Acquisition of auditory profiles for good and impaired hearing

Abstract

Objective: The aim of this study was to develop a user-friendly way of measuring patients’ threshold and supra-threshold hearing, with potential for application in clinical research. The end-product of these tests is a graphical profile summarizing absolute threshold, frequency selectivity, and compression characteristics across a spectrum of frequencies (0.25–6 kHz). Design: A battery of three psychophysical hearing tests consisted of measures of absolute threshold, frequency selectivity, and compression. An automated, cued, single-interval, adaptive tracking procedure was employed. The tests results were collated and used to generate a readily visualized ‘profile’ for each listener. Study sample: Participants were 83 adults (57 impaired-hearing and 26 good-hearing, age 20–75 years). Results: Listeners tolerated the tests well. Single-ear profiles were obtained in an average of 74 minutes testing time (range 46–120 minutes). The variability of individual measurements was low. Substantial differences between normal and impaired listeners and also among the impaired listeners were observed. Qualitative differences in compression and frequency-selectivity were seen that could not be predicted by threshold measurements alone. Conclusions: The hearing profiles are informative with respect to supra-threshold hearing performance and the information is easily accessible through the graphical display. Further development is required for routine use in a clinical context.     

An examination of speech reception thresholds measured in a simulated reverberant cafeteria environment

Objective: There is increasing demand in the hearing research community for the creation of laboratory environments that better simulate challenging real-world listening environments. The hope is that the use of such environments for testing will lead to more meaningful assessments of listening ability, and better predictions about the performance of hearing devices. Here we present one approach for simulating a complex acoustic environment in the laboratory, and investigate the effect of transplanting a speech test into such an environment. Design: Speech reception thresholds were measured in a simulated reverberant cafeteria, and in a more typical anechoic laboratory environment containing background speech babble. Study sample: The participants were 46 listeners varying in age and hearing levels, including 25 hearing-aid wearers who were tested with and without their hearing aids. Results: Reliable SRTs were obtained in the complex environment, but led to different estimates of performance and hearing-aid benefit from those measured in the standard environment. Conclusions: The findings provide a starting point for future efforts to increase the real-world relevance of laboratory-based speech tests.     

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

Abstract

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.     

Exploring the influence of culture on hearing help-seeking and hearing-aid uptake

Objective: The purpose of this paper was to highlight the importance of cultural influence in understanding hearing-help seeking and hearing-aid uptake. Design: Information on audiological services in different countries and ‘theories related to cross-culture’ is presented, followed by a general discussion. Study sample: Twenty-seven relevant literature reviews on hearing impairment, cross-cultural studies, and the health psychology model and others as secondary resources. Results: Despite the adverse consequences of hearing impairment and the significant potential benefits of audiological rehabilitation, only a small number of those with hearing impairment seek professional help and take up appropriate rehabilitation. Therefore, hearing help-seeking and hearing-aid uptake has recently become the hot topic for clinicians and researchers. Previous research has identified many contributing factors for hearing help-seeking with self-reported hearing disability being one of the main factors. Although significant differences in help-seeking and hearing-aid adoption rates have been reported across countries in population studies, limited literature on the influence of cross-cultural factors in this area calls for an immediate need for research. Conclusions: This paper highlights the importance of psychological models and cross-cultural research in the area of hearing help-seeking and hearing-aid uptake, and consequently some directions for future research are proposed.     

The contribution of amplitude envelope cues to sentence identification in young and aged listeners

OBJECTIVE: The purpose of this study was to examine the importance of amplitude envelope cues to sentence identification for aged listeners. We also examined the effect of increasing alterations (i.e., compression ratio) and amount of available frequency content (i.e., number of channels) for this population. DESIGN: Thirty-six listeners were classified according to their age (35 or younger versus 65 and older) and hearing status (normal hearing versus hearing impaired). Within each hearing status, mean hearing threshold thresholds for the young and aged listeners were matched as closely as possible through 4 kHz to control for sensitivity differences across age, and all listeners passed a cognitive screening battery. Accuracy of synthetic sentence identification was measured using stimuli processed to restrict spectral information. Performance was measured as a function of age, hearing status, amount of spectral information, and degradation of the amplitude envelope (using fast-acting compression with compression ratios ranging from 1:1 to 5:1). RESULTS: Mean identification scores decreased significantly with increasing age, the presence of hear- c ing loss, the removal of spectral information, and with increasing distortion of the amplitude envelope (i.e., higher compression ratios). There was a consistent performance gap between young and aged listeners, regardless of the magnitude of change to the amplitude envelope. This suggests that some cue other than amplitude envelope variations is inaccessible to the aged listeners. CONCLUSIONS: Although aged listeners performed more poorly overall, they did not show greater susceptibility to alterations in amplitude-envelope cues, such as those produced by fast-acting amplitude compression systems. It is therefore unlikely that compression parameters such as attack and release time or compression ratio would need to be a differentially programmed for aged listeners. Instead, the data suggest two possibilities: aged listeners have difficulty accessing the fine-structure temporal cues present in speech, and/or performance is degraded by age-related loss of function at a central processing level.     

