Entropy as a Measure of Auditory Environment Diversity: An Ecological Momentary Assessment (EMA) Approach.

OBJECTIVES: To determine the validity and usefulness of entropy computed using ecological momentary assessment (EMA) data as a measure of auditory environment diversity. DESIGN: We conducted two secondary analyses on existing EMA datasets. The first determined the construct validity of auditory environment entropy by examining the effect of COVID-19 on entropy. To demonstrate entropy's usefulness, the second examined if entropy could predict the benefit of hearing aid (HA) noise reduction features. RESULTS: Consistent with the known effect of COVID-19 on social lifestyle, COVID-19 significantly reduced auditory environment diversity, supporting entropy's construct validity. HA users with higher entropy reported poorer outcomes and perceived more benefit from HA features, supporting the feasibility of using entropy to predict communication performance and feature benefit. CONCLUSIONS: Entropy derived from EMA data is a valid and useful auditory environment diversity measure. This measure could allow researchers to better understand the communication needs of people with hearing loss.

Auditory Environments and Hearing Aid Feature Activation Among Younger and Older Listeners in an Urban and Rural Area.

OBJECTIVES: The purpose of this study was to investigate differences in auditory environments and hearing aid feature activation between younger listeners with normal hearing and older listeners with hearing loss in an urban and rural location. We hypothesized that (1) urban dwellers and younger listeners would encounter more diverse and demanding auditory environments than rural dwellers and older listeners, respectively; (2) the advanced hearing aid features (noise reduction and directional microphone) of urban dwellers and younger listeners would be activated more frequently than rural dwellers and older listeners, respectively. DESIGN: The design of this study was cross-sectional with repeated measures. A total of 12 older adults with hearing loss (OHL-U) and 11 younger adults with normal hearing (YNH-U) were recruited from an urban area (Berkeley, California) and 13 older adults with hearing loss (OHL-R) and 10 YNH-U were recruited from a rural area (Iowa City, Iowa). Participants wore hearing aids that recorded data about their listening environments and completed ecological momentary assessments for 1 week. RESULTS: The YNH-U group experienced higher sound pressure levels and hearing aid features were activated more frequently than in the OHL groups. The OHL-R group experienced significantly less diverse sound pressure levels than the YNH-U group. The YNH-R group had sound levels between the YNH-U group and the OHL groups but without significant differences from any other group. The YNH groups showed a greater likelihood of hearing aid feature activation than the OHL-R group. CONCLUSIONS: Demographics affect auditory environments and the activation of hearing aid features. Younger urban dwellers have the most diverse or demanding auditory environments and hearing aid feature activation, and older, rural dwellers with hearing loss have the least diverse or demanding auditory environments and hearing aid feature activation. Future studies of real-world auditory environments and audiology intervention effectiveness should consider location in recruitment and interpretation of results.

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.

Effect of Noise Reduction on Cortical Speech-in-Noise Processing and Its Variance due to Individual Noise Tolerance.

OBJECTIVES: Despite the widespread use of noise reduction (NR) in modern digital hearing aids, our neurophysiological understanding of how NR affects speech-in-noise perception and why its effect is variable is limited. The current study aimed to (1) characterize the effect of NR on the neural processing of target speech and (2) seek neural determinants of individual differences in the NR effect on speech-in-noise performance, hypothesizing that an individual's own capability to inhibit background noise would inversely predict NR benefits in speech-in-noise perception. DESIGN: Thirty-six adult listeners with normal hearing participated in the study. Behavioral and electroencephalographic responses were simultaneously obtained during a speech-in-noise task in which natural monosyllabic words were presented at three different signal-to-noise ratios, each with NR off and on. A within-subject analysis assessed the effect of NR on cortical evoked responses to target speech in the temporal-frontal speech and language brain regions, including supramarginal gyrus and inferior frontal gyrus in the left hemisphere. In addition, an across-subject analysis related an individual's tolerance to noise, measured as the amplitude ratio of auditory-cortical responses to target speech and background noise, to their speech-in-noise performance. RESULTS: At the group level, in the poorest signal-to-noise ratio condition, NR significantly increased early supramarginal gyrus activity and decreased late inferior frontal gyrus activity, indicating a switch to more immediate lexical access and less effortful cognitive processing, although no improvement in behavioral performance was found. The across-subject analysis revealed that the cortical index of individual noise tolerance significantly correlated with NR-driven changes in speech-in-noise performance. CONCLUSIONS: NR can facilitate speech-in-noise processing despite no improvement in behavioral performance. Findings from the current study also indicate that people with lower noise tolerance are more likely to get more benefits from NR. Overall, results suggest that future research should take a mechanistic approach to NR outcomes and individual noise tolerance.

