Relations Between Self-Reported Daily-Life Fatigue, Hearing Status, and Pupil Dilation During a Speech Perception in Noise Task

Hearing Impairment: Reduced Pupil Dilation Response and Frontal Activation During Degraded Speech Perception

PURPOSE

A relevant aspect of listening is the effort required during speech processing, which can be assessed by pupillometry. Here, we assessed the pupil dilation response of normal-hearing (NH) and hard of hearing (HH) individuals during listening to clear sentences and masked or degraded sentences. We combined this assessment with functional magnetic resonance imaging (fMRI) to investigate the neural correlates of the pupil dilation response.

METHOD

Seventeen NH participants (Mage = 46 years) were compared to 17 HH participants (Mage = 45 years) who were individually matched in age and educational level. Participants repeated sentences that were presented clearly, that were distorted, or that were masked. The sentence intelligibility level of masked and distorted sentences was 50% correct. Silent baseline trials were presented as well. Performance measures, pupil dilation responses, and fMRI data were acquired.

RESULTS

HH individuals had overall poorer speech reception than the NH participants, but not for noise-vocoded speech. In addition, an interaction effect was observed with smaller pupil dilation responses in HH than in NH listeners for the degraded speech conditions. Hearing impairment was associated with higher activation across conditions in the left superior temporal gyrus, as compared to the silent baseline. However, the region of interest analysis indicated lower activation during degraded speech relative to clear speech in bilateral frontal regions and the insular cortex, for HH compared to NH listeners. Hearing impairment was also associated with a weaker relation between the pupil response and activation in the right inferior frontal gyrus. Overall, degraded speech evoked higher frontal activation than clear speech.

CONCLUSION

Brain areas associated with attentional and cognitive-control processes may be increasingly recruited when speech is degraded and are related to the pupil dilation response, but this relationship is weaker in HH listeners.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.27162135.

Relations Among Multiple Dimensions of Self-Reported Listening Effort in Response to an Auditory Psychomotor Vigilance Task

PURPOSE

Listening effort is a broad construct, and there is no consensus on how to subdivide listening effort into dimensions. This project focuses on the subjective experience of effortful listening and tests if cognitive workload, mental fatigue, and mood are interrelated dimensions.

METHOD

Two online studies tested young adults (n = 74 and n = 195) and measured subjective workload, fatigue (subscales of fatigue and energy), and mood (subscales of positive and negative mood) before and after a challenging listening task. In the listening effort task, participants responded to intermittent 1-kHz target tones in continuous white noise for approximately 12 min.

RESULTS

Correlations and principal component analysis showed that fatigue and mood were distinct but interrelated constructs that weakly correlated with workload. Effortful listening provoked increased fatigue and decreased energy and positive mood yet did not influence negative mood or workload.

CONCLUSIONS

The findings suggest that self-reported listening effort has multiple dimensions that can have different responses to the same effortful listening episode. The results can help guide evidence-based development of clinical listening effort tests and may reveal mechanisms for how listening effort relates to quality of life in those with hearing impairment.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.26418976.

Impact of light on task-evoked pupil responses during cognitive tasks

Light has many non-image-forming functions including modulation of pupil size and stimulation of alertness and cognition. Part of these non-image-forming effects may be mediated by the brainstem locus coeruleus. The processing of sensory inputs can be associated with a transient pupil dilation that is likely driven in part by the phasic activity of the locus coeruleus. In the present study, we aimed to characterise the task-evoked pupil response associated with auditory inputs under different light levels and across two cognitive tasks. We continuously monitored the pupil of 20 young healthy participants (mean [SD] 24.05 [4.0] years; 14 women) whilst they completed an attentional and an emotional auditory task whilst exposed to repeated 30-40-s blocks of light interleaved with darkness periods. Blocks could either consist of monochromatic orange light (0.16 melanopic equivalent daylight illuminance (EDI) lux) or blue-enriched white light of three different levels [37, 92, 190 melanopic EDI lux; 6500 K]. For the analysis, 15 and then 14 participants were included in the attentional and emotional tasks, respectively. Generalised linear mixed models showed a significant main effect of light level on the task-evoked pupil responses triggered by the attentional and emotional tasks (p ≤ 0.0001). The impact of light was different for the target versus non-target stimulus of the attentional task but was not different for the emotional and neutral stimulus of the emotional task. There is a smaller sustained pupil size during brighter light blocks but, a higher light level triggers a stronger task-evoked pupil response to auditory stimulation, presumably through the recruitment of the locus coeruleus.

Auditory Challenges and Listening Effort in School-Age Children With Autism: Insights From Pupillary Dynamics During Speech-in-Noise Perception

PURPOSE

This study aimed to investigate challenges in speech-in-noise (SiN) processing faced by school-age children with autism spectrum conditions (ASCs) and their impact on listening effort.

METHOD

Participants, including 23 Mandarin-speaking children with ASCs and 19 age-matched neurotypical (NT) peers, underwent sentence recognition tests in both quiet and noisy conditions, with a speech-shaped steady-state noise masker presented at 0-dB signal-to-noise ratio in the noisy condition. Recognition accuracy rates and task-evoked pupil responses were compared to assess behavioral performance and listening effort during auditory tasks.

RESULTS

No main effect of group was found on accuracy rates. Instead, significant effects emerged for autistic trait scores, listening conditions, and their interaction, indicating that higher trait scores were associated with poorer performance in noise. Pupillometric data revealed significantly larger and earlier peak dilations, along with more varied pupillary dynamics in the ASC group relative to the NT group, especially under noisy conditions. Importantly, the ASC group's peak dilation in quiet mirrored that of the NT group in noise. However, the ASC group consistently exhibited reduced mean dilations than the NT group.

CONCLUSIONS

Pupillary responses suggest a different resource allocation pattern in ASCs: An initial sharper and larger dilation may signal an intense, narrowed resource allocation, likely linked to heightened arousal, engagement, and cognitive load, whereas a subsequent faster tail-off may indicate a greater decrease in resource availability and engagement, or a quicker release of arousal and cognitive load. The presence of noise further accentuates this pattern. This highlights the unique SiN processing challenges children with ASCs may face, underscoring the importance of a nuanced, individual-centric approach for interventions and support.

Changes in Listening Effort Through Pupil Response After Atresioplasty in Children With Congenital Aural Atresia

OBJECTIVES

This study aimed to determine whether the improvement of hearing by surgical treatment alleviates cognitive demands through pupil response in patients with unilateral congenital aural atresia (CAA).

DESIGN

A prospective study was performed on patients with unilateral CAA who were scheduled to undergo primary atresioplasty between November 2017 and May 2020. Pure-tone audiometry, auditory digit span test, Korean Speech Perception in