The contour test of loudness perception

Test-retest reliability of cortical auditory evoked potential indices of central auditory nervous system inhibition in people with and without tinnitus

The purpose of this study was to determine the test-retest reliability of cortical auditory evoked potentials (CAEPs) called onset-offset and sensory gating CAEPs. Further, this study compared test-retest reliability across people with and without tinnitus, across different stimulus frequencies (broadband noise, 0.25 kHz, 2 kHz, 8 kHz), and across different CAEP quantification approaches. The results of this study indicated that both sensory gating and onset-offset CAEPs were reliable, however reliability was maximized under certain experimental conditions. Specifically, people with tinnitus did exhibit differences in reliability for the sensory gating CAEP, although this did depend on the bandpass filter that was used to analyze the sensory gating response. Further, reliability was the strongest when the stimulus was a broadband noise as opposed to frequency-specific tones. Regarding CAEP quantification approach, reliability was the strongest for CAEP types that were larger in amplitude and robust CAEP measurements including peak-to-peak amplitude and total response area. Overall, these findings do indicate that both the sensory gating and onset-offset CAEP are reliable for people with and without tinnitus. However, certain experimental methods can be applied to maximize reliability such as using a broadband noise stimulus and/or measuring peak-to-peak amplitude and total response area.

Convergent validity of cortical auditory evoked potential indices of central auditory nervous system inhibition in people with and without tinnitus

Tinnitus is the perception of a ringing, buzzing, or other sound without the presence of an external stimulus. Reduced central auditory nervous system inhibition is a commonly reported mechanism contributing to a person's tinnitus perception. Different cortical auditory evoked potential (CAEP) studies have supported the presence of reduced inhibition in people with tinnitus. Although previous CAEPs used to study tinnitus do broadly represent inhibitory function, it is not entirely clear if the different CAEPs present similarly within an individual. To address this gap in knowledge, the current study evaluated the convergent validity between different CAEPs that broadly reflect inhibitory function, called sensory gating and onset-offset CAEPs. Convergent validity between sensory gating and onset-offset CAEPs was evaluated as a function of participant tinnitus status, stimulus frequency, and CAEP quantification approach. The results indicated that sensory gating and onset-offset CAEP responses indicative of inhibitory function did not demonstrate strong convergent validity. Further, the strength of convergent validity did not differ between people with and without tinnitus. However, experimental factors that yielded more robust CAEPs, such as broadband stimuli, and more comprehensive measures of amplitude, such as total response area, resulted in better convergent validity compared to higher frequency stimuli and more isolated measures of amplitude like peak amplitude. Overall, these findings suggest that the specific inhibitory mechanisms represented by sensory gating and onset-offset CAEPs differ. Therefore, each CAEP may be better suited to study distinct populations and/or inhibitory functions.

Two Tests for Quantifying Aided Hearing at Low- and High-Input Levels

Under- and overamplification of sound is a common problem in hearing aid fitting. This paper describes the implementation of two new variants of the hearing in noise test for quantifying aided hearing at the lower and upper ends of the range of everyday-life sound levels. We present results from experiments carried out with 30 adult hearing aid users to determine the respective test-retest reliabilities. Participants completed a test battery consisting of the standard Danish hearing in noise test, a variant targeting the lower threshold of audibility and a variant targeting the limit of loudness discomfort. The participants completed the test battery twice for reliability analysis. The results revealed a significant difference between test and retest for both the hearing in noise test and the two hearing in noise test variants. However, the effect sizes for the differences were all very small. A calculation of Pearson correlation coefficients showed that both the hearing in noise test and the two new hearing in noise test variants had significant and strong correlations between test and retest. The within-subject standard deviations were determined to be 0.8 dB for hearing in noise test, 0.9 dB for lower-end test, and 2.2 dB for upper-end test. The findings demonstrate that both the lower-end test and upper-end test have high test-retest reliabilities, and thus can provide consistent and reliable results.

Sensory and affective dimensions in loudness perception: Insights from young adults

Traditional psychoacoustic measures often lack accuracy in diagnosing hyperacusis and other sound tolerance disorders, possibly due to their reliance on artificial stimuli and unidimensional scales. The aim of this study was to assess loudness across sensory and affective dimensions using natural sounds, drawing on pain research wherein intensity and unpleasantness are assessed separately. We hypothesized that similar distinctions apply to loudness perception. A total of 102 young adults with normal to mild hearing loss rated 32 sound stimuli (pleasant, unpleasant, neutral, and artificial) at 10 intensities (40 to 100 dBA) on sensory and affective scales. They also completed the Hyperacusis Questionnaire, the Noise Sensitivity Scale, and the Hospital Anxiety and Depression Scale. Mixed linear models indicated both correlations and dissociations between scales that varied according to intensity and valence. Louder stimuli were rated as more unpleasant, but only at high intensities. On the sensory scale, sounds were perceived as louder with increasing intensity; however, at low to moderate intensities, pleasant and neutral sounds were rated as louder, whereas at higher intensities, artificial and unpleasant stimuli were rated as louder. On the affective scale, the perception of unpleasantness also increased with intensity, but less steeply. At high intensities, artificial stimuli were rated similarly to unpleasant stimuli. Noise sensitivity scores predicted louder and more unpleasant ratings, whereas depression scores were associated with softer and less pleasant perceptions. This study highlights the need for multidimensional approaches in audiology and suggests that the integration of sensory and affective scales with natural stimuli may improve the diagnosis and treatment of sound tolerance disorders.

Audiological Characteristics of a Sample of Adults With Misophonia

PURPOSE

The aim of this study was to describe the audiological test results from a sample of 60 adults with self-reported misophonia.

METHOD

Audiological testing was completed prior to participant randomization in a controlled trial for misophonia treatment. Participants completed the Inventory of Hyperacusis Symptoms Survey (IHS), the Tinnitus and Hearing Survey (THS), the Misophonia Questionnaire (MQ), and behavioral and objective audiometric measures.

RESULTS

Hearing thresholds were less than 25 dBHL for 97% of the participants. Loudness discomfort levels for tonal stimuli suggested hyperacusis in 25% of the sample. Total scores on the IHS indicated that 12% met the clinical cutoff for hyperacusis, and, on the THS, 27% experienced problems with tinnitus, 77% experienced problems with hearing, and 53% experienced problems with sound tolerance. On the MQ, 37% indicated mild levels of misophonia and 58% indicated moderate levels. For speech-in-noise testing, a mild signal-to-noise ratio loss was present for 15% of participants. Most of the participants had present distortion product otoacoustic emissions (DPOAEs).

CONCLUSIONS

Audiological data on individuals with misophonia are lacking. In this article, we present results from audiological testing on 60 adults with self-reported misophonia. Most had normal peripheral hearing sensitivity based on pure-tone audiometry and DPOAE measures; some had difficulties with sound sensitivities and understanding speech-in-noise, self-report indicated problems with hyperacusis, tinnitus, and hearing difficulty.

Toward parametric Bayesian adaptive procedures for multi-frequency categorical loudness scaling

A series of Bayesian adaptive procedures to estimate loudness growth across a wide frequency range from individual listeners was developed, and these procedures were compared. Simulation experiments were conducted based on multinomial psychometric functions for categorical loudness scaling across ten test frequencies estimated from 61 listeners with normal hearing and 87 listeners with sensorineural hearing loss. Adaptive procedures that optimized the stimulus selection based on the interim estimates of two types of category-boundary models were tested. The first type of model was a phenomenological model of category boundaries adopted from previous research studies, while the other type was a data-driven model derived from a previously collected set of categorical loudness scaling data. An adaptive procedure without Bayesian active learning was also implemented. Results showed that all adaptive procedures provided convergent estimates of the loudness category boundaries and equal-loudness contours between 250 and 8000 Hz. Performing post hoc model fitting, using the data-driven model, on the collected data led to satisfactory accuracies, such that all adaptive procedures tested in the current study, independent of modeling approach and stimulus-selection rules, were able to provide estimates of the equal-loudness-level contours between 20 and 100 phons with root-mean-square errors typically under 6 dB after 100 trials.

