The Quest for Ecological Validity in Hearing Science: What It Is, Why It Matters, and How to Advance It

Speech Perception and Language Abilities Among Children Using Cochlear Implants: Findings From a Primary School Age Cohort in South India

OBJECTIVES

This study aimed to profile the speech perception and language abilities of a cohort of pediatric cochlear implant (CI) users in primary school years. It also aimed to understand the intercorrelations among audiological, child, and environmental characteristics, speech perception, and language skills and to explore the predictors of speech perception and language skills.

DESIGN

A cross-sectional design was used for the study. The participants were 222 pediatric CI users (106 boys; 116 girls) with a mean chronological age of 10.51 (SD ± 1.28) years. Participants had received CIs at a mean age of 2.93 (SD ± 0.95) years, with the mean duration of CI use being 7.43 (SD ± 1.15) years at the time of assessment. Participants completed an assessment battery comprising speech perception (phoneme discrimination, open-set speech perception in quiet) and language (semantics, syntax) tasks. Selected audiological, child, and environmental characteristics were documented. The mean and SDs of the measures across age categories (8 to 12 years) and the proportion of children attaining scores better than 80%, between 50 and 80%, and poorer than 50% of the total possible score in each task were computed to generate a profile of speech perception and language abilities. Correlational and regression analyses assessed the intercorrelations among the variables and predictors of speech perception and language abilities.

RESULTS

A large proportion (79.0%) of children in the study group obtained scores better than 80% for phoneme discrimination, whereas only 17.8% scored better than 80% for open-set speech perception in quiet. Additionally, 42.8 and 20.8% of children scored better than 80% for semantics and syntax, respectively. Speech perception and language abilities demonstrated moderate-strong intercorrelations, contributing to a significant proportion of the total variance explained in phoneme discrimination (42.9%), open-set speech perception (61.8%), semantics (63.0%), and syntax (60.8%). Phoneme discrimination and open-set speech perception emerged as large contributors to variance in overall language abilities. Among the audiological factors, only hearing age contributed to a small proportion of variance (3 to 6%) across children's speech perception and language performance.

CONCLUSIONS

Children using CI demonstrated highly variable performance in speech perception and expressive language skills during primary school. Although children demonstrated improved performance in phoneme discrimination and semantics, they continued to face challenges in the (quiet) speech perception and syntax abilities. The effect of audiological, child, and environmental factors was minimal in explaining the variance in speech perception and language abilities, which shared a bidirectional relationship. The findings relating to mid-term outcomes, ranging from 4 to 9 years after cochlear implantation, suggest the need for continued support and targeted interventions for developing speech perception and language abilities in the primary school years to optimize outcomes among pediatric CI users.

Associations of frailty, self-reported balance problems, hearing abilities, and posturography in a sample of older adults

OBJECTIVE

The aim of this study was to identify risk factors for self-reported balance problems, and to analyse associations between hearing and balance.

DESIGN

A battery of tests was administered to assess hearing and balance performance, as well as additional health-related factors indicative of frailty and fall risk. In a retrospective analysis, logistic regression was used to identify risk factors for self-reported balance problems and linear regression was used to identify associations between hearing ability and functional balance.

STUDY SAMPLE

For the risk factor analysis, 199 volunteers aged 55-81 years (mean:67) were divided into two groups according to their self-reported balance problems. Only participants lacking self-reported balance problems (n = 157) were included in the second analysis.

RESULTS

Female gender, frailty, and fine-motor skills were statistically significant predictors of self-reported balance problems. Functional balance performance was related to hearing impairment for dynamic, but not for static, balance tasks.

CONCLUSION

For a holistic approach to healthcare and regardless of age, individuals with multiple comorbidities and/or phenotypic signs of frailty should be considered at risk for falls. For further research, it was shown that dynamic, rather than static, balance tasks may be needed to gain deeper insights into the relationship between hearing and balance.

Evaluation of Communication Outcomes With Over-the-Counter Hearing Aids

OBJECTIVES

Over-the-counter (OTC) hearing aids are a treatment option for adults with mild-to-moderate hearing loss. Previous investigations demonstrated the benefits of OTC hearing aids, primarily self-fit OTCs (i.e., self-adjustable with a smartphone or tablet), on self-reported hearing aid benefit and speech recognition using standardized measures. However, less is known regarding whether OTC hearing aids effectively improve aspects of everyday communication, particularly with preprogrammed OTCs (i.e., OTCs with manufacturer-defined programs). The goal of this study was to evaluate the benefits of preprogrammed OTC hearing aids for two important aspects of communication: (1) conversation efficiency, or the time taken during conversations with a familiar communication partner (e.g., one's spouse) and (2) auditory recall following speech recognition, a critical aspect of participation during conversations.

DESIGN

This study used a within-subject design with thirty adults with mild-to-moderate hearing loss and their familiar communication partners. Participants were fitted with preprogrammed OTC hearing aids using the default program with the best match to target for each listener. The primary outcome measures were conversation efficiency and auditory recall. Speech recognition-in-noise served as a secondary measure. Conversation efficiency was evaluated using the DiapixUK task, a "spot-the-difference" conversation task in quiet, and measured as the sum of time taken to correctly identify differences between two similar pictures. Within-subject comparisons were made for hearing aid condition (without and with OTC hearing aids in the default setting). Auditory recall was assessed with the Repeat and Recall Test following speech recognition-in-noise with low- and high-context sentence presentations at 5- and 10-dB signal to noise ratios. In addition to the mentioned hearing aid conditions, an additional comparison was made with the OTC hearing aid noise-reduction program. Linear mixed-effects models were used to evaluate the effect of OTC hearing aid use on primary measures of efficiency and recall. Friedman signed-rank test was used to evaluate speech recognition scores.

RESULTS

We did not find a significant improvement in conversation efficiency with OTC hearing aid use compared with the unaided condition. For auditory recall, we observed the poorest median recall scores with the default program and the best median scores with the noise-reduction program, although neither observation was statistically significant. Sentence recognition scores were near ceiling in the unaided condition and were poorest with use of the OTC hearing aids in the default program across most signal to noise ratio and context test conditions. Our findings did not show improvements in communication outcomes with OTC hearing aid use. Small to medium effect sizes for our data may be indicative of the limitations of the OTC hearing aids to improve communication outcomes for our sampled population and communication scenarios.

CONCLUSIONS

The results of this study provide insights into the effects of OTC hearing aids on communication abilities at first fitting. We identified features of preprogrammed OTC hearing aids that may be limiting potential communication benefits among listeners with mild-to-moderate hearing loss. Future investigations that compare communication outcomes across various types of OTC hearing aids may provide valuable insights for identifying the most suitable recipients for specific OTC hearing aid models.

Neural speech tracking in a virtual acoustic environment: audio-visual benefit for unscripted continuous speech

The audio-visual benefit in speech perception-where congruent visual input enhances auditory processing-is well-documented across age groups, particularly in challenging listening conditions and among individuals with varying hearing abilities. However, most studies rely on highly controlled laboratory environments with scripted stimuli. Here, we examine the audio-visual benefit using unscripted, natural speech from untrained speakers within a virtual acoustic environment. Using electroencephalography (EEG) and cortical speech tracking, we assessed neural responses across audio-visual, audio-only, visual-only, and masked-lip conditions to isolate the role of lip movements. Additionally, we analysed individual differences in acoustic and visual features of the speakers, including pitch, jitter, and lip-openness, to explore their influence on the audio-visual speech tracking benefit. Results showed a significant audio-visual enhancement in speech tracking with background noise, with the masked-lip condition performing similarly to the audio-only condition, emphasizing the importance of lip movements in adverse listening situations. Our findings reveal the feasibility of cortical speech tracking with naturalistic stimuli and underscore the impact of individual speaker characteristics on audio-visual integration in real-world listening contexts.

Effective Design for Experiments on Small-Group Conversation: Insights From an Example Study

With current advances in experimental techniques, there is a renewed interest in studying communication behavior, reflecting a desire to improve our understanding of hearing disability and the effects of treatment interventions at the level of in-the-moment behaviors. Group conversations are among the most challenging situations for people with hearing loss. Experiments on group conversations are increasingly common and disproportionately more demanding than dyad studies to design and execute. Thorough design and planning are critical for successfully capturing valid behavioral data, highlighting the value of sharing behind-the-scenes experiences with the researcher community. We have completed a laboratory study of four-way group conversations involving people with and without hearing loss. This article describes the goals and compromises involved in our design choices and evaluates their effectiveness through participant feedback. Aspects covered include contrasts and covariates, group composition and physical arrangement, participant characteristics, hearing devices, participant experience, physical environment, conversational task, and measurement modalities. Next, we briefly describe the experiment's execution. Finally, we analyze and discuss participants' feedback and reflect on what proved effective, what did not, and what design "worries" proved founded or unfounded. We hope thereby to provide support and inspiration for others who may be faced with similar design challenges. The main message is that such an experiment can be carried out successfully and in such a way that the behavioral and self-report data collected are likely to carry a relatively high degree of ecological validity while still supporting experimental and statistical control.

