Gregory Matthew Ellis

Auditory gap detection thresholds are an important tool for evaluating temporal processing deficits in human listeners, but current tests are too cumbersome for widespread clinical use. This letter describes the development and validation of a rapid 18-trial test for assessing gap detection based on an earlier binaural tone-in-noise paradigm. Results from 616 normal-hearing listeners show psychometric properties similar to the clinical gaps-in-noise test and provide normative values that support preliminary use as a screener for temporal processing deficits in clinical populations.

Prior work shows that individuals who frequently experience symptoms following noise exposure have greater hearing complaints and worse tone-in-noise detection abilities even with “normal” audiometric thresholds. This study extends previous work by quantifying the impact of post-exposure hearing symptoms on speech-in-noise (SIN) detection. Intelligibility and response times were examined in two large samples of U.S. service members (SMs) who completed tablet-based questionnaires, pure-tone audiometry, and SIN tests based on the Modified Rhyme Test (MRT). In Experiment 1, 1551 SMs completed a version of the MRT based on the clinical MRT80. In Experiment 2, 4768 SMs completed an abbreviated MRT without carrier phrases. Participants were categorized based on hearing acuity and questionnaire responses. Mixed-effects models predicted MRT outcomes using better-ear four-frequency pure-tone average (PTA4), post-exposure hearing symptom history, and noise exposure as predictors. Both experiments showed effects of post-exposure symptom history and PTA4 on accuracy and response time. Overall, SMs with a history of post-exposure hearing symptoms exhibited deficits in SIN performance, even with normal audiometric thresholds. These findings suggest that symptoms consistent with temporary threshold shifts (TTS) may indicate underlying auditory damage, underscoring the importance of considering TTS in hearing conservation, clinical assessment, and research.

Purpose: The purpose of this study was to determine the differences between self-reported hearing difficulties, response time, and blast exposure history for those with and without auditory processing deficits, which were classified based on abnormal results on behavioral speech-in-noise and binaural-processing assessments. The study also examined factors that contributed to low-gain hearing aid (LGHA) benefit. Method: Military service members were recruited for the research study. Participants were classified into three groups based on their performance on auditory processing tests: failing two tests (dual deficit [DualDef], n = 47), failing one test (single deficit [SingleDef], n = 207), and failing zero tests (Control, n = 5,046). All participants had normal hearing thresholds (NHTs) defined by ≤ 25 dB HL at frequencies 500–6000 Hz. Results: Participants who failed at least one auditory processing test (DualDef and SingleDef groups) reported significantly more hearing difficulties and had significantly slower response times than the Control group. The DualDef group also had significantly more hearing difficulties relative to the SingleDef group. More than half of the participants in the DualDef and SingleDef groups reported having blast exposure, compared to less than 40% in the control group. Participants who reported blast exposure also reported significantly better LGHA benefit compared to those who reported having no blast exposure. Conclusion: This study appears to validate the use of performance on behavioral listening tests to identify individuals who may be suffering from auditory processing deficits and might benefit from LGHAs, particularly when the symptoms are related to a history of blast exposure.

Purpose: Some bilinguals may exhibit lower performance when recognizing speech in noise (SiN) in their second language (L2) compared to monolinguals in their first language. Poorer performance has been found mostly for late bilinguals (L2 acquired after childhood) listening to sentences containing linguistic context and less so for simultaneous/early bilinguals (L2 acquired during childhood) and when testing context-free stimuli. However, most previous studies tested younger participants, meaning little is known about interactions with age; the purpose of this study was to address this gap. Method: Context-free SiN understanding was measured via the Modified Rhyme Test (MRT) in 3,803 young and middle-aged bilingual and monolingual adults (ages 18–57 years; 19.6% bilinguals, all L2 English) with normal to near-normal hearing. Bilingual adults included simultaneous ( n = 462), early ( n = 185), and late ( n = 97) bilinguals. Performance on the MRT was measured with both accuracy and response time. A self-reported measure of current English use was also collected for bilinguals to evaluate its impact on MRT performance. Results: Current age impacted MRT accuracy scores differently for each listener group. Relative to monolinguals, simultaneous and early bilinguals showed decreased performance with older age. Response times slowed with increasing current age at similar rates for all groups, despite faster overall response times for monolinguals. Among all bilingual listeners, greater current English language use predicted higher MRT accuracy. For simultaneous bilinguals, greater English use was associated with faster response times. Conclusions: SiN outcomes in bilingual adults are impacted by age at time of testing and by fixed features of their language history (i.e., age of acquisition) as well as language practices, which can shift over time (i.e., current language use). Results support routine querying of language history and use in the audiology clinic. Supplemental Material: https://doi.org/10.23641/asha.28405430

