Manufacturer Predicted And Measured REAR Values In Adult Hearing Aid Fitting: Accuracy And Clinical Usefulness

Difference in SII provided by initial fit and NAL-NL2 and its relation to self-reported hearing aid outcomes

OBJECTIVE

The speech intelligibility index (SII) is used to quantify the audibility of the speech. This study examined the relationship between self-reported hearing aid (HA) outcomes and the difference in aided SII (SIIA) calculated from the initial fit (IF) gain and that prescribed as per the second generation of National Acoustic Laboratory Non-Linear (NAL-NL2).

DESIGN

A prospective observational study.

STUDY SAMPLE

The study included 718 first-time and 253 experienced HA users. All users had a valid real-ear measurement (REM) at three input levels (55, 65 and 80 dB SPL).

RESULTS

The gain provided by IF was lower than NAL-NL2 at 55 and 65 dB SPL. IF gain exhibited reduced compression than NAL-NL2 as input levels increased from 55 to 80 dB SPL. On average, the SIIA provided by IF was significantly lower than that for NAL-NL2 at all input levels. The difference in SIIA between IF and NAL-NL2 at 80 dB SPL input level with 0 dB signal-to-noise ratio (SNR) turned out to be a predictor for self-reported outcome for first-time HA users.

CONCLUSION

The study suggests that an SIIA close to that provided by NAL-NL2 at high input levels would be preferred to obtain a better self-reported outcome. .

Did Changes to Adult Hearing Aid Pathways Due to COVID-19 Affect Patient Outcomes? A Service Evaluation

Objective:

The objective of this study was to determine whether changes to adult hearing aid provision during COVID-19 affected patient outcomes or service efficiency.

Design:

A service evaluation compared three cohorts: patients who had hearing aid provision prior to the COVID-19 pandemic (the conventional pathway); patients who had hearing aid provision during the initial national lockdown (remote fittings); and patients who had hearing aid provision during the gradual reopening phase (a blended service with both face-to-face and remote service provision). Outcomes measured the effectiveness and efficiency of the service, using the Glasgow Hearing Aid Benefit/Difference Profiles (GHABP/DP) and number of follow-up appointments required. Results were assessed using descriptive statistics and error bars, separately for new and existing users.

Sample:

This study included 240 hearing aid users.

Results:

Remote fittings adversely impacted the effectiveness of provision for new hearing aid users with a reduction in all GHABP domains. While new users' benefit was equally as good for blended and conventional service provision, blended provision was less efficient and required more follow-up visits. For existing hearing aid users, no differences were seen in GHADP outcomes of different pathways and remote fittings increased service efficiency.

Conclusions:

Remote hearing aid fittings are less effective for new users than hearing aids fitted using standard face-to-face service provision or service provision using a blended model of remote and face-to-face care. Current pathways using a blended model of care are less efficient but equally effective for new hearing aid users compared with provision prior to COVID-19 and result in equivalent patient outcomes in terms of benefit.

Supplemental Material:

https://doi.org/10.23641/asha.21067585

Real-Ear-to-Coupler Difference: Physical and Perceptual Differences

PURPOSE

The real-ear-to-coupler difference (RECD) is a recommended measure for accurate hearing aid fittings, especially for pediatric populations. However, for adults, many clinicians question whether it is necessary.

METHOD

Hearing aids were fit on two groups of 85 older adults seen at a Veterans Administration audiology clinic. One group was fit using RECD measurements, whereas the second group was fit with population-based average RECD values. The two groups had similar pure-tone hearing thresholds.

RESULTS

Like previous studies, there was little difference between the measured RECD for the right and left ears among the participants. Although the majority of the measured RECDs were within 1 SD of the mean, approximately 20% of those measured were outside of the normal range. It also was found that all participants produced lower (improved) Hearing Handicap Inventory for Elderly-Screening (HHIE-S) scores from pre- to postfitting, thus suggesting a reduction in self-perceived hearing handicap.

CONCLUSIONS

Despite having similar prefitting HHIE-S scores, those participants who had their hearing aids fit using measured RECD values had lower postfitting scores than the group that was fit with average RECD values. Furthermore, there was a significant difference between the groups on several questions of the International Outcome Inventory-Hearing Aids, suggesting that there was higher satisfaction with the fittings based on the custom RECD rather than the fittings based on the average RECD. This study demonstrated that, in addition to performing verification using real-ear measurements, accurate conversion of dB HL to dB SPL using personalized RECD likely improved hearing aid satisfaction.

Optimising hearing aid output to paediatric prescriptive targets improves outcomes in children

OBJECTIVE

This study examined the accuracy of hearing aid output to DSL v5.0 Child targets in a group of children who wear hearing aids, and the impact on their auditory outcomes.