Input-related demands: vocoded sentences evoke different pupillometrics and subjective listening effort than sentences in speech-shaped noise.

OBJECTIVES: The Framework for Effortful Listening (FUEL) suggests five input-related demands can alter listening effort: source, transmission, listener, message and context factors. We hypothesised that vocoded sentences represented a source factor degradation and sentences in speech-shaped noise represented a transmission factor degradation. We used pupillometry and a subjective scale to examine our hypothesis. DESIGN: Participants listened to vocoded sentences and sentences in speech-shaped noise at several difficulty levels designed to produce similar word recognition abilities; they also listened to unprocessed sentences. Within-participant pupillometrics and subjective listening effort were analysed. Post-hoc analyses were performed to examine if word recognition accuracy differentially influenced pupil responses. STUDY SAMPLES: Twenty young adults with normal hearing. RESULTS: Baseline pupil diameter was significantly smaller, peak pupil dilation was significantly larger, peak pupil dilation latency was significantly shorter, and subjective listening effort was significantly greater for the vocoded sentences than the sentences-in-noise. Word recognition ability also affected pupillometrics, but only for the vocoded sentences. CONCLUSIONS: Our findings suggest that source factor degradations result in greater listening effort than transmission factor degradations. Future research should address how clinical interventions tailored towards different input-related demands may lead to reduced listening effort and improve patient outcomes.

Effects of high-pressure processing on the physicochemical properties and glycemic index of fruit puree in a hyperglycemia mouse model.

BACKGROUND: In this study, the duration of high-pressure processing (HPP) required to achieve a 5 log reduction of Escherichia coli O157:H7 in fruit purees was evaluated. Banana, cantaloupe, and dragon fruit purees were subjected to HPP at 600 MPa for 300, 270, and 270 s, respectively, and their physicochemical properties and enzyme activities were then analysed. Diabetic mice were fed fresh and HPP-treated purees to observe their effects on the glycemic index (GI) and postprandial blood glucose response. RESULTS: Compared with their fresh counterparts, the HPP-treated banana and dragon fruit purees exhibited significantly higher viscosities, lower glucose concentrations, and higher glucose dialysis retardation indices and showed disrupted sucrose invertase and polygalacturonase activities. The GI and postprandial blood glucose response were not significantly different between the fresh and HPP-treated cantaloupe purees. By contrast, the peak time of glucose response (Tmax ) was delayed from 30 min to 60 min, and the area under the receiver operating characteristic curve was reduced by 40% in the mice fed HPP-treated banana and dragon fruit purees. The GIs of the HPP-treated banana and dragon fruit purees (were 50.3 and 44.8, respectively) were significantly lower than those of their fresh counterparts (85.1 and 75.2, respectively). CONCLUSION: HPP can change the physicochemical properties of fruit purees, resulting in stabilized blood glucose levels and lower GIs after consumption. Therefore, purees processed in this manner would benefit consumers and patients with diabetes/pre-diabetes who need to maintain stable blood glucose levels (Fig. S1). © 2022 Society of Chemical Industry.

Comparisons of the Sensitivity and Reliability of Multiple Measures of Listening Effort.