Purpose: Some bilinguals may exhibit lower performance when understanding speech in noise (SIN) in their second language (L2) compared to monolinguals in their first language. Poorer performance has been found mostly for late bilinguals (L2 acquired after childhood) listening to sentences containing linguistic context, and less so for simultaneous/early bilinguals (L2 acquired during childhood) and when testing context-free stimuli. However, most previous studies tested younger participants, meaning little is known about interactions with age; the purpose of this study was to address this gap.Method: Context-free SIN understanding was measured via the Modified Rhyme Test (MRT) in 3836 young and middle-aged bilingual and monolingual adults (ages 18–57; 19.5% bilinguals, all L2 English) with normal to near-normal hearing. Bilingual adults included simultaneous (n = 466), early (n = 185), and late (n = 97) bilinguals. Performance on the MRT was measured with both accuracy and response time. A self-reported measure of current English use was also collected for bilinguals to evaluate its impact on MRT performance.Results: Age impacted MRT accuracy scores differently for each listener group. Relative to monolinguals, simultaneous and early bilinguals showed decreased performance with older age. Response times slowed with older age at similar rates for all groups, despite faster overall response times for monolinguals. Among all bilingual listeners, greater current English language use predicted higher MRT accuracy. For simultaneous bilinguals, greater English use was associated with faster response times. Conclusions: Speech-in-noise outcomes in bilingual adults are impacted not only by fixed features of their language history (i.e. age of acquisition) but also by language practices which can shift over time (i.e. current language use), supporting routine querying of language history and use in the Audiology clinic.

Objectives: The objective of this project was to quantify the relative efficacy of a four-frequency pure-tone average in the better ear (PTA4), the Hearing subscale of the Tinnitus and Hearing Survey (THS-H), and a combination of the two in predicting speech-in-noise performance, hearing aid recommendation, and hearing aid use among United States service members (SMs). Design: A two-analysis retrospective study was performed. The first analysis examined the degree to which better-ear PTA4 alone, THS-H alone, and better-ear PTA4 in conjunction with THS-H predicted performance on a speech-in-noise test, the modified rhyme test. Three binomial mixed-effects models were fitted using better-ear PTA4 alone, THS-H alone, and both measures as primary predictors of interest. Age and sex were included as covariates in all models. The models were compared to one another using Chi-square goodness-of-fit tests and the best-fitting model was examined. Data from 5988 SMs were analyzed in the first analysis. The second analysis examined the degree to which better-ear PTA4 alone, THS-H alone, and better-ear PTA4 in conjunction with THS-H predicted two hearing aid-related outcomes: recommendation for hearing aids by a clinician and hearing aid use. Three receiver operating characteristic curves were fit for each question for better-ear PTA4 alone, THS-H alone, and better-ear PTA4 + THS-H. The area under the curve was bootstrapped to generate confidence intervals to compare the three measures. Data from 8001 SMs were analyzed in the second analysis. Results: In the first analysis, all three models explained more variance than chance; however, the better-ear PTA4 + THS-H model was a significantly better fit than either the better-ear PTA4 alone or the THS-H alone models. Significant main effects of better-ear PTA4 and THS-H indicated that proportion correct decreased as better-ear PTA4 and THS-H increased. A significant interaction was observed such that proportion correct decreased more rapidly if both better-ear PTA4 and THS-H were increasing in tandem. In the second analysis, better-ear PTA4 + THS-H showed good predictive discrimination of a prior hearing aid recommendation. For predicting hearing aid use, better-ear PTA4 was the only predictor with an area under the curve bootstrapped confidence interval that overlapped 0.50, indicating better-ear PTA4 alone is a chance predictor for hearing aid use. Both THS-H alone and better-ear PTA4 + THS-H predicted hearing aid use better than chance, but had poor discrimination overall. Conclusions: Adding the THS-H to the better-ear PTA4 improves predictions of speech intelligibility in noise, has good predictive strength for hearing aid recommendations, and predicts hearing aid use better than chance. This study provides evidence for using surveys in conjunction with objective data when evaluating hearing ability and recommending interventions. These findings are relevant to discourse regarding self-administered hearing healthcare.