Effects of cochlear impairment and equivalent-threshold masking on psychoacoustic tuning curves.

Psychoacoustic tuning curves in simultaneous masking were measured in three groups: listeners with hearing impairment of primarily cochlear origin, normal listeners with equivalent-threshold masking (ETM) and normal listeners tested in the quiet. ETM was produced by presenting a continuous back-ground noise that was spectrally shaped to yield masked thresholds within 3 dB of each impaired listener's quiet thresholds. For the tuning curves, the level of a 50-Hz-wide noise band necessary to mask a 10-dB SL tone was measured for six masker frequencies. Results under ETM indicate that the shape of the tuning curve depends not only on masked threshold at the probe frequency but also on the spectral shape of the masker. Tuning curves are abnormally broad in some impaired listeners even when the effects of their elevated thresholds, audiometric configuration and altered intensity perception are taken into account by comparisons with normal listeners with ETM.     

Evaluation of the effects of nonlinear frequency compression on speech recognition and sound quality for adults with mild to moderate hearing loss

Objective: While potentially improving audibility for listeners with considerable high frequency hearing loss, the effects of implementing nonlinear frequency compression (NFC) for listeners with moderate high frequency hearing loss are unclear. The purpose of this study was to investigate the effects of activating NFC for listeners who are not traditionally considered candidates for this technology. Design: Participants wore study hearing aids with NFC activated for a 3–4 week trial period. After the trial period, they were tested with NFC and with conventional processing on measures of consonant discrimination threshold in quiet, consonant recognition in quiet, sentence recognition in noise, and acceptableness of sound quality of speech and music. Study sample: Seventeen adult listeners with symmetrical, mild to moderate sensorineural hearing loss participated. Better ear, high frequency pure-tone averages (4, 6, and 8 kHz) were 60 dB HL or better. Results: Activating NFC resulted in lower (better) thresholds for discrimination of /s/, whose spectral center was 9 kHz. There were no other significant effects of NFC compared to conventional processing. Conclusion: These data suggest that the benefits, and detriments, of activating NFC may be limited for this population.     

Sex-specific predictors of hearing-aid use in older persons: The age,gene/environment susceptibility - Reykjavik study

Objective: We estimate the prevalence of hearing-aid use in Iceland and identify sex-specific factors associated with use. Design: Population-based cohort study. Study sample: A total of 5172 age, gene/environment susceptibility - Reykjavik study (AGES-RS) participants, aged 67 to 96 years (mean age 76.5 years), who completed air-conduction and pure-tone audiometry. Results: Hearing-aid use was reported by 23.0% of men and 15.9% of women in the cohort, although among participants with at least moderate hearing loss in the better ear (pure-tone average [PTA] of thresholds at 0.5, 1, 2, and 4 kHz ≥ 35 dB hearing level [HL]) it was 49.9% and did not differ by sex. Self-reported hearing loss was the strongest predictor of hearing-aid use in men [OR: 2.68 (95% CI: 1.77, 4.08)] and women [OR: 3.07 (95% CI: 1.94, 4.86)], followed by hearing loss severity based on audiometry. Having diabetes or osteoarthritis were significant positive predictors of use in men, whereas greater physical activity and unimpaired cognitive status were important in women. Conclusions: Hearing-aid use was comparable in Icelandic men and women with moderate or greater hearing loss. Self-recognition of hearing loss was the factor most predictive of hearing-aid use; other influential factors differed for men and women.     

Effects of hearing loss on echo thresholds

OBJECTIVE: The purpose of this investigation was to determine the effects of hearing loss on the perception of echoes. DESIGN: Echo thresholds were measured for eight listeners with normal hearing and nine listeners with impaired hearing. Pairs of 4-msec noise bursts were presented to each listener with onset-to-onset delays ranging from 2 to 16 msec. Echo thresholds were obtained at signal presentation levels of 10, 20, 30, 40, and 50 dB SL. RESULTS: Results revealed differences between the psychometric functions of the two subject groups. Psychometric functions of the subjects with impaired hearing indicated higher echo thresholds than for the subjects with normal hearing. In addition, echo thresholds at 10 dB SL were significantly higher than echo thresholds measured at 40 dB SL for both subject groups. CONCLUSION: Listeners with impaired hearing exhibit higher echo thresholds than listeners with normal hearing. The higher echo thresholds for listeners with impaired hearing may account, at least in part, for difficulty on tasks such as localization in everyday listening environments.     

