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Background Ecological momentary assessment (EMA) is a methodology involving repeated surveys to collect in-situ self-reports that describe respondents' current or recent experiences. Audiology literature comparing in-situ and retrospective self-reports is scarce.Purpose To compare the sensitivity of in-situ and retrospective self-reports in detecting the outcome difference between hearing aid technologies, and to determine the association between in-situ and retrospective self-reports.Research Design An observational study.Study Sample Thirty-nine older adults with hearing loss.Data Collection and Analysis The study was part of a larger clinical trial that compared the outcomes of a prototype hearing aid (denoted as HA1) and a commercially available device (HA2). In each trial condition, participants wore hearing aids for 4 weeks. Outcomes were measured using EMA and retrospective questionnaires. To ensure that the outcome data could be directly compared, the Glasgow Hearing Aid Benefit Profile was administered as an in-situ self-report (denoted as EMA-GHABP) and as a retrospective questionnaire (retro-GHABP). Linear mixed models were used to determine if the EMA- and retro-GHABP could detect the outcome difference between HA1 and HA2. Correlation analyses were used to examine the association between EMA- and retro-GHABP.Results For the EMA-GHABP, HA2 had significantly higher (better) scores than HA1 in the GHABP subscales of benefit, residual disability, and satisfaction (p = 0.029–0.0015). In contrast, the difference in the retro-GHABP score between HA1 and HA2 was significant only in the satisfaction subscale (p = 0.0004). The correlations between the EMA- and retro-GHABP were significant in all subscales (p = 0.0004 to Conclusion The study suggests that in-situ self-reports collected using EMA could have a higher sensitivity than retrospective questionnaires. Therefore, EMA is worth considering in clinical trials that aim to compare the outcomes of different hearing aid technologies. The weak to moderate association between in-situ and retrospective self-reports suggests that these two types of measures assess different aspects of hearing aid outcomes.

Auditory environments can influence the communication function of individuals with hearing loss and the effects of hearing aids. Therefore, a tool that can objectively characterize a patient’s real-world auditory environments is needed.To use the Language Environment Analysis (LENA) system to quantify the auditory environments of adults with hearing loss, to examine if the use of hearing aids changes a user’s auditory environment, and to determine the association between LENA variables and self-report hearing aid outcome measures.This study used a crossover design.Participants included 22 adults with mild-to-moderate hearing loss, age 64–82 yr.Participants were fitted with bilateral behind-the-ear hearing aids from a major manufacturer.The LENA system consists of a digital language processor (DLP) that is worn by an individual and records up to 16 hr of the individual’s auditory environment. The recording is then automatically categorized according to time spent in different types of auditory environments (e.g., meaningful speech and TV/electronic sound) by the LENA algorithms. The LENA system also characterizes the user’s auditory environment by providing the sound levels of different auditory categories. Participants in the present study wore a LENA DLP in an unaided condition and aided condition, which each lasted six to eight days. Participants wore bilateral hearing aids in the aided condition. Percentage of time spent in each auditory environment, as well as median levels of TV/electronic sounds and speech, were compared between subjects’ unaided and aided conditions using paired sample t tests. LENA data were also compared to self-report measures of hearing disability and hearing aid benefit using Pearson correlations.Overall, participants spent the greatest percentage of time in silence (∼40%), relative to other auditory environments. Participants spent ∼12% and 26% of their time in meaningful speech and TV/electronic sound environments, respectively. No significant differences were found between mean percentage of time spent in each auditory environment in the unaided and aided conditions. Median TV/electronic sound levels were on average 2.4 dB lower in the aided condition than in the unaided condition; speech levels were not significantly different between the two conditions. TV/electronic sound and speech levels did not significantly correlate with self-report data.The LENA system can provide rich data to characterize the everyday auditory environments of older adults with hearing loss. Although TV/electronic sound level was significantly lower in the aided than unaided condition, the use of hearing aids seemed not to substantially change users’ auditory environments. Because there is no significant association between objective LENA variables and self-report questionnaire outcomes, these two types of measures may assess different aspects of communication function. The feasibility of using LENA in clinical settings is discussed.

The existence of binaural interference, defined here as poorer speech recognition with both ears than with the better ear alone, is well documented. Studies have suggested that its prevalence may be higher in the elderly population. However, no study to date has explored binaural interference in groups of younger and older adults in conditions that favor binaural processing (i.e., in spatially separated noise). Also, the effects of hearing loss have not been studied.To examine binaural interference through speech perception tests, in groups of younger adults with normal hearing, older adults with normal hearing for their age, and older adults with hearing loss.A cross-sectional study.Thirty-three participants with symmetric thresholds were recruited from the University of Iowa community. Participants were grouped as follows: younger with normal hearing (18–28 yr, n = 12), older with normal hearing for their age (73–87 yr, n = 9), and older with hearing loss (78–94 yr, n = 12). Prior noise exposure was ruled out.The Connected Speech Test (CST) and Hearing in Noise Test (HINT) were administered to all participants bilaterally, and to each ear separately. Test materials were presented in the sound field with speech at 0° azimuth and the noise at 180°. The Dichotic Digits Test (DDT) was administered to all participants through earphones. Hearing aids were not used during testing. Group results were compared with repeated measures and one-way analysis of variances, as appropriate. Within-subject analyses using pre-established critical differences for each test were also performed.The HINT revealed no effect of condition (individual ear versus bilateral presentation) using group analysis, although within-subject analysis showed that 27% of the participants had binaural interference (18% had binaural advantage). On the CST, there was significant binaural advantage across all groups with group data analysis, as well as for 12% of the participants at each of the two signal-to-babble ratios (SBRs) tested. One participant had binaural interference at each SBR. Finally, on the DDT, a significant right-ear advantage was found with group data, and for at least some participants. Regarding age effects, more participants in the pooled elderly groups had binaural interference (33.3%) than in the younger group (16.7%), on the HINT. The presence of hearing loss yielded overall lower scores, but none of the comparisons between bilateral and unilateral performance were affected by hearing loss.Results of within-subject analyses on the HINT agree with previous findings of binaural interference in ≥17% of listeners. Across all groups, a significant right-ear advantage was also seen on the DDT. HINT results support the notion that the prevalence of binaural interference is likely higher in the elderly population. Hearing loss, however, did not affect the differences between bilateral and better unilateral scores. The possibility of binaural interference should be considered when fitting hearing aids to listeners with symmetric hearing loss. Comparing bilateral to unilateral (unaided) performance on tests such as the HINT may provide the clinician with objective data to support subjective preference for one hearing aid as opposed to two.

Background: Ecological momentary assessment (EMA) is a methodology involving repeated assessments/surveys to collect data describing respondents’ current or very recent experiences and related contexts in their natural environments. The use of EMA in audiology research is growing. Purpose: This study examined the construct validity (i.e., the degree to which a measurement reflects what it is intended to measure) of EMA in terms of measuring speech understanding and related listening context. Experiment 1 investigated the extent to which individuals can accurately report their speech recognition performance and characterize the listening context in controlled environments. Experiment 2 investigated whether the data aggregated across multiple EMA surveys conducted in uncontrolled, real-world environments would reveal a valid pattern that was consistent with the established relationships between speech understanding, hearing aid use, listening context, and lifestyle. Research Design: This is an observational study. Study Sample: Twelve and twenty-seven adults with hearing impairment participated in Experiments 1 and 2, respectively. Data Collection and Analysis: In the laboratory testing of Experiment 1, participants estimated their speech recognition performance in settings wherein the signal-to-noise ratio was fixed or constantly varied across sentences. In the field testing the participants reported the listening context (e.g., noisiness level) of several semicontrolled real-world conversations. Their reports were compared to (1) the context described by normal-hearing observers and (2) the background noise level measured using a sound level meter. In Experiment 2, participants repeatedly reported the degree of speech understanding, hearing aid use, and listening context using paper-and-pencil journals in their natural environments for 1 week. They also carried noise dosimeters to measure the sound level. The associations between (1) speech understanding, hearing aid use, and listening context, (2) dosimeter sound level and self-reported noisiness level, and (3) dosimeter data and lifestyle quantified using the journals were examined. Results: For Experiment 1, the reported and measured speech recognition scores were highly correlated across all test conditions (r = 0.94 to 0.97). The field testing results revealed that most listening context properties reported by the participants were highly consistent with those described by the observers (74–95% consistency), except for noisiness rating (58%). Nevertheless, higher noisiness rating was associated with higher background noise level. For Experiment 2, the EMA results revealed several associations: better speech understanding was associated with the use of hearing aids, front-located speech, and lower dosimeter sound level; higher noisiness rating was associated with higher dosimeter sound level; listeners with more diverse lifestyles tended to have higher dosimeter sound levels. Conclusions: Adults with hearing impairment were able to report their listening experiences, such as speech understanding, and characterize listening context in controlled environments with reasonable accuracy. The pattern of the data aggregated across multiple EMA surveys conducted in a wide range of uncontrolled real-world environment was consistent with the established knowledge in audiology. The two experiments suggested that, regarding speech understanding and related listening contexts, EMA reflects what it is intended to measure, supporting its construct validity in audiology research.