Effects of Hearing Loss and Hearing Aids on the Perception of Natural Sounds and Soundscapes: A Survey of Hearing Care Professional Opinions

PURPOSE

The goal was to gain insight into the effects of hearing loss and hearing aids (HAs) on the perception of "natural sounds" and their importance in daily life by documenting the opinions of hearing care professionals (HCPs).

METHOD

A questionnaire was designed where HCPs were asked to rate their patients' perception of natural sounds before and after receiving an HA. The online survey was conducted with 301 HCPs in France.

RESULTS

According to respondents, the incidence of hearing natural sounds increased substantially at the end of the trial period relative to the start, especially for patients living in remote rural areas. Respondents also indicated an increase in listening accuracy, pleasantness, and importance of natural sounds at the end of the trial period. The majority of respondents indicated (a) that their patients find it important to listen to natural sounds and (b) that they are satisfied with their HAs in that respect.

CONCLUSIONS

This study demonstrates the importance of natural sounds for most people with hearing loss. It highlights the effects of HA on patients' awareness of natural sounds and suggests that future research should consider the patients' place of residence.

Management of Audiological Disorders in Cochlear Implants: Outcomes in Demanding Listening Situations and Future Perspectives

Severe to profound sensorineural hearing loss can nowadays successfully be treated by cochlear implantation [...].

Sounds of Nature and Hearing Loss: A Call to Action

The ability to monitor surrounding natural sounds and scenes is important for performing many activities in daily life and for overall well-being. Yet, unlike speech, perception of natural sounds and scenes is relatively understudied in relation to hearing loss, despite the documented restorative health effects. We present data from first-time hearing aid users describing "rediscovered" natural sounds they could now perceive with clarity. These data suggest that hearing loss not only diminishes recognition of natural sounds, but also limits people's awareness of the richness of their environment, thus limiting their connection to it. Little is presently known about the extent hearing aids can restore the perception of abundance, clarity, or intensity of natural sounds. Our call to action outlines specific steps to improve the experience of natural sounds and scenes for people with hearing loss-an overlooked aspect of their quality of life.

Incorporating Virtual Reality Agents During a Dichotic Speech Reception Task: Insights From the Heart

OBJECTIVES

Listening effort is moderated by not only task difficulty, but also success importance. In real communication scenarios, success importance varies based upon the social context. However, in the laboratory, it can be challenging to manipulate social context without compromising experimental control. Outside of hearing sciences, studies have applied virtual reality (VR) to incorporate social context in a controlled and repeatable manner. Several of these studies have demonstrated that social manipulations in VR can reliably elicit changes in cardiovascular measures. Here, we investigated the effect of adding VR agents to a speech reception task, while measuring from the cardiovascular system.

DESIGN

Twenty-eight, normally hearing participants undertook a dichotic speech reception task. Sentences in stationary noise were presented dichotically, that is, different sentences presented simultaneously to each ear. Participants were tasked to either repeat one of the sentences (single-sentence condition) or both of the sentences (dual-sentence condition). The task was conducted under two VR conditions: (1) in the presence of agents, who provided sporadic performance feedback and (2) in the presence of nonagent controls, without any feedback given. Alongside task performance, we quantified changes in cardiovascular measures, relative to pretask baselines: heart rate variability, pre-ejection period, heart rate, and blood pressure. After each condition, participants rated their subjective effort, difficulty, performance, and engagement.

RESULTS

Performance and the subjective perception of performance were lower, while subjective effort and difficulty were higher, in the dual-sentence condition, compared with the single-sentence condition. Heart rate was the only cardiovascular measure that was sensitive to the experimental manipulations. Contrary to our expectations, heart rate increased in the nonagent control conditions, compared with the agent conditions. An exploratory analysis revealed heart rate fluctuations within a trial: heart rate was higher during the first 6 sec of the trial (reflecting the presentence masking noise and the sentence presentation) in the dual-sentence condition, compared with the single-sentence condition.

CONCLUSIONS

This study was the first to incorporate VR agents who provided performance feedback during a dichotic speech reception task. Our results suggest that the VR agents did not increase success importance, which could be attributed to a lack of realism of the agents. We also demonstrated that the cardiovascular response to experimental manipulations may differ depending on the data window selected for analysis.

Examining sound levels across different time scales measured from body-worn dosimetersa)

Studies are increasingly investigating listeners' acoustic environments using real-world data collection methods to personalize interventions for hearing loss and understand individual differences in intervention outcomes. A pressing methods question is the extent to which the time scale of the sample and number of sampling periods need to be considered. The purpose of this study was to characterize the extent to which the sound levels in a listener's vicinity, one common measure of acoustic environments, change across different time scales. Listeners wore a personal noise dosimeter continuously for one-week sampling periods at three time points. The effects of season, week, day of the week, and time of day on acoustic environment demand (proportion of samples ≥ 40 dB LAeq and mean sound levels for samples ≥ 40 dB LAeq) and diversity (the distribution of LAeq values, quantified by entropy) were characterized. Acoustic environment demand and diversity were relatively similar across seasons and weeks but varied more between days and across the day. Results suggest that a single one-week sampling period, collected at any time of year but balanced across days of the week and time of day, may capture sufficient information about a listener's acoustic environments to inform decisions about interventions.

A qualitative study of the role of hearing aid use and physical fit accessories in a sample of older adults

OBJECTIVE

The purpose of the study was to qualitatively describe the experiences of hearing aid and physical fit accessories use during physical activity and exercise participation in a sample of older adults with hearing loss.

DESIGN

A prospective qualitative research design was employed with the use of focus groups with older adult participants who were fitted with hearing aids and physical fit accessories.

STUDY SAMPLE

Twelve older adults with hearing loss (six experienced and six new hearing aid users, age range 64 - 88 years) were recruited in this study.

RESULTS

The barriers to hearing at physical activity and exercise environments were related to reverberation, loud music, and instructor's location and position relative to exercise members, whereas facilitators were aided hearing, the instructor projecting their voice and demonstrating the moves. The most preferred physical fit accessories were the retention lock and the corded and cordless hearing aid sleeves. The least preferred accessories were the hearing aid-to-glasses connector and stick'n stay tape.

CONCLUSIONS

Individual differences and needs were factored into different perspectives on hearing aid and physical fit accessory use, emphasising patient-centered approach when coaching and counselling on device use for physical activity and exercise.

Beyond hearing: the impact of Cochlear implantation on the quality of life of users and their communication partners after 1 year

OBJECTIVE

To assess the impact of cochlear implantation (CI) and speech perception outcomes on the quality of life (QoL) of adult CI users and their communication partners (CP) one-year post-implantation.

DESIGN

This research is part of a prospective multicenter study in The Netherlands, called SMILE (Societal Merit of Intervention for hearing Loss Evaluation).

STUDY SAMPLE

Eighty adult CI users completed speech perception testing and the Nijmegen Cochear Implant Questionnaire (NCIQ). Fifty-four CPs completed the Hearing Impairment Impact - Significant Other Profile (HII-SOP).

RESULTS

CI resulted in a large improvement in the QoL of both users and CPs. Despite this, some users still reported difficulties in the NCIQ sub-domains Social Interactions, Activity Limitations and Self-esteem. Similarly, some CPs still reported moderate and severe third-party disability on the HII-SOP. Additionally, the correlation between speech perception results and self-reported QoL was weak to negligible for both groups.

CONCLUSIONS

Speech perception in quiet is not an accurate measure of real-life success with a CI. A subset of CI users and CPs still experience substantial QoL challenges regardless of speech perception performance. To improve counselling and intervention, QoL measures should be a standard part of the CI care pathway for CI users and their CPs.

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.

Ambulatory autonomic nervous system activity in relation to hearing impairment

Previous research has demonstrated that hearing impairment is associated with heightened subjective experiences of listening effort, fatigue, and stress, impacting daily functioning. This study aimed to evaluate whether hearing impairment alters physiological stress systems and whether different aspects of hearing impairment could vary in predicting dysregulation in these systems. Hallmark measures of parasympathetic and sympathetic nervous system activity were derived from electrocardiography, impedance cardiography, and electrodermal activity recordings taken from 133 individuals, aged 37 to 73, over two 24-hr periods, including sleep. Using ecological momentary assessment (EMA), participants reported mood, listening effort, and fatigue seven times daily. Hearing impairment was quantified through pure tone thresholds, speech perception in noise testing, and the Amsterdam Inventory for Auditory Disability questionnaire (Amsterdam Inventory). Using mixed models, we compared average daytime and sleep values of physiological measures across the 2 days, and their daytime-to-sleep contrast, based on each hearing impairment assessment. Results indicated that all three hearing impairment assessments were strong predictors of EMA outcomes of listening effort and fatigue. Contrary to expectations, hearing impairment did not have a significant impact on parasympathetic activity in daily life or on skin sympathetic activity. However, individuals with higher impairment exhibited a larger change in a cardiac sympathetic measure, the pre-ejection period, during wakefulness compared to sleep. Overall, hearing impairment had a small impact on autonomic nervous system functioning in daily life, but the effects were potentially attenuated by reduced exposure to listening demand in those with hearing impairment.

