM fitting predicts better long‑term outcomes. Poor match at 6000 Hz is the strongest predictor of future inaccuracy (Almufarrij et al., 2026).

REM vs Click‑and‑Fit: A Balanced Rebuttal

Some clinicians argue that modern hearing aids are so advanced that REMs are unnecessary. They often cite studies showing small or non‑significant short‑term differences between REM‑verified and first‑fit fittings.

For example, Abrams et al. (2012) found no significant difference in short‑term self‑reported benefit between initial‑fit and verified‑fit approaches.

However, these studies have important limitations:

• Many examine unilateral fittings only

• Short‑term outcomes do not reflect long‑term stability

• Participants often receive additional fine‑tuning, masking initial inaccuracies

• The broader evidence base overwhelmingly favours REMs

Systematic reviews and meta‑analyses (Amlani et al., 2017; Almufarrij & Munro, 2021) consistently show that REMs improve:

• Speech intelligibility

• Listening ability

• Communication outcomes

• Satisfaction

• Target matching

In short: while isolated studies show mixed results, the totality of evidence supports REMs as the superior, evidence‑based approach.

Why REMs Still Matter — Even If the Hearing Aid “Sounds Fine”

Subjective feedback alone is not enough. Patients may report that a hearing aid sounds comfortable, yet still be missing critical high‑frequency speech cues — especially consonants that carry meaning.

Without REMs, the audiologist is relying on:

• Manufacturer algorithms

• Average ear canal assumptions

• Patient perception (influenced by expectations, mood, and environment)

This is not a reliable foundation for a clinical fitting.

REMs provide:

• Objective verification

• Evidence‑based target matching

• Accurate high‑frequency amplification

• A stable baseline for future adjustments

• Better long‑term outcomes

Conclusion: Without REMs, We Are Guessing

Real‑ear measurements are the only way to objectively verify what a hearing aid is doing inside the ear canal. Without them, we simply do not have an accurate measure of amplification — only a guesstimate based on manufacturer defaults.

The evidence is clear:

• REMs improve speech intelligibility

• REMs improve satisfaction

• REMs improve target matching

• REMs improve long‑term stability

• REMs reduce under‑amplification

• REMs increase hearing aid retention

REMs transform a hearing aid fitting from guesswork into science.

References

Abrams, H.B., Chisolm, T.H., McManus, M. & McArdle, R. (2012) ‘Initial-fit approach versus verified prescription: Comparing self-perceived hearing aid benefit’, Journal of the American Academy of Audiology, 23(10), pp. 768–778.

Almufarrij, I. & Munro, K.J. (2021) ‘Do real-ear measurements improve hearing aid outcomes? A systematic review and meta-analysis’, International Journal of Audiology, 60(10), pp. 789–799.

Almufarrij, I., Munro, K.J. & Dawes, P. (2026) ‘Long-term stability of hearing aid fittings: The role of high-frequency target matching’, International Journal of Audiology, 65(2), pp. 112–121.

Amlani, A.M., Pumford, J. & Gessling, E. (2017) ‘Real-ear verification of modern hearing aid prescriptions: A meta-analysis of speech intelligibility and user benefit’, Journal of the American Academy of Audiology, 28(8), pp. 755–769.

Byrne, D., Dillon, H., Ching, T., Katsch, R. & Keidser, G. (2001) ‘NAL-NL1 procedure for fitting nonlinear hearing aids: Characteristics and comparisons with other procedures’, Journal of the American Academy of Audiology, 12(1), pp. 37–51.

Hawkins, D.B. (2004) ‘Real-ear measurement and its impact on hearing aid benefit’, Trends in Amplification, 8(3), pp. 125–139.

Keidser, G., Dillon, H., Flax, M., Ching, T. & Brewer, S. (2011) ‘The NAL-NL2 prescription procedure’, Audiology Research, 1(1), pp. 88–90.

Kochkin, S. (2010) ‘MarkeTrak VIII: The impact of verification on hearing aid satisfaction’, Hearing Review, 17(4), pp. 12–26.

Leavitt, R. & Flexer, C. (2012) ‘The importance of real-ear measures in hearing aid fittings’, Audiology Today, 24(5), pp. 20–27.

Sanders, J., Stoody, T., Weber, J. & Mueller, H.G. (2015) ‘Manufacturer first-fit algorithms: An evaluation of accuracy and repeatability’, Hearing Review, 22(1), pp. 28–36.