DESIGN

For each participant, the output of the initial hearing aid fitting was compared to DSL v5.0 Child prescriptive targets and again after the fitting was adjusted using coupler-based verification and RECD measures. Outcomes for initial and adjusted fittings were examined using the Speech Intelligibility Index (SII), Parent's Evaluation of Aural/Oral Performance of Children (PEACH) rating scale, and speech perception tests in quiet and noise.

STUDY SAMPLE

Sixty-eight children aged 3 months to 17 years with moderate to profound hearing loss participated in the study.

RESULTS

Fit-to-targets improved significantly after hearing aids were adjusted to match targets to within 5 dB RMSE. Adjusted hearing aids provided increased aided audibility compared to initial fittings and resulted in improved speech perception scores and parent-reported hearing performance. Fifty percent of the children aged 6 to 17 years preferred their adjusted fitting compared to 10% who preferred their initial fitting.

CONCLUSIONS

Improvement in fit-to-target to a validated paediatric prescriptive formula using best practice procedures can result in improved auditory outcomes and possible self-reported satisfaction.

Anticipating real-ear insertion response using an external auditory canal model

OBJECTIVES

This study aimed to determine the acoustic characteristics of the external auditory canal (EAC) and predict the real-ear aided response (REAR) using an EAC model that includes the standing wave effect.

METHODS

The EAC transfer function equations were derived by summing the incoming and outgoing waves. First, we investigated the real-ear unaided gain (REUG). Second, seven patients (eight ears) wearing hearing aids (HAs) were enrolled as subjects to examine the REAR. We conducted wideband tympanometry (WBT) to measure the absorbance, the frequency response at 65 dB (65dB-FR) of the HAs, and the measured REAR for an international speech test signal (ISTS) at 65 dB.

RESULTS

The EAC model that includes the standing-wave effect is considered to be valid from examination of the REUG. A significant correlation was found between the measured and calculated REARs at 900 Hz, 1000 Hz, 2000 Hz, and 3000 Hz in an uncorrelated test. A two-way analysis of variance (ANOVA) found significant differences in the 65dB-FR and the measured REARs at 800, 900, 1000, and 2000 Hz, but this difference disappeared after correction of the calculated acoustic characteristics of the EAC.

CONCLUSIONS

By measuring the WBT characteristics and correcting them with an EAC model, the in-situ REAR can be determined from the HA characteristics in the mid-frequency range. There is a risk of insufficient HA amplification in the mid-frequency range when no real-ear measurements are performed.

Comparison of performance with hearing aid programmed to NAL-NL1 first-fit and optimized-fit

PURPOSE

The initial-fit provided by the hearing aid manufacturer's software is generally a display of measurement done in the ear simulators. The need for verification of hearing aid output and gain in the real ear using probe-microphone measurement to match the prescriptive target is highlighted. The objective of the study was to evaluate the difference in real-ear aided response (REAR), real-ear insertion gain (REIG), aided thresholds, articulation index (AI) and word recognition score (WRS) in quiet, with hearing aid programmed to NAL-NL1 first-fit and NAL-NL1 optimized-fit using the probe-microphone technique.

METHODS

In a repeated measure experimental design, 11 participants with a mean age of 41.09 (SD=±9.95) years having moderate and moderately-severe sensorineural hearing loss were tested monaurally in two aided conditions, with a 16-channel hearing aid programmed for manufacturer's NAL-NL1 first-fit and optimized-fit to NAL-NL1 using probe-microphone verification. The REAR, REIG, aided threshold, articulation index and word recognition scores in quiet were obtained for both aided conditions.

RESULTS

The REAR, REIG, aided threshold, AI and WRS in quiet were significantly better with the NAL-NL1 optimized-fit compared to manufacturer's NAL-NL1 first-fit.

CONCLUSION

The optimized-fit yields better audibility and improved word recognition in quiet. This supports best practice guidelines of many professional organizations regarding the use of probe-microphone measurement as the "Gold standard" for verification of hearing aid fitting, thereby providing better satisfaction and quality of life to hearing aid users.

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.

Fit-to-Targets and Aided Speech Intelligibility Index Values for Hearing Aids Fitted to the DSL v5-Adult Prescription

BACKGROUND

 Matching hearing aid output levels to prescribed targets is a component of preferred practice, yet recent normative data on appropriateness of fittings are lacking. Verification measures that assess closeness of fit-to-target include raw deviations from target, root-mean-squared-error (RMSE) deviations from target, and aided Speech Intelligibility Index (SII) values. Establishing normative ranges for these measures may help hearing professionals determine whether a patient's fit-to-targets and/or aided speech audibility is typical for his or her degree of hearing loss.