Realistic dual-task listening-while-balancing in older adults with normal hearing and hearing loss with and without hearing aids

Age-related hearing loss is a risk factor for mobility problems and falls, possibly due to poor access to spatial sounds or the higher allocation of attention required to listen, thereby reducing cognitive resources to support mobility. Introducing stabilizing spatial sounds or reducing cognitive load through hearing aids could possibly improve balance performance; however, evidence is mixed. Few studies have evaluated the effects of hearing aids and spatial sounds on balance during realistic, multisensory, dual-tasking conditions. This study used virtual reality to simulate a listening-while-balancing task in 22 older adults with normal hearing and 22 hearing aid users, tested with their aids on versus off. Participants performed a competing digits listening task (two, four digits) and a standing postural task, alone and in combination (dual task) under different visual, postural, and acoustical loads. Listening accuracy and postural outcomes (centre of pressure mean velocity, anterior-posterior standard deviation, medial-lateral standard deviation) were collected. With respect to listening accuracy, as expected, normal hearing adults had higher listening accuracy than those with hearing loss (aided better than unaided) and both groups performed better with eyes closed (vs. open) and under lower postural loads (firm vs. compliant). With respect to postural performance, hearing aids did not remarkably improve balance overall, with no effects on dual-task costs to posture. Other factors related to the complexity of the conditions (i.e., listening, visual, postural demands) differently influenced dual-task costs to posture in individuals with and without hearing loss. Overall, these results contribute to our understanding of how age-related hearing loss and hearing aids affect balance-related outcomes under realistic, complex, multisensory, multitasking conditions.

The Audible Contrast Threshold (ACT) test: A clinical spectro-temporal modulation detection test

Over the last decade, multiple studies have shown that hearing-impaired listeners' speech-in-noise reception ability, measured with audibility compensation, is closely associated with performance in spectro-temporal modulation (STM) detection tests. STM tests thus have the potential to provide highly relevant beyond-the-audiogram information in the clinic, but the available STM tests have not been optimized for clinical use in terms of test duration, required equipment, and procedural standardization. The present study introduces a quick-and-simple clinically viable STM test, named the Audible Contrast Threshold (ACT™) test. First, an experimenter-controlled STM measurement paradigm was developed, in which the patient is presented bilaterally with a continuous audibility-corrected noise via headphones and asked to press a pushbutton whenever they hear an STM target sound in the noise. The patient's threshold is established using a Hughson-Westlake tracking procedure with a three-out-of-five criterion and then refined by post-processing the collected data using a logistic function. Different stimulation paradigms were tested in 28 hearing-impaired participants and compared to data previously measured in the same participants with an established STM test paradigm. The best stimulation paradigm showed excellent test-retest reliability and good agreement with the established laboratory version. Second, the best stimulation paradigm with 1-second noise "waves" (windowed noise) was chosen, further optimized with respect to step size and logistic-function fitting, and tested in a population of 25 young normal-hearing participants using various types of transducers to obtain normative data. Based on these normative data, the "normalized Contrast Level" (in dB nCL) scale was defined, where 0 ± 4 dB nCL corresponds to normal performance and elevated dB nCL values indicate the degree of audible contrast loss. Overall, the results of the present study suggest that the ACT test may be considered a reliable, quick-and-simple (and thus clinically viable) test of STM sensitivity. The ACT can be measured directly after the audiogram using the same set up, adding only a few minutes to the process.

Similar gaze behaviour during dialogue perception in congenitally deaf children with cochlear Implants and normal hearing children

BACKGROUND

Perceptual and speech production abilities of children with cochlear implants (CIs) are usually tested by word and sentence repetition or naming tests. However, these tests are quite far apart from daily life linguistic contexts.

AIM

Here, we describe a way of investigating the link between language comprehension and anticipatory verbal behaviour promoting the use of more complex listening situations.

METHODS AND PROCEDURE

The setup consists in watching the audio-visual dialogue of two actors. Children's gaze switches from one speaker to the other serve as a proxy of their prediction abilities. Moreover, to better understand the basis and the impact of anticipatory behaviour, we also measured children's ability to understand the dialogue content, their speech perception and memory skills as well as their rhythmic skills, that also require temporal predictions. Importantly, we compared children with CI performances with those of an age-matched group of children with normal hearing (NH).

OUTCOMES AND RESULTS

While children with CI revealed poorer speech perception and verbal working memory abilities than NH children, there was no difference in gaze anticipatory behaviour. Interestingly, in children with CI only, we found a significant correlation between dialogue comprehension, perceptual skills and gaze anticipatory behaviour.

CONCLUSION

Our results extend to a dialogue context of previous findings showing an absence of predictive deficits in children with CI. The current design seems an interesting avenue to provide an accurate and objective estimate of anticipatory language behaviour in a more ecological linguistic context also with young children.

WHAT THIS PAPER ADDS

What is already known on the subject Children with cochlear implants seem to have difficulties extracting structure from and learning sequential input patterns, possibly due to signal degradation and auditory deprivation in the first years of life. They also seem to have a reduced use of contextual information and slow language processing among children with hearing loss. What this paper adds to existing knowledge Here we show that when adopting a rather complex linguistic context such as watching a dialogue of two individuals, children with cochlear implants are able to use the speech and language structure to anticipate gaze switches to the upcoming speaker. What are the clinical implications of this work? The present design seems an interesting avenue to provide an accurate and objective estimate of anticipatory behaviour in a more ecological and dynamic linguistic context. Importantly, this measure is implicit and it has been previously used with very young (normal-hearing) children, showing that they spontaneously make anticipatory gaze switches by age two. Thus, this approach may be of interest to refine the speech comprehension assessment at a rather early age after cochlear implantation where explicit behavioural tests are not always reliable and sensitive.

Sensorineural hearing loss alters auditory discrimination of natural soundscapes

OBJECTIVE

The ability to discriminate natural soundscapes recorded in a temperate terrestrial biome was measured in 15 hearing-impaired (HI) listeners with bilateral, mild to severe sensorineural hearing loss and 15 normal-hearing (NH) controls.

DESIGN

Soundscape discrimination was measured using a three-interval oddity paradigm and the method of constant stimuli. On each trial, sequences of 2-second recordings varying the habitat, season and period of the day were presented diotically at a nominal SPL of 60 or 80 dB.

RESULTS

Discrimination scores were above chance level for both groups, but they were poorer for HI than NH listeners. On average, the scores of HI listeners were relatively well accounted for by those of NH listeners tested with stimuli spectrally-shaped to match the frequency-dependent reduction in audibility of individual HI listeners. However, the scores of HI listeners were not significantly correlated with pure-tone audiometric thresholds and age.

CONCLUSIONS

These results indicate that the ability to discriminate natural soundscapes associated with changes in habitat, season and period of the day is disrupted but it is not abolished. The deficits of the HI listeners are partly accounted for by reduced audibility. Supra-threshold auditory deficits and individual listening strategies may also explain differences between NH and HI listeners.

Hearing at the Mall: Multibeam Processing Technology Improves Hearing Group Conversations in a Real-World Food Court Environment

PURPOSE

This study aimed to evaluate conversation hearing with an adaptive beamforming hearing aid that supports adaptive tracking of multiple talkers in an ecologically valid, real-world food court environment in a busy mall.

METHOD

Twenty older adult experienced hearing aid wearers with sensorineural hearing loss were fitted in the lab with binaural receiver-in-the-canal style hearing aids set with two programs, each having a different beamforming strategy. The participant and two researchers then met in a moderately noisy and reverberant food court at a local mall where the participant was asked to listen to a conversation between the two researchers. Participants rated the extent of their agreement with 10 positively worded statements specific to the conversation twice, once for each program. Participants then provided program-preference ratings for seven different aspects of a conversation during which the programs were switched back and forth by the researcher, so that participants were unaware of the condition to which they were listening.

RESULTS

Real-world subjective ratings for all domains resulted in positive values on average for both programs. Pairwise comparisons indicated that the intervention algorithm had higher absolute ratings on five of the 10 criteria including understanding, clarity, focus, listening effort, and background noise. Ratings for preference between programs indicated a significant preference for the intervention algorithm for all seven criteria.

CONCLUSIONS

In a real-world setting, the use of hearing aids with separate processing of sounds from the front and back hemisphere provided positive subjective ratings. However, following a group conversation with multiple conversation partners, improvements in the algorithm to account for the locations of interlocutors and the natural head turning of the hearing aid wearer that occurs during a conversation by adding and controlling multiple adaptive beams in the front hemisphere significantly influenced preference for all aspects rated.

Uses of Linguistic Context in Speech Listening: Does Acquired Hearing Loss Lead to Reduced Engagement of Prediction?