Introducing real-life listening features into the clinical test environment: Part I: Measuring the hearing performance and evaluating the listening effort of individuals with normal hearing

Objective: Controlled clinical test environments are very different from real-life listening situations in which speaker and background noise level variations can hinder a person’s ability to hear and follow conversations. This study was performed to evaluate the ability of people with normal hearing to follow a single speaker in the presence of background noise, and to explore relations between those measures and the listeners’ subjective assessments, listening effort, and sound quality judgements.

Methods: A group of adults with normal hearing were evaluated using the following battery of tests: (i) Roving Level Test, (ii) the Just Understanding Speech Test, (iii) Performance Perceptual Test, (iv) the Visual Analogue Scale to evaluate listening effort, and (iv) with a sound quality questionnaire.

Results: The results show that people with normal hearing tend to accurately estimate their hearing abilities, and both the listening effort required and speech recognition thresholds tend to increase with increasing background noise.

Discussion: Implementing a battery of tests that evaluate speech-in-noise listening abilities, listening effort, and subjective hearing perception might provide greater insight into hearing performance than traditional measures. Additionally, the data generated in this study can be used for comparison with measures obtained from hearing impaired and hearing device listeners, and as such, has the potential to guide counselling and rehabilitation to a range of clinical populations.

Conclusion: The examination of both the self-estimated and verified performance measurements in simulated real-life listening situations can provide audiologists with a comprehensive and realistic profile of a person’s hearing performance.     

Semantic context improves speech intelligibility and reduces listening effort for listeners with hearing impairment

Objective: We investigated whether speech intelligibility and listening effort for hearing-aid users is affected by semantic context and hearing-aid setting. Design: Participants heard target sentences spoken in a reverberant background of cafeteria noise and competing speech. Participants reported each sentence verbally. Eight participants also rated listening effort after each sentence. Sentence topic was either the same as, or different from, the previous target sentence. Study sample: Twenty participants with sensorineural hearing loss were fit binaurally with Signia receiver-in-the-canal hearing aids. Participants performed the task twice: once using the hearing aid’s omnidirectional setting and once using the “Reverberant Room” setting, designed to aid listening in reverberant environments. Results: Participants achieved better speech intelligibility for same-topic than different-topic sentences, and when they used the “Reverberant Room” than the omnidirectional hearing-aid setting. Participants who rated effort showed a reliable reduction in listening effort for same-topic sentences and for the “Reverberant Room” hearing-aid setting. The improvement in speech intelligibility from semantic context (i.e. same-topic compared to different-topic sentences) was greater than the improvement gained from changing hearing-aid setting. Conclusions: These findings highlight the enormous potential of cognitive (specifically, semantic) factors for improving speech intelligibility and reducing perceived listening effort in noise for hearing-aid users.     

The relationship of locus of control,self-control,and acceptable noise levels for young listeners with normal hearing

Abstract

Objective: Background noise acceptance while listening to speech, assessed via the acceptable noise level (ANL) measure, has been shown to be an accurate predictor of hearing-aid success. No specific listener characteristics have been identified as being related to a listener's ability to accept background noise. The purpose of this study was to determine whether or not locus of control and self-control are related to ANL. Design: Correlational design. Study sample: Participants were seventy young adults (21 male, 49 female; aged 19 to 39 years) with normal hearing. Participants completed psychological profiles that evaluated locus of control and self-control and their ANLs were measured. Results: Results revealed correlations between ANL and self-control. Listeners with higher levels of self-control accepted more background noise than listeners with lower levels of self-control. Conclusions: This research suggests that exercises aimed at strengthening a listener's auditory self-control may lead to improved background noise acceptance. Improvement in background noise acceptance could lead to improved hearing-aid success. Future research should explore these possibilities.     

Development of a German reading span test with dual task design for application in cognitive hearing research

Objective: To report the development of a standardized German version of a reading span test (RST) with a dual task design. Special attention was paid to psycholinguistic control of the test items and time-sensitive scoring. We aim to establish our RST version to use for determining an individual's working memory in the framework of hearing research in German contexts. Design: RST stimuli were controlled and pretested for psycholinguistic factors. The RST task was to read sentences, quickly determine their plausibility, and later recall certain words to determine a listener's individual reading span. RST results were correlated with outcomes of additional sentence-in-noise tests measured in an aided and an unaided listening condition, each at two reception thresholds. Study sample: Item plausibility was pre-determined by 28 native German participants. An additional 62 listeners (45–86 years, M = 69.8) with mild-to-moderate hearing loss were tested for speech intelligibility and reading span in a multicenter study. Results: The reading span test significantly correlated with speech intelligibility at both speech reception thresholds in the aided listening condition. Conclusion: Our German RST is standardized with respect to psycholinguistic construction principles of the stimuli, and is a cognitive correlate of intelligibility in a German matrix speech-in-noise test.     