Device and Fitting Protocol for a Transitional Intervention for Debilitating Hyperacusis

PURPOSE

This report describes a hearing device and corresponding fitting protocol designed for use in a transitional intervention for debilitating loudness-based hyperacusis.

METHOD

The intervention goal is to transition patients with hyperacusis from their typical counterproductive sound avoidance behaviors (i.e., sound attenuation and limited exposure to healthy low-level sounds) into beneficial sound therapy treatment that can expand their dynamic range to the point where they can tolerate everyday sounds and experience an improved quality of life. This requires a combination of counseling and sound therapy, the latter of which is provided via the hearing device technology, signal processing, and precision fitting approach described in this report. The device combines a miniature behind-the-ear sound processor and a custom earpiece designed to maximize the attenuation of external sounds. Output-limiting loudness suppression is used to restrict exposure to offending high-level sounds while unity gain amplification maximizes exposure to healthy and tolerable lower level sounds. The fitting process includes measurement of the real-ear unaided response, the real-ear measurement (REM) system noise floor, the real-ear occluded response, real-ear insertion gain, and the output limit. With these measurements, the device can achieve the prescribed unity gain needed to provide transparent access to comfortable sound levels. It also supports individualized configuration of the therapeutic noise from an on-board sound generator and adaptive output limiting based on treatment-induced increases in dynamic range.

RESULTS AND CONCLUSION

The utility of this device and fitting protocol, in combination with structured counseling, is highlighted in the outcomes of a successful 6-month trial of the transitional intervention described in a companion report in this issue.

Results of a 6-Month Field Trial of a Transitional Intervention for Debilitating Hyperacusis

PURPOSE

We present results from a 6-month field trial of a transitional intervention for debilitating primary hyperacusis, including a combination of structured counseling; promotion of safe, comfortable, and healthy sound exposure; and therapeutic broadband sound from sound generators. This intervention is designed to overcome barriers to successful delivery of therapeutic sound as a tool to downregulate neural hyperactivity in the central auditory pathways (i.e., the maladaptive mechanism believed to account for primary hyperacusis) and, together with the counseling, reduce the associated negative emotional and physiological reactions to debilitating hyperacusis.

METHOD

Twelve adults with normal or near-normal audiometric thresholds, complaints consistent with their pretreatment loudness discomfort levels ≤ 75 dB HL at multiple frequencies, and hearing questionnaire scores ≥ 24 completed the sound therapy-based intervention. The low-level broadband therapeutic sound was delivered by ear-level devices fitted bilaterally with either occluding earpieces and output-limiting loudness suppression (LS; to limit exposure to offensive sound levels) or open domes to maximize comfort and exposure to sound therapy. Thresholds for LS (primary outcome) were incrementally adjusted across six monthly visits based on treatment-driven change in loudness judgments for running speech in sound field. Secondary outcomes included categorical loudness judgments, speech understanding, and questionnaires to assess the hyperacusis problem, quality of life, and depression. An exit survey assessed satisfaction with and benefit from the intervention and the counseling, therapeutic sound, and LS components.

RESULTS

The mean change in LS (34.8 dB) was highly significant (effect size = 2.045). Eleven of 12 participants achieved ≥ 16-dB change in LS, consistent with highly significant change in sound-based questionnaire scores. Exit surveys indicated satisfaction with and benefit from the intervention.

CONCLUSION

The transitional intervention was successful in improving the hyperacusis conditions of 11 of 12 study participants while reducing their sound avoidance behaviors and reliance on sound protection.

The human pupil and face encode sound affect and provide objective signatures of tinnitus and auditory hypersensitivity disorders

Sound is jointly processed along acoustic and emotional dimensions. These dimensions can become distorted and entangled in persons with sensory disorders, producing a spectrum of loudness hypersensitivity, phantom percepts, and - in some cases - debilitating sound aversion. Here, we looked for objective signatures of disordered hearing (DH) in the human face. Pupil dilations and micro facial movement amplitudes scaled with sound valence in neurotypical listeners but not DH participants with chronic tinnitus (phantom ringing) and sound sensitivity. In DH participants, emotionally evocative sounds elicited abnormally large pupil dilations but blunted and invariant facial reactions that jointly provided an accurate prediction of individual tinnitus and hyperacusis questionnaire handicap scores. By contrast, EEG measures of central auditory gain identified steeper neural response growth functions but no association with symptom severity. These findings highlight dysregulated affective sound processing in persons with bothersome tinnitus and sound sensitivity disorders and introduce approaches for their objective measurement.

Development and Evaluation of a Loudness Validation Method With Natural Signals for Hearing Aid Fitting

Loudness is a fundamental dimension of auditory perception. When hearing impairment results in a loudness deficit, hearing aids are typically prescribed to compensate for this. However, the relationship between an individual's specific hearing impairment and the hearing aid fitting strategy used to address it is usually not straightforward. Various iterations of fine-tuning and troubleshooting by the hearing care professional are required, based largely on experience and the introspective feedback from the hearing aid user. We present the development of a new method for validating an individual's loudness perception of natural signals relative to a normal-hearing reference. It is a measurement method specifically designed for the situation typically encountered by hearing care professionals, namely, with hearing-impaired individuals in the free field with their hearing aids in place. In combination with the qualitative user feedback that the measurement is fast and that its results are intuitively displayed and easily interpretable, the method fills a gap between existing tools and is well suited to provide concrete guidance and orientation to the hearing care professional in the process of individual gain adjustment.

Hyperacusis Diagnosis and Management in the United States: Clinical Audiology Practice Patterns

PURPOSE

Hyperacusis often leads to debilitating psychosocial consequences, but there is no standard protocol for its diagnosis and management in the United States. In this study, we surveyed U.S. clinical audiologists to understand their education and clinical practices surrounding the evaluation and treatment of hyperacusis.

METHOD

An online survey was distributed to clinical audiologists across the United States. Survey responses were quantified using descriptive statistics and inductive content analysis.

RESULTS

Hyperacusis definitions and clinical practice patterns varied widely across the 102 respondents. Respondents cited a lack of education and training as the primary barrier to effective audiological diagnosis and management of hyperacusis, with most respondents reporting ≤ 5 hr of hyperacusis education. Other primary barriers to effective audiological management of hyperacusis included time constraints, reimbursement, poor sensitivity and specificity of available diagnostic tools, and poor efficacy of available treatments and management strategies. Most respondents (82.5%) agreed that audiologists are the primary professionals who are responsible for implementing hyperacusis interventions. However, 63.3% of respondents reported that their clinic does not have a hyperacusis management protocol, and 80.0% routinely recommend treatment that is outside their scope of practice to implement (cognitive behavioral therapy).

CONCLUSIONS

Clinical audiologists in the United States do not receive uniform education on hyperacusis, and they report multiple barriers to its evidence-based diagnosis and management. Effective hyperacusis management necessitates a multidisciplinary approach. The information obtained via this survey will pave the way toward the refinement of interprofessional education programs and the development of systematic, evidence-based clinical protocols for hyperacusis.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.24431188.

Sound Level Changes the Auditory Cortical Activation Detected with Functional Near-Infrared Spectroscopy

BACKGROUND

Functional near-infrared spectroscopy (fNIRS) is a viable non-invasive technique for functional neuroimaging in the cochlear implant (CI) population; however, the effects of acoustic stimulus features on the fNIRS signal have not been thoroughly examined. This study examined the effect of stimulus level on fNIRS responses in adults with normal hearing or bilateral CIs. We hypothesized that fNIRS responses would correlate with both stimulus level and subjective loudness ratings, but that the correlation would be weaker with CIs due to the compression of acoustic input to electric output.

METHODS

Thirteen adults with bilateral CIs and 16 with normal hearing (NH) completed the study. Signal-correlated noise, a speech-shaped noise modulated by the temporal envelope of speech stimuli, was used to determine the effect of stimulus level in an unintelligible speech-like stimulus between the range of soft to loud speech. Cortical activity in the left hemisphere was recorded.

RESULTS

Results indicated a positive correlation of cortical activation in the left superior temporal gyrus with stimulus level in both NH and CI listeners with an additional correlation between cortical activity and perceived loudness for the CI group. The results are consistent with the literature and our hypothesis.