Research investigating the complex interplay of cognitive mechanisms involved in speech listening for people with hearing loss has been gaining prominence. In particular, linguistic context allows the use of several cognitive mechanisms that are not well distinguished in hearing science, namely those relating to "postdiction", "integration", and "prediction". We offer the perspective that an unacknowledged impact of hearing loss is the differential use of predictive mechanisms relative to age-matched individuals with normal hearing. As evidence, we first review how degraded auditory input leads to reduced prediction in people with normal hearing, then consider the literature exploring context use in people with acquired postlingual hearing loss. We argue that no research on hearing loss has directly assessed prediction. Because current interventions for hearing do not fully alleviate difficulty in conversation, and avoidance of spoken social interaction may be a mediator between hearing loss and cognitive decline, this perspective could lead to greater understanding of cognitive effects of hearing loss and provide insight regarding new targets for intervention.

Factors to Describe the Outcome Characteristics of a CI Recipient

Background: In cochlear implant (CI) treatment, there is a large variability in outcome. The aim of our study was to identify the independent audiometric measures that are most directly relevant for describing this variability in outcome characteristics of CI recipients. An extended audiometric test battery was used with selected adult patients in order to characterize the full range of CI outcomes. Methods: CI users were recruited for this study on the basis of their postoperative results and divided into three groups: low (1st quartile), moderate (medium decentile), and high hearing performance (4th quartile). Speech recognition was measured in quiet by using (i) monosyllabic words (40-80 dB SPL), (ii) speech reception threshold (SRT) for numbers, and (iii) the German matrix test in noise. In order to reconstruct demanding everyday listening situations in the clinic, the temporal characteristics of the background noise and the spatial arrangements of the signal sources were varied for tests in noise. In addition, a survey was conducted using the Speech, Spatial, and Qualities (SSQ) questionnaire and the Listening Effort (LE) questionnaire. Results: Fifteen subjects per group were examined (total N = 45), who did not differ significantly in terms of age, time after CI surgery, or CI use behavior. The groups differed mainly in the results of speech audiometry. For speech recognition, significant differences were found between the three groups for the monosyllabic tests in quiet and for the sentences in stationary (S0°N0°) and fluctuating (S0°NCI) noise. Word comprehension and sentence comprehension in quiet were both strongly correlated with the SRT in noise. This observation was also confirmed by a factor analysis. No significant differences were found between the three groups for the SSQ questionnaire and the LE questionnaire results. The results of the factor analysis indicate that speech recognition in noise provides information highly comparable to information from speech intelligibility in quiet. Conclusions: The factor analysis highlighted three components describing the postoperative outcome of CI patients. These were (i) the audiometrically measured supra-threshold speech recognition and (ii) near-threshold audibility, as well as (iii) the subjective assessment of the relationship to real life as determined by the questionnaires. These parameters appear well suited to setting up a framework for a test battery to assess CI outcomes.

Communication Under Sharply Degraded Auditory Input and the "2-Sentence" Problem

OBJECTIVES

Despite performing well in standard clinical assessments of speech perception, many cochlear implant (CI) users report experiencing significant difficulties when listening in real-world environments. We hypothesize that this disconnect may be related, in part, to the limited ecological validity of tests that are currently used clinically and in research laboratories. The challenges that arise from degraded auditory information provided by a CI, combined with the listener's finite cognitive resources, may lead to difficulties when processing speech material that is more demanding than the single words or single sentences that are used in clinical tests.

DESIGN

Here, we investigate whether speech identification performance and processing effort (indexed by pupil dilation measures) are affected when CI users or normal-hearing control subjects are asked to repeat two sentences presented sequentially instead of just one sentence.

RESULTS

Response accuracy was minimally affected in normal-hearing listeners, but CI users showed a wide range of outcomes, from no change to decrements of up to 45 percentage points. The amount of decrement was not predictable from the CI users' performance in standard clinical tests. Pupillometry measures tracked closely with task difficulty in both the CI group and the normal-hearing group, even though the latter had speech perception scores near ceiling levels for all conditions.

CONCLUSIONS

Speech identification performance is significantly degraded in many (but not all) CI users in response to input that is only slightly more challenging than standard clinical tests; specifically, when two sentences are presented sequentially before requesting a response, instead of presenting just a single sentence at a time. This potential "2-sentence problem" represents one of the simplest possible scenarios that go beyond presentation of the single words or sentences used in most clinical tests of speech perception, and it raises the possibility that even good performers in single-sentence tests may be seriously impaired by other ecologically relevant manipulations. The present findings also raise the possibility that a clinical version of a 2-sentence test may provide actionable information for counseling and rehabilitating CI users, and for people who interact with them closely.

Enhancing Cochlear Implant Outcomes across Age Groups: The Interplay of Forward Focus and Advanced Combination Encoder Coding Strategies in Noisy Conditions

Background: Hearing in noise is challenging for cochlear implant users and requires significant listening effort. This study investigated the influence of ForwardFocus and number of maxima of the Advanced Combination Encoder (ACE) strategy, as well as age, on speech recognition threshold and listening effort in noise. Methods: A total of 33 cochlear implant recipients were included (age ≤ 40 years: n = 15, >40 years: n = 18). The Oldenburg Sentence Test was used to measure 50% speech recognition thresholds (SRT50) in fluctuating and stationary noise. Speech was presented frontally, while three frontal or rear noise sources were used, and the number of ACE maxima varied between 8 and 12. Results: ForwardFocus significantly improved the SRT50 when noise was presented from the back, independent of subject age. The use of 12 maxima further improved the SRT50 when ForwardFocus was activated and when noise and speech were presented frontally. Listening effort was significantly worse in the older age group compared to the younger age group and was reduced by ForwardFocus but not by increasing the number of ACE maxima. Conclusion: Forward Focus can improve speech recognition in noisy environments and reduce listening effort, especially in older cochlear implant users.

Feasibility of an Adaptive Version of the Everyday Conversational Sentences in Noise Test

PURPOSE

To investigate potential reasons for the mismatch between laboratory/clinic-based sentence-in-noise performance and real-world listening abilities, we recently developed a corpus of natural, spontaneously spoken speech with three vocal effort levels (Everyday Conversational Sentences in Noise [ECO-SiN]). Here, we examined the feasibility of using the ECO-SiN corpus for adaptive speech-in-noise testing, which might be a desirable format in certain situations (e.g., during a clinical visit).

METHOD

Ten young, normal-hearing adults, along with 20 older adults with hearing loss participated in the study. Speech reception thresholds (SRTs) were obtained using ECO-SiN sentences, which were systematically compared to the SRTs obtained using traditional Bamford-Kowal-Bench-like sentences.

RESULTS

Results demonstrated the properties of the test compared favorably with those of a standard test based on scripted and clearly spoken sentences. Moreover, whereas normal-hearing listeners received a benefit from an increase in vocal effort, the participants with hearing loss showed a disbenefit that increased with increasing hearing loss.

CONCLUSION

The adaptive version of the ECO-SiN test is feasible for research and clinical testing.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.25146338.

Vehicle noise: comparison of loudness ratings in the field and the laboratory

OBJECTIVE

Distorted loudness perception is one of the main complaints of hearing aid users. Measuring loudness perception in the clinic as experienced in everyday listening situations is important for loudness-based hearing aid fitting. Little research has been done comparing loudness perception in the field and in the laboratory.

DESIGN

Participants rated the loudness in the field and in the laboratory of 36 driving actions. The field measurements were recorded with a 360° camera and a tetrahedral microphone. The recorded stimuli, which are openly accessible, were presented in three conditions in the laboratory: 360° video recordings with a head-mounted display, video recordings with a desktop monitor and audio-only.

STUDY SAMPLES

Thirteen normal-hearing participants and 18 hearing-impaired participants with hearing aids.

RESULTS

The driving actions were rated as louder in the laboratory than in the field for the condition with a desktop monitor and for the audio-only condition. The less realistic a laboratory condition was, the more likely it was for a participant to rate a driving action as louder. The field-laboratory loudness differences were bigger for louder sounds.

CONCLUSION

The results of this experiment indicate the importance of increasing realism and immersion when measuring loudness in the clinic.

Note on the Dual-Task Paradigm and its Use to Measure Listening Effort

People regularly communicate in complex environments, requiring them to flexibly shift their attention across multiple sources of sensory information. Increasing recruitment of the executive functions that support successful speech comprehension in these multitasking settings is thought to contribute to the sense of effort that listeners often experience. One common research method employed to quantify listening effort is the dual-task paradigm in which individuals recognize speech and concurrently perform a secondary (often visual) task. Effort is operationalized as performance decrements on the secondary task as speech processing demands increase. However, recent reviews have noted critical inconsistencies in the results of dual-task experiments, likely in part due to how and when the two tasks place demands on a common set of mental resources and how flexibly individuals can allocate their attention to them. We propose that in order to move forward to address this gap, we need to first look backward: better integrating theoretical models of resource capacity and allocation as well as of task-switching that have been historically developed in domains outside of hearing research (viz., cognitive psychology and neuroscience). With this context in mind, we describe how dual-task experiments could be designed and interpreted such that they provide better and more robust insights into the mechanisms that contribute to effortful listening.

