Consistency of Hearing Aid Setting Preference in Simulated Real-World Environments: Implications for Trainable Hearing Aids

Effects of entropy in real-world noise on speech perception in listeners with normal hearing and hearing lossa)

Hearing aids show more benefit in traditional laboratory speech-in-noise tests than in real-world noisy environments. Real-world noise comprises a large range of acoustic properties that vary randomly and rapidly between and within environments, making quantifying real-world noise and using it in experiments and clinical tests challenging. One approach is to use acoustic features and statistics to quantify acoustic properties of real-world noise and control for them or measure their relationship to listening performance. In this study, the complexity of real-world noise from different environments was quantified using entropy in both the time- and frequency-domains. A distribution of noise segments from low to high entropy were extracted. Using a trial-by-trial design, listeners with normal hearing and hearing loss (in aided and unaided conditions) repeated back sentences embedded in these noise segments. Entropy significantly affected speech perception, with a larger effect of entropy in the time-domain than the frequency-domain, a larger effect for listeners with normal hearing than for listeners with hearing loss, and a larger effect for listeners with hearing loss in the aided than unaided condition. Speech perception also differed between most environment types. Combining entropy with the environment type improved predictions of speech perception above the environment type alone.

Self-Adjustment of Hearing Aid Amplification for Lower Speech Levels: Independent Ratings, Paired Comparisons, and Speech Recognition

PURPOSE

Self-adjustment of hearing aid amplification enables wearers to customize the hearing aid output to match their preferences and could become an important tool for programming direct-to-consumer devices for people with mild-to-moderate hearing loss. One risk is that user-selected settings may provide inadequate audibility. This study assessed that risk by quantifying relationships between self-adjusted settings, subjective preferences, and speech recognition performance using speech at low levels in quiet, where achieving high speech audibility requires sufficient amplification.

METHOD

Fifteen people with symmetric, mild-to-moderate sensorineural hearing loss self-adjusted hearing aid amplification while listening to speech in quiet at 45, 55, and 65 dBA. After self-adjustment, 11 participants made blinded ratings of their self-adjusted fit, their NAL-NL2 prescriptive fit, and experimenter-created fits with reduced gain. Participants completed blinded paired comparisons and sentence recognition assessments using these settings.

RESULTS

The gain of self-adjusted fits showed a large range of variability between participants. On average, self-adjusted gain was similar to NAL-NL2 prescribed gain for input signals of 55 dBA and slightly greater than prescribed gain for 45-dBA signals. Speech recognition scores for NAL-NL2 fits were consistently high, and differences in speech recognition results were strongly correlated with the overall preferences obtained from paired comparisons.

CONCLUSIONS

Self-adjusted fits are highly variable between individuals for low-audibility conditions. Nonetheless, self-adjusted fits are at least as satisfactory as NAL-NL2 fits, and listeners tend to disfavor settings that result in poorer speech recognition. The findings argue against concerns that self-adjustment will result in inadequate audibility compared to prescribed settings.

Is the outcome of fitting hearing aids to adults affected by whether an audiogram-based prescription formula is individually applied? A systematic review protocol

INTRODUCTION

Hearing aids are typically programmed using the individual's audiometric thresholds. Developments in technology have resulted in a new category of direct-to-consumer devices, which are not programmed using the individual's audiometric thresholds. This review aims to identify whether programming hearing aids using the individual's audiogram-based prescription results in better outcomes for adults with hearing loss.

METHODS AND ANALYSIS

The methods of this review are reported in line with Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocols guidelines. On 23 August 2020, eight different databases were systematically searched without any restrictions: EMBASE, MEDLINE, PubMed, PsycINFO, Web of Science, Cochrane Library, Emcare and Academic Search Premier. To ensure that this review includes the most recent evidence, the searches will be repeated at the final write-up stage. The population of interest of this review will be adults with any degree or type of hearing loss. The studies should compare hearing aids programmed using an audiogram-based prescription (and verified in the real ear) with those not programmed on the basis of the individual's audiogram. The primary outcome of interest is consumers' listening preferences. Hearing-specific health-related quality of life, self-reported listening ability, speech intelligibility of words and sentences in quiet and noisy situations, sound quality ratings and adverse events are the secondary outcomes of interest. Both randomised and non-randomised controlled trials will be included. The quality of each individual study and the overall evidence will be assessed using Downs and Black's checklist and the Grading of Recommendations, Assessment, Development and Evaluations tool, respectively.

ETHICS AND DISSEMINATION

We will only retrieve and analyse data from published studies, so no ethical approval is required. The review findings will be published in a peer-reviewed journal and presented at scientific conferences.

PROSPERO REGISTRATION NUMBER

CRD42020197232.

Does Probe-Tube Verification of Real-Ear Hearing Aid Amplification Characteristics Improve Outcomes in Adults? A Systematic Review and Meta-Analysis

This systematic review, the first on this topic, aimed to investigate if probe-tube verification of real-ear hearing aid amplification characteristics improves outcomes in adults. The review was preregistered in the Prospective Register of Systematic Reviews and performed in accordance with the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses. After assessing more than 1,420 records from seven databases, six experimental studies (published between 2012 and 2019) met the inclusion criteria; five were included in the meta-analyses. The primary outcome of interest (hearing-specific, health-related quality of life) was not reported in any study. There were moderate and statistically significant positive effects of probe-tube real-ear measurement (REM), compared with the manufacturer’s initial fit, on speech intelligibility in quiet settings (standardized mean difference [SMD]: 0.59) and user’s final preference (proportion difference: 52.2%). There were small but statistically significant positive effects of REM on self-reported listening abilities (SMD: 0.22) and speech intelligibility in noise (SMD: 0.15). The quality of evidence for these outcomes ranged from high to very low. The findings show that REMs improve outcomes statistically, but this is based on a small number of studies and a limited number of participants. It is currently unclear if the benefits are of material importance because minimum clinically important differences have not been established for most of the outcomes. Ultimately, there needs to be a cost-effectiveness analysis to show that statistically significant benefits, which exceed the minimum clinically important difference, are worth the cost involved.