OBJECTIVES: The objective of this study was to evaluate the sensitivity and reliability of one subjective (rating scale) and three objective (dual-task paradigm, pupillometry, and skin conductance response amplitude) measures of listening effort across multiple signal to noise ratios (SNRs). DESIGN: Twenty adults with normal hearing attended two sessions and listened to sentences presented in quiet and in stationary noise at three different SNRs: 0, -3, and -5 dB. Listening effort was assessed by examining change in reaction time (dual-task paradigm), change in peak to peak pupil diameter (pupillometry), and change in mean skin conductance response amplitude; self-reported listening effort on a scale from 0 to 100 was also evaluated. Responses were averaged within each SNR and based on three word recognition ability categories (≤50%, 51% to 71%, and >71%) across all SNRs. Measures were considered reliable if there were no significant changes between sessions, and intraclass correlation coefficients were a minimum of 0.40. Effect sizes were calculated to compare the sensitivity of the measures. RESULTS: Intraclass correlation coefficient values indicated fair-to-moderate reliability for all measures while individual measurement sensitivity was variable. Self-reports were sensitive to listening effort but were less reliable, given that subjective effort was greater during the dual task than either of the physiologic measures. The dual task was sensitive to a narrow range of word recognition abilities but was less reliable as it exhibited a global decrease in reaction time across sessions. Pupillometry was consistently sensitive and reliable to changes in listening effort. Skin conductance response amplitude was not sensitive or reliable while the participants listened to the sentences. Skin conductance response amplitude during the verbal response was sensitive to poor (≤50%) speech recognition abilities; however, it was less reliable as there was a significant change in amplitude across sessions. CONCLUSIONS: In this study, pupillometry was the most sensitive and reliable objective measure of listening effort. Intersession variability significantly influenced the other objective measures of listening effort, which suggests challenges for cross-study comparability. Therefore, intraclass correlation coefficients combined with other statistical tests more fully describe the reliability of measures of listening effort across multiple difficulties. Minimizing intersession variability will increase measurement sensitivity. Further work toward standardized methods and analysis will strengthen our understanding of the reliability and sensitivity of measures of listening effort and better facilitate cross-modal and cross-study comparisons.

The Influence of Forced Social Isolation on the Auditory Ecology and Psychosocial Functions of Listeners With Cochlear Implants During COVID-19 Mitigation Efforts.

OBJECTIVES: The impact of social distancing on communication and psychosocial variables among individuals with hearing impairment during COVID-19 pandemic. It was our concern that patients who already found themselves socially isolated (Wie et al. 2010) as a result of their hearing loss would be perhaps more susceptible to changes in their communication habits resulting in further social isolation, anxiety, and depression. We wanted to better understand how forced social isolation (as part of COVID-19 mitigation) effected a group of individuals with hearing impairment from an auditory ecology and psychosocial perspective. We hypothesized that the listening environments would be different as a result of social isolation when comparing subject's responses regarding activities and participation before COVID-19 and during the COVID-19 pandemic. This change would lead to an increase in experienced and perceived social isolation, anxiety, and depression. DESIGN: A total of 48 adults with at least 12 months of cochlear implant (CI) experience reported their listening contexts and experiences pre-COVID and during-COVID using Ecological Momentary Assessment (EMA; methodology collecting a respondent's self-reports in their natural environments) through a smartphone-based app, and six paper and pencil questionnaires. The Smartphone app and paper-pencil questionnaires address topics related to their listening environment, social isolation, depression, anxiety, lifestyle and demand, loneliness, and satisfaction with amplification. Data from these two-time points were compared to better understand the effects of social distancing on the CI recipients' communication abilities. RESULTS: EMA demonstrated that during-COVID CI recipients were more likely to stay home or be outdoors. CI recipients reported that they were less likely to stay indoors outside of their home relative to the pre-COVID condition. Social distancing also had a significant effect on the overall signal-to-noise ratio of the environments indicating that the listening environments had better signal-to-noise ratios. CI recipients also reported better speech understanding, less listening effort, less activity limitation due to hearing loss, less social isolation due to hearing loss, and less anxiety due to hearing loss. Retrospective questionnaires indicated that social distancing had a significant effect on the social network size, participant's personal image of themselves, and overall loneliness. CONCLUSIONS: Overall, EMA provided us with a glimpse of the effect that forced social isolation has had on the listening environments and psychosocial perspectives of a select number of CI listeners. CI participants in this study reported that they were spending more time at home in a quieter environments during-COVID. Contrary to our hypothesis, CI recipients overall felt less socially isolated and reported less anxiety resulting from their hearing difficulties during-COVID in comparison to pre-COVID. This, perhaps, implies that having a more controlled environment with fewer speakers provided a more relaxing listening experience.