Attention Mobilization as a Modulator of Listening Effort: Evidence From Pupillometry

Listening to speech in noise can require substantial mental effort, even among younger normal-hearing adults. The task-evoked pupil response (TEPR) has been shown to track the increased effort exerted to recognize words or sentences in increasing noise. However, few studies have examined the trajectory of listening effort across longer, more natural, stretches of speech, or the extent to which expectations about upcoming listening difficulty modulate the TEPR. Seventeen younger normal-hearing adults listened to 60-s-long audiobook passages, repeated three times in a row, at two different signal-to-noise ratios (SNRs) while pupil size was recorded. There was a significant interaction between SNR, repetition, and baseline pupil size on sustained listening effort. At lower baseline pupil sizes, potentially reflecting lower attention mobilization, TEPRs were more sustained in the harder SNR condition, particularly when attention mobilization remained low by the third presentation. At intermediate baseline pupil sizes, differences between conditions were largely absent, suggesting these listeners had optimally mobilized their attention for both SNRs. Lastly, at higher baseline pupil sizes, potentially reflecting overmobilization of attention, the effect of SNR was initially reversed for the second and third presentations: participants initially appeared to disengage in the harder SNR condition, resulting in reduced TEPRs that recovered in the second half of the story. Together, these findings suggest that the unfolding of listening effort over time depends critically on the extent to which individuals have successfully mobilized their attention in anticipation of difficult listening conditions.

Automated Measurement of Speech Recognition, Reaction Time, and Speech Rate and Their Relation to Self-Reported Listening Effort for Normal-Hearing and Hearing-Impaired Listeners Using various Maskers

In speech audiometry, the speech-recognition threshold (SRT) is usually established by adjusting the signal-to-noise ratio (SNR) until 50% of the words or sentences are repeated correctly. However, these conditions are rarely encountered in everyday situations. Therefore, for a group of 15 young participants with normal hearing and a group of 12 older participants with hearing impairment, speech-recognition scores were determined at SRT and at four higher SNRs using several stationary and fluctuating maskers. Participants' verbal responses were recorded, and participants were asked to self-report their listening effort on a categorical scale (self-reported listening effort, SR-LE). The responses were analyzed using an Automatic Speech Recognizer (ASR) and compared to the results of a human examiner. An intraclass correlation coefficient of r = .993 for the agreement between their corresponding speech-recognition scores was observed. As expected, speech-recognition scores increased with increasing SNR and decreased with increasing SR-LE. However, differences between speech-recognition scores for fluctuating and stationary maskers were observed as a function of SNR, but not as a function of SR-LE. The verbal response time (VRT) and the response speech rate (RSR) of the listeners' responses were measured using an ASR. The participants with hearing impairment showed significantly lower RSRs and higher VRTs compared to the participants with normal hearing. These differences may be attributed to differences in age, hearing, or both. With increasing SR-LE, VRT increased and RSR decreased. The results show the possibility of deriving a behavioral measure, VRT, measured directly from participants' verbal responses during speech audiometry, as a proxy for SR-LE.

Combining Cardiovascular and Pupil Features Using k-Nearest Neighbor Classifiers to Assess Task Demand, Social Context, and Sentence Accuracy During Listening

In daily life, both acoustic factors and social context can affect listening effort investment. In laboratory settings, information about listening effort has been deduced from pupil and cardiovascular responses independently. The extent to which these measures can jointly predict listening-related factors is unknown. Here we combined pupil and cardiovascular features to predict acoustic and contextual aspects of speech perception. Data were collected from 29 adults (mean  =  64.6 years, SD  =  9.2) with hearing loss. Participants performed a speech perception task at two individualized signal-to-noise ratios (corresponding to 50% and 80% of sentences correct) and in two social contexts (the presence and absence of two observers). Seven features were extracted per trial: baseline pupil size, peak pupil dilation, mean pupil dilation, interbeat interval, blood volume pulse amplitude, pre-ejection period and pulse arrival time. These features were used to train k-nearest neighbor classifiers to predict task demand, social context and sentence accuracy. The k-fold cross validation on the group-level data revealed above-chance classification accuracies: task demand, 64.4%; social context, 78.3%; and sentence accuracy, 55.1%. However, classification accuracies diminished when the classifiers were trained and tested on data from different participants. Individually trained classifiers (one per participant) performed better than group-level classifiers: 71.7% (SD  =  10.2) for task demand, 88.0% (SD  =  7.5) for social context, and 60.0% (SD  =  13.1) for sentence accuracy. We demonstrated that classifiers trained on group-level physiological data to predict aspects of speech perception generalized poorly to novel participants. Individually calibrated classifiers hold more promise for future applications.

Sensitivity, reliability and convergent validity of sequential dual-task measures of listening effort

OBJECTIVE

The aim of the current study was to assess the sensitivity, reliability and convergent validity of objective measures of listening effort collected in a sequential dual-task.

DESIGN

On each trial, participants viewed a set of digits and listened to a spoken sentence presented at one of a range of signal-to-noise ratios (SNR) and then typed the sentence-final word and recalled the digits. Listening effort measures included word response time, digit recall accuracy and digit response time. In Experiment 1, SNR on each trial was randomised. In Experiment 2, SNR varied in a blocked design, and in each block self-reported listening effort was also collected.

STUDY SAMPLES

Separate groups of 40 young adults participated in each experiment.

RESULTS

Effects of SNR were observed for all measures. Linear effects of SNR were generally observed even with word recognition accuracy factored out of the models. Among the objective measures, reliability was excellent, and repeated-measures correlations, though not between-subjects correlations, were nearly all significant.

CONCLUSION

The objective measures assessed appear to be sensitive and reliable indices of listening effort that are non-redundant with speech intelligibility and have strong within-participants convergent validity. Results support use of these measures in future studies of listening effort.

The Impact of Hearing Aids on Listening Effort and Listening-Related Fatigue - Investigations in a Virtual Realistic Listening Environment

Participation in complex listening situations such as group conversations in noisy environments sets high demands on the auditory system and on cognitive processing. Reports of hearing-impaired people indicate that strenuous listening situations occurring throughout the day lead to feelings of fatigue at the end of the day. The aim of the present study was to develop a suitable test sequence to evoke and measure listening effort (LE) and listening-related fatigue (LRF), and, to evaluate the influence of hearing aid use on both dimensions in mild to moderately hearing-impaired participants. The chosen approach aims to reconstruct a representative acoustic day (Time Compressed Acoustic Day [TCAD]) by means of an eight-part hearing-test sequence with a total duration of approximately 2½ h. For this purpose, the hearing test sequence combined four different listening tasks with five different acoustic scenarios and was presented to the 20 test subjects using virtual acoustics in an open field measurement in aided and unaided conditions. Besides subjective ratings of LE and LRF, behavioral measures (response accuracy, reaction times), and an attention test (d2-R) were performed prior to and after the TCAD. Furthermore, stress hormones were evaluated by taking salivary samples. Subjective ratings of LRF increased throughout the test sequence. This effect was observed to be higher when testing unaided. In three of the eight listening tests, the aided condition led to significantly faster reaction times/response accuracies than in the unaided condition. In the d2-R test, an interaction in processing speed between time (pre- vs. post-TCAD) and provision (unaided vs. aided) was found suggesting an influence of hearing aid provision on LRF. A comparison of the averaged subjective ratings at the beginning and end of the TCAD shows a significant increase in LRF for both conditions. At the end of the TCAD, subjective fatigue was significantly lower when wearing hearing aids. The analysis of stress hormones did not reveal significant effects.

Impact of SNR, peripheral auditory sensitivity, and central cognitive profile on the psychometric relation between pupillary response and speech performance in CI users

Despite substantial technical advances and wider clinical use, cochlear implant (CI) users continue to report high and elevated listening effort especially under challenging noisy conditions. Among all the objective measures to quantify listening effort, pupillometry is one of the most widely used and robust physiological measures. Previous studies with normally hearing (NH) and hearing-impaired (HI) listeners have shown that the relation between speech performance in noise and listening effort (as measured by peak pupil dilation) is not linear and exhibits an inverted-U shape. However, it is unclear whether the same psychometric relation exists in CI users, and whether individual differences in auditory sensitivity and central cognitive capacity affect this relation. Therefore, we recruited 17 post-lingually deaf CI adults to perform speech-in-noise tasks from 0 to 20 dB SNR with a 4 dB step size. Simultaneously, their pupillary responses and self-reported subjective effort were recorded. To characterize top-down and bottom-up individual variabilities, a spectro-temporal modulation task and a set of cognitive abilities were measured. Clinical word recognition in quiet and Quality of Life (QoL) were also collected. Results showed that at a group level, an inverted-U shape psychometric curve between task difficulty (SNR) and peak pupil dilation (PPD) was not observed. Individual shape of the psychometric curve was significantly associated with some individual factors: CI users with higher clinical word and speech-in-noise recognition showed a quadratic decrease of PPD over increasing SNRs; CI users with better non-verbal intelligence and lower QoL showed smaller average PPD. To summarize, individual differences in CI users had a significant impact on the psychometric relation between pupillary response and task difficulty, hence affecting the interpretation of pupillary response as listening effort (or engagement) at different task difficulty levels. Future research and clinical applications should further characterize the possible effects of individual factors (such as motivation or engagement) in modulating CI users' occurrence of 'tipping point' on their psychometric functions, and develop an individualized method for reliably quantifying listening effort using pupillometry.

