How to program modern hearing aids for verification

Advanced features in REM

There is much literature on the subject of using real-ear measurements (REM) for verification of hearing aid fitting. In our review of the literature from the last decade, we found, not surprisingly, that as hearing aids came into their own in the digital age the advancements tended to make verification methods more complicated.

How could the Hearing Care Professional (HCP) ensure that measurements were accurate? Initially, directional microphones were identified as a feature that could affect accuracy, but this could be overcome simply by using proper patient positioning facing the REM speaker. 

However, advanced features—such as automatic directional microphone control, automatic volume control, noise reduction, digital scene classifiers, and expansion—have become common in hearing aids, and their impact on REM may be less obvious. Complicating matters, proprietary naming of features often does not offer clues as to how one might expect them to affect REM.

Leads to user satisfaction

There is much literature on the subject of using real-ear measurements (REM) for verification of hearing aid fitting. In our review of the literature from the last decade, we found, not surprisingly, that as hearing aids came into their own in the digital age the advancements tended to make verification methods more complicated.

How could the Hearing Care Professional (HCP) ensure that measurements were accurate? Initially, directional microphones were identified as a feature that could affect accuracy, but this could be overcome simply by using proper patient positioning facing the REM speaker. 

However, advanced features—such as automatic directional microphone control, automatic volume control, noise reduction, digital scene classifiers, and expansion—have become common in hearing aids, and their impact on REM may be less obvious. Complicating matters, proprietary naming of features often does not offer clues as to how one might expect them to affect REM.

A dedicated program

ReSound fitting software includes a dedicated program aptly named “REM test” that is intended for REM. It disables special signal processing, such as environmentally dependent gain features, noise reduction, directionality, and binaural features, so that the HCP can measure the gain and output of the hearing aids without these features impacting the measurement. Other manufacturers have similar test modes for performing REM.

Conclusion

Using speech-based stimuli like the International Speech Test Signal (ISTS) during real-ear measurements (REM) provides accurate, real-world verification of modern hearing aids without disabling advanced features. In contrast, steady noise signals can activate noise reduction and distort results. To ensure efficient, realistic fittings and better patient satisfaction, clinicians should use speech stimuli and proper positioning when performing REM.