Question
How does auditory aging impact hearing aid fitting strategies and default processing settings?
Answer
The normal aging process significantly impacts the auditory system in a few different ways, creating challenges that necessitate specific considerations in hearing aid fitting. For example, as individuals age, they often experience a loss in temporal fine structure, which is crucial for pitch perception, localization, and understanding speech in noisy environments. Oftentimes, the loss of temporal fine structure doesn’t show up on routine pure tone audiometry, and begins to occur at an earlier age than many realize. The loss of temporal fine structure in the aging cochlea means older adults become more dependent on the speech envelope for perception – you might need to think back to your Hearing Science 101 course on that concept. Consequently, when fitting hearing aids, it's vital to preserve the integrity of the speech envelope and avoid introducing additional distortion. An already distorted auditory system, a result of normal aging, is susceptible to further degradation from “aggressive” signal processing. By “aggressive,” we mean settings such as high compression ratios or very fast release times. These default compression parameters can negatively affect speech clarity and sound quality.
To address these age-related changes, some recently published clinical guidelines emphasize minimizing distortion and improving the signal-to-noise ratio (SNR). One of the primary recommendations is to use slower-acting compression as a default for older adults, especially in noisy situations. Faster-acting compression can distort speech cues by reducing spectral contrast within the temporal gaps of the speech signal. Additionally, leveraging directional microphone technology, such as bilateral adaptive beamforming, is the most effective tool for enhancing SNR. It's also recommended to use custom molds with parallel vents over instant-fit domes whenever possible, as the open acoustics of domes can create slit leak venting effects that can greatly diminish the effectiveness of directional microphones and noise reduction features.
Different hearing aid manufacturers have varying default settings, or "out-of-the-box" configurations, for features like compression, noise reduction, and directionality. For instance, some brands may default to a slower-acting compression, which aligns well with the guidelines for older adults, while others might use syllabic (faster) release times. Real-ear measurements are essential in confirming that the compression being applied is effective and not excessive, ideally keeping the compression ratio at or below 1.7. It is easy to “eyeball” the effective compression ratio when you conduct real-ear measures at soft, average, and loud inputs, as we demonstrate in our course. Clinicians should be aware of their manufacturer's defaults and be prepared to adjust them, such as by creating a separate program with slower release times to better meet the individual needs and preferences of older patients per the aforementioned guidelines. Taking the time to align with these guidelines, looking at what’s happening in the ear (not what you see on the fitting software on your laptop), gives patients a better shot at improved speech intelligibility, better listening comfort, and optimized sound quality.
Watch this CEU course from Signia to learn more about this topic: The Devil is in the Defaults: How Various Signal Processing Strategies Influence Fine-Tuning Decisions in Older Adults by Navid Taghvaei, AuD, ABAC, CCC-A; Brian Taylor, AuD
References
Taghvaei, N., & Taylor, B. (2025). The devil is in the defaults: How various signal processing strategies influence fine-tuning decisions in older adults. [Continuing education course]. AudiologyOnline. https://www.audiologyonline.com/audiology-ceus/course/devil-in-defaults-various-signal-40918
Moon, I. J., & Hong, S. H. (2014). What is temporal fine structure, and why is it important? Korean Journal of Audiology, 18(1), 1–7. https://doi.org/10.7874/kja.2014.18.1.1
Moore, B. C. J. (2008). The role of temporal fine structure processing in pitch perception, masking, and speech perception for normal-hearing and hearing-impaired people. Journal of the Association for Research in Otolaryngology, 9(4), 399–406. https://doi.org/10.1007/s10162-008-0143-x
Windle, R. (2024, January 8). 20Q: Changes to auditory processing and cognition during normal aging – Should it affect hearing aid programming? Part 1 – Changes associated with normal aging [Continuing education course]. AudiologyOnline. https://www.audiologyonline.com/audiology-ceus/course/20q-changes-to-auditory-processing-39167
Windle, R., Dillon, H., & Heinrich, A. (2023). A review of auditory processing and cognitive change during normal ageing, and the implications for setting hearing aids for older adults. Frontiers in Neurology, 14, 1122420. https://doi.org/10.3389/fneur.2023.1122420
Windle, R. (2024, February 1). 20Q: Changes to auditory processing and cognition during normal aging – should it affect hearing aid programming? Part 2 – Programming hearing aids for older adults. AudiologyOnline. https://www.audiologyonline.com/articles/20q-changes-to-auditory-processing-part-2-28792