GPS predicts stability of listening environment characteristics in one location over time among older hearing aid users.

OBJECTIVE: Hearing aid technology can allow users to "geo-tag" hearing aid preferences using the Global Positioning System (GPS). This technology assumes that listening environment characteristics that affect hearing aid benefit change little in a location over time. The purpose of this study was to investigate whether certain characteristics (reverberation, signal type, listening activity, noise location, noisiness, talker familiarity, talker location, and visual cues) changed in a location over time. Design: Participants completed GPS-tagged surveys on smartphones to report on characteristics of their listening environments. Coordinates were used to create indices that described how much listening environment characteristics changed in a location over time. Indices computed in one location were compared to indices computed across all locations for each participant. Study sample: 54 adults with hearing loss participated in this study (26 males and 38 females; 30 experienced hearing aid users and 24 new users). Results: A location dependency was observed for all characteristics. Characteristics were significantly different from one another in their stability over time. Conclusions: Listening environment characteristics changed less over time in a given location than in participants' lives generally. The effectiveness of GPS-dependent hearing aid settings likely depends on the accuracy and location definition of the GPS feature.

Efficacy and Effectiveness of Advanced Hearing Aid Directional and Noise Reduction Technologies for Older Adults With Mild to Moderate Hearing Loss.

OBJECTIVES: The purpose of the present study was to investigate the laboratory efficacy and real-world effectiveness of advanced directional microphones (DM) and digital noise reduction (NR) algorithms (i.e., premium DM/NR features) relative to basic-level DM/NR features of contemporary hearing aids (HAs). The study also examined the effect of premium HAs relative to basic HAs and the effect of DM/NR features relative to no features. DESIGN: Fifty-four older adults with mild-to-moderate hearing loss completed a single-blinded crossover trial. Two HA models, one a less-expensive, basic-level device (basic HA) and the other a more-expensive, advanced-level device (premium HA), were used. The DM/NR features of the basic HAs (i.e., basic features) were adaptive DMs and gain-reduction NR with fewer channels. In contrast, the DM/NR features of the premium HAs (i.e., premium features) included adaptive DMs and gain-reduction NR with more channels, bilateral beamformers, speech-seeking DMs, pinna-simulation directivity, reverberation reduction, impulse NR, wind NR, and spatial NR. The trial consisted of four conditions, which were factorial combinations of HA model (premium versus basic) and DM/NR feature status (on versus off). To blind participants regarding the HA technology, no technology details were disclosed and minimal training on how to use the features was provided. In each condition, participants wore bilateral HAs for 5 weeks. Outcomes regarding speech understanding, listening effort, sound quality, localization, and HA satisfaction were measured using laboratory tests, retrospective self-reports (i.e., standardized questionnaires), and in-situ self-reports (i.e., self-reports completed in the real world in real time). A smartphone-based ecological momentary assessment system was used to collect in-situ self-reports. RESULTS: Laboratory efficacy data generally supported the benefit of premium DM/NR features relative to basic DM/NR, premium HAs relative to basic HAs, and DM/NR features relative to no DM/NR in improving speech understanding and localization performance. Laboratory data also indicated that DM/NR features could improve listening effort and sound quality compared with no features for both basic- and premium-level HAs. For real-world effectiveness, in-situ self-reports first indicated that noisy or very noisy situations did not occur very often in participants' daily lives (10.9% of the time). Although both retrospective and in-situ self-reports indicated that participants were more satisfied with HAs equipped with DM/NR features than without, there was no strong evidence to support the benefit of premium DM/NR features and premium HAs over basic DM/NR features and basic HAs, respectively. CONCLUSIONS: Although premium DM/NR features and premium HAs outperformed their basic-level counterparts in well-controlled laboratory test conditions, the benefits were not observed in the real world. In contrast, the effect of DM/NR features relative to no features was robust both in the laboratory and in the real world. Therefore, the present study suggests that although both premium and basic DM/NR technologies evaluated in the study have the potential to improve HA outcomes, older adults with mild-to-moderate hearing loss are unlikely to perceive the additional benefits provided by the premium DM/NR features in their daily lives. Limitations concerning the study's generalizability (e.g., participant's lifestyle) are discussed.