Multilevel Modeling of Gaze From Listeners With Hearing Loss Following a Realistic Conversation

PURPOSE

There is a need for tools to study real-world communication abilities in people with hearing loss. We outline a potential method for this that analyzes gaze and use it to answer the question of when and how much listeners with hearing loss look toward a new talker in a conversation.

METHOD

Twenty-two older adults with hearing loss followed a prerecorded two-person audiovisual conversation in the presence of babble noise. We compared their eye-gaze direction to the conversation in two multilevel logistic regression (MLR) analyses. First, we split the conversation into events classified by the number of active talkers within a turn or a transition, and we tested if these predicted the listener's gaze. Second, we mapped the odds that a listener gazed toward a new talker over time during a conversation transition.

RESULTS

We found no evidence that our conversation events predicted changes in the listener's gaze, but the listener's gaze toward the new talker during a silence-transition was predicted by time: The odds of looking at the new talker increased in an s-shaped curve from at least 0.4 s before to 1 s after the onset of the new talker's speech. A comparison of models with different random effects indicated that more variance was explained by differences between individual conversation events than by differences between individual listeners.

CONCLUSIONS

MLR modeling of eye-gaze during talker transitions is a promising approach to study a listener's perception of realistic conversation. Our experience provides insight to guide future research with this method.

At-home computerized executive-function training to improve cognition and mobility in normal-hearing adults and older hearing aid users: a multi-centre, single-blinded randomized controlled trial

BACKGROUND

Hearing loss predicts cognitive decline and falls risk. It has been argued that degraded hearing makes listening effortful, causing competition for higher-level cognitive resources needed for secondary cognitive or motor tasks. Therefore, executive function training has the potential to improve cognitive performance, in turn improving mobility, especially when older adults with hearing loss are engaged in effortful listening. Moreover, research using mobile neuroimaging and ecologically valid measures of cognition and mobility in this population is limited. The objective of this research is to examine the effect of at-home cognitive training on dual-task performance using laboratory and simulated real-world conditions in normal-hearing adults and older hearing aid users. We hypothesize that executive function training will lead to greater improvements in cognitive-motor dual-task performance compared to a wait-list control group. We also hypothesize that executive function training will lead to the largest dual-task improvements in older hearing aid users, followed by normal-hearing older adults, and then middle-aged adults.

METHODS

A multi-site (Concordia University and KITE-Toronto Rehabilitation Institute, University Health Network) single-blinded randomized controlled trial will be conducted whereby participants are randomized to either 12 weeks of at-home computerized executive function training or a wait-list control. Participants will consist of normal-hearing middle-aged adults (45-60 years old) and older adults (65-80 years old), as well as older hearing aid users (65-80 years old, ≥ 6 months hearing aid experience). Separate samples will undergo the same training protocol and the same pre- and post-evaluations of cognition, hearing, and mobility across sites. The primary dual-task outcome measures will involve either static balance (KITE site) or treadmill walking (Concordia site) with a secondary auditory-cognitive task. Dual-task performance will be assessed in an immersive virtual reality environment in KITE's StreetLab and brain activity will be measured using functional near infrared spectroscopy at Concordia's PERFORM Centre.

DISCUSSION

This research will establish the efficacy of an at-home cognitive training program on complex auditory and motor functioning under laboratory and simulated real-world conditions. This will contribute to rehabilitation strategies in order to mitigate or prevent physical and cognitive decline in older adults with hearing loss.

TRIAL REGISTRATION

Identifier: NCT05418998. https://clinicaltrials.gov/ct2/show/NCT05418998.

Auditory, Lexical, and Multitasking Demands Interactively Impact Listening Effort

PURPOSE

This study examined the extent to which acoustic, linguistic, and cognitive task demands interactively impact listening effort.

METHOD

Using a dual-task paradigm, on each trial, participants were instructed to perform either a single task or two tasks. In the primary word recognition task, participants repeated Northwestern University Auditory Test No. 6 words presented in speech-shaped noise at either an easier or a harder signal-to-noise ratio (SNR). The words varied in how commonly they occur in the English language (lexical frequency). In the secondary visual task, participants were instructed to press a specific key as soon as a number appeared on screen (simpler task) or one of two keys to indicate whether the visualized number was even or odd (more complex task).

RESULTS

Manipulation checks revealed that key assumptions of the dual-task design were met. A significant three-way interaction was observed, such that the expected effect of SNR on effort was only observable for words with lower lexical frequency and only when multitasking demands were relatively simpler.

CONCLUSIONS

This work reveals that variability across speech stimuli can influence the sensitivity of the dual-task paradigm for detecting changes in listening effort. In line with previous work, the results of this study also suggest that higher cognitive demands may limit the ability to detect expected effects of SNR on measures of effort. With implications for real-world listening, these findings highlight that even relatively minor changes in lexical and multitasking demands can alter the effort devoted to listening in noise.

Community Perspectives on Hearing Loss in Rural Alaska

OBJECTIVES

The aim of this study is to present an explanatory model of hearing loss in the Bering Strait region of Alaska in order to contextualize the results of a cluster randomized trial and propose implications for regional hearing-related health care.

DESIGN

To promote ecological validity, or the generalizability of trial findings to real world experiences, qualitative methods (focus groups and interviews) were used within a mixed methods cluster randomized trial evaluating school hearing screening and follow-up processes in 15 communities in the Bering Strait region of Alaska. Focus groups were held between April and August 2017, and semistructured interviews were conducted between December 2018 and August 2019. Convenience sampling was used for six of the 11 focus groups to capture broad community feedback. Purposive sampling was used for the remaining five focus groups and for all interviews to capture a variety of experiences with hearing loss. Audio recordings of focus groups and interviews were transcribed, and both notes and transcripts were deidentified. All notes and transcripts were included in the analysis. The constant comparative method was used to develop a codebook by iteratively moving between transcripts and preliminary themes. Researchers then used this codebook to code data from all focus groups and interviews using qualitative analysis software (NVIVO 12, QSR International) and conducted thematic analyses to distill the findings presented in this article.

RESULTS

Participants in focus groups (n = 116) and interviews (n = 101) shared perspectives in three domains: etiology, impact, and treatment of hearing loss. Regarding etiology, participants emphasized noise-induced hearing loss but also discussed infection-related hearing loss and various causes of ear infections. Participants described the impact of hearing loss on subsistence activities, while also detailing social, academic, and economic consequences. Participants described burdensome treatment pathways that are repetitive and often travel and time intensive. Communication breakdowns within these pathways were also described. Some participants spoke positively of increased access via onsite hearing health care services in "field clinics" as well as via telemedicine services. Others described weaknesses in these processes (infrequent field clinics and communication delays in telemedicine care pathways). Participants also described home remedies and stigma surrounding the treatment for hearing loss.

CONCLUSIONS

Patient-centered health care requires an understanding of context. Explanatory models of illness are context-specific ways in which patients and their networks perceive and describe the experience of an illness or disability. In this study, we documented explanatory models of hearing loss to foster ecological validity and better understand the relevance of research findings to real-life hearing-related experiences. These findings suggest several areas that should be addressed in future implementation of hearing health care interventions elsewhere in rural Alaska, including management of repetitious treatments, awareness of infection-mediated hearing loss, mistrust, and communication breakdowns. For hearing-related health care in this region, these findings suggest localized recommendations for approaches for prevention and treatment. For community-based hearing research, this study offers an example of how qualitative methods can be used to generate ecologically valid (i.e., contextually grounded) findings.

Ecologically valid virtual reality-based technologies for assessment and rehabilitation of acquired brain injury: a systematic review

Purpose

A systematic review was conducted to examine the state of the literature regarding using ecologically valid virtual environments and related technologies to assess and rehabilitate people with Acquired Brain Injury (ABI).

Materials and methods

A literature search was performed following the PRISMA guidelines using PubMed, Web of Science, ACM and IEEE databases. The focus was on assessment and intervention studies using ecologically valid virtual environments (VE). All studies were included if they involved individuals with ABI and simulated environments of the real world or Activities of Daily Living (ADL).

Results

Seventy out of 363 studies were included in this review and grouped and analyzed according to the nature of its simulation, prefacing a total of 12 kitchens, 11 supermarkets, 10 shopping malls, 16 streets, 11 cities, and 10 other everyday life scenarios. These VE were mostly presented on computer screens, HMD's and laptops and patients interacted with them primarily via mouse, keyboard, and joystick. Twenty-five out of 70 studies had a non-experimental design.