Towards a Unifying Basis of Auditory Thresholds: The Effects of Hearing Loss on Temporal Integration Reconsidered

For signal detection and identification, the auditory system needs to integrate sound over time. It is frequently assumed that the quantity ultimately integrated is sound intensity and that the integrator is located centrally. However, we have recently shown that absolute thresholds are much better specified as the temporal integral of the pressure envelope than of intensity, and we proposed that the integrator resides in the auditory pathways first synapse. We also suggested a physiologically plausible mechanism for its operation, which was ultimately derived from the specific rate of temporal integration, i.e., the decrease of threshold sound pressure levels with increasing duration. In listeners with sensorineural hearing losses, that rate seems reduced, but it is not fully understood why. Here we propose that in such listeners there may be an elevation in the baseline above which sound pressure is effective in driving the system, in addition to a reduction in sensitivity. We test this simple model using thresholds of cats to stimuli of differently shaped temporal envelopes and durations obtained before and after hearing loss. We show that thresholds, specified as the temporal integral of the effective pressure envelope, i.e., the envelope of the pressure exceeding the elevated baseline, behave almost exactly as the lower thresholds, specified as the temporal integral of the total pressure envelope before hearing loss. Thus, the mechanism of temporal integration is likely unchanged after hearing loss, but the effective portion of the stimulus is. Our model constitutes a successful alternative to the model currently favored to account for altered temporal integration in listeners with sensorineural hearing losses, viz., reduced peripheral compression. Our model does not seem to be at variance with physiological observations and it also qualitatively accounts for a number of phenomena observed in such listeners with suprathreshold stimuli.     

Effects of amplitude compression on first- and second-order modulation detection thresholds in cochlear implant listeners

The aim of this study was to examine the effects of instantaneous non-linear amplitude mapping on the detection of single-component and multicomponent temporal envelopes. To address this issue, first- and secondorder amplitude modulation detection thresholds were measured in four cochlear implant users with the intervention of the compression device of the implant processor. The compression device is set to produce either a strongly or a weakly logarithmic mapping of stimulus amplitude to electrical amplitude. ‘First-order’ modulation detection thresholds indicate the ability of listeners to detect sinusoidal amplitude modulation (SAM) applied to a white noise carrier; they are measured as a function of the rate of that modulation, f_m. ‘Second-order’ modulation detection thresholds indicate the ability to detect sinusoidal modulation applied to the depth of a sinusoidally amplitude-modulated signal (here, a 16-Hz sinusoidally amplitude-modulated white noise); they are measured as a function of the rate of the modulation applied to the modulation depth (referred to as f_m'). In each task, stimuli are transformed by the implant processor and are presented through one electrode at approximately the same level. The results show that, in cochlear implant listeners, both first- and second-order modulation detection thresholds measured at the lower rates (≤7 Hz) decrease slightly by about 3–6 dB when the stronger compression is used. No effect of compression is observed at higher rates. These results suggest that instantaneous logarithmic amplitude mapping has beneficial— but limited—effects on the detection of single-component and multicomponent temporal envelopes. These results are discussed in light of current models of temporal envelope processing.     

Hearing-aid outcomes in Chinese adults: Clinical application and psychometric properties of the Chinese version of the Satisfaction with Amplification in Daily Life questionnaire

Objective: To adapt the Satisfaction with Amplification in Daily Life questionnaire into Chinese (the SADL-CH questionnaire) and investigate hearing-aid satisfaction in a group of adult Hong Kong Chinese fitted with free hearing aids. Design: Cross-sectional survey. Study sample: One hundred and twenty-five experienced hearing-aid users. Methods: The subjects completed a history form seeking demographic data and a questionnaire combining the SADL-CH instrument with questions seeking subjects’ subjective ratings of satisfaction with some hearing-aid features and overall satisfaction with their hearing aid. Results: The SADL-CH questionnaire had a good internal consistency reliability estimate (α =?0.79) comparable to that of the original version. SADL-CH scores were observed to have significant correlations with other satisfaction ratings on some hearing-aid features and the overall satisfaction measure. A high degree of test-retest reliability (intraclass correlation coefficient =?0.79) was observed. Confirmatory factor analysis revealed that the SADL-CH questionnaire had a four-factor structure. Interim norms were derived for the SADL-CH questionnaire. The level of hearing-aid satisfaction in Chinese adults was generally lower than that reported in studies conducted among Western populations. Conclusion: The SADL-CH questionnaire is a reliable and valid instrument for measuring hearing-aid satisfaction.     