Characteristics of Real-World Signal to Noise Ratios and Speech Listening Situations of Older Adults With Mild to Moderate Hearing Loss.

OBJECTIVES: The first objective was to determine the relationship between speech level, noise level, and signal to noise ratio (SNR), as well as the distribution of SNR, in real-world situations wherein older adults with hearing loss are listening to speech. The second objective was to develop a set of prototype listening situations (PLSs) that describe the speech level, noise level, SNR, availability of visual cues, and locations of speech and noise sources of typical speech listening situations experienced by these individuals. DESIGN: Twenty older adults with mild to moderate hearing loss carried digital recorders for 5 to 6 weeks to record sounds for 10 hours per day. They also repeatedly completed in situ surveys on smartphones several times per day to report the characteristics of their current environments, including the locations of the primary talker (if they were listening to speech) and noise source (if it was noisy) and the availability of visual cues. For surveys where speech listening was indicated, the corresponding audio recording was examined. Speech-plus-noise and noise-only segments were extracted, and the SNR was estimated using a power subtraction technique. SNRs and the associated survey data were subjected to cluster analysis to develop PLSs. RESULTS: The speech level, noise level, and SNR of 894 listening situations were analyzed to address the first objective. Results suggested that as noise levels increased from 40 to 74 dBA, speech levels systematically increased from 60 to 74 dBA, and SNR decreased from 20 to 0 dB. Most SNRs (62.9%) of the collected recordings were between 2 and 14 dB. Very noisy situations that had SNRs below 0 dB comprised 7.5% of the listening situations. To address the second objective, recordings and survey data from 718 observations were analyzed. Cluster analysis suggested that the participants' daily listening situations could be grouped into 12 clusters (i.e., 12 PLSs). The most frequently occurring PLSs were characterized as having the talker in front of the listener with visual cues available, either in quiet or in diffuse noise. The mean speech level of the PLSs that described quiet situations was 62.8 dBA, and the mean SNR of the PLSs that represented noisy environments was 7.4 dB (speech = 67.9 dBA). A subset of observations (n = 280), which was obtained by excluding the data collected from quiet environments, was further used to develop PLSs that represent noisier situations. From this subset, two PLSs were identified. These two PLSs had lower SNRs (mean = 4.2 dB), but the most frequent situations still involved speech from in front of the listener in diffuse noise with visual cues available. CONCLUSIONS: The present study indicated that visual cues and diffuse noise were exceedingly common in real-world speech listening situations, while environments with negative SNRs were relatively rare. The characteristics of speech level, noise level, and SNR, together with the PLS information reported by the present study, can be useful for researchers aiming to design ecologically valid assessment procedures to estimate real-world speech communicative functions for older adults with hearing loss.

Output signal-to-noise ratio and speech perception in noise: effects of algorithm.

OBJECTIVE: The aims of this study were to: 1) quantify the amount of change in signal-to-noise ratio (SNR) as a result of compression and noise reduction (NR) processing in devices from three hearing aid (HA) manufacturers and 2) use the SNR changes to predict changes in speech perception. We hypothesised that the SNR change would differ across processing type and manufacturer, and that improvements in SNR would relate to improvements in performance. DESIGN: SNR at the output of the HAs was quantified using a phase-inversion technique. A linear mixed model was used to determine whether changes in SNR across HA conditions were predictive of changes in aided speech perception in noise. STUDY SAMPLE: Two groups participated: 25 participants had normal-hearing and 25 participants had mild to moderately severe sensorineural hearing loss. RESULTS: The HAs programmed for both groups changed the SNR by a small, but statistically significant amount. Significant interactions in SNR changes were observed between HA devices and processing types. However, the change in SNR was not predictive of changes in speech perception. CONCLUSION: Although observed significant changes in SNR resulting from compression and NR did not convert to changes in speech perception, these algorithms may serve other purposes.

Psychometric Functions of Dual-Task Paradigms for Measuring Listening Effort.