CONCLUSIONS

These results support the potential of fNIRS to examine auditory stimulus level effects at a group level and the importance of controlling for stimulus level and loudness in speech recognition studies. Further research is needed to better understand cortical activation patterns for speech recognition as a function of both stimulus presentation level and perceived loudness.

Effect of Realistic Test Conditions on Perception of Speech, Music, and Binaural Cues in Normal-Hearing Listeners

PURPOSE

The purpose of this study was to determine the feasibility of online testing in a quiet room for three auditory perception experiments in normal-hearing listeners: speech, music, and binaural cue.

METHOD

Under Experiment 1, sentence perception was measured using fixed signal-to-noise ratios (SNRs: +10 dB, 0 dB, and -10 dB) and using adaptive speech reception threshold (SRT) procedures. The correct scores were compared between quiet room and soundproof booth listening environments. Experiment 2 was designed to compare melodic contour identification between the two listening environments. Melodic contour identification was assessed with 1, 2, and 4 semitone spacings. Under Experiment 3, interaural level difference (ILD) and interaural time differences (ITD) were measured as a function of carrier frequency. For both measures, two modulated tones (400-ms duration and 100-Hz modulation rate) were sequentially presented through headphones to both ears, and subjects were asked to indicate whether the sound moved to the left or right ear. The measured ITD and ILD were then compared between the two listening environments.

RESULTS

There were no significant differences in any outcome measures (SNR- and SRT-based speech perception, melodic contour identification, and ITD/ILD) between the two listening environments.

CONCLUSIONS

These results suggest that normal-hearing listeners may not require a controlled listening environment in any of the three auditory assessments. As comparable data can be obtained via the online testing tool, using the online auditory experiments is recommended.

Acoustic deprivation modulates central gain in human auditory brainstem and cortex

Beyond reduced audibility, there is convincing evidence that the auditory system adapts according to the principles of homeostatic plasticity in response to a hearing loss. Such compensatory changes include modulation of central auditory gain mechanisms. Earplugging is a common experimental method that has been used to introduce a temporary, reversible hearing loss that induces changes consistent with central gain modulation. In the present study, young, normal-hearing adult participants wore a unilateral earplug for two weeks, during which we measured changes in the acoustic reflex threshold (ART), loudness perception, and cortically-evoked (40 Hz) auditory steady-state response (ASSR) to assess potential modulation in central gain with reduced peripheral input. The ART decreased on average by 8 to 10 dB during the treatment period, with modest increases in loudness perception after one week but not after two weeks of earplug use. Significant changes in both the magnitude and hemispheric laterality of source-localized cortical ASSR measures revealed asymmetrical changes in stimulus-driven cortical activity over time. The ART results following unilateral earplugging are consistent with the literature and suggest that homeostatic plasticity is evident in the brainstem. The novel findings from the cortical ASSR in the present study indicates that reduced peripheral input induces adaptive homeostatic plasticity reflected as both an increase in central gain in the auditory brainstem and reduced cortical activity ipsilateral to the deprived ear. Both the ART and the novel use of the 40-Hz ASSR provide sensitive measures of central gain modulation in the brainstem and cortex of young, normal hearing listeners, and thus may be useful in future studies with other clinical populations.

Effects of reverberation on speech intelligibility in noise for hearing-impaired listeners

Reverberation can have a strong detrimental effect on speech intelligibility in noise. Two main monaural effects were studied here: the temporal smearing of the target speech, which makes the speech less understandable, and the temporal smearing of the noise, which reduces the opportunity for listening in the masker dips. These phenomena have been shown to affect normal-hearing (NH) listeners. The aim of this study was to understand whether hearing-impaired (HI) listeners are more affected by reverberation, and if so to identify which of these two effects is responsible. They were investigated separately and in combination, by applying reverberation either on the target speech, on the noise masker, or on both sources. Binaural effects were not investigated here. Intelligibility scores in the presence of stationary and modulated noise were systematically compared for both NH and HI listeners in these situations. At the optimal signal-to-noise ratios (SNRs) (that is to say, the SNRs with the least amount of floor and ceiling effects), the temporal smearing of both the speech and the noise had a similar effect for the HI and NH listeners, so that reverberation was not more detrimental for the HI listeners. There was only a very limited dip listening benefit at this SNR for either group. Some differences across group appeared at the SNR maximizing dip listening, but they could not be directly related to an effect of reverberation, and were rather due to floor effects or to the reduced ability of the HI listeners to benefit from dip listening, even in the absence of reverberation.

Effects of reverberation on speech intelligibility in noise for hearing-impaired listeners

Reverberation can have a strong detrimental effect on speech intelligibility in noise. Two main monaural effects were studied here: the temporal smearing of the target speech, which makes the speech less understandable, and the temporal smearing of the noise, which reduces the opportunity for listening in the masker dips. These phenomena have been shown to affect normal-hearing (NH) listeners. The aim of this study was to understand whether hearing-impaired (HI) listeners are more affected by reverberation, and if so to identify which of these two effects is responsible. They were investigated separately and in combination, by applying reverberation either on the target speech, on the noise masker, or on both sources. Binaural effects were not investigated here. Intelligibility scores in the presence of stationary and modulated noise were systematically compared for both NH and HI listeners in these situations. At the optimal signal-to-noise ratios (SNRs) (that is to say, the SNRs with the least amount of floor and ceiling effects), the temporal smearing of both the speech and the noise had a similar effect for the HI and NH listeners, so that reverberation was not more detrimental for the HI listeners. There was only a very limited dip listening benefit at this SNR for either group. Some differences across group appeared at the SNR maximizing dip listening, but they could not be directly related to an effect of reverberation, and were rather due to floor effects or to the reduced ability of the HI listeners to benefit from dip listening, even in the absence of reverberation.

Clinical and investigational tools for monitoring noise-induced hyperacusis

Hyperacusis is a recognized perceptual consequence of acoustic overexposure that can lead to debilitating psychosocial effects. Despite the profound impact of hyperacusis on quality of life, clinicians and researchers lack objective biomarkers and standardized protocols for its assessment. Outcomes of conventional audiologic tests are highly variable in the hyperacusis population and do not adequately capture the multifaceted nature of the condition on an individual level. This presents challenges for the differential diagnosis of hyperacusis, its clinical surveillance, and evaluation of new treatment options. Multiple behavioral and objective assays are emerging as contenders for inclusion in hyperacusis assessment protocols but most still await rigorous validation. There remains a pressing need to develop tools to quantify common nonauditory symptoms, including annoyance, fear, and pain. This review describes the current literature on clinical and investigational tools that have been used to diagnose and monitor hyperacusis, as well as those that hold promise for inclusion in future trials.

Self-Adjustment of Hearing Aid Amplification for Lower Speech Levels: Independent Ratings, Paired Comparisons, and Speech Recognition

PURPOSE

Self-adjustment of hearing aid amplification enables wearers to customize the hearing aid output to match their preferences and could become an important tool for programming direct-to-consumer devices for people with mild-to-moderate hearing loss. One risk is that user-selected settings may provide inadequate audibility. This study assessed that risk by quantifying relationships between self-adjusted settings, subjective preferences, and speech recognition performance using speech at low levels in quiet, where achieving high speech audibility requires sufficient amplification.

METHOD

Fifteen people with symmetric, mild-to-moderate sensorineural hearing loss self-adjusted hearing aid amplification while listening to speech in quiet at 45, 55, and 65 dBA. After self-adjustment, 11 participants made blinded ratings of their self-adjusted fit, their NAL-NL2 prescriptive fit, and experimenter-created fits with reduced gain. Participants completed blinded paired comparisons and sentence recognition assessments using these settings.

RESULTS

The gain of self-adjusted fits showed a large range of variability between participants. On average, self-adjusted gain was similar to NAL-NL2 prescribed gain for input signals of 55 dBA and slightly greater than prescribed gain for 45-dBA signals. Speech recognition scores for NAL-NL2 fits were consistently high, and differences in speech recognition results were strongly correlated with the overall preferences obtained from paired comparisons.