Low- (or mild-) gain hearing aids (LGHAs) are increasingly considered for individuals with normal peripheral hearing but significant self-reported hearing difficulties (SHDs). This study assesses the benefits of LGHAs as a management option for individuals with normal hearing thresholds (NHTs) and SHDs, comparing LGHA use and benefit to individuals with non-significant hearing difficulties (NHDs) and those with peripheral hearing loss. Questionnaires addressing hearing aid usage, benefit, hearing difficulties, and tinnitus were administered to 186 individuals who self-identified as hearing aid users in a sample of 6652 service members who were receiving their annual hearing tests. Participants were divided into SHD and NHD groups based on the normative cutoff of the Tinnitus and Hearing Survey-Hearing Subscale (THS-H), and into hearing impairment (HI) and NHT based on their audiometric air-conduction thresholds. Individuals with SHDs and NHTs reported higher LGHA usage and benefit than individuals with NHDs and NHTs. Comparable use and benefit were noted between groups with SHDs regardless of peripheral hearing loss status. The findings support LGHAs as a suitable management option for individuals with NHTs and SHDs, as indicated by hearing aid use and benefit. Quantifying the level of perceived auditory processing deficits (i.e., SHDs), notably with the THS-H, enhances sensitivity in identifying those who may benefit the most from this treatment option.

Objectives: Hearing aid processing in realistic listening environments is difficult to study effectively. Often the environment is unpredictable or unknown, such as in wearable aid trials with subjective report by the wearer. Some laboratory experiments create listening environments to exert tight experimental control, but those environments are often limited by physical space, a small number of sound sources, or room absorptive properties. Simulation techniques bridge this gap by providing greater experimental control over listening environments, effectively bringing aspects of the real-world into the laboratory. This project used simulation to study the effects of wide-dynamic range compression (WDRC) and digital noise reduction (DNR) on speech intelligibility in a reverberant environment with six spatialized competing talkers. The primary objective of this study was to determine the efficacy of WDRC and DNR in a complex listening environment using virtual auditory space techniques. Design: Participants of greatest interest were listeners with hearing impairment. A group of listeners with clinically normal hearing was included to assess the effects of the simulation absent the complex effects of hearing loss. Virtual auditory space techniques were used to simulate a small restaurant listening environment with two different reverberation times (0.8 and 1.8 sec) in a range of signal to noise ratios (SNRs) (−8.5 to 11.5 dB SNR). Six spatialized competing talkers were included to further enhance realism. A hearing aid simulation was used to examine the degree to which speech intelligibility was affected by slow and fast WDRC in conjunction with the presence or absence of DNR. The WDRC and DNR settings were chosen to be reasonable estimates of hearing aids currently available to consumers. Results: A WDRC × DNR × Hearing Status interaction was observed, such that DNR was beneficial for speech intelligibility when combined with fast WDRC speeds, but DNR was detrimental to speech intelligibility when WDRC speeds were slow. The pattern of the WDRC × DNR interaction was observed for both listener groups. Significant main effects of reverberation time and SNR were observed, indicating better performance with lower reverberation times and more positive SNR. Conclusions: DNR reduced low-amplitude noise before WDRC-amplified the low-intensity portions of the signal, negating one potential downside of fast WDRC and leading to an improvement in speech intelligibility in this simulation. These data suggest that, in some real-world environments that include both reverberation and noise, older listeners with hearing impairment may find speech to be more intelligible if DNR is activated when the hearing aid has fast compression time constants. Additional research is needed to determine the appropriate DNR strength and to confirm results in wearable hearing aids and a wider range of listening environments.