PURPOSE

 This article aims to characterize the range of fit-to-target and the range of aided SII associated with hearing aid fittings using the Desired Sensation Level version 5.0 (DSL v5-adult) prescription with adults, considering also hearing aid style, venting, and audiometric characteristics.

RESEARCH DESIGN

 A descriptive and correlational study of data collected from a retrospective chart review.

RESULTS

 Hearing aid fittings to 281 ears were compiled. The four-frequency average deviation from target (RMSE) was within ± 5 dB of target in 77% of fittings for mid-level speech. Deviation from targets increased with hearing loss, particularly when the loss is greater than 85 dB hearing level or if the loss was steeply sloping. Venting increased the deviation from targets in the low frequencies. Aided SII values strongly correlated with the participants' hearing thresholds. Clinical ranges for RMSE and aided SII were developed for characterization of fitting outcomes.

CONCLUSION

 Fitting to DSL v5-adult targets was observed within ± 5 dB absolute deviation, or within 5 dB RMSE, on average for typical adult hearing aid fittings. Confidence intervals for deviation from target and aided SII are proposed.

Does probe-tube verification of real-ear hearing aid amplification characteristics improve outcomes in adult hearing aid users? A protocol for a systematic review

INTRODUCTION

Using a probe-tube microphone to measure and adjust the real-ear performance of the hearing aid to match the prescription target is recommended and widely used in clinical practice. Hearing aid fitting software can approximately match the amplification characteristics of the hearing aid to the prescription without real-ear measurements (REMs), but using REM improves the match to the prescribed target. What is unclear is if the improved match results in a better patient-reported outcome. The primary objective of this review is to determine whether the use of REM improves patient-reported outcomes in adult hearing aid users.

METHODS AND ANALYSIS

The review's methods are in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocols guidelines. MEDLINE, EMBASE, PsycINFO, CINAHL, Web of Science and CENTRAL via Cochrane Library will be searched to identify relevant studies. The review's population of interest will include adults with any degree of sensorineural or mixed hearing loss who have been prescribed with acoustic hearing aids. The included studies should compare REM fitting to the initial fit provided by the manufacturer's fitting software. Hearing-specific health-related quality of life is the primary outcome but secondary outcomes include self-reported listening ability, speech recognition scores, generic health-related quality of life, hours of use, number of required follow-up sessions and adverse events. Randomised and non-randomised controlled trials will be included. The risk of bias in the included studies will be evaluated using Down and Black's checklist. The quality of the overall evidence will be assessed using the Grading of Recommendations, Assessment, Development and Evaluations tool.

ETHICS AND DISSEMINATION

Ethical approval will not be sought because this systematic review will only retrieve and analyse data from published studies. Review results will be published in a peer-reviewed journal and presented at relevant scientific conferences.

PROSPERO REGISTRATION NUMBER

CRD42020166074.

Meeting the Best Practice for Hearing Aid Verification in Children: Challenges and Future Directions

Purpose This study examined the current pediatric amplification practice with an emphasis on hearing aid verification using probe microphone measurement (PMM), among audiologists in Klang Valley, Malaysia. Frequency of practice, access to PMM system, practiced protocols, barriers, and perception toward the benefits of PMM were identified through a survey. Method A questionnaire was distributed to and filled in by the audiologists who provided pediatric amplification service in Klang Valley, Malaysia. One hundred eight (N = 108) audiologists, composed of 90.3% women and 9.7% men (age range: 23-48 years), participated in the survey. Results PMM was not a clinical routine practiced by a majority of the audiologists, despite its recognition as the best clinical practice that should be incorporated into protocols for fitting hearing aids in children. Variations in practice existed warranting further steps to improve the current practice for children with hearing impairment. The lack of access to PMM equipment was 1 major barrier for the audiologists to practice real-ear verification. Practitioners' characteristics such as time constraints, low confidence, and knowledge levels were also identified as barriers that impede the uptake of the evidence-based practice. Conclusions The implementation of PMM in clinical practice remains a challenge to the audiology profession. A knowledge-transfer approach that takes into consideration the barriers and involves effective collaboration or engagement between the knowledge providers and potential stakeholders is required to promote the clinical application of evidence-based best practice.