CONCLUSIONS

Self-adjusted fits are highly variable between individuals for low-audibility conditions. Nonetheless, self-adjusted fits are at least as satisfactory as NAL-NL2 fits, and listeners tend to disfavor settings that result in poorer speech recognition. The findings argue against concerns that self-adjustment will result in inadequate audibility compared to prescribed settings.

Estimated cochlear neural degeneration is associated with loudness hypersensitivity in individuals with normal audiograms

In animal models, cochlear neural degeneration (CND) is associated with excess central gain and hyperacusis, but a compelling link between reduced cochlear neural inputs and heightened loudness perception in humans remains elusive. The present study examined whether greater estimated cochlear neural degeneration (eCND) in human participants with normal hearing thresholds is associated with heightened loudness perception and sound aversion. Results demonstrated that loudness perception was heightened in ears with greater eCND and in subjects who self-report loudness aversion via a hyperacusis questionnaire. These findings suggest that CND may be a potential trigger for loudness hypersensitivity.

Audiologic Assessment

Prior to the fitting of hearing aids, clinicians and patients must discuss the best treatment options for the physical and audiologic needs of the patients. To be able to confidently make these decisions, the clinician should complete a medical and audiological case history. Additionally, clinicians need accurate results from a comprehensive audiologic evaluation. The evaluation should include the following: pure-tone testing, word recognition testing, speech-in-noise testing, and loudness discomfort level measures. This article will outline the process and procedures for acquiring this information in line with the Audiology Practice Standards Organization (APSO) Guidelines for Adult Hearing Aid Fittings Standards 1 and 4. This article will also discuss how results can affect decision-making during the hearing aid selection and fitting process.

Clinical Practice Patterns With Pediatric Loudness Perception Measures

PURPOSE

Obtaining a patient's loudness discomfort level (LDL) can assist the audiologist in defining their dynamic range so that the hearing device fitting can ensure that low-level sounds are audible, average-level sounds are comfortable, and more intense sounds are loud but not too loud. A 2016 survey showed that 67.5% of 350 pediatric audiologist reported to never or rarely measure LDLs with pediatric patients. The purpose of this study was to identify factors influencing this previously reported limited use of LDL measures.

METHOD

Sixty-two pediatric audiologists in the United States were surveyed using a questionnaire that sought to improve our understanding of the (non)use of loudness perception measures with pediatric patients and to assess familiarity with various loudness perception measurements. In addition, the questionnaire gathered information about the needs of pediatric audiologists in relation to LDL measures.

RESULTS

Audiologist report being largely unfamiliar with methods of assessing loudness perception in children, with categorical loudness scaling being the method with which they are most familiar. In addition, audiologists reported being more willing and able to measure LDLs in older compared to younger pediatric patients. Limited use of pediatric loudness perception measures appears to be driven by a lack of familiarity with measurement methods and the belief that loudness perception measures may not be useful for clinical practice.

CONCLUSIONS

Findings highlight audiologists' need for further information regarding the relevance of loudness perception measurements with pediatric patients and the need for easy-to-implement LDL measurement procedures for pediatric patients of all ages.

Evaluation of Remote Categorical Loudness Scaling

PURPOSE

The aims of this study were to (a) demonstrate the feasibility of administering categorical loudness scaling (CLS) tests in a remote setting, (b) assess the reliability of remote compared with laboratory CLS results, and (c) provide preliminary evidence of the validity of remote CLS testing.

METHOD

CLS data from 21 adult participants collected in a home setting were compared to CLS data collected in a laboratory setting from previous studies. Five participants took part in studies in both settings. Precalibrated equipment was delivered to participants who performed headphone output level checks and measured ambient noise levels. After a practice run, CLS measurements were collected for two runs at 1 and 4 kHz.

RESULTS

Mean headphone output levels were within 1.5 dB of the target calibration level. Mean ambient noise levels were below the target level. Within-run variability was similar between the two settings, but across-run bias was smaller for data collected in the laboratory setting compared with the remote setting. Systematic differences in CLS functions were not observed for the five individuals who participated in both settings.

CONCLUSIONS

This study demonstrated that precise stimulus levels can be delivered and background noise levels can be controlled in a home environment. Across-run bias for remote CLS was larger than for in-laboratory CLS, indicating that further work is needed to improve the reliability of CLS data collected in remote settings. Supplemental Material https://doi.org/10.23641/asha.17131856.

AudioChip: A Deep Phenotyping Approach for Deconstructing and Quantifying Audiological Phenotypes of Self-Reported Speech Perception Difficulties

OBJECTIVES

About 15% of U.S. adults report speech perception difficulties despite showing normal audiograms. Recent research suggests that genetic factors might influence the phenotypic spectrum of speech perception difficulties. The primary objective of the present study was to describe a conceptual framework of a deep phenotyping method, referred to as AudioChipping, for deconstructing and quantifying complex audiometric phenotypes.

DESIGN

In a sample of 70 females 18 to 35 years of age with normal audiograms (from 250 to 8000 Hz), the study measured behavioral hearing thresholds (250 to 16,000 Hz), distortion product otoacoustic emissions (1000 to 16,000 Hz), click-evoked auditory brainstem responses (ABR), complex ABR (cABR), QuickSIN, dichotic digit test score, loudness discomfort level, and noise exposure background. The speech perception difficulties were evaluated using the Speech, Spatial, and Quality of Hearing Scale-12-item version (SSQ). A multiple linear regression model was used to determine the relationship between SSQ scores and audiometric measures. Participants were categorized into three groups (i.e., high, mid, and low) using the SSQ scores before performing the clustering analysis. Audiometric measures were normalized and standardized before performing unsupervised k-means clustering to generate AudioChip.

RESULTS

The results showed that SSQ and noise exposure background exhibited a significant negative correlation. ABR wave I amplitude, cABR offset latency, cABR response morphology, and loudness discomfort level were significant predictors for SSQ scores. These predictors explained about 18% of the variance in the SSQ score. The k-means clustering was used to split the participants into three major groups; one of these clusters revealed 53% of participants with low SSQ.

CONCLUSIONS

Our study highlighted the relationship between SSQ and auditory coding precision in the auditory brainstem in normal-hearing young females. AudioChip was useful in delineating and quantifying internal homogeneity and heterogeneity in audiometric measures among individuals with a range of SSQ scores. AudioChip could help identify the genotype-phenotype relationship, document longitudinal changes in auditory phenotypes, and pair individuals in case-control groups for the genetic association analysis.

Effect of the Target and Conflicting Frequency and Time Ranges on Consonant Enhancement in Normal-Hearing Listeners

In this paper, the effects of intensifying useful frequency and time regions (target frequency and time ranges) and the removal of detrimental frequency and time regions (conflicting frequency and time ranges) for consonant enhancement were determined. Thirteen normal-hearing (NH) listeners participated in two experiments. In the first experiment, the target and conflicting frequency and time ranges for each consonant were identified under a quiet, dichotic listening condition by analyzing consonant confusion matrices. The target frequency range was defined as the frequency range that provided the highest performance and was decreased 40% from the peak performance from both high-pass filtering (HPF) and low-pass filtering (LPF) schemes. The conflicting frequency range was defined as the frequency range that yielded the peak errors of the most confused consonants and was 20% less than the peak error from both filtering schemes. The target time range was defined as a consonant segment that provided the highest performance and was decreased 40% from that peak performance when the duration of the consonant was systematically truncated from the onset. The conflicting time ranges were defined on the coincided target time range because, if they temporarily coincide, the conflicting frequency ranges would be the most detrimental factor affecting the target frequency ranges. In the second experiment, consonant recognition was binaurally measured in noise under three signal processing conditions: unprocessed, intensified target ranges by a 6-dB gain (target), and combined intensified target and removed conflicting ranges (target-conflicting). The results showed that consonant recognition improved significantly with the target condition but greatly deteriorated with a target-conflicting condition. The target condition helped transmit voicing and manner cues while the target-conflicting condition limited the transmission of these cues. Confusion analyses showed that the effect of the signal processing on consonant improvement was consonant-specific: the unprocessed condition was the best for /da, pa, ma, sa/; the target condition was the best for /ga, fa, va, za, ʒa/; and the target-conflicting condition was the best for /na, ʃa/. Perception of /ba, ta, ka/ was independent of the signal processing. The results suggest that enhancing the target ranges is an efficient way to improve consonant recognition while the removal of conflicting ranges negatively impacts consonant recognition.