OBJECTIVES: The purpose of the study was to characterize the psychometric functions that describe task performance in dual-task listening effort measures as a function of signal to noise ratio (SNR). DESIGN: Younger adults with normal hearing (YNH, n = 24; experiment 1) and older adults with hearing impairment (n = 24; experiment 2) were recruited. Dual-task paradigms wherein the participants performed a primary speech recognition task simultaneously with a secondary task were conducted at a wide range of SNRs. Two different secondary tasks were used: an easy task (i.e., a simple visual reaction-time task) and a hard task (i.e., the incongruent Stroop test). The reaction time (RT) quantified the performance of the secondary task. RESULTS: For both participant groups and for both easy and hard secondary tasks, the curves that described the RT as a function of SNR were peak shaped. The RT increased as SNR changed from favorable to intermediate SNRs, and then decreased as SNRs moved from intermediate to unfavorable SNRs. The RT reached its peak (longest time) at the SNRs at which the participants could understand 30 to 50% of the speech. In experiments 1 and 2, the dual-task trials that had the same SNR were conducted in one block. To determine if the peak shape of the RT curves was specific to the blocked SNR presentation order used in these experiments, YNH participants were recruited (n = 25; experiment 3) and dual-task measures, wherein the SNR was varied from trial to trial (i.e., nonblocked), were conducted. The results indicated that, similar to the first two experiments, the RT curves had a peak shape. CONCLUSIONS: Secondary task performance was poorer at the intermediate SNRs than at the favorable and unfavorable SNRs. This pattern was observed for both YNH and older adults with hearing impairment participants and was not affected by either task type (easy or hard secondary task) or SNR presentation order (blocked or nonblocked). The shorter RT at the unfavorable SNRs (speech intelligibility < 30%) possibly reflects that the participants experienced cognitive overload and/or disengaged themselves from the listening task. The implication of using the dual-task paradigm as a listening effort measure is discussed.

Predicting three-month and 12-month post-fitting real-world hearing-aid outcome using pre-fitting acceptable noise level (ANL).

OBJECTIVE: Determine the extent to which pre-fitting acceptable noise level (ANL), with or without other predictors such as hearing-aid experience, can predict real-world hearing-aid outcomes at three and 12 months post-fitting. DESIGN: ANLs were measured before hearing-aid fitting. Post-fitting outcome was assessed using the international outcome inventory for hearing aids (IOI-HA) and a hearing-aid use questionnaire. Models that predicted outcomes (successful vs. unsuccessful) were built using logistic regression and several machine learning algorithms, and were evaluated using the cross-validation technique. STUDY SAMPLE: A total of 132 adults with hearing impairment. RESULTS: The prediction accuracy of the models ranged from 61% to 68% (IOI-HA) and from 55% to 61% (hearing-aid use questionnaire). The models performed more poorly in predicting 12-month than three-month outcomes. The ANL cutoff between successful and unsuccessful users was higher for experienced (∼18 dB) than first-time hearing-aid users (∼10 dB), indicating that most experienced users will be predicted as successful users regardless of their ANLs. CONCLUSIONS: Pre-fitting ANL is more useful in predicting short-term (three months) hearing-aid outcomes for first-time users, as measured by the IOI-HA. The prediction accuracy was lower than the accuracy reported by some previous research that used a cross-sectional design.

The importance of high-frequency audibility with and without visual cues on speech recognition for listeners with normal hearing.

OBJECTIVE: To examine the impact of visual cues, speech materials, age and listening condition on the frequency bandwidth necessary for optimizing speech recognition performance. DESIGN: Using a randomized repeated measures design; speech recognition performance was assessed using four speech perception tests presented in quiet and noise in 13 LP filter conditions and presented in multimodalities. Participants' performance data were fitted with a Boltzmann function to determine optimal performance (10% below performance achieved in FBW). STUDY SAMPLE: Thirty adults (18-63 years) and thirty children (7-12 years) with normal hearing. RESULTS: Visual cues significantly reduced the bandwidth required for optimizing speech recognition performance for listeners. The type of speech material significantly impacted the bandwidth required for optimizing performance. Both groups required significantly less bandwidth in quiet, although children required significantly more than adults. The widest bandwidth required was for the phoneme detection task in noise where children required a bandwidth of 7399 Hz and adults 6674 Hz. CONCLUSIONS: Listeners require significantly less bandwidth for optimizing speech recognition performance when assessed using sentence materials with visual cues. That is, the amount of bandwidth systematically decreased as a function of increased contextual, linguistic, and visual content.

