Did you know that there are nearly 20 journals that publish articles related to hearing aid technology, signal processing, and fitting? And that each year, more than 200 articles are published related to hearing aids? In the words of the great philosopher Frank Zappa, “So much to read, so little time.” Well, we’re here to help!
For the past 16 years (or so), at each AAA annual conference, we have reviewed what we believe to be the top hearing aid articles from the past year. Our definition of top articles has a clinically practical slant—that is, we select well-designed articles where the findings might have a direct impact for audiologists fitting hearing aids. We typically choose representative articles from the different areas of the overall fitting process: prefitting testing, selection of signal processing, verification, and outcome measures. And, of course, there always are a few key articles specifically focused on the pediatric population.
As usual, there were several excellent articles published in 2018, and many of these had direct clinical relevance. For example, have you ever wondered if entry-level hearing aids perform just as well as premier models? You might recall that we talked about this a few years back when Robyn Cox and colleagues published their series of articles. Well, that topic is coming back in 2019, as Wu and co-workers at the University of Iowa conducted a similar comparison, which included both laboratory and real-world outcomes. Their design for data collection was a little different, however, as they used ecological momentary assessment (EMA) as part of the real-world portion. And, of course, there have been advances in the premier hearing aids, such as bilateral beamforming, since the Cox research.
So what model of hearing aid was the winner? Different from the Cox research? Are differences more likely to show up when EMA is used? We’ll give you the low-down at AAA 2019 in Columbus!
What does Goldilocks have to do with fitting hearing aids? In the near future, when over-the-counter (OTC) products are rolled out, the relationship might be quite significant. Patients likely will have to decide on their own if their product is “too hot,” “too cold,” or “just right.” It’s not surprising then, that an Ear and Hearing article from last year was titled “A Goldilocks Approach to Hearing Aid Self-Fitting.”
The primary goal of this study was to determine the feasibility and outcome of an alternative self-adjustment approach that includes a generic starting response designed for a mild-to-moderate hearing loss, similar to that of current hearing aids.
Boothroyd and Mackersie asked (and answered) research questions such as: How do the self-adjusted level, spectrum, and speech intelligibility index (SII) compare with those provided by a generic starting response? How does the self-adjusted level, spectrum, and SII compare with those provided by the NAL-NL2? Does hearing aid experience affect the outcome? Does the inclusion of a speech-perception test affect outcome? And, how do self-adjustments made by hearing aid users compare to their existing hearing aids? All good things to know when the OTC world arrives.
A related article from last year was from Peggy Nelson and colleagues. This group also used self-adjustment to determine listener preference and performance, specifically for listening to speech in quiet and in noise. A primary research question was to determine if most listeners set their gain to a lower (or higher) level in the presence of noise. If so, then automatic gain changes might be satisfactory and preset noise-reduction algorithms would satisfy most users. However, the authors point out that, if different listeners set their gain differently for a given listening condition, this would suggest that preset noise-reduction programs are not ideal, and that self-adjustment is a valuable tool with which to quickly and accurately determine the optimum setting. We’ll tell you how this all played out.
In the area of hearing aid verification, a topic that was popular in 2018 was autoREMfit (fitting using automatic real-ear measures). This has been around for nearly 20 years, but there is renewed interest as it is now available from most major hearing aid manufacturers and most probe-microphone systems. The “auto” part of this procedure is that the probe-mic equipment and the hearing aid fitting software talk to each other. The software collects on-going real-ear information from the probe-mic system, and, then, makes changes in the hearing aid output, based on some preliminary measures, and measured ear canal SPL at the moment. The notion is that these automatic adjustments will make the fitting closer to a preselected prescribed target output, such as that of the NAL-NL2 or the DSLv5.0 (Desired Sensation Level, Version 5.0). In theory, the resulting fit-to-target should be about as good as that which could be obtained manually by an experienced audiologist using the programming software. The assumed advantage is that you would get the job done faster, especially when conducting simultaneous bilateral fittings. We’ll be reporting on some early research with this procedure, and also talking about some potential pitfalls.
The past year also resulted in some important publications in the area of pediatric hearing aid fittings. We reported on the longitudinal outcomes of children with hearing impairment (LOCHI) study three years into data collection, and now the research team +published a series of papers reporting on their five-year findings. We’ll focus on the implications for clinical practice.
Not surprising, the data support that early fitting of hearing devices is key to achieving better speech, language, and functional performance outcomes for children. We’ll discuss the relationship between speech perception and cognitive abilities, the impact of maternal education, and the impact of language on hearing in noise. We also will answer question everyone is asking: Which prescriptive targets (if met) provide a better pediatric hearing aid fitting—NAL-NL2 or DSL v.5? We’ll look at the results according to audiometric measures, speech and language abilities, and a first look at parent report.
So, there you have it. A brief glimpse into a few of the topics and articles that we’ll be reviewing at our annual get-together. We hope to see you there, and will try our best to convince you that talking about hearing aid research actually can be fun.