Evaluation and Management of Misophonia Using a Hybrid Telecare Approach: A Case Report

Decreased sound tolerance (DST) is a negative reaction to environmental sounds and is estimated to affect 3.5% of the population. This case report presents the evaluation and management of an adult female with severe, longstanding misophonia. Her evaluation included comprehensive audiometric testing (including uncomfortable loudness levels) and a detailed assessment of the impact of DST on her life. She enrolled in tinnitus retraining therapy and began receiving treatment aiming to facilitate habituation of bothersome environmental sounds. This case was complicated by the advent of the coronavirus disease 2019 (COVID-19) pandemic and a telemedicine hybrid approach was employed to increase access to audiologic care. Using this structure, some appointments occurred in person in the clinic and others occurred via a telemedicine video visit format. Telemedicine video visits facilitated in-depth discussions, afforded the opportunity to answer questions, and provided the option of cloud-based remote programming of on-ear devices. Future care will continue to employ a hybrid approach.

Deficit or Difference? Effects of Altered Auditory Feedback on Speech Fluency and Kinematic Variability in Adults Who Stutter

Purpose The purpose of this study was to test whether adults who stutter (AWS) display a different range of sensitivity to delayed auditory feedback (DAF). Two experiments were conducted to assess the fluency of AWS under long-latency DAF and to test the effect of short-latency DAF on speech kinematic variability in AWS. Method In Experiment 1, 15 AWS performed a conversational speaking task under nonaltered auditory feedback and 250-ms DAF. The rates of stuttering-like disfluencies, other disfluencies, and speech errors and articulation rate were compared. In Experiment 2, 13 AWS and 15 adults who do not stutter (AWNS) read three utterances under four auditory feedback conditions: nonaltered auditory feedback, amplified auditory feedback, 25-ms DAF, and 50-ms DAF. Across-utterance kinematic variability (spatiotemporal index) and within-utterance variability (percent determinism and stability) were compared between groups. Results In Experiment 1, under 250-ms DAF, the rate of stuttering-like disfluencies and speech errors increased significantly, while articulation rate decreased significantly in AWS. In Experiment 2, AWS exhibited higher kinematic variability than AWNS across the feedback conditions. Under 25-ms DAF, the spatiotemporal index of AWS decreased significantly compared to the other feedback conditions. AWS showed lower overall percent determinism than AWNS, but their percent determinism increased under 50-ms DAF to approximate that of AWNS. Conclusions Auditory feedback manipulations can alter speech fluency and kinematic variability in AWS. Longer latency auditory feedback delays induce speech disruptions, while subtle auditory feedback manipulations potentially benefit speech motor control. Both AWS and AWNS are susceptible to auditory feedback during speech production, but AWS appear to exhibit a distinct continuum of sensitivity.

Detection, Speech Recognition, Loudness, and Preference Outcomes With a Direct Drive Hearing Aid: Effects of Bandwidth

Direct drive hearing devices, which deliver a signal directly to the middle ear by vibrating the tympanic membrane via a lens placed in contact with the umbo, are designed to provide an extension of audible bandwidth, but there are few studies of the effects of these devices on preference, speech intelligibility, and loudness. The current study is the first to compare aided speech understanding between narrow and extended bandwidth conditions for listeners with hearing loss while fitted with a direct drive hearing aid system. The study also explored the effect of bandwidth on loudness perception and investigated subjective preference for bandwidth. Fifteen adult hearing aid users with symmetrical sensorineural hearing loss participated in a prospective, within-subjects, randomized single-blind repeated-measures study. Participants wore the direct drive hearing aids for 4 to 15 weeks (average 6 weeks) prior to outcome measurement. Outcome measures were completed in various bandwidth conditions achieved by reducing the gain of the device above 5000 Hz or by filtering the stimuli. Aided detection thresholds provided evidence of amplification to 10000 Hz. A significant improvement was found in high-frequency consonant detection and recognition, as well as for speech in noise performance in the full versus narrow bandwidth conditions. Subjective loudness ratings increased with provision of the full bandwidth available; however, real-world trials showed most participants were able to wear the full bandwidth hearing aids with only small adjustments to the prescription method. The majority of participants had either no preference or a preference for the full bandwidth setting.

Consistency of Hearing Aid Setting Preference in Simulated Real-World Environments: Implications for Trainable Hearing Aids

Trainable hearing aids let users fine-tune their hearing aid settings in their own listening environment: Based on consistent user-adjustments and information about the acoustic environment, the trainable aids will change environment-specific settings to the user's preference. A requirement for effective fine-tuning is consistency of preference for similar settings in similar environments. The aim of this study was to evaluate consistency of preference for settings differing in intensity, gain-frequency slope, and directionality when listening in simulated real-world environments and to determine if participants with more consistent preferences could be identified based on profile measures. A total of 52 adults (63-88 years) with hearing varying from normal to a moderate sensorineural hearing loss selected their preferred setting from pairs differing in intensity (3 or 6 dB), gain-frequency slope (±1.3 or ± 2.7 dB/octave), or directionality (omnidirectional vs. cardioid) in four simulated real-world environments: traffic noise, a monologue in traffic noise at 5 dB signal-to-noise ratio, and a dialogue in café noise at 5 and at 0 dB signal-to-noise ratio. Forced-choice comparisons were made 10 times for each combination of pairs of settings and environment. Participants also completed nine psychoacoustic, cognitive, and personality measures. Consistency of preference, defined by a setting preferred at least 9 out of 10 times, varied across participants. More participants obtained consistent preferences for larger differences between settings and less difficult environments. The profile measures did not predict consistency of preference. Trainable aid users could benefit from counselling to ensure realistic expectations for particular adjustments and listening situations.

The hearing health of live-music sound engineers

Most studies of hearing loss prevention in the music industry focus on the risk of hearing injury to musicians. However, live-music sound engineers (LMSE) may also be at risk of hearing injury due to their work-related sound exposure. We studied 27 LMSE, all of whom underwent otologic examination, including audiometry, distortion product otoacoustic emissions, speech discrimination and uncomfortable loudness levels, and completed a questionnaire investigating their history of sound exposure and use of hearing protectors. Hearing thresholds were significantly poorer than normative data across several frequencies, and a substantial proportion reported constant tinnitus (30%) and reduced sound tolerance (41%). Use of hearing protection was relatively low, with many reporting interference with their job when using it. Our results suggest that LMSE are at risk of hearing injury due to their work-related sound exposure.

Understanding Variability in Individual Response to Hearing Aid Signal Processing in Wearable Hearing Aids

OBJECTIVES

Previous work has suggested that individual characteristics, including amount of hearing loss, age, and working memory ability, may affect response to hearing aid signal processing. The present study aims to extend work using metrics to quantify cumulative signal modifications under simulated conditions to real hearing aids worn in everyday listening environments. Specifically, the goal was to determine whether individual factors such as working memory, age, and degree of hearing loss play a role in explaining how listeners respond to signal modifications caused by signal processing in real hearing aids, worn in the listener's everyday environment, over a period of time.

DESIGN

Participants were older adults (age range 54-90 years) with symmetrical mild-to-moderate sensorineural hearing loss. We contrasted two distinct hearing aid fittings: one designated as mild signal processing and one as strong signal processing. Forty-nine older adults were enrolled in the study and 35 participants had valid outcome data for both hearing aid fittings. The difference between the two settings related to the wide dynamic range compression and frequency compression features. Order of fittings was randomly assigned for each participant. Each fitting was worn in the listener's everyday environments for approximately 5 weeks before outcome measurements. The trial was double blind, with neither the participant nor the tester aware of the specific fitting at the time of the outcome testing. Baseline measures included a full audiometric evaluation as well as working memory and spectral and temporal resolution. The outcome was aided speech recognition in noise.