Measuring listening effort: driving simulator versus simple dual-task paradigm.

OBJECTIVES: The dual-task paradigm has been widely used to measure listening effort. The primary objectives of the study were to (1) investigate the effect of hearing aid amplification and a hearing aid directional technology on listening effort measured by a complicated, more real world dual-task paradigm and (2) compare the results obtained with this paradigm to a simpler laboratory-style dual-task paradigm. DESIGN: The listening effort of adults with hearing impairment was measured using two dual-task paradigms, wherein participants performed a speech recognition task simultaneously with either a driving task in a simulator or a visual reaction-time task in a sound-treated booth. The speech materials and road noises for the speech recognition task were recorded in a van traveling on the highway in three hearing aid conditions: unaided, aided with omnidirectional processing (OMNI), and aided with directional processing (DIR). The change in the driving task or the visual reaction-time task performance across the conditions quantified the change in listening effort. RESULTS: Compared to the driving-only condition, driving performance declined significantly with the addition of the speech recognition task. Although the speech recognition score was higher in the OMNI and DIR conditions than in the unaided condition, driving performance was similar across these three conditions, suggesting that listening effort was not affected by amplification and directional processing. Results from the simple dual-task paradigm showed a similar trend: hearing aid technologies improved speech recognition performance, but did not affect performance in the visual reaction-time task (i.e., reduce listening effort). The correlation between listening effort measured using the driving paradigm and the visual reaction-time task paradigm was significant. The finding showing that our older (56 to 85 years old) participants' better speech recognition performance did not result in reduced listening effort was not consistent with literature that evaluated younger (approximately 20 years old), normal hearing adults. Because of this, a follow-up study was conducted. In the follow-up study, the visual reaction-time dual-task experiment using the same speech materials and road noises was repeated on younger adults with normal hearing. Contrary to findings with older participants, the results indicated that the directional technology significantly improved performance in both speech recognition and visual reaction-time tasks. CONCLUSIONS: Adding a speech listening task to driving undermined driving performance. Hearing aid technologies significantly improved speech recognition while driving, but did not significantly reduce listening effort. Listening effort measured by dual-task experiments using a simulated real-world driving task and a conventional laboratory-style task was generally consistent. For a given listening environment, the benefit of hearing aid technologies on listening effort measured from younger adults with normal hearing may not be fully translated to older listeners with hearing impairment.

Implementing Ecological Momentary Assessment in Audiological Research: Opportunities and Challenges.

Ecological momentary assessment (EMA) is a way to evaluate experiences in everyday life. It is a powerful research tool but can be complex and challenging for beginners. Application of EMA in audiological research brings with it opportunities and challenges that differ from other research disciplines. This tutorial discusses important considerations when conducting EMA studies in hearing care. While more research is needed to develop specific guidelines for the various potential applications of EMA in hearing research, we hope this article can alert hearing researchers new to EMA to pitfalls when using EMA and help strengthen their study design. The current article elaborates study design details, such as choice of participants, representativeness of the study period for participants' lives, and balancing participant burden with data requirements. Mobile devices and sensors to collect objective data on the acoustic situation are reviewed alongside different possibilities for EMA setups ranging from online questionnaires paired with a timer to proprietary apps that also have access to parameters of a hearing device. In addition to considerations for survey design, a list of questionnaire items from previous studies is provided. For each item, an example and a list of references are given. EMA typically provides data sets that are rich but also challenging in that they are noisy, and there is often unequal amount of data between participants. After recommendations on how to check the data for compliance, reactivity, and careless responses, methods for statistical analysis on the individual level and on the group level are discussed including special methods for direct comparison of hearing device programs.

The effect of hearing aid signal-processing schemes on acceptable noise levels: perception and prediction.