To evaluate the impact of non-adaptive matched and mismatched gain reduction schemes on localization in spatially-separated noise.Inspired by the function of commercial noise reduction algorithms, five frequency-specific gain reduction filter schemes were created, three for a modulated babble-noise and two for an unmodulated speech-shaped noise. Applying these schemes as both matched and mismatched conditions across ears, localization of five everyday sounds in noise was measured in a virtual environment using insert earphones. The performance in the reference scheme (no gain reduction in either ear) was measured as well.Twenty-four adult bilateral hearing-aid users were enrolled in this study.One of the two mismatched gain reduction schemes for the unmodulated noise had a small but negative impact on localization compared to the reference scheme. For that scheme more high-frequency reduction was noted than for the other schemes. Matching gain reduction across ears restored the deteriorated localization performance. No localization performance differences were observed in the modulated babble-noise regardless of whether the scheme was matched or mismatched across ears.The impact of noise-induced gain reduction on localization in noise was trivial in the study regardless of whether gain reduction schemes were matched or not across ears.

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.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.Two groups participated: 25 participants had normal-hearing and 25 participants had mild to moderately severe sensorineural hearing loss.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.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.

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. Language: en

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.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.Fifteen adults with sensorineural hearing loss participated in both experiments.Significant Back-DIR benefit (relative to omnidirectional processing) was observed in the follow-up experiment, while not in the original experiment.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.

Background: Communication while traveling in an automobile often is very difficult for hearing aid users. This is because the automobile/road noise level is usually high, and listeners/drivers often do not have access to visual cues. Since the talker of interest usually is not located in front of the listener/driver, conventional directional processing that places the directivity beam toward the listener's front may not be helpful and, in fact, could have a negative impact on speech recognition (when compared to omnidirectional processing). Recently, technologies have become available in commercial hearing aids that are designed to improve speech recognition and/or listening effort in noisy conditions where talkers are located behind or beside the listener. These technologies include (1) a directional microphone system that uses a backward-facing directivity pattern (Back-DIR processing), (2) a technology that transmits audio signals from the ear with the better signal-to-noise ratio (SNR) to the ear with the poorer SNR (Side-Transmission processing), and (3) a signal processing scheme that suppresses the noise at the ear with the poorer SNR (Side-Suppression processing). Purpose: The purpose of the current study was to determine the effect of (1) conventional directional microphones and (2) newer signal processing schemes (Back-DIR, Side-Transmission, and Side-Suppression) on listener's speech recognition performance and preference for communication in a traveling automobile. Research Design: A single-blinded, repeated-measures design was used. Study Sample: Twenty-five adults with bilateral symmetrical sensorineural hearing loss aged 44 through 84 yr participated in the study. Data Collection and Analysis: The automobile/road noise and sentences of the Connected Speech Test (CST) were recorded through hearing aids in a standard van moving at a speed of 70 mph on a paved highway. The hearing aids were programmed to omnidirectional microphone, conventional adaptive directional microphone, and the three newer schemes. CST sentences were presented from the side and back of the hearing aids, which were placed on the ears of a manikin. The recorded stimuli were presented to listeners via earphones in a sound-treated booth to assess speech recognition performance and preference with each programmed condition. Results: Compared to omnidirectional microphones, conventional adaptive directional processing had a detrimental effect on speech recognition when speech was presented from the back or side of the listener. Back-DIR and Side-Transmission processing improved speech recognition performance (relative to both omnidirectional and adaptive directional processing) when speech was from the back and side, respectively. The performance with Side-Suppression processing was better than with adaptive directional processing when speech was from the side. The participants' preferences for a given processing scheme were generally consistent with speech recognition results. Conclusions: The finding that performance with adaptive directional processing was poorer than with omnidirectional microphones demonstrates the importance of selecting the correct microphone technology for different listening situations. The results also suggest the feasibility of using hearing aid technologies to provide a better listening experience for hearing aid users in automobiles.

Background: Transient noise can be disruptive for people wearing hearing aids. Ideally, the transient noise should be detected and controlled by the signal processor without disrupting speech and other intended input signals. A technology for detecting and controlling transient noises in hearing aids was evaluated in this study. Purpose: The purpose of this study was to evaluate the effectiveness of a transient noise reduction strategy on various transient noises and to determine whether the strategy has a negative impact on sound quality of intended speech inputs. Research Design: This was a quasi-experimental study. The study involved 24 hearing aid users. Each participant was asked to rate the parameters of speech clarity, transient noise loudness, and overall impression for speech stimuli under the algorithm-on and algorithm-off conditions. During the evaluation, three types of stimuli were used: transient noises, speech, and background noises. The transient noises included “knife on a ceramic board,” “mug on a tabletop,” “office door slamming,” “car door slamming,” and “pen tapping on countertop.” The speech sentences used for the test were presented by a male speaker in Mandarin. The background noises included “party noise” and “traffic noise.” All of these sounds were combined into five listening situations: (1) speech only, (2) transient noise only, (3) speech and transient noise, (4) background noise and transient noise, and (5) speech and background noise and transient noise. Results: There was no significant difference on the ratings of speech clarity between the algorithm-on and algorithm-off (t-test, p = 0.103). Further analysis revealed that speech clarity was significant better at 70 dB SLP than 55 dB SPL (p < 0.001). For transient noise loudness: under the algorithm-off condition, the percentages of subjects rating the transient noise to be somewhat soft, appropriate, somewhat loud, and too loud were 0.2, 47.1, 29.6, and 23.1%, respectively. The corresponding percentages under the algorithm-on were 3.0, 72.6, 22.9, and 1.4%, respectively. A significant difference on the ratings of the transient noise loudness was found between the algorithm-on and algorithm-off (t-test, p < 0.001). For overall impression for speech stimuli: under the algorithm-off condition, the percentage of subjects rating the algorithm to be not helpful at all, somewhat helpful, helpful, and very helpful for speech stimuli were 36.5, 20.8, 33.9, and 8.9%, respectively. Under the algorithm-on condition, the corresponding percentages were 35.0, 19.3, 30.7, and 15.0%, respectively. Statistical analysis revealed there was a significant difference on the ratings of overall impression on speech stimuli. The ratings under the algorithm-on condition were significantly more helpful for speech understanding than the ratings under algorithm-off (t-test, p < 0.001). Conclusions: The transient noise reduction strategy appropriately controlled the loudness for most of the transient noises and did not affect the sound quality, which could be beneficial to hearing aid wearers.