RESULTS

The two hearing aid fittings resulted in different amounts of signal modification, with significantly less modification for the mild signal processing fitting. The effect of signal processing on speech intelligibility depended on an individual's age, working memory capacity, and degree of hearing loss. Speech recognition with the strong signal processing decreased with increasing age. Working memory interacted with signal processing, with individuals with lower working memory demonstrating low speech intelligibility in noise with both processing conditions, and individuals with higher working memory demonstrating better speech intelligibility in noise with the mild signal processing fitting. Amount of hearing loss interacted with signal processing, but the effects were small. Individual spectral and temporal resolution did not contribute significantly to the variance in the speech intelligibility score.

CONCLUSIONS

When the consequences of a specific set of hearing aid signal processing characteristics were quantified in terms of overall signal modification, there was a relationship between participant characteristics and recognition of speech at different levels of signal modification. Because the hearing aid fittings used were constrained to specific fitting parameters that represent the extremes of the signal modification that might occur in clinical fittings, future work should focus on similar relationships with more diverse types of signal processing parameters.

Speech recognition, loudness, and preference with extended bandwidth hearing aids for adult hearing aid users

Objective: In contrast to the past, some current hearing aids can provide gain for frequencies above 4-5 kHz. This study assessed the effect of wider bandwidth on outcome measures using hearing aids fitted with the DSL v5.0 prescription.Design: There were two conditions: an extended bandwidth condition, for which the maximum available bandwidth was provided, and a restricted bandwidth condition, in which gain was reduced for frequencies above 4.5 kHz. Outcome measures were assessed in both conditions.Study sample: Twenty-four participants with mild-to-moderately-severe sensorineural high-frequency sloping hearing loss.Results: Providing extended bandwidth resulted in maximum audible output frequency values of 7.5 kHz on average for an input level of 65 dB SPL. An improvement in consonant discrimination scores (4.1%), attributable to better perception of /s/, /z/, and /t/ phonemes, was found in the extended bandwidth condition, but no significant change in loudness perception or preferred listening levels was found. Most listeners (79%) had either no preference (33%) or some preference for the extended bandwidth condition (46%).Conclusions: The results suggest that providing the maximum bandwidth available with modern hearing aids fitted with DSL v5.0, using targets from 0.25 to 8 kHz, can be beneficial for the tested population.

Listening to music while running alters ground reaction forces: a study of acute exposure to varying speed and loudness levels in young women and men

PURPOSE

Music listening while running enhances physiological and psychological features, resulting in a more enjoyable experience. The possible influence of music on ground reaction forces (GRF) during running, however, is unknown. Considering the 'distracting' role of music on runner's attention, we hypothesized that music would cover foot impacts against the ground. This study verified such hypothesis by testing the effects of different music volumes while running at different velocities.

METHODS

Fifty fit volunteers (F:M = 22:8; 23 ± 2 years) performed 2-min running stints over 3 random conditions (80-dB, 85-dB music; 'no music'), at 3 velocities (8, 10, 12 km/h). Participants ran on a sensorized treadmill that recorded GRF during all experiments.

RESULTS

Listening to 85-dB music resulted in greater GRF at 8 (p = 0.0005) and 10 km/h (p = 0.04) but not 12 km/h (p = 0.35) and not with 80-dB volume. Gender-based analyses revealed significant Condition × gender interactions only for 85-dB music vs. 'no music'. Bonferroni-adjusted comparisons revealed significant music-induced increases in GRF only in men at 8 km/h (+ 4.1 kg/cm², p < 0.0005; women: + 0.8 kg/cm², p = 0.47) and 10 km/h (+ 3.3 kg/cm², p = 0.004; women: + 0.8 kg/cm², p = 0.51) but not at 12 km/h.

CONCLUSION

In active men, listening to loud music while running results in increased GRF, whereas no effect was observed in women. The lack of music effect in women may be related to structural factors, such as larger hip width-to-femoral length ratio, possibly resulting in different loading patterns. The present preliminary findings introduce high-volume music listening as a new potential risk factor for injury in young runners.

Activation in human auditory cortex in relation to the loudness and unpleasantness of low-frequency and infrasound stimuli

Low frequency noise (LFS) and infrasound (IS) are controversially discussed as potential causes of annoyance and distress experienced by many people. However, the perception mechanisms for IS in the human auditory system are not completely understood yet. In the present study, sinusoids at 32 Hz (at the lower limit of melodic pitch for tonal stimulation), as well as 8 Hz (IS range) were presented to a group of 20 normal hearing subjects, using monaural stimulation via a loudspeaker sound source coupled to the ear canal by a long silicone rubber tube. Each participant attended two experimental sessions. In the first session, participants performed a categorical loudness scaling procedure as well as an unpleasantness rating task in a sound booth. In the second session, the loudness scaling procedure was repeated while brain activation was measured using functional magnetic resonance imaging (fMRI). Subsequently, activation data were collected for the respective stimuli presented at fixed levels adjusted to the individual loudness judgments. Silent trials were included as a baseline condition. Our results indicate that the brain regions involved in processing LFS and IS are similar to those for sounds in the typical audio frequency range, i.e., mainly primary and secondary auditory cortex (AC). In spite of large variation across listeners with respect to judgments of loudness and unpleasantness, neural correlates of these interindividual differences could not yet be identified. Still, for individual listeners, fMRI activation in the AC was more closely related to individual perception than to the physical stimulus level.

The Characteristics of Adults with Severe Hearing Loss

BACKGROUND

Severe hearing loss impairs communication in a wide range of listening environments. However, we lack data as to the specific objective and subjective abilities of listeners with severe hearing loss. Insight into those abilities may inform treatment choices.

PURPOSE

The primary goal was to describe the audiometric profiles, spectral resolution ability, and objective and subjective speech perception of a sample of adult listeners with severe hearing loss, and to consider the relationships among those measures. We also considered the typical fitting received by individuals with severe loss, in terms of hearing aid style, electroacoustic characteristics, and features, as well as supplementary device use.

RESEARCH DESIGN

A within-subjects design was used.

STUDY SAMPLE

Participants included 36 adults aged 54-93 yr with unilateral or bilateral severe hearing loss.

DATA COLLECTION AND ANALYSIS

Testing included a full hearing and hearing aid history; audiometric evaluation; loudness growth and dynamic range; spectral resolution; assessment of cochlear dead regions; objective and subjective assessment of speech recognition; and electroacoustic evaluation of current hearing aids. Regression models were used to analyze relationships between hearing loss, spectral resolution, and speech recognition.

RESULTS

For speech in quiet, 60% of the variance was approximately equally accounted for by amount of hearing loss, spectral resolution, and number of dead regions. For speech in noise, only a modest proportion of performance variance was explained by amount of hearing loss. In general, participants were wearing amplification of appropriate style and technology for their hearing loss, but the extent of assistive technology use was low. Subjective communication ratings depended on the listening situation, but in general, were similar to previously published data for adults with mild-to-moderate loss who did not wear hearing aids.

CONCLUSIONS

The present data suggest that the range of abilities of an individual can be more fully captured with comprehensive testing. Such testing also offers an opportunity for informed counseling regarding realistic expectations for hearing aid use and the availability of hearing assistive technology.

Potential Consequences of Spectral and Binaural Loudness Summation for Bilateral Hearing Aid Fitting

Aversiveness of loud sounds is a frequent complaint by hearing aid users, especially when fitted bilaterally. This study investigates whether loudness summation can be held responsible for this finding. Two aspects of loudness summation should be taken into account: spectral loudness summation for broadband signals and binaural loudness summation for signals that are presented binaurally. In this study, the effect of different symmetrical hearing losses was studied. Measurements were obtained with the widely used technique of Adaptive Categorical Loudness Scaling. For large bandwidths, spectral loudness summation for hearing-impaired listeners was found to be greater than that for normal-hearing listeners, both for monaurally and binaurally presented signals. For binaural loudness summation, the effect of hearing loss was not significant. In all cases, individual differences were substantial.