Computational Modeling of Individual Differences in Behavioral Estimates of Cochlear Nonlinearities

Temporal masking curves (TMCs) are often used to estimate cochlear compression in individuals with normal and impaired hearing. These estimates may yield a wide range of individual differences, even among subjects with similar quiet thresholds. This study used an auditory model to assess potential sources of variance in TMCs from 51 listeners in Poling et al. [J Assoc Res Otolaryngol, 13:91–108 (2012)]. These sources included threshold elevation, the contribution of outer and inner hair cell dysfunction to threshold elevation, compression of the off-frequency linear reference, and detection efficiency. Simulations suggest that detection efficiency is a primary factor contributing to individual differences in TMCs measured in normal-hearing subjects, while threshold elevation and the contribution of outer and inner hair cell dysfunction are primary factors in hearing-impaired subjects. Approximating the most compressive growth rate of the cochlear response from TMCs was achieved only in subjects with the highest detection efficiency. Simulations included off-frequency nonlinearity in basilar membrane and inner hair cell processing; however, this nonlinearity did not improve predictions, suggesting that other sources, such as the decay of masking and the strength of the medial olivocochlear reflex, may mimic off-frequency nonlinearity. Findings from this study suggest that sources of individual differences can play a strong role in behavioral estimates of compression, and these sources should be considered when using forward masking to study cochlear function in individual listeners or across groups of listeners.     

Sounds perceived as annoying by hearing-aid users in their daily soundscape

Abstract

Background: The noises in modern soundscapes continue to increase and are a major origin for annoyance. For a hearing-impaired person, a hearing aid is often beneficial, but noise and annoying sounds can result in non-use of the hearing aid, temporary or permanently. Objective: The purpose of this study was to identify annoying sounds in a daily soundscape for hearing-aid users. Design: A diary was used to collect data where the participants answered four questions per day about annoying sounds in the daily soundscape over a two-week period. Study sample: Sixty adult hearing-aid users. Results: Of the 60 participants 91% experienced annoying sounds daily when using hearing aids. The annoying sound mentioned by most users, was verbal human sounds, followed by other daily sound sources categorized into 17 groups such as TV/radio, vehicles, and machine tools. When the hearing-aid users were grouped in relation to age, hearing loss, gender, hearing-aid experience, and type of signal processing used in their hearing aids, small and only few significant differences were found when comparing their experience of annoying sounds. Conclusions: The results indicate that hearing-aid users often experience annoying sounds and improved clinical fitting routines may reduce the problem.     

Temporal intraspeech masking of plosive bursts: effects of hearing loss and frequency shaping.

PURPOSE: The purposes were (a) to compare masking of consonant bursts by adjacent vowels for listeners with and without hearing loss and (b) to determine the extent to which the temporal intraspeech masking can be reduced by a simulated hearing-aid frequency-response shaping. METHOD: Fourteen adults with sensorineural hearing loss and 10 with normal hearing participated. Seven of the participants with hearing loss had flat or gradually sloping audiograms, and 7 had steeply sloping losses. Stimuli consisted of 3 consonant bursts (/t/, /p/, /k/) presented in isolation and in vowel-consonant-vowel combinations using the vowel /a/ with formant transition information removed. Normal-hearing listeners were tested using unfiltered stimuli. Listeners with hearing loss were tested using unfiltered stimuli and stimuli filtered to approximate a hearing aid frequency response prescribed by NAL-R. All listeners were tested under earphones at the most comfortable level for the vowel stimulus. Temporal intraspeech masking was quantified as the threshold shift produced by the adjacent vowels. RESULTS: Average intraspeech masking for listeners with steeply sloping hearing loss was significantly higher than that of normal-hearing listeners and those with flat/gradually sloping losses. Greater intraspeech masking was observed for /t/ and /p/ than for /k/. On average, frequency shaping significantly reduced the amount of intraspeech masking for listeners with steeply sloping hearing losses. Even with appropriate amplification/spectral shaping, however, temporal intraspeech masking remained greater than normal for several individuals. CONCLUSION: Findings suggest that some individuals with steeply sloping losses may need additional signal processing to supplement frequency shaping to overcome the effect of temporal intraspeech masking.