OBJECTIVES: A number of clinical measures of directivity, including the front-to-back ratio (FBR) and front-to-side ratio (FSR), have been suggested to audiologists to monitor the functionality of hearing aids with directional microphones. These suggestions, however, are based on the assumption that directivity measured clinically changes monotonically when compared with changes measured using the directivity index (DI) and perceptual directional benefit. The objective of the present study was to empirically examine this assumption. In addition, the reliability of the clinical directivity measure was estimated to establish a referral threshold for defective directional microphone hearing aids. DESIGN: The directivity of the directional microphones of two behind-the-ear hearing aids was systematically degraded by plugging the microphone ports. The directivity was measured using four clinical measures: the FBR and FSR performed in the test chamber of a hearing aid analyzer and in sound field. Each measure was repeated four times in each directivity-degraded condition. The degraded directivity was also assessed using the DI measure in an anechoic chamber. The perceptual directional benefit in each directivity-degraded condition was obtained by testing 10 hearing-impaired adults in a sound field with diffuse noise using the Hearing in Noise Test (HINT). RESULTS: The results of the DI and HINT measures showed strong correlation between the two FSRs (test chamber and sound field), while the two FBRs showed no correlation. The directivity generated by the FBRs could remain unchanged even when the directional microphone had lost more than 50% of its directivity. The results further indicated that the measures performed in the sound field were more reliable than those performed in the test chamber. Based on the results of the reliability measures, a 30% change in directivity was suggested as the referral threshold signifying defective directional systems. CONCLUSIONS: Because the FSR predicts the DI and HINT measurements more accurately than does the FBR, it is suggested that clinicians use the FSR to monitor hearing aid directivity. By using the FSR measure and informed by the suggested referral threshold, clinicians would be able to correctly identify defective directional microphone hearing aids at an early stage, rather than at a point when the directivity has been diminished completely or even reversed.

Objectives: The field tests performed in the current investigation examined how visual cues impact the benefit provided by directional (DIR) microphone hearing aids in the real world. Specifically, the study tested the hypotheses that (1 ) the provision of visual cues would reduce the preference for DIR processing (re: omnidirectional [OMNI] microphone) and (2) laboratory audiovisual (AV) testing would predict real-world outcomes better than auditory-only testing. Design: The same 24 hearing-impaired adults enrolled in the laboratory testing of this study compared microphone modes (DIR versus OMNI processing) in their everyday activities three times a day for 4 wk using paper and pencil journals. In each comparison, the participants were asked to identify an environment that favored DIR processing (e.g., the talker standing in front of the user and noise at his or her back), listen to speech amid noise via both the DIR and OMNI microphone modes, and then record the preferred microphone mode in the journal. To further understand what the listeners based their preference on, the participants were also asked to provide the reasons for their preferences. Microphone modes were compared when the listeners' eyes were either open or closed. Results: The field results first suggested that OMNI processing was more frequently preferred over DIR processing. Visual cues were not found to have a significant effect on preference for DIR processing. Furthermore, the analysis revealed that when listeners indicated "louder" or "less internal noise" as the reasons for their microphone preference, the likelihood of preferring the OMNI mode increased significantly, suggesting that OMNI processing was preferred for its louder output and lower internal circuit noise level. Finally, the preference score obtained by the laboratory preference judgment task under the AV condition was shown to be the best predictor of microphone preference in the real world. Conclusions: The field data did not reveal the effect of visual cues on preference for DIR processing because preference was not altered by the availability of visual cues. This negative result may be due to the unsuccessful control of visual cues during the field trial. However, the finding that AV laboratory testing predicted field outcomes more accurately than did auditory-only testing demonstrates the role of visual cues in the real world and emphasizes the necessity of using AV testing in the laboratory to evaluate DIR microphone hearing aids. Furthermore, this study demonstrates the importance of factors other than DIR benefit—such as loudness and hearing aid internal noise—in determining preference for microphone mode in the real world.

The aim of this study was to evaluate a clinical test proposed to verify the output setting of hearing aids. Across three test sites, 56 bilaterally fitted hearing aid users were recruited. They answered questions about real-life loudness discomfort experiences and then completed the output verification test. Using an ascending method, a 1,500 kHz narrowband noise and a selection of broadband environmental noises were presented in 5 dB steps from 80 to 90 dB SPL. Response options included 'acceptably loud', and 'uncomfortably loud'. A swept pure tone presented at 90 dB SPL was also administered. Some loudness discomfort was reportedly experienced in real life by 82% of the participants. Generally, the test noises produced low specificity, with the 1,500 kHz narrowband noise being the best predictor of loudness discomfort experiences in real life, while the swept pure tone showed low sensitivity. Individual reactions to specific sounds and the test equipment and environment used are argued to affect the laboratory performance. A better understanding of these factors is needed before the test can be improved. an ser mejoradas.

The purpose of this study was to determine the impact of a digital noise reduction (DNR) scheme implemented in a current commercial hearing aid. In a double-blinded design, three conditions of onset time (4, 8, 16 seconds) were randomly assigned to the 25 subjects, plus one condition wherein the noise-reduction feature was disengaged. Subsequently, a fifth trial/condition, wherein the subject had access to three memories in which the different onsets were programmed, was carried out. For each of the five conditions, the subjects had an at-home trial, prior to obtaining self-report measures. Laboratory measures of speech perception showed no effect of the DNR, with or without the provision of visual cues. Laboratory-based ratings of ease of listening showed DNR-on (all onset times) to be rated significantly better than DNR-off; for ratings of listening comfort, the 4-second onset time was rated significantly lower (poorer) than the 8-second onset or the DNR-off condition; for ratings of sound quality, DNR-on or -off had no differential effect. Self-report measures indicated significantly higher aversiveness in the DNR-off condition compared to the pre-test scores.

The directivity of an adaptive directional microphone hearing aid (DMHA) cannot be assessed by the method that calls for presenting a "probe" signal from a single loudspeaker to the DMHA that moves to different angles. This method is invalid because the probe signal itself changes the polar pattern. This paper proposes a method for assessing the adaptive DMHA using a "jammer" signal, presented from a second loudspeaker rotating with the DMHA, that simulates a noise source and freezes the polar pattern. Measurement at each angle is obtained by two sequential recordings from the DMHA, one using an input of a probe and a jammer, and the other with an input of the same probe and a phase-inverted jammer. After canceling out the jammer, the remaining response to the probe signal can be used to assess the directivity. In this paper, the new method is evaluated by comparing responses from five adaptive DMHAs to different jammer intensities and locations. This method was shown to be an accurate and reliable way to assess the directivity of the adaptive DMHA in a high-intensity-jammer condition.

New objective and accurate feedback detection method, transfer function variation criterion (TVC), has been developed for evaluating the performance of feedback cancellation techniques. The proposed method is able to classify stable, unstable, and sub-oscillatory stages of feedback in hearing aids. The sub-oscillatory stage is defined as a state where the hearing aid user may perceive distortion of sound quality without the occurrence of oscillation. This detection algorithm focuses on the transfer function variation of hearing aids and the relationship between system stability and feedback oscillation. The transfer functions are obtained using the FIR Wiener filtering algorithm off-line. An anechoic test box is used for the exact and reliable evaluation of different hearing aids. The results are listed and compared with the conventional power concentration ratio (PCR), which has been generally adopted as a feedback detection method for the performance evaluation of hearing aids. The possibility of real-time implementation is discussed in terms of a more convenient and exact performance evaluation of feedback cancellation techniques.

Objective In this investigation, a method for computing a directivity index (DI) on a manikin for directional microphones in hearing aids was proposed and evaluated comparatively to other conventional methods. Design Test devices included first- and second-order directional microphones. Signal presentation, implemented in an anechoic chamber, involved a single noise source rotated completely around the directional microphone in a hearing aid, in free field and on a manikin, at a defined radius. The area covered was equivalent to the approximate surface area of a sphere. It was anticipated that an equal angular resolution of 10 degrees (elevation and azimuth) would effectively estimate the DI of first-, second-, and higher-order directional microphone systems located in a hearing aid on a manikin. A total of 450 spatially varied presentation points were analyzed, each weighted in reference to direction of arrival on the directional microphone. Results Empiric differences between the DI derived from the 3D-DI method proposed in this investigation and the conventionally derived 2D-DI method DI on a manikin were as large as 3.8 dB in the higher frequencies, depending on the device under test. Conclusions The magnitude of these differences was dependent on the device under test microphone location. The further the microphone was placed into the ear of the manikin, the larger the empiric differences.