Conclusion

Evidence about the clinical impact of ecologically valid VE is still modest, and further research with more extensive samples is needed. It is important to standardize neuropsychological and motor outcome measures to strengthen conclusions between studies.

Systematic review registration

identifier CRD42022301560, https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=301560.

Speech comprehension in noise-considerations for ecologically valid assessment of communication skills ability with cochlear implants

BACKGROUND

Nowadays, cochlear implant (CI) patients mostly show good to very good speech comprehension in quiet, but there are known problems with communication in everyday noisy situations. There is thus a need for ecologically valid measurements of speech comprehension in real-life listening situations for hearing-impaired patients. The additional methodological effort must be balanced with clinical human and spatial resources. This study investigates possible simplifications of a complex measurement setup.

METHODS

The study included 20 adults from long-term follow-up after CI fitting with postlingual onset of hearing impairment. The complexity of the investigated listening situations was influenced by changing the spatiality of the noise sources and the temporal characteristics of the noise. To compare different measurement setups, speech reception thresholds (SRT) were measured unilaterally with different CI processors and settings. Ten normal-hearing subjects served as reference.

RESULTS

In a complex listening situation with four loudspeakers, differences in SRT from CI subjects to the control group of up to 8 dB were found. For CI subjects, this SRT correlated with the situation with frontal speech signal and fluctuating interference signal from the side with R2 = 0.69. For conditions with stationary interfering signals, R2 values <0.2 were found.

CONCLUSION

There is no universal solution for all audiometric questions with respect to the spatiality and temporal characteristics of noise sources. In the investigated context, simplification of the complex spatial audiometric setting while using fluctuating competing signals was possible.

Listening efficiency in adult cochlear-implant users compared with normally-hearing controls at ecologically relevant signal-to-noise ratios

Introduction

Due to having to work with an impoverished auditory signal, cochlear-implant (CI) users may experience reduced speech intelligibility and/or increased listening effort in real-world listening situations, compared to their normally-hearing (NH) peers. These two challenges to perception may be usefully integrated in a measure of listening efficiency: conceptually, the amount of accuracy achieved for a certain amount of effort expended.

Methods

We describe a novel approach to quantifying listening efficiency based on the rate of evidence accumulation toward a correct response in a linear ballistic accumulator (LBA) model of choice decision-making. Estimation of this objective measure within a hierarchical Bayesian framework confers further benefits, including full quantification of uncertainty in parameter estimates. We applied this approach to examine the speech-in-noise performance of a group of 24 CI users (M age: 60.3, range: 20-84 years) and a group of 25 approximately age-matched NH controls (M age: 55.8, range: 20-79 years). In a laboratory experiment, participants listened to reverberant target sentences in cafeteria noise at ecologically relevant signal-to-noise ratios (SNRs) of +20, +10, and +4 dB SNR. Individual differences in cognition and self-reported listening experiences were also characterised by means of cognitive tests and hearing questionnaires.

Results

At the group level, the CI group showed much lower listening efficiency than the NH group, even in favourable acoustic conditions. At the individual level, within the CI group (but not the NH group), higher listening efficiency was associated with better cognition (i.e., working-memory and linguistic-closure) and with more positive self-reported listening experiences, both in the laboratory and in daily life.

Discussion

We argue that listening efficiency, measured using the approach described here, is: (i) conceptually well-motivated, in that it is theoretically impervious to differences in how individuals approach the speed-accuracy trade-off that is inherent to all perceptual decision making; and (ii) of practical utility, in that it is sensitive to differences in task demand, and to differences between groups, even when speech intelligibility remains at or near ceiling level. Further research is needed to explore the sensitivity and practical utility of this metric across diverse listening situations.

Effects of aging on cortical representations of continuous speech

Understanding speech in a noisy environment is crucial in day-to-day interactions and yet becomes more challenging with age, even for healthy aging. Age-related changes in the neural mechanisms that enable speech-in-noise listening have been investigated previously; however, the extent to which age affects the timing and fidelity of encoding of target and interfering speech streams is not well understood. Using magnetoencephalography (MEG), we investigated how continuous speech is represented in auditory cortex in the presence of interfering speech in younger and older adults. Cortical representations were obtained from neural responses that time-locked to the speech envelopes with speech envelope reconstruction and temporal response functions (TRFs). TRFs showed three prominent peaks corresponding to auditory cortical processing stages: early (∼50 ms), middle (∼100 ms), and late (∼200 ms). Older adults showed exaggerated speech envelope representations compared with younger adults. Temporal analysis revealed both that the age-related exaggeration starts as early as ∼50 ms and that older adults needed a substantially longer integration time window to achieve their better reconstruction of the speech envelope. As expected, with increased speech masking envelope reconstruction for the attended talker decreased and all three TRF peaks were delayed, with aging contributing additionally to the reduction. Interestingly, for older adults the late peak was delayed, suggesting that this late peak may receive contributions from multiple sources. Together these results suggest that there are several mechanisms at play compensating for age-related temporal processing deficits at several stages but which are not able to fully reestablish unimpaired speech perception.NEW & NOTEWORTHY We observed age-related changes in cortical temporal processing of continuous speech that may be related to older adults' difficulty in understanding speech in noise. These changes occur in both timing and strength of the speech representations at different cortical processing stages and depend on both noise condition and selective attention. Critically, their dependence on noise condition changes dramatically among the early, middle, and late cortical processing stages, underscoring how aging differentially affects these stages.

Auditory discrimination of natural soundscapes

A previous modelling study reported that spectro-temporal cues perceptually relevant to humans provide enough information to accurately classify "natural soundscapes" recorded in four distinct temperate habitats of a biosphere reserve [Thoret, Varnet, Boubenec, Ferriere, Le Tourneau, Krause, and Lorenzi (2020). J. Acoust. Soc. Am. 147, 3260]. The goal of the present study was to assess this prediction for humans using 2 s samples taken from the same soundscape recordings. Thirty-one listeners were asked to discriminate these recordings based on differences in habitat, season, or period of the day using an oddity task. Listeners' performance was well above chance, demonstrating effective processing of these differences and suggesting a general high sensitivity for natural soundscape discrimination. This performance did not improve with training up to 10 h. Additional results obtained for habitat discrimination indicate that temporal cues play only a minor role; instead, listeners appear to base their decisions primarily on gross spectral cues related to biological sound sources and habitat acoustics. Convolutional neural networks were trained to perform a similar task using spectro-temporal cues extracted by an auditory model as input. The results are consistent with the idea that humans exclude the available temporal information when discriminating short samples of habitats, implying a form of a sub-optimality.

Combining Multiple Psychophysiological Measures of Listening Effort: Challenges and Recommendations

About one-third of all recently published studies on listening effort have used at least one physiological measure, providing evidence of the popularity of such measures in listening effort research. However, the specific measures employed, as well as the rationales used to justify their inclusion, vary greatly between studies, leading to a literature that is fragmented and difficult to integrate. A unified approach that assesses multiple psychophysiological measures justified by a single rationale would be preferable because it would advance our understanding of listening effort. However, such an approach comes with a number of challenges, including the need to develop a clear definition of listening effort that links to specific physiological measures, customized equipment that enables the simultaneous assessment of multiple measures, awareness of problems caused by the different timescales on which the measures operate, and statistical approaches that minimize the risk of type-I error inflation. This article discusses in detail the various obstacles for combining multiple physiological measures in listening effort research and provides recommendations on how to overcome them.

A Review of Virtual Reality for Individuals with Hearing Impairments

Virtual Reality (VR) technologies have the potential to be applied in a clinical context to improve training and rehabilitation for individuals with hearing impairment. The introduction of such technologies in clinical audiology is in its infancy and requires devices that can be taken out of laboratory settings as well as a solid collaboration between researchers and clinicians. In this paper, we discuss the state of the art of VR in audiology with applications to measurement and monitoring of hearing loss, rehabilitation, and training, as well as the development of assistive technologies. We review papers that utilize VR delivered through a head-mounted display (HMD) and used individuals with hearing impairment as test subjects, or presented solutions targeted at individuals with hearing impairments, discussing their goals and results, and analyzing how VR can be a useful tool in hearing research. The review shows the potential of VR in testing and training individuals with hearing impairment, as well as the need for more research and applications in this domain.