Análise comparativa dos métodos prescritivos NAL-NL2 e DSL v5.0a na adaptação do AASI em idosos

RESUMO Objetivo Analisar comparativamente os métodos prescritivos NAL-NL2 e DSL v5.0a de acordo com programação individualizada do AASI para o indivíduo idoso com deficiência auditiva. Método Participaram do estudo 60 indivíduos idosos com deficiência auditiva, submetidos à mensuração da RECD (Real Ear to Coupler Difference) e programação individualizada do AASI com os métodos prescritivos NAL-NL2 e DSL v5.0a. A verificação do desempenho com cada prescrição foi realizada por meio das medidas da REAR (Real Ear Aided Response), cálculo do SII (Speech Intelligibility Index) e teste HINT (Hearing In Noise Test). A análise estatística comparativa foi realizada por meio do teste “t” pareado. Resultados O método NAL-NL2 apresentou melhor desempenho na avaliação da REAR em frequências baixas e altas para sons de média e forte intensidade, em frequências altas para sons de fraca intensidade, e no cálculo do SII para sons fracos. O método DSL v5.0a apresentou melhores resultados na avaliação da REAR em frequências médias para sons médios, em frequências baixas e médias para sons fracos, no cálculo do SII para sons médios e fortes, e no teste HINT no silêncio e ruído. Conclusão Os achados deste estudo apontam para um desempenho equivalente entre os métodos DSL v5.0a e NAL-NL2 na adaptação do AASI em idosos com deficiência auditiva. A amplificação calculada pela DSL v5.0a forneceu melhor percepção de fala no silêncio.

A preliminary investigation into hearing aid fitting based on automated real-ear measurements integrated in the fitting software: test-retest reliability, matching accuracy and perceptual outcomes

OBJECTIVE

The recent integration of automated real-ear measurements (REM) in the fitting software facilitates the hearing aid fitting process. Such a fitting strategy, TargetMatch (TM), was evaluated. Test-retest reliability and matching accuracy were quantified, and compared to a REM-based fitting with manual adjustment. Also, it was investigated whether TM leads to better perceptual outcomes compared to a FirstFit (FF) approach, using software predictions only. Design and study sample: Ten hearing impaired participants were enrolled in a counterbalanced single-blinded cross-over study comparing TM and FF. Aided audibility, speech intelligibility and real-life benefits were assessed. Repeated measurements of both TM and REMs with manual adjustment were performed.

RESULTS

Compared to a REM-based fitting with manual adjustment, TM had higher test-retest reliability. Also, TM outperformed the other fitting strategies in terms of matching accuracy. Compared to a FF, improved aided audibility and real-life benefits were found. Speech intelligibility did not improve.

CONCLUSIONS

Preliminary data suggest that automated REMs increase the likelihood of meeting amplification targets compared with a FF. REMs integrated in the fitting software provide additional reliability and accuracy compared to traditional REMs. Findings need to be verified in a larger and more varied sample.

Verification and validation of hearing aids: Opportunity not an obstacle

Verification and validation are objective and subjective measurements of hearing aid function. Many studies have provided rationales for performing these measurements as necessary for hearing aid practitioners to provide the highest level of care. Several researchers have suggested that completing these measurements as part of routine clinical care will reduce the number of return visits, reduce the number of aids returned for credit, and increase patient satisfaction. The purpose of this review article is to provide background, method and rationale for practitioners to use these measurements to improve their practice of hearing healthcare.

Temporal resolution with a prescriptive fitting formula

PURPOSE

Authors of previous work using laboratory-based paradigms documented that wide dynamic range compression (WDRC) may improve gap detection compared to linear amplification. The purpose of this study was to measure temporal resolution using WDRC fit with compression ratios set for each listener’s hearing loss.

METHOD

Nineteen adults with mild-to-moderate hearing loss fitted with WDRC or linear amplification set to a prescriptive fitting method participated in this study. Subjects detected amplitude modulations and gaps. Two types of noise carrier were used: narrowband (1995–2005 Hz) and broadband (100–8000 Hz).

RESULTS

Small differences between WDRC and linear amplification were observed in the measures of temporal resolution. Modulation detection thresholds worsened by a mean of 0.7 dB with WDRC compared to linear amplification. This reduction was observed for both carrier types. Gap detection thresholds did not differ between the 2 amplification conditions.

CONCLUSIONS

WDRC set using a prescriptive fitting method with individualized compression ratios had a small but statistically significant effect on measures of modulation thresholds. Differences were not observed between the two amplification conditions for the measures of gap detection. These findings contrast with previous work using fixed compression ratios, suggesting that the effect of the fitting method on the compression ratio should be considered when attempting to generalize the effect of WDRC on temporal resolution to the clinical setting.

The accuracy of matching target insertion gains with open-fit hearing aids

PURPOSE

To assess the accuracy with which target insertion gains were matched for a single type of open-fit hearing aid, both on initial fitting and after adjustment.