To determine the effects of frequency compression on music perception, and the impact of previous music training and hearing status. It was hypothesized that lesser amounts of compression would be preferred, and that this pattern of preference would be more evident in the musically trained groups.A paired-comparison paradigm was used. Subjects listened to pairs of musical passages as processed by a hearing aid with different frequency-compression settings. Subjects indicated their preferred passage and the strength of their preference.Fifty-seven subjects divided in four groups, according to hearing status (normal hearing, mild-to-moderate hearing loss), and previous music experience (trained, not trained).Subjects generally preferred the conditions with the lesser amount of compression. Listeners in the group with previous music training showed stronger preference for less compression than those without training, as did listeners with normal hearing when compared to subjects with hearing loss.Although less frequency compression was in general preferred, there was more variability in the comparisons involving the default settings for a 50-dB hearing loss (i.e. start frequency 4000 Hz, compression ratio 2.5:1) and no compression, suggesting that mild amounts of compression may not be detrimental to perceived sound quality.

Objectives: Children who are hard of hearing (CHH) have restricted access to acoustic and linguistic information. Increased audibility provided by hearing aids (HAs) influences language outcomes, but the advantages of appropriately fit HAs can only be realized if children wear their devices on a consistent basis. The purpose of this article was to characterize long-term HA use in CHH, based on parent-report measures, and identify factors that influence longitudinal trends in HA use. Design: Participants were parents of 290 children with mild to severe hearing loss. At every visit, parents estimated the average amount of time the child used HAs per day during the week and on the weekends. Parent reports of daily HA use were analyzed to determine if different patterns of HA use were observed longitudinally during the study. Independent predictor variables were then related to longitudinal trends in HA use within three age groups (infant, preschool, school age). Results: On average across multiple visits, parents reported that their children wore their HAs for 10.63 hr per day (SD = 3.29). Data logging values were lower than parent-report measures (M = 8.44, SD = 4.06), suggesting that parents overestimated daily HA use. The majority of children in each age group wore HAs at least 8 hr per day from their first research testing interval to their last, based on parent-report measures. Maternal education level predicted longitudinal trends in HA use for infants and school-age CHH. Degree of hearing loss was related to trends in school-age children only. Conclusions: These results indicated that the majority of CHH increased HA use over time, but a sizable minority demonstrated a low level of use or decreased use in the time period studied. Maternal education level influenced longitudinal trends in daily HA use. Degree of hearing loss influenced trends in school-age children only. Audiologists and early intervention service providers might aid in improving HA use by providing regular hands-on training with the HAs and individualized problem-based strategies to address the challenges families experience with attaining a high level of use. Families may also benefit from practical demonstrations of the benefits of consistent HA use, such as hearing loss simulations, examples of listening in noise with and without HAs, or listening to malfunctioning HAs.

This clinical trial was undertaken to evaluate the benefit obtained from hearing aids employing second-order adaptive directional microphone technology, used in conjunction with digital noise reduction. Data were collected for 49 subjects across two sites. New and experienced hearing aid users were fit bilaterally with behind-the-ear hearing aids using the National Acoustics Laboratory—Nonlinear version 1 (NAL-NL1) prescriptive method with manufacturer default settings for various parameters of signal processing (e.g., noise reduction, compression, etc.). Laboratory results indicated that (1) for the stationary noise environment, directional microphones provided better speech perception than omnidirectional microphones, regardless of the number of microphones; and (2) for the moving noise environment, the three-microphone option (whether in adaptive or fixed mode) and the two-microphone option in its adaptive mode resulted in better performance than the two-microphone fixed mode, or the omnidirectional modes.

Objective: A primary purpose of fitting hearing aids is to improve the audibility of speech; however, hearing aid gain is typically measured by using standardized nonspeech signals, e.g., swept pure tones, speech-weighted broadband noise, or modulated noise. When compression hearing aids are tested with these nonspeech input signals, the measured gain can be substantially different than if a real speech input signal were used. The purpose of this study was to systematically evaluate the effects of release time, compression ratio, and number of compression channels, as well as interactions of these parameters, on the gain difference between several common nonspeech hearing aid test signals and speech. It was hypothesized that the difference in hearing aid gain between static nonspeech signals and speech would increase as release time, compression ratio, and number of channels increased. Design: Speech and several common nonspeech hearing aid test signals, matched at overall root-mean-square levels corresponding to average (65 dB SPL) and loud (80 dB SPL) conversational speech, were input into a master hearing aid circuit, and the gain of the circuit was measured in one-third octave bands. The hearing aid was programmed as a moderate-gain (23 dB) wide dynamic range compression instrument with a compression threshold of 50 dB SPL. The release time, compression ratio, and number of compression channels of the circuit were systematically adjusted by programming software. The one-third octave band gain differences between the nonspeech signals and speech were measured for all combinations of the compression settings. Multiple regression analysis was used to evaluate the effects of each compression parameter, and interactions of the parameters, on the gain difference between each nonspeech signal and speech. Results: One-third octave band gain differences between nonspeech and speech signals (calculated as nonspeech signal minus speech signal) ranged from −3.1 to 10.4 dB, depending on frequency, nonspeech test signal, and input signal level. In most cases, the compression parameters accounted for more than 70% of the variance in gain differences between the speech and nonspeech signals. At an input level of 65 dB, increases in the release time and compression ratio led to an increase in the gain difference between most nonspeech signals and speech at most frequencies. Increases in the number of channels caused an increase in the gain difference when the spectra of the nonspeech signals differed from the speech spectrum. The effects of release time and number of channels increased as the compression ratio increased. At an 80 dB input level, increasing the compression ratio led to a decrease in the gain difference between the nonspeech signals and speech. Release time and number of channels had little to no effect at the higher input level. Conclusions: The compression parameters of release time, compression ratio, and number of compression channels explain most of the variance in differences in hearing aid gain between nonspeech and speech signals. It may be cumbersome, however, to quantitatively define this relationship for all hearing aid circuits. It is therefore recommended that hearing aid “use” gain or output be measured with a real speech signal. If a nonspeech signal must be used, then it should have spectral and temporal properties that are similar to speech.

The effectiveness of an adaptive directional microphone design, as implemented in the Phonak Claro behind-the-ear hearing aid, is evaluated. Participants were fit bilaterally and tested in 2 environments, an anechoic chamber and a moderately reverberant classroom, with the microphones in the fixed (cardioid) setting and the adaptive setting. Five speakers were placed between 110° and 250° azimuth around the listener. Speech-weighted noise was presented from those speakers at an overall level (OAL) of 65 dB (A). Noise was increased by 8 dB from 1 speaker at a time, using 2-s modulation and random assignment, while the output from the other speakers was reduced to maintain the constant OAL. Results of 2 speech perception tasks used as outcome measures indicated that the adaptive system was not able to follow the dominant noise source in the presence of lower level noise sources. Selfreport measures obtained after blinded home trials were consistent with laboratory findings that the participants did not perceive this adaptive microphone design to be more effective than the default fixed-microphone option.

In this study, the performance of 48 listeners with normal hearing was compared to the performance of 46 listeners with documented hearing loss. Various conditions of directional and omnidirectional hearing aid use were studied. The results indicated that when the noise around a listener was stationary, a first- or second-order directional microphone allowed a group of hearing-impaired listeners with mild-to-moderate, bilateral, sensorineural hearing loss to perform similarly to normal hearing listeners on a speech-in-noise task (i.e., they required the same signal-to-noise ratio to achieve 50% understanding). When the noise source was moving around the listener, only the second-order (three-microphone) system set to an adaptive directional response (where the polar pattern changes due to the change in noise location) allowed a group of hearing-impaired individuals with mild-to-moderate sensorineural hearing loss to perform similarly to young, normal-hearing individuals.