OBJECTIVES: The acceptable noise level (ANL) test determines the maximum noise level that an individual is willing to accept while listening to speech. The first objective of the present study was to systematically investigate the effect of wide dynamic range compression processing (WDRC), and its combined effect with digital noise reduction (DNR) and directional processing (DIR), on ANL. Because ANL represents the lowest signal-to-noise ratio (SNR) that a listener is willing to accept, the second objective was to examine whether the hearing aid output SNR could predict aided ANL across different combinations of hearing aid signal-processing schemes. DESIGN: Twenty-five adults with sensorineural hearing loss participated in the study. ANL was measured monaurally in two unaided and seven aided conditions, in which the status of the hearing aid processing schemes (enabled or disabled) and the location of noise (front or rear) were manipulated. The hearing aid output SNR was measured for each listener in each condition using a phase-inversion technique. The aided ANL was predicted by unaided ANL and hearing aid output SNR, under the assumption that the lowest acceptable SNR at the listener's eardrum is a constant across different ANL test conditions. RESULTS: Study results revealed that, on average, WDRC increased (worsened) ANL by 1.5 dB, while DNR and DIR decreased (improved) ANL by 1.1 and 2.8 dB, respectively. Because the effects of WDRC and DNR on ANL were opposite in direction but similar in magnitude, the ANL of linear/DNR-off was not significantly different from that of WDRC/DNR-on. The results further indicated that the pattern of ANL change across different aided conditions was consistent with the pattern of hearing aid output SNR change created by processing schemes. CONCLUSIONS: Compared with linear processing, WDRC creates a noisier sound image and makes listeners less willing to accept noise. However, this negative effect on noise acceptance can be offset by DNR, regardless of microphone mode. The hearing aid output SNR derived using the phase-inversion technique can predict aided ANL across different combinations of signal-processing schemes. These results suggest a close relationship between aided ANL, signal-processing scheme, and hearing aid output SNR.

Hearing-aid users' voices: a factor that could affect directional benefit.

OBJECTIVE: Backward-facing directional processing (Back-DIR) is an algorithm that employs an anti-cardioid directivity pattern to enhance speech arriving from behind the listener. An experiment that was originally designed to evaluate Back-DIR, together with its follow-up experiment, are reported to illustrate how hearing-aid users' voices could affect directional benefit. DESIGN: Speech recognition performance was measured in a speech-180°/noise-0° configuration, with aids programmed to Back-DIR enabled or omnidirectional processing. In the original experiment, the conventional hearing-in-noise test (HINT) was used, wherein listeners repeated heard sentences. In the follow-up experiment, a modified HINT was used, wherein a carrier phrase was presented before each sentence. STUDY SAMPLE: Fifteen adults with sensorineural hearing loss participated in both experiments. RESULTS: Significant Back-DIR benefit (relative to omnidirectional processing) was observed in the follow-up experiment, while not in the original experiment. CONCLUSIONS: In the original experiment, hearing aids were affected by listeners' voices such that Back-DIR was not always activated when the target speech was presented. In the follow-up experiment, listeners' voice effects were eliminated by the carrier phrase activating Back-DIR before the sentences were presented. The results suggest that the effect of hearing-aid technologies is highly dependent on the characteristics of listening conditions.

Acceptable noise level (ANL) and real-world hearing-aid success in Taiwanese listeners.

OBJECTIVE: The objective of this prospective study was to investigate the relationship between acceptable noise level (ANL), which was measured using Taiwanese and the international speech test signal (ISTS), and real-world hearing-aid success for listeners who were representative of the population commonly seen in clinics. DESIGN: Unaided ANLs were measured pre-hearing-aid fitting. Hearing-aid success was assessed three months post-fitting using the international outcome inventory for hearing aids (IOI-HA) and a hearing-aid use questionnaire. STUDY SAMPLE: Eighty adults with hearing impairment completed the study. RESULTS: Both Taiwanese and ISTS ANLs were significantly associated with hearing-aid success, with higher ANLs suggesting poorer outcomes. However, the ANL's prediction accuracy for the probability of hearing-aid success was either much lower than that suggested by some literature, or was not much different from that of simply predicting all listeners as successful users. CONCLUSIONS: The current study suggested the possibility of using ANL to predict hearing-aid success. However, the usefulness of ANL as a clinical tool is unlikely to be as great as indicated by the literature.