Toward a clinically viable spectro-temporal modulation test for predicting supra-threshold speech reception in hearing-impaired listeners

The ability of hearing-impaired listeners to detect spectro-temporal modulation (STM) has been shown to correlate with individual listeners' speech reception performance. However, the STM detection tests used in previous studies were overly challenging especially for elderly listeners with moderate-to-severe hearing loss. Furthermore, the speech tests considered as a reference were not optimized to yield ecologically valid outcomes that represent real-life speech reception deficits. The present study investigated an STM detection measurement paradigm with individualized audibility compensation, focusing on its clinical viability and relevance as a real-life supra-threshold speech intelligibility predictor. STM thresholds were measured in 13 elderly hearing-impaired native Danish listeners using four previously established (noise-carrier based) and two novel complex-tone carrier based STM stimulus variants. Speech reception thresholds (SRTs) were measured (i) in a realistic spatial speech-on-speech set up and (ii) using co-located stationary noise, both with individualized amplification. In contrast with previous related studies, the proposed measurement paradigm yielded robust STM thresholds for all listeners and conditions. The STM thresholds were positively correlated with the SRTs, whereby significant correlations were found for the realistic speech-test condition but not for the stationary-noise condition. Three STM stimulus variants (one noise-carrier based and two complex-tone based) yielded significant predictions of SRTs, accounting for up to 53% of the SRT variance. The results of the study could form the basis for a clinically viable STM test for quantifying supra-threshold speech reception deficits in aided hearing-impaired listeners.

Human Auditory Ecology: Extending Hearing Research to the Perception of Natural Soundscapes by Humans in Rapidly Changing Environments

Research in hearing sciences has provided extensive knowledge about how the human auditory system processes speech and assists communication. In contrast, little is known about how this system processes "natural soundscapes," that is the complex arrangements of biological and geophysical sounds shaped by sound propagation through non-anthropogenic habitats [Grinfeder et al. (2022). Frontiers in Ecology and Evolution. 10: 894232]. This is surprising given that, for many species, the capacity to process natural soundscapes determines survival and reproduction through the ability to represent and monitor the immediate environment. Here we propose a framework to encourage research programmes in the field of "human auditory ecology," focusing on the study of human auditory perception of ecological processes at work in natural habitats. Based on large acoustic databases with high ecological validity, these programmes should investigate the extent to which this presumably ancestral monitoring function of the human auditory system is adapted to specific information conveyed by natural soundscapes, whether it operate throughout the life span or whether it emerges through individual learning or cultural transmission. Beyond fundamental knowledge of human hearing, these programmes should yield a better understanding of how normal-hearing and hearing-impaired listeners monitor rural and city green and blue spaces and benefit from them, and whether rehabilitation devices (hearing aids and cochlear implants) restore natural soundscape perception and emotional responses back to normal. Importantly, they should also reveal whether and how humans hear the rapid changes in the environment brought about by human activity.

[Speech comprehension in noise-considerations for ecologically valid assessment of communication skills ability with cochlear implants. German version]

BACKGROUND

Nowadays, cochlear implant (CI) patients mostly show good to very good speech comprehension in quiet, but there are known problems with communication in everyday noisy situations. There is thus a need for ecologically valid measurements of speech comprehension in real-life listening situations for hearing-impaired patients. The additional methodological effort must be balanced with clinical human and spatial resources. This study investigates possible simplifications of a complex measurement setup.

METHODS

The study included 20 adults from long-term follow-up after CI fitting with postlingual onset of hearing impairment. The complexity of the investigated listening situations was influenced by changing the spatiality of the noise sources and the temporal characteristics of the noise. To compare different measurement setups, speech reception thresholds (SRT) were measured unilaterally with different CI processors and settings. Ten normal-hearing subjects served as reference.

RESULTS

In a complex listening situation with four loudspeakers, differences in SRT from CI subjects to the control group of up to 8 dB were found. For CI subjects, this SRT correlated with the situation with frontal speech signal and fluctuating interference signal from the side with R2 = 0.69. For conditions with stationary interfering signals, R2 values <0.2 were found.

CONCLUSION

There is no universal solution for all audiometric questions with respect to the spatiality and temporal characteristics of noise sources. In the investigated context, simplification of the complex spatial audiometric setting while using fluctuating competing signals was possible.

The significance of right ear auditory processing to balance

Although the association between balance and hearing thresholds at different frequencies in the right/left ear is crucial, it has received scant empirical attention. Balance is widely ignored when evaluating hearing in adults. This study examined the relative contribution of left versus right ear hearing at different frequencies to balance, and the mediating role of suprathreshold speech perception on age-balance associations. Pure tone hearing thresholds (500-4000 Hz), suprathreshold speech perception, balance, and risk of falling were evaluated in 295 adults. The results indicate that the right ear contributes more to balance than the left ear. This might imply dominance of the left hemisphere in processing hearing cues for balance. Frequencies within the speech range (500/1000/2000 Hz) were correlated with balance and mediated the interaction between age and balance. These results should be considered when tailoring hearing and balance rehabilitation programs.

Interactions between acoustic challenges and processing depth in speech perception as measured by task-evoked pupil response

Speech perception under adverse conditions is a multistage process involving a dynamic interplay among acoustic, cognitive, and linguistic factors. Nevertheless, prior research has primarily focused on factors within this complex system in isolation. The primary goal of the present study was to examine the interaction between processing depth and the acoustic challenge of noise and its effect on processing effort during speech perception in noise. Two tasks were used to represent different depths of processing. The speech recognition task involved repeating back a sentence after auditory presentation (higher-level processing), while the tiredness judgment task entailed a subjective judgment of whether the speaker sounded tired (lower-level processing). The secondary goal of the study was to investigate whether pupil response to alteration of dynamic pitch cues stems from difficult linguistic processing of speech content in noise or a perceptual novelty effect due to the unnatural pitch contours. Task-evoked peak pupil response from two groups of younger adult participants with typical hearing was measured in two experiments. Both tasks (speech recognition and tiredness judgment) were implemented in both experiments, and stimuli were presented with background noise in Experiment 1 and without noise in Experiment 2. Increased peak pupil dilation was associated with deeper processing (i.e., the speech recognition task), particularly in the presence of background noise. Importantly, there is a non-additive interaction between noise and task, as demonstrated by the heightened peak pupil dilation to noise in the speech recognition task as compared to in the tiredness judgment task. Additionally, peak pupil dilation data suggest dynamic pitch alteration induced an increased perceptual novelty effect rather than reflecting effortful linguistic processing of the speech content in noise. These findings extend current theories of speech perception under adverse conditions by demonstrating that the level of processing effort expended by a listener is influenced by the interaction between acoustic challenges and depth of linguistic processing. The study also provides a foundation for future work to investigate the effects of this complex interaction in clinical populations who experience both hearing and cognitive challenges.

Neural tracking as a diagnostic tool to assess the auditory pathway

When a person listens to sound, the brain time-locks to specific aspects of the sound. This is called neural tracking and it can be investigated by analysing neural responses (e.g., measured by electroencephalography) to continuous natural speech. Measures of neural tracking allow for an objective investigation of a range of auditory and linguistic processes in the brain during natural speech perception. This approach is more ecologically valid than traditional auditory evoked responses and has great potential for research and clinical applications. This article reviews the neural tracking framework and highlights three prominent examples of neural tracking analyses: neural tracking of the fundamental frequency of the voice (f0), the speech envelope and linguistic features. Each of these analyses provides a unique point of view into the human brain's hierarchical stages of speech processing. F0-tracking assesses the encoding of fine temporal information in the early stages of the auditory pathway, i.e., from the auditory periphery up to early processing in the primary auditory cortex. Envelope tracking reflects bottom-up and top-down speech-related processes in the auditory cortex and is likely necessary but not sufficient for speech intelligibility. Linguistic feature tracking (e.g. word or phoneme surprisal) relates to neural processes more directly related to speech intelligibility. Together these analyses form a multi-faceted objective assessment of an individual's auditory and linguistic processing.

Ecological Validity, External Validity, and Mundane Realism in Hearing Science

Tests of hearing function are typically conducted in conditions very different from those in which people need to hear and communicate. Even when test conditions are more similar, they cannot represent the diversity of situations that may be encountered by individuals in daily life. As a consequence, it is necessary to consider external validity: the extent to which findings are likely to generalize to conditions beyond those in which data are collected. External validity has long been a concern in many fields and has led to the development of theories and methods aimed at improving generalizability of laboratory findings. Within hearing science, along with related fields, efforts to address generalizability have come to focus heavily on realism: the extent to which laboratory conditions are similar to conditions found in everyday settings of interest. In fact, it seems that realism is now tacitly equated with generalizability. The term that has recently been applied to this approach by many researchers is ecological validity . Recent usage of the term ecological validity within hearing science, as well as other fields, is problematic for three related reasons: (i) it encourages the conflation of the separate concepts of realism and validity; (ii) it diverts attention from the need for methods of quantifying generalization directly; and (iii) it masks a useful longstanding definition of ecological validity within the field of ecological psychology. The definition of ecological validity first used within ecological psychology-the correlation between cues received at the peripheral nervous system and the identity of distant objects or events in the environment-is entirely different from its current usage in hearing science and many related fields. However, as part of an experimental approach known as representative design , the original concept of ecological validity can play a valuable role in facilitating generalizability. This paper will argue that separate existing terms should be used when referring to realism and generalizability, and that the definition of ecological validity provided by the Lens Model may be a valuable conceptual tool within hearing science.