Objectives The research questions of this study were: (1) Are children using nonlinear frequency compression (NLFC) in their hearing aids getting better access to the speech signal than children using conventional processing schemes? The authors hypothesized that children whose hearing aids provided wider input bandwidth would have more access to the speech signal, as measured by an adaptation of the Speech Intelligibility Index, and (2) are speech and language skills different for children who have been fit with the two different technologies; if so, in what areas? The authors hypothesized that if the children were getting increased access to the speech signal as a result of their NLFC hearing aids (question 1), it would be possible to see improved performance in areas of speech production, morphosyntax, and speech perception compared with the group with conventional processing. Design Participants included 66 children with hearing loss recruited as part of a larger multisite National Institutes of Health-funded study, Outcomes for Children with Hearing Loss, designed to explore the developmental outcomes of children with mild to severe hearing loss. For the larger study, data on communication, academic and psychosocial skills were gathered in an accelerated longitudinal design, with entry into the study between 6 months and 7 years of age. Subjects in this report consisted of 3-, 4-, and 5-year-old children recruited at the North Carolina test site. All had at least at least 6 months of current hearing aid usage with their NLFC or conventional amplification. Demographic characteristics were compared at the three age levels as well as audibility and speech/language outcomes; speech-perception scores were compared for the 5-year-old groups. Results Results indicate that the audibility provided did not differ between the technology options. As a result, there was no difference between groups on speech or language outcome measures at 4 or 5 years of age, and no impact on speech perception (measured at 5 years of age). The difference in Comprehensive Assessment of Spoken Language and mean length of utterance scores for the 3-year-old group favoring the group with conventional amplification may be a consequence of confounding factors such as increased incidence of prematurity in the group using NLFC. Conclusions Children fit with NLFC had similar audibility, as measured by a modified Speech Intelligibility Index, compared with a matched group of children using conventional technology. In turn, there were no differences in their speech and language abilities.

The purpose of this study was to determine whether different release times, as implemented in a commercial two-channel AGC hearing aid, would result in differing speech intelligibility performance, user preference, or use time. In experiment one, 14 subjects were fitted with a two-channel multi-memory AGC hearing aid. Four memories were programmed to have identical frequency responses and output limitation characteristics. Only the release times were varied, with the low channel/high channel set as follows (in ms): 20/35, 20/150, 100/35, 500/7. Results obtained from the NST (+5 S/N), magnitude estimations of intelligibility, and data-logging of use time did not show any release-time pair to be superior to any other. In experiment two, 10 subjects participated in a forced-choice, paired-comparison procedure using the same release-time pairs from experiment one. Auditory stimuli consisted of three input levels, consisting of speech, speech in noise, and music. Results indicated no release-time pair to be superior in any listening condition. Results may be explained, in part, by the use of a curvilinear compression circuit and the milder hearing loss exhibited by the subjects. Future investigation of the effect of release-time variation should be carried out on circuits with adjustable compression parameters (and fixed compression ratios) with listeners exhibiting different degrees of hearing loss.

Objectives Hearing aids (HAs) provide the basis for improving audibility and minimizing developmental delays in children with mild to severe hearing loss. Multiple guidelines exist to recommend methods for optimizing amplification in children, but few previous studies have reported HA fitting outcomes for a large group of children. The present study sought to evaluate the proximity of the fitting to prescriptive targets and aided audibility of speech, as well as survey data from pediatric audiologists who provided HAs for the children in the present study. Deviations from prescriptive target were predicted to have a negative impact on aided audibility. In addition, children who were fitted using verification with probe microphone measurements were expected to have smaller deviations from prescriptive targets and greater audibility than cohorts fitted without these measures. Design HA fitting data from 195 children with mild to severe hearing losses were analyzed as part of a multicenter study evaluating outcomes in children with hearing loss. Proximity of fitting to prescriptive targets was quantified by calculating the average root-mean-square (RMS) error of the fitting compared with Desired Sensation Level prescriptive targets for 500, 1000, 2000, and 4000 Hz. Aided audibility was quantified using the Speech Intelligibility Index. Survey data from the pediatric audiologists who fit amplification for children in the present study were collected to evaluate trends in fitting practices and relate those patterns to proximity of the fitting to prescriptive targets and aided audibility. Results More than half (55%) of the children in the study had at least 1 ear that deviated from prescriptive targets by more than 5 dB RMS on average. Deviation from prescriptive target was not predicted by pure-tone average, assessment method, or reliability of assessment. Study location was a significant predictor of proximity to prescriptive target with locations that recruited participants who were fit at multiple clinical locations (University of Iowa and Boys Town National Research Hospital) having larger deviations from target than the location where the participants were recruited primarily from a single, large pediatric audiology clinic (University of North Carolina). Fittings based on average real-ear to coupler differences resulted in larger deviations from prescriptive targets than fittings based on individually measured real-ear to coupler differences. Approximately 26% of the children in the study has aided audibility less than 0.65 on the Speech Intelligibility Index (SII). Aided audibility was significantly predicted by the proximity to prescriptive targets and pure-tone average, but not age in months. Conclusions Children in the study had a wide range of fitting outcomes in terms of proximity to prescriptive targets (RMS error) and aided speech audibility (SII). Even when recommended HA verification strategies were reported, fittings often exceeded the criteria for both proximity to the prescriptive target and aided audibility. The implications for optimizing amplification for children are also discussed.

Background: Frequency-lowering signal processing in hearing aids has re-emerged as an option toimprove audibility of the high frequencies by expanding the input bandwidth. Few studies have inves-tigated the usefulness of the scheme as an option for bimodal users (i.e., combined use of a cochlearimplant and a contralateral hearing aid). In this study, that question was posed.Purpose: The purposes of this study were (1) to determine if frequency compression was a better bimo-dal option than conventional amplification and (2) to determine the impact of a frequency-compressionhearing aid on speech recognition abilities.ResearchDesign: Thereweretwoseparateexperimentsinthisstudy.Thefirstexperimentinvestigatedthe contribution of a frequency-compression hearing aid to contralateral cochlear implant (CI) perform-ance for localization and speech perception in noise. The second experiment assessed monaural con-sonant and vowel perception in quiet using the frequency-compression and conventional hearing aidwithout the use of a contralateral CI or hearing aid.StudySample:Tensubjectsfittedwithacochlearimplantandhearingaidparticipatedinthefirstexperi-ment.Seventeenadultsubjectswithacochlearimplantandhearingaidortwohearingaidsparticipatedinthe second experiment. To be included, subjects had to have a history of postlingual deafness, a mod-erate or moderate-to-severe hearing loss, and have not worn this type of frequency-lowering hearing aidpreviously.Data Collection and Analysis: In the first experiment, performance using the frequency-compressionandconventionalhearingaidswasassessedontestsofsoundlocalization,speechperceptioninaback-ground of noise, and two self-report questionnaires. In the second experiment, consonant and vowelperception in quiet was assessed monaurally for the two conditions. In both experiments, subjects alter-nateddailybetweenafrequency-compression and conventionalhearingaidfor 2mo. Theparametersoffrequency compression were set individually for each subject, and audibility was measured for the fre-quency compression and conventional hearing aid programs by comparing estimations of the SpeechIntelligibilityIndex(SII)usingamodifiedalgorithm(Bentleretal,2011).Inbothexperiments,theoutcomemeasureswereadministeredfollowingthehearingaidfittingtoassessperformanceatbaselineandafter2 mo of use.Results:Forthisgroupofsubjects,theresultsrevealednosignificantdifferencebetweenthefrequency-compression and conventional hearing aid on tests of localization and consonant recognition. Spondee-in-noiseand vowelperceptionscoresweresignificantlyhigher withthe conventionalhearingaidcomparedto the frequency-compression hearing aid after 2 mo of use.Conclusions: These results suggest that, for the subjects in this study, frequency compression is not abetter bimodal option than conventional amplification. In addition, speech perception may be negatively*DepartmentofCommunicationSciencesandDisorders,AugustanaCollege;†DepartmentofCommunicationSciencesandDisorders,Universityof Iowa; ‡Department of Otolaryngology—Head and Neck Surgery, University of IowaAnn E. Perreau, 639 38th Street, Rock Island, IL 61201; Phone: 309-794-8935; Fax: 309-794-3497; E-mail: annperreau@augustana.eduPhonakAGprovideddevicesforthisstudy.TheGraduateCollegeandtheDepartmentofCommunicationSciencesandDisordersattheUniversityof Iowa contributed financially.J Am Acad Audiol 24:105–120 (2013)