Group Means and Intersubject and Intrasubject Variability Estimates for Absolute and Relative (Categorical) Loudness Judgments of Typical Young Adult Listeners

Purpose This brief research note is motivated by an ever-increasing need for typical repeated-measures loudness judgments and variability estimates of the kind necessary to conduct evidence-based treatment studies and clinical trials. Method These judgments and variability data, originally collected but not reported by Formby, Payne, Yang, Wu, and Parton (2017) , are presented here for relative (categorical) and absolute loudness judgments for typical young adult listeners with normal auditory function. Results As shown in this research note, these data may differ appreciably between young and older adult listeners with audiometric pure-tone thresholds within the clinically normal range. Conclusion In general, these findings highlight the need for good age-based, repeated-measures data for planning and powering evidence-based treatment studies and, specifically, for clinical trials that rely on categorical loudness judgments (i.e., as measured with the Contour Test of loudness; Cox, Alexander, Taylor, & Gray, 1997 ) as primary and secondary outcome measures.

Tinnitus and Auditory Perception After a History of Noise Exposure: Relationship to Auditory Brainstem Response Measures

OBJECTIVES

To determine whether auditory brainstem response (ABR) wave I amplitude is associated with measures of auditory perception in young people with normal distortion product otoacoustic emissions (DPOAEs) and varying levels of noise exposure history.

DESIGN

Tinnitus, loudness tolerance, and speech perception ability were measured in 31 young military Veterans and 43 non-Veterans (19 to 35 years of age) with normal pure-tone thresholds and DPOAEs. Speech perception was evaluated in quiet using Northwestern University Auditory Test (NU-6) word lists and in background noise using the words in noise (WIN) test. Loudness discomfort levels were measured using 1-, 3-, 4-, and 6-kHz pulsed pure tones. DPOAEs and ABRs were collected in each participant to assess outer hair cell and auditory nerve function.

RESULTS

The probability of reporting tinnitus in this sample increased by a factor of 2.0 per 0.1 µV decrease in ABR wave I amplitude (95% Bayesian confidence interval, 1.1 to 5.0) for males and by a factor of 2.2 (95% confidence interval, 1.0 to 6.4) for females after adjusting for sex and DPOAE levels. Similar results were obtained in an alternate model adjusted for pure-tone thresholds in addition to sex and DPOAE levels. No apparent relationship was found between wave I amplitude and either loudness tolerance or speech perception in quiet or noise.

CONCLUSIONS

Reduced ABR wave I amplitude was associated with an increased risk of tinnitus, even after adjusting for DPOAEs and sex. In contrast, wave III and V amplitudes had little effect on tinnitus risk. This suggests that changes in peripheral input at the level of the inner hair cell or auditory nerve may lead to increases in central gain that give rise to the perception of tinnitus. Although the extent of synaptopathy in the study participants cannot be measured directly, these findings are consistent with the prediction that tinnitus may be a perceptual consequence of cochlear synaptopathy.

Evaluation of a Protocol for Integrated Speech Audiometry

Purpose This project was aimed at evaluating the reliability, validity, and clinical utility of a protocol for integrated measurements of the most comfortable level (MCL) and uncomfortable level (UCL) for speech, in combination with the speech recognition threshold (SRT). We also evaluated the validity of using spondee words when measuring speech MCL and UCL. Method In a randomized block design, equal numbers of women and men with normal hearing, aged 18-29 years, were assigned to each of 3 experimental stimulus conditions: spondee singlets, spondee triplets, or connected discourse ( n = 12 per group). Following measurement of the SRT, a modified method of limits was employed to establish, on a 7-point loudness rating scale, an ascending MCL, a descending MCL, and an ascending UCL. A single instructional set covered all loudness measurements. Test times were tracked electronically to assess clinical efficiency. All test conditions were repeated during each of 2 separate test sessions. Results Mean SRTs, MCLs, and UCLs across the 3 different experimental groups were found not to differ statistically or clinically (mean differences < 5 dB). Intrasession and intersession reliability for the various measures were excellent, and testing of all listeners was completed in a timely manner. In a follow-up experiment with adults with normal hearing who were only a decade older than participants in our main experiment, the older group was found to have significantly higher MCLs and UCLs. Conclusions Spondee words can be used routinely to obtain reliable, valid, and clinically efficient measures of MCLs and UCLs for speech, in a protocol combined with the SRT. Spondees, presented singly, yielded the greatest level of efficiency overall. Results support a recommendation to obtain an ascending measurement of MCL prior to a descending measurement and to establish the MCL by averaging the 2 values.

The Physiologic and Psychophysical Consequences of Severe-to-Profound Hearing Loss

Substantial loss of cochlear function is required to elevate pure-tone thresholds to the severe hearing loss range; yet, individuals with severe or profound hearing loss continue to rely on hearing for communication. Despite the impairment, sufficient information is encoded at the periphery to make acoustic hearing a viable option. However, the probability of significant cochlear and/or neural damage associated with the loss has consequences for sound perception and speech recognition. These consequences include degraded frequency selectivity, which can be assessed with tests including psychoacoustic tuning curves and broadband rippled stimuli. Because speech recognition depends on the ability to resolve frequency detail, a listener with severe hearing loss is likely to have impaired communication in both quiet and noisy environments. However, the extent of the impairment varies widely among individuals. A better understanding of the fundamental abilities of listeners with severe and profound hearing loss and the consequences of those abilities for communication can support directed treatment options in this population.

Loudness Perception of Pure Tones in Parkinson's Disease

PURPOSE

Reduced intensity is a hallmark of speech production in Parkinson's disease (PD). Previous work has examined the perception of intensity in PD to explain these speech deficits. This study reports loudness ratings of pure tones by individuals with PD and controls, all with normal thesholds for older adults.

METHOD

Twenty individuals with PD and 23 age- and sex-matched controls rated the loudness of pure tones from 1 (very soft) to 7 (uncomfortably loud). Tones at 500, 750, 1000, 2000, and 4000 Hz were presented from 35 to 80 dB HL (or until a rating of 7 was given). A mixed-model analysis of variance was performed on ratings to assess the effects of group, frequency, sound intensity, and ear. Loudness growth slopes were determined for each participant and analyzed by group.

RESULTS

The mean loudness growth slopes of the control and PD groups did not significantly differ.

CONCLUSIONS

No difference was found in loudness growth slopes in response to externally generated tones in PD. This is in contrast with the findings of previous studies of self-generated speech and externally presented speech. The underlying causes for impaired perception and production of loudness in PD require further investigation.

Influence of suppression on restoration of spectral loudness summation in listeners with hearing loss

Loudness depends on both the intensity and spectrum of a sound. Listeners with normal hearing perceive a broadband sound as being louder than an equal-level narrowband sound because loudness grows nonlinearly with level and is then summed across frequency bands. This difference in loudness as a function of bandwidth is reduced in listeners with sensorineural hearing loss (SNHL). Suppression, the reduction in the cochlear response to one sound by the simultaneous presentation of another sound, is also reduced in listeners with SNHL. Hearing-aid gain that is based on loudness measurements with pure tones may fail to restore normal loudness growth for broadband sounds. This study investigated whether hearing-aid amplification that mimics suppression can improve loudness summation for listeners with SNHL. Estimates of loudness summation were obtained using measurements of categorical loudness scaling (CLS). Stimuli were bandpass-filtered noises centered at 2 kHz with bandwidths in the range of 0.1-6.4 kHz. Gain was selected to restore normal loudness based on CLS measurements with pure tones. Gain that accounts for both compression and suppression resulted in better restoration of loudness summation, compared to compression alone. However, restoration was imperfect, suggesting that additional refinements to the signal processing and gain-prescription algorithms are needed.

Effect of audibility on better-ear glimpsing as a function of frequency in normal-hearing and hearing-impaired listeners

Better-ear glimpsing (BEG) is an auditory phenomenon that helps understanding speech in noise by utilizing interaural level differences (ILDs). The benefit provided by BEG is limited in hearing-impaired (HI) listeners by reduced audibility at high frequencies. Rana and Buchholz [(2016). J. Acoust. Soc. Am. 140(2), 1192-1205] have shown that artificially enhancing ILDs at low and mid frequencies can help HI listeners understanding speech in noise, but the achieved benefit is smaller than in normal-hearing (NH) listeners. To understand how far this difference is explained by differences in audibility, audibility was carefully controlled here in ten NH and ten HI listeners and speech reception thresholds (SRTs) in noise were measured in a spatially separated and co-located condition as a function of frequency and sensation level. Maskers were realized by noise-vocoded speech and signals were spatialized using artificially generated broadband ILDs. The spatial benefit provided by BEG and SRTs improved consistently with increasing sensation level, but was limited in the HI listeners by loudness discomfort. Further, the HI listeners performed similar to NH listeners when differences in audibility were compensated. The results help to understand the hearing aid gain that is required to maximize the spatial benefit provided by ILDs as a function of frequency.