METHOD

The hearing aids were fitted using the first-fit setting in the programming software and the target formula was selected as NAL-NL1. The difference between the real ear insertion gain (REIG) and the NAL-NL1 target REIG was recorded. The initial fitting was considered acceptable if the difference was less than 10 dB at all frequencies. If an initial fitting was not acceptable, the frequency-gain response was modified. The difference between the final REIG and the NAL-NL1 target REIG was recorded as final target mismatch.

RESULTS

Of the 51 initial fittings, 36 (71%) failed to achieve a match within ±10 dB of the NAL-NL1 insertion gain target at 1 or more frequencies between 0.25 and 4 kHz. After the authors adjusted the frequency-gain response of the hearing aids, only 9 fittings (18%) failed to achieve a match.

CONCLUSION

These outcomes suggest that target insertion gains for the open-fit hearing aids used here are rarely achieved with a first fitting but can usually be achieved through adjustments based on REIG measurements.

Real ear measurement methods for open fit hearing aids: modified pressure concurrent equalization (MPCE) versus modified pressure stored equalization (MPSE)

OBJECTIVE

The aim of this study was to assess differences between real ear insertion gains (REIG) measured with the modified pressure concurrent equalization (MPCE) and modified pressure stored equalization (MPSE) methods for open fittings in a typical audiology patient population.

DESIGN

REIGs were compared for the two methods using a warble tone sweep at 65 dB SPL. The differences between the two methods at 0.25, 0.5, 1, 2, 3, 4 and 6 kHz were recorded.

STUDY SAMPLE

Eighty-three ears of a consecutive sample of 48 candidates for open-fit hearing aids were included.

RESULTS

The mean difference between MPSE and MPCE REIGs was less than 1 dB at all frequencies. Analysis of variance showed that the main effect of method was not significant, and there was no significant interaction between method and frequency.

CONCLUSIONS

The results for the MPSE and MPCE methods did not differ significantly for the patients with mild-to-moderate hearing losses tested here, for whom REIGs were generally less than 20 dB. Further research is needed to identify the REIG values at which the differences between MPCE and MPSE methods become clinically significant.

Verificação da prótese auditiva realizada face a face e via teleconsulta: medidas repetidas

OBJETIVO: avaliar as medidas repetidas da resposta de ressonância da orelha externa sem (REUR) e com uso de amplificação (REAR) e o ganho de inserção (REIG), realizados face a face e via teleconsulta. MÉTODO: estudo prospectivo longitudinal. Foram realizadas quatro repetições da REUR, REAR e REIG (com estímulo speech noise apresentado em 65 dB NPS e 0º azimute) em 19 orelhas de adultos ouvintes normais, via face a face (F) e teleconsulta síncrona por controle remoto de aplicativo (T) e vídeo interativo. O software Polycom PVX foi utilizado para compartilhamento e transmissão de áudio e vídeo. A conexão foi realizada via LAN (Local Area Network) USP na velocidade de 384 kbps Foi calculado o erro causal (Dalhberg) entre as quatro medidas para frequências de 250 a 8000 Hz. RESULTADOS: os erros casuais entre as medidas F e T foram muito semelhantes, sendo maiores nas frequências acima de 4 kHz. As diferenças e variações entre as medidas F e T estavam dentro da magnitude de variabilidade do procedimento de medidas com microfone sonda. CONCLUSÃO: as medidas com microfone sonda via teleconsulta fornece resultados confiáveis e similares aos obtidos pelo procedimento padrão.

Are real-ear measurements (REM) accurate when using the modified pressure with stored equalization (MPSE) method?

Audiologists typically verify hearing instrument fitting using real-ear measurements (REM). Recently the modified pressure with stored equalization method (MPSE) has been recommended for use when verifying open non-occluding hearing instruments. The MPSE method does not use a reference microphone to maintain loudspeaker output during real-ear measurements and is therefore susceptible to changes in the signal level at the client's ear which result from movement of the client's head and torso during the verification process. To determine the size of these errors, the real-ear unaided response (REUR) was measured prior to and following the fitting of a non-functioning hearing aid in the contralateral ear. Twenty young adults participated. Identical head positions for the two measurements should yield zero difference measures across all frequencies measured. Loudspeaker-to-client azimuths of 0 degrees and 45 degrees were investigated. Mean difference measures across the frequencies investigated were less than 1 dB for both azimuths with one standard deviation from these mean differences typically less than 1.5 dB. Results suggest that the MPSE method does not introduce clinically significant errors in real-ear measurements when verifying hearing instrument fitting in the population examined.