Background: Listening demand, or auditory lifestyle, is an important factor that needs to be considered when selecting a hearing aid and specific amplification features. Although elderly adults often report having fewer listening demands, auditory lifestyles of people in different age groups have not been objectively quantified and compared. Although it is assumed that the social lifestyles of older adults, e.g., retirement, place fewer demands on hearing, this assumption has not been examined empirically. Purpose: The purposes of the current study were to (1) objectively characterize and compare the auditory lifestyle of younger and older adults with hearing impairment and (2) examine the relationships between age, social lifestyle, and auditory lifestyle. Research Design: This is a nonexperimental study using a correlational design. Study Sample: Twenty-seven adults with bilateral hearing impairment aged 40–88 yr were recruited and served as subjects. Data Collection and Analysis: To objectively quantify auditory lifestyle, participants carried noise dosimeters to measure sound levels in their daily lives for 1 wk. To help interpret the dosimeter data, participants used paper-and-pencil journals to describe their listening activities and environments. The auditory lifestyle was also subjectively quantified by the Auditory Lifestyle and Demand Questionnaire (ALDQ). Three self-report inventories were used to characterize participants' social lifestyles: Social Network Index, Welin Activity Scale, and Social Convoy Questionnaire. Results: A total of 1,267 journal entries covering 2,032 hr of dosimeter recordings were obtained from participants for analyses. Although younger and older participants reported spending comparable time in a given category of listening event, the dosimeter-measured sound level was higher for younger listeners. For auditory lifestyle quantified by dosimeter, correlation analyses revealed that older age was associated with lower Social Network Index scores (smaller social networks) and fewer listening demands. Regression models further indicated that the Social Network Index score more accurately predicted listening demand than age. Finally, path analysis suggested that the effect of age on listening demand was mediated by the Social Network Index score. Self-report auditory lifestyle measured by the ALDQ was not associated with age and social lifestyle. Conclusions: The results indicate that older listeners tend to encounter quieter listening situations than younger listeners. The data are also consistent with the hypothesis that older adults have less active social lifestyles that place fewer demands on hearing. Therefore, the current study suggests the important role of social lifestyle in listening demand and the need to consider this factor in clinical management of hearing loss.

OBJECTIVES Acoustically, directional microphone hearing aids are less able to improve signal-to-noise ratio in more-reverberant environments. However, because auditory-visual (AV) omnidirectional performance is more likely to approach the ceiling level in less-reverberant environments, listeners may perceive a smaller directional benefit in these environments. The first objective of this study was to investigate the influence of AV ceiling performance on the relationship between reverberation and directional benefit. The second objective was to determine whether a modified speech intelligibility index (mSII) model could predict directional benefit across AV listening conditions with different levels of reverberation. DESIGN Nineteen adults with sensorineural hearing loss were recruited. Directional benefit was measured using the auditory-only (AO) Hearing in Noise Test (HINT) and the AV version of the Connected Speech Test (CST) in environments containing either low or moderate levels of reverberation (reverberation time = 0.2 sec and 0.7 sec, respectively). The AO mSII was calculated for both speech materials. To predict AV directional benefit, the AO mSII was converted to the AV mSII using the correction equations specified by American National Standards Institute S3.5-1997 (R2007) and the new equations developed based on the data collected in a low-reverberation sound booth in a previous study. RESULTS As the test environment became more reverberant, a decrease in directional benefit was measured using the HINT. In contrast, the results of the AV CST revealed that directional benefit was higher in the more-reverberant condition. Although the mSII model accurately predicted the HINT-measured directional benefit, the model using the American National Standards Institute correction equations underestimated the directional benefit measured using the AV CST in both reverberation conditions. Applying the newer equations, the model resulted in a more accurate prediction in the low-reverberation condition. However, AV directional benefit in the moderately reverberant condition was still underestimated. CONCLUSIONS Hearing aid users would achieve the greatest directional benefit in situations in which they do not reach ceiling performance. The present study suggests that in the real world these situations may include face-to-face communication occurring in environments with higher reverberation. The opposite trends demonstrated by the HINT and AV CST highlight the importance of using ecologically valid laboratory testing to estimate the real-world effectiveness of a hearing aid and its technology. As a likely result of the difference in the effect on speech cues between noise and reverberation, the new equations developed from the low-reverberation booth failed to predict AV directional benefit in the more-reverberant environment. The mSII model with visual cue correction equations would be able to provide accurate predictions for AV directional benefit when the acoustic environments are similar to the ones used to derive the equations.

The directivity index (DI) and polar pattern of directional hearing aids are typically measured in an anechoic chamber, which is expensive and not commonly found. This article proposes a quasi-anechoic technique to measure hearing aid directivity in small and reverberant enclosures using the root-mean-square amplitude of the first 3 ms of the hearing aid's response to the input signal.The hearing aid's planar DI and polar pattern were measured using the proposed method in an audiologic booth with low reverberation, a room with moderate reverberation, and an anechoic chamber. The measurement was repeated four times for each aid in each environment. The results were compared to the directivity obtained in the anechoic chamber using two benchmark measurements.Eight hearing aids with a fixed directional mode were tested.The results revealed that the error of the proposed method in DI was smaller than 0.3 dB in 94% of the measurement conditions. The standard deviation of the DI was smaller than 0.1 dB in 94% of the conditions. These results suggest that the proposed quasi-anechoic method provides an accurate and repeatable way to assess non-adaptive directional microphone hearing aids in small non-anechoic enclosures.

This report is the first of two detailing a longitudinal follow-up of hearing aid users. Sixty-five subjects were followed for 12 months post-hearing aid fitting. Objective tests included insertion gain, the Speech Perception in Noise (SPIN) test (Kalikow, Stevens & Elliott, 1977; Bilger, Neutzel, Rabinowitz, & Rzeczkowski, 1984) and the Nonsense Syllable Test (NST) (Levitt & Resnick, 1978) presented in quiet and noise backgrounds. Initially each subject’s hearing aid was fit to the revised National Acoustic Laboratories prescriptive formula (NAL-R) (Byrne & Dillon, 1986) using insertion gain measures. Use gain, measured at 6 and 12 months post-fitting, indicated that subjects generally used those prescribed values, except for subjects in the steeply sloping configuration subgroup. The NST and SPIN tests were administered at the fitting and at 1, 3, 6, and 12 months post-fitting. No change in performance, or training effect, was found for the group or for factors of experience, degree of hearing loss, configuration of hearing loss, use time, or circuit type. Failure to demonstrate a training effect may be attributed, in part, to the fact that initial speech recognition testing was done with the hearing aid volume set at the prescribed values. None of the circuits used showed performance superiority, except when comparing scores for the NST obtained in a quiet background to those obtained in a background of speech-weighted noise. In that comparison, the users of adaptive filter circuits exhibited less deterioration of performance in a noise background.

