Hearing professional fitting a patient with real ear verification

Real-Ear Measurements vs Speech Mapping: What's the Difference?

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REM (real ear measurements) and LSM (live speech mapping) are two different fitting procedures hearing care providers use to verify that a hearing instrument is customized to a patient's unique ear characteristics. To learn more about why we conduct real-ear verification, you can read our blog post, Benefits of Real Ear Measurement and Live Speech Mapping.


REM and LSM are distinct tests with differing procedures, though the terms are often used interchangeably. This is because they serve the same purpose, however the differences in how the fitting is conducted can be significant for you and your patients.


Many hearing care professionals are unsure whether they should be conducting real ear measurements or live speech mapping and how to recognize the differences between them. Here are some key ways you can distinguish between REM and LSM tests to determine which one is right for you.


What Are Real Ear Measurements?

REM, or real ear measurement, was the first form of in-ear verification developed in the early 1980s. You will most likely hear real-ear verification referred to as REM because real ear measurements were the first tests produced by diagnostic manufacturers. You may also hear it referenced as Insitu or Probe microphone measurements. "REM" is now often used as an all-encompassing term to describe both true real ear measures and speech mapping.

The most significant differences between REM and LSM are the type of stimuli used for the fitting and how adjustments are made to the hearing instrument.


Traditional REM uses non-speech stimuli to fit hearing aids, essentially noise, to adjust the gain or output of hearing instruments. Similar to speech mapping, modern REM systems such as the AVANT REM Speech+ allow you to use a stimulus that mimics human speech such as the ISTS (international speech test signal) to help make more accurate adjustments.


A provider fitting with real ear measurements conducts several different tests to determine a patient’s gain or output levels, including a necessary unaided response test. The results of these tests are used to adjust the hearing aid’s software.


REM also typically takes longer to do than speech mapping because the tests run for a set amount of time. The stimulus length varies between manufacturers, but MedRx's lasts for approximately 15 seconds. Adjustments cannot be made during this run time, so the provider must alternate between adjusting in the manufacturer’s fitting software and rerunning the tests to confirm that the patient is receiving ample gain or output.


What is Live Speech Mapping?

Advancements in technology have allowed hearing aid manufacturers to include features that provide patients with a more rounded listening experience, making it more important than ever to have options for speech mapping. Speech mapping can not only fit a patient's hearing aid to their unique anatomy, but it can use real speech stimuli to demonstrate how a patient would perceive SPLs with their new device.


These stimuli can be:

  • recorded speech that uses all the phonemes of speech
  • the International Speech Testing Signal (ISTS)
  • live speech using a spouse or family member’s voice


Contrary to traditional REM, in speech mapping, a provider can analyze the patient's aided response to the stimulus in real-time and compare it to the patient's audiogram, the Modified Aided Speech Spectrum, or the patient's MCL and UCL. It eliminates the need to go back and forth between tests and adjustments in the hearing aid software. With speech mapping, it's also unnecessary to conduct an unaided response test, though it can be helpful for certain patients. 


Because of these factors, fittings with speech mapping can save time, are more accurate and better suited for the complex hearing aids patients are more likely to use today.

Do I Need to Use REM/LSM for Best Practices?

Performing real-ear verification of some sort is considered audiology best practices. You can opt for REM or LSM, depending on your preferences or the patient's needs.


When you confirm that your patient's hearing aids are fit for not only their prescriptive loss but their unique ear's characteristics as well, you can be sure that they'll receive the most accurate fit. In turn, you may even see a reduction in hearing aid returns and refittings.


Though it can mean spending more time with a patient upfront, conducting real-ear verification demonstrates that you are willing to help your patient get the best fit from their hearing instrument that you can.


If you're already verifying with REM but are interested in learning speech mapping to help your patients get an even more customized fit, MedRx can help you. Our LSM modules are intuitive to use and easy to learn, especially when you're already familiar with our real-ear measurements.


MedRx REM/LSM Options

MedRx's STUDIO software includes a REM and LSM module. To carry out these tests, MedRx offers two different hardware options to meet your needs for patient verification. Both hardware options include the REM and LSM modules.


The AVANT REM Speech+ is MedRx's REM and LSM verification system. The AVANT REM Speech+ is compatible with MedRx's original AVANT software or the new STUDIO modules.


The REM Speech+ is a PC-based binaural verification system and includes features such as:

  • REM AutoFit Capability
  • Targets for MSS (Modified Speech Spectrum), DSL v5.0, NAL-NL1 and NAL-NL2
  • HLS (Hearing Loss Simulator) & MHA (Master Hearing Aid) for 3rd Party Demonstration


The system is compatible with Noah, Blueprint OMS, TIMS, and Sycle to help streamline your patient visits. In the MedRx REM module, a Manual Signal Control (MSC) allows the clinician to play the stimulus for an unlimited amount of time until the MSC button is pressed again. This feature lets the clinician control the duration of the stimulus to adjust the hearing aid software while it is still running.


Similarly, the Live Speech Mapping module includes an "on top mode" that allows you to adjust the hearing aid's software with the stimulus window open and running in real-time.


MedRx AVANT REM Speech+ Hardware



The AVANT ARC is a two-in-one audiometer and real-ear verification system. Whether you have space constraints, test and fit in the same room, or conduct tests and fit hearing instruments on the go, the AVANT ARC provides everything you need in one compact hardware system.


In addition to all of the same features provided by the REM Speech+, the AVANT ARC is also a complete dual-channel diagnostic audiometer. 


MedRx AVANT ARC Audiometer and Real Ear Measurement Hardware



Our compact and portable design allows hearing care providers to consolidate equipment and save space space, while never compromising on test quality. MedRx software also integrates with all MedRx computerized equipment for a seamless patient exam from start to finish to follow-up.

Real Ear Measurements vs. Speech Mapping

REM and LSM are both valuable tests that can be used to verify that your patient’s hearing aids are fit for their unique ear anatomy. While REM takes slightly longer, it can be better suited for linear instruments. Conversely, LSM allows you to test and fit simultaneously, saving time and increasing test accuracy.


Though many hearing care professionals are often intimidated by adding another step to their exam routine, real-ear verification can offer your office a valuable service for your patients and ultimately serve to streamline your operations.


If you're interested in learning more about getting started with a MedRx verification system, contact us at (888)392-1234 to schedule a free online demonstration!