Deriving loudness growth functions from categorical loudness scaling data

The goal of this study was to reconcile the differences between measures of loudness obtained with continuous, unbounded scaling procedures, such as magnitude estimation and production, and those obtained using a limited number of discrete categories, such as categorical loudness scaling (CLS). The former procedures yield data with ratio properties, but some listeners find it difficult to generate numbers proportional to loudness and the numbers cannot be compared across listeners to explore individual differences. CLS, where listeners rate loudness on a verbal scale, is an easier task, but the numerical values or categorical units (CUs) assigned to the points on the scale are not proportional to loudness. Sufficient CLS data are now available to assign values in sones, a scale proportional to loudness, to the loudness categories. As a demonstration of this approach, data from Heeren, Hohmann, Appell, and Verhey [J. Acoust. Soc. Am. 133, EL314-EL319 (2013)] were used to develop a CUsone metric, whose values were then substituted for the original CU values in reanalysis of a large set of CLS data obtained by Rasetshwane, Trevino, Gombert, Liebig-Trehearn, Kopun, Jesteadt, Neely, and Gorga [J. Acoust. Soc. Am. 137, 1899-1913 (2015)]. The resulting data are well fitted by power functions and are in general agreement with previously published results obtained with magnitude estimation, magnitude production, and cross modality matching.

Auditory and Cognitive Factors Associated with Speech-in-Noise Complaints following Mild Traumatic Brain Injury

BACKGROUND

Auditory complaints following mild traumatic brain injury (MTBI) are common, but few studies have addressed the role of auditory temporal processing in speech recognition complaints.

PURPOSE

In this study, deficits understanding speech in a background of speech noise following MTBI were evaluated with the goal of comparing the relative contributions of auditory and nonauditory factors.

RESEARCH DESIGN

A matched-groups design was used in which a group of listeners with a history of MTBI were compared to a group matched in age and pure-tone thresholds, as well as a control group of young listeners with normal hearing (YNH).

STUDY SAMPLE

Of the 33 listeners who participated in the study, 13 were included in the MTBI group (mean age = 46.7 yr), 11 in the Matched group (mean age = 49 yr), and 9 in the YNH group (mean age = 20.8 yr).

DATA COLLECTION AND ANALYSIS

Speech-in-noise deficits were evaluated using subjective measures as well as monaural word (Words-in-Noise test) and sentence (Quick Speech-in-Noise test) tasks, and a binaural spatial release task. Performance on these measures was compared to psychophysical tasks that evaluate monaural and binaural temporal fine-structure tasks and spectral resolution. Cognitive measures of attention, processing speed, and working memory were evaluated as possible causes of differences between MTBI and Matched groups that might contribute to speech-in-noise perception deficits.

RESULTS

A high proportion of listeners in the MTBI group reported difficulty understanding speech in noise (84%) compared to the Matched group (9.1%), and listeners who reported difficulty were more likely to have abnormal results on objective measures of speech in noise. No significant group differences were found between the MTBI and Matched listeners on any of the measures reported, but the number of abnormal tests differed across groups. Regression analysis revealed that a combination of auditory and auditory processing factors contributed to monaural speech-in-noise scores, but the benefit of spatial separation was related to a combination of working memory and peripheral auditory factors across all listeners in the study.

CONCLUSIONS

The results of this study are consistent with previous findings that a subset of listeners with MTBI has objective auditory deficits. Speech-in-noise performance was related to a combination of auditory and nonauditory factors, confirming the important role of audiology in MTBI rehabilitation. Further research is needed to evaluate the prevalence and causal relationship of auditory deficits following MTBI.

Relations among Auditory Brainstem and Middle Latency Response Measures, Categorical Loudness Judgments, and Their Associated Physical Intensities

This study characterizes changes in response properties of toneburst-evoked auditory brainstem responses (ABRs) and/or middle latency responses (MLRs) as a function of perceived loudness and physical intensity of these stimuli and delineates the range of levels corresponding to categorical loudness judgments for these stimuli. ABRs/MLRs were recorded simultaneously to 500- and 2,000-Hz tonebursts in 10 normal-hearing adults at levels corresponding to each listener's loudness judgments for four categories on Contour Test of Loudness. Group mean ABR wave V and MLR wave Pa latency values increased significantly as loudness judgments decreased. Group mean amplitude values for ABR wave V-V' and MLR wave Na-Pa increased as the listeners' categorical judgments increased. Listeners assigned a broad range (30 to 40 dB) of stimulus intensities when judging loudness of these stimuli within a specific loudness category. This was true for all four loudness categories and both frequencies. Thus, it appears that tone-evoked ABR/MLR response measures reflect, in part, the listener's perception of loudness. Response latencies are a more sensitive indicator of listener's loudness percept than corresponding response amplitudes. An appreciable range of signal levels was judged to be categorically equivalent across listeners. Thus, limiting how loudness judgments can be applied to prescriptive hearing aid fittings in individuals who cannot provide accurate loudness judgments.

Repeated Measurement of Absolute and Relative Judgments of Loudness: Clinical Relevance for Prescriptive Fitting of Aided Target Gains for soft, Comfortable, and Loud, But Ok Sound Levels

This study was undertaken with the purpose of streamlining clinical measures of loudness growth to facilitate and enhance prescriptive fitting of nonlinear hearing aids. Repeated measures of loudness at 500 and 3,000 Hz were obtained bilaterally at monthly intervals over a 6-month period from three groups of young adult listeners. All volunteers had normal audiometric hearing sensitivity and middle ear function, and all denied problems related to sound tolerance. Group 1 performed judgments of soft and loud, but OK for presentation of ascending sound levels. We defined these judgments operationally as absolute judgments of loudness. Group 2 initially performed loudness judgments across a continuum of seven loudness categories ranging from judgments of very soft to uncomfortably loud for presentation of ascending sound levels per the Contour Test of Loudness; we defined these judgments as relative judgments of loudness. In the same session, they then performed the absolute judgments for soft and loud, but OK sound levels. Group 3 performed the same set of loudness judgments as did group 2, but the task order was reversed such that they performed the absolute judgments initially within each test session followed by the relative judgments. The key findings from this study were as follows: (1) Within group, the absolute and relative tasks yielded clinically similar judgments for soft and for loud, but OK sound levels. These judgments were largely independent of task order, ear, frequency, or trial order within a given session. (2) Loudness judgments increased, on average, by ∼3 dB between the first and last test session, which is consistent with the commonly reported acclimatization effect reported for incremental changes in loudness discomfort levels as a consequence of chronic bilateral hearing aid use. (3) Measured and predicted comfortable judgments of loudness were in good agreement for the individual listener and for groups of listeners. These comfortable judgments bisect the measured levels judged for soft and for loud, but OK sounds. (4) Loudness judgments within the same loudness category varied across listeners within group by as much as 50 to 60 dB. Such large variation in judgments of loudness is problematic, especially because hearing-impaired listeners are known to exhibit similarly large ranges of intersubject response variation and, yet, poplar prescriptive fitting strategies continue to use average rather than individual loudness data to fit nonlinear hearing aids. The primary conclusions drawn from these findings are that reliable absolute judgments of soft and loud, but OK are clinically practical and economical to measure and, from these judgments, good estimates of comfortable loudness can also be predicted for individuals or for groups of listeners. Such loudness data, as measured as described in this report, offer promise for streamlining and enhancing prescriptive fitting of nonlinear hearing aids to target gain settings for soft (audible), comfortable, and loud, but OK (tolerable) sound inputs for the individual listener.