Hearing aid equivalent input noise (EIN) measures assume the primary source of internal noise to be located prior to amplification and to be constant regardless of input level. EIN will underestimate internal noise in the case that noise is generated following amplification. The present study investigated the internal noise levels of six hearing aids (HAs). Concurrent with HA processing of a speech-like stimulus with both adaptive features (acoustic feedback cancellation, digital noise reduction, microphone directionality) enabled and disabled, internal noise was quantified for various stimulus levels as the variance across repeated trials. Changes in noise level as a function of stimulus level demonstrated that (1) generation of internal noise is not isolated to the microphone, (2) noise may be dependent on input level, and (3) certain adaptive features may contribute to internal noise. Quantifying internal noise as the variance of the output measures allows for noise to be measured under real-world processing conditions, accounts for all sources of noise, and is predictive of internal noise audibility.

The directional microphone systems of modern digital hearing aids are capable of changing their spatial directivity pattern and/or the microphone mode in response to changes in the properties of environmental sounds. These adaptive/automatic features make measurement of a hearing aid’s directivity in a given test environment very difficult. Assessing the directivity of such systems requires a signal that can record the system’s response while not changing the system’s directivity. This paper proposes a method using a signal cancellation technique involving impulse responses to acoustically assess a hearing aid’s directivity (referred to as the IR method). The impulse is presumed to be undetectable to the adaptive/automatic system because it contains little energy and a short response could be recorded before the system actually reacts. In the current study, the IR method was evaluated by testing five adaptive/automatic directional hearing aids in noise of various intensities. The results revealed that the IR method was an accurate and repeatable way to assess slow-acting directional systems in noise of varying intensities and fast-acting systems in noise of high intensities.

The purpose of the laboratory tests of the current investigation was to examine how visual cues impact directional (DIR) benefit and preference for the DIR microphone hearing aid (re: the omnidirectional [OMNI] microphone). Specifically, three hypotheses were examined: (1) the presence of visual cues would improve OMNI-aided performance to ceiling levels and therefore reduce DIR benefit and preference, (2) DIR benefit measured in the audiovisual (AV) condition could not be predicted by that measured using auditory-only (AO) testing, and (3) with visual cues, listeners with greater lipreading skills would perceive less DIR benefit than did listeners with lesser lipreading skills.Twenty-four adults with sensorineural hearing loss were recruited. Their speech recognition performances were measured in two hearing aid microphone modes (DIR and OMNI), at various signal-to-noise ratios (SNR, -10 to +10 dB in 4-dB steps) and under two presentation conditions (AV and AO) by using the AV version of the Connected Speech Test. Microphone preference (DIR versus OMNI) was also assessed with and without visual cues at each of the SNRs by using the same Connected Speech Test sentences. Lipreading skills were measured using the Utley test.The speech recognition data revealed that the participants obtained significantly less DIR benefit in the AV condition because their AV performances were at the ceiling level. Consistent with this, the likelihood of preferring DIR processing was significantly reduced when visual cues were available to the listeners. Further, DIR benefit measured in the AV condition was not correlated with that measured in the AO condition while being significantly and negatively correlated with lipreading skill.These results suggest that AO laboratory testing overestimates the DIR benefit and preference for DIR processing that hearing aid users may have in most face-to-face conversations in typical SNR, real-world environments. Additionally, because the DIR benefit measured in the AV condition cannot be predicted by the benefit score obtained from traditional AO laboratory testing, the effect of visual cues should be considered in establishing a valid laboratory/clinical environment and protocol for DIR microphone hearing aid testing. In light of these findings, consultations should be provided for hearing aid users with superior lipreading skills to help them adjust their expectations regarding the possibly small perceivable benefit gained from DIR microphone hearing aids.

Purpose The purpose of this study was to evaluate and quantitatively model the independent and interactive effects of compression ratio, number of compression channels, and release time on the dynamic range of continuous speech. Method A CD of the Rainbow Passage (J. E. Bernthal & N. W. Bankson, 1993) was used. The hearing aid was a programmable, digital, wide dynamic range compression instrument. A fully crossed design and multiple regression analyses were used to evaluate and model the effects of release time (32, 128, and 1024 ms), compression ratio (1:1, 2:1, and 4:1), and number of compression channels (1, 2, and 4 channels) on the short-term octave-band dynamic range of speech. Dynamic range of speech was defined as the range between the 1% and 70% exceedance levels within each octave band. Results As the compression ratio and number of channels increased, and as the release time decreased, the dynamic range of speech decreased. The effects of channels and release time increased as the compression ratio increased. In all conditions, the amount of effective compression for speech was less than the nominal compression ratio. Conclusion A multiple regression model is provided that predicts the effects of various combinations of compression parameters on the dynamic range of speech.

Clinical measurement of the loudness discomfort level (LDL) historically has been part of the hearing aid fitting procedure, and this clinical practice remains popular today. LDL measurements also are recommended in contemporary hearing aid fitting protocols. Yet, surveys show that many hearing aid users are dissatisfied with the loudness of their hearing aids. In this evidence-based review article, we evaluate the effectiveness of clinical LDL measurements. Specifically, we asked the question "Are the clinical measurements of LDL for adult patients predictive of aided acceptance and satisfaction of loudness for high inputs in the real world?" Nearly 200 articles were reviewed; three met the criteria set forth in this review. The evidence supported using unaided LDLs for selecting the maximum real-ear output of hearing aids. No study using aided LDLs or aided loudness verification met the criteria. The level of the evidence for the three articles using unaided LDLs was low; no higher than Level 4. The limited number of studies, the level of evidence, and the statistical power of the studies prevents us from making a strong recommendation concerning the clinical use of LDL measures. Additional research in this area, especially research employing randomized controlled trials would be a useful addition to this body of literature.

The purpose of this study was to assess the relationship between the directivity of a directional microphone hearing aid and listener performance. Hearing aids were fit bilaterally to 19 subjects with sensorineural hearing loss, and five microphone conditions were assessed: omnidirectional, cardioid, hypercardioid, supercardioid, and "monofit," wherein the left hearing aid was set to omnidirectional and the right hearing aid to hypercardioid. Speech perception performance was assessed using the Hearing in Noise Test (HINT) and the Connected Speech Test (CST). Subjects also assessed eight domains of sound quality for three stimuli (speech in quiet, speech in noise, and music). A diffuse soundfield system composed of eight loudspeakers forming the corners of a cube was used to output the background noise for the speech perception tasks and the three stimuli used for sound quality judgments. Results indicated that there were no significant differences in the HINT or CST performance, or sound quality judgments, across the four directional microphone conditions when tested in a diffuse field. Of particular interest was the monofit condition: Performance on speech perception tests was the same whether one or two directional microphones were used.

Output from a moderate-gain behind-the-ear hearing aid was measured in HA-1 and HA-2 couplers. For the HA-1 coupling, a standard full-shell earmold with #13 tubing throughout was used. The results suggest that when this earmold configuration is used, the gain and output assumed from HA-2 specifications may not be realized in the higher frequency region. Questionnaires sent to all U.S. earmold manufacturers indicated that only one of those manufacturers considered a “standard” earmold to be one incorporating a “horn” effect in the canal portion of the mold; over 70% of the manufacturers reported inserting tubing to the end of the canal portion as a standard procedure. Measures of real-ear-to-coupler differences (RECD) should be obtained with consideration for this earmold effect.

The purpose of this study was to determine whether the label attached to the hearing aid being presented would bias outcome measures towards newer technological designs.Two groups of subjects participated in this investigation. The groups were matched for age, gender, previous hearing aid experience, degree and configuration of hearing loss. Group A wore each of two digital hearing aids for 1 mo; Group B wore the same digital hearing aid for 2 mo, but the subjects were given the impression they were changing hearing aids after 1 mo. In each group the subjects were told that one of the months they were wearing a "digital" hearing aid and one of the months they were wearing a "conventional" hearing aid. Outcome measures consisted of a number of behavioral speech perception tasks and self-report measures, each completed at the onset and after 1 mo use with the hearing aids.Labeling effects were observed for many of the outcome measures. Using a mixed-model factorial analysis of variance to control for irrelevant variables and to explore interaction terms, prejudice (digital versus conventional labeling) was treated as a within-subject factor while the subject group (A or B) and clinician were treated as between-subject factors. Although only the APHAB RV and BN scales showed significant labeling effects on their own, the group of tests used in this study showed a significant labeling effect as a whole (p0.01). The total influence of labeling and related interaction terms indicated labeling-related effects accounted for 2 to 32% of the variance in individual outcome measures.The results of this investigation indicate a need for double-blinding in hearing aid research aimed at assessing the effectiveness of newer technologies, as well as a need for clinicians to critically evaluate the research describing the potential advantages of certain circuit options.

To measure hearing aid performance using circuitry representative of the major eras of technological advancement during the 20th century.Twenty subjects with audiometric profiles consistent with hearing aid candidacy were fit with each of seven hearing aids. No directional microphones were used and binaural benefit was not assessed. Each hearing aid was fit to the strategy or fitting scheme of the era, or that which was intended by the presenting manufacturer. Electroacoustic and/or real ear measures of gain, output, bandwidth, and distortion were obtained. Objective outcome measures assessing speech perception in backgrounds of noise were obtained. Subjective outcome measures of sound quality and ease of listening were obtained in the laboratory and in real life settings.Electroacoustic and real ear measures indicate that gain and bandwidth have increased, and output and distortion have decreased with current electronic aids. Speech perception ability across the different outcome measures showed significantly poorer performance with the body and linear hearing aids when input levels were high; when input levels were low, outcome measures with hearing aids using a dynamic range compression were not negatively affected. At the most adverse signal to noise ratios, none of the hearing aids was shown to be superior. Measured bandwidth did not correlate highly with speech perception ability for any of the objective outcome measures used. For the subjective measures of sound quality done in a blinded manner, no significant differences were found across different listening situations for current hearing aids.The two most important factors for aided speech perception appear to be the audibility and distortion of the signal. No current compression scheme proved superior with the outcome measures used in this investigation.

The aided performance and benefit achieved with linear and two-channel wide dynamic range compression (WDRC) in-the-canal (ITC) hearing aids were established in 55 individuals. Study participants had been wearing either linear or adaptive-frequency-response (Bass Increase at Low Levels, BILL) ITC hearing aids for approximately one year before participation in this study. Outcome measures included aided performance and objective benefit in quiet and noise at a variety of speech levels (50, 60, and 75 dB SPL), at various levels of babble background (quiet, signal-to-babble ratios of +5 and +10 dB), and for various types of test materials (monosyllabic words and sentences in connected speech). Several subjective measures of aided performance (sound-quality judgments and magnitude estimates of listening effort) and relative benefit (improvement in listening effort and the Hearing Aid Performance Inventory, HAPI) were also obtained. Finally, self-report measures of hearing-aid use were also obtained using daily logs. Participants completed all outcome measures for the linear ITC hearing aids first, following 2 months of usage, and then repeated all outcome measures for the WDRC instruments after a subsequent 2-month period of use. In general, although both types of hearing aids demonstrated significant benefit, the results indicated that the WDRC instruments were superior to the linear devices for many of the outcome measures. This tended to be the case most frequently when low speech levels were used. Many of the performance differences between devices most likely can be ascribed to differences in gain, and prescriptive approaches (DSL[i/o] vs. NAL-R), for the fixed volume control testing performed in this study.

Hearing aid benefit refers to a relative change in performance on a particular measure between aided and unaided listening conditions. A number of studies in recent years have investigated the hypothesis that hearing aid benefit increases over time after the initial fitting of the aid. Both objective (speech recognition) and subjective (questionnaire) measures have been used to measure hearing aid benefit. Some studies have reported a positive increase over time in group mean benefit, and some have reported no change in benefit, whereas none have reported a group mean negative change in benefit. However, individual subjects in these studies can show changes in benefit in either a positive or negative direction. The variability across subjects in each study has been large in comparison with the observed amount of benefit increase. In this review of the literature, it is argued that the studies present essentially similar results and the range of values across subjects in the various studies shows considerable overlap. Although there does appear to be a tendency for hearing aid benefit to increase over time, there are other, much stronger, factors influencing changes in hearing aid benefit that make it impossible at present to predict which patients will show a reliable increase (or decrease) in hearing aid benefit over time.

Recently several methods for obtaining clinical measures of loudness growth through the use of categorical scaling (CS) have been proposed for the selection of hearing aids. These methods use differing test signals or suggest frequency‐specific level corrections in an attempt to reflect the loudness perception of hearing aid‐processed speech. While some decisions regarding the stimuli utilized for loudness perception procedures are based on measured relationships to speech signals, the effect on loudness perception of changing signal type and bandwidth (as measured by CS) remains unclear. The relationships between the CS loudness growth of signals of differing type, (pure tones, noise bands, filtered/temporally inverted/passband speech) and bandwidth were examined for subjects with both normal and impaired hearing. Results suggest that when the bandwidth is similar (e.g., pure tone and 1/3 oct), signal type does not have significant bearing on loudness perception. As expected, increasing the bandwidth beyond the critical band affected loudness growth, as wideband speech stimuli were judged to be significantly louder than narrow‐band speech at equivalent overall sound levels. In this investigation, similar loudness growth patterns were noted across category ratings for all test signal bandwidths. In contrast, loudness growth data obtained using an intelligible speech signal [Cox et al., The American Academy of Audiology (1994a)], revealed loudness growth patterns for speech were fundamentally different than those obtained for tones. Implications for hearing aid fitting strategies are discussed.Recently several methods for obtaining clinical measures of loudness growth through the use of categorical scaling (CS) have been proposed for the selection of hearing aids. These methods use differing test signals or suggest frequency‐specific level corrections in an attempt to reflect the loudness perception of hearing aid‐processed speech. While some decisions regarding the stimuli utilized for loudness perception procedures are based on measured relationships to speech signals, the effect on loudness perception of changing signal type and bandwidth (as measured by CS) remains unclear. The relationships between the CS loudness growth of signals of differing type, (pure tones, noise bands, filtered/temporally inverted/passband speech) and bandwidth were examined for subjects with both normal and impaired hearing. Results suggest that when the bandwidth is similar (e.g., pure tone and 1/3 oct), signal type does not have significant bearing on loudness perception. As expected, increasing the bandwidth bey...

In an earlier publication, various transformations used in hearing aid research and its application were summarized. As a result of continued interest and requests, additional transfer functions are provided in this addendum.

In a recent tutorial for the journal, Palmer et al. [J. Acoust. Soc. Am. 103, 1705–1721 (1998)] reviewed the literature on the potential for increases in hearing aid benefit over time (acclimatization). Their review might leave some readers with the impression that acclimatization has implications for the fitting and selection of hearing aids today. We (Turner and Bentler), along with two other researchers in the field (Humes and Cox), conducted a similar review of the literature a few years earlier [Turner et al., Ear and Hearing 17, 14S–28S (1996)] and found little evidence of a robust effect. The bulk of the existing evidence, including the most recent studies on this topic, support earlier conclusions, i.e., that there is no evidence for the existence of a strong acclimatization effect in current hearing aid use.

A method for computing a directivity index (DI) on a manikin for directional microphones in hearing aids is proposed and investigated. Test devices included first‐ and second‐order directional microphones in hearing aids. Signal presentation involved a single noise source rotated completely around the directional microphone, in free field and on a manikin, at a defined radius. The area covered was equivalent to the approximate surface area of a sphere. It was anticipated that an equal angular resolution of 10 deg (elevation and azimuth) would effectively estimate the DI of first‐, second‐, and higher‐order directional microphone systems located in a hearing aid on a manikin. A total of 450 spatially varied presentation points was analyzed, each weighted in reference to direction of arrival on the directional microphone. The absolute difference between the Directivity Index derived from the modified method proposed in this investigation and the conventionally derived Directivity Index on a manikin were as large as 3.8 dB in the higher frequencies, depending on the device under test. The magnitude of these differences was dependent on microphone location. In other words, the further the microphone was placed into the ear of the manikin, the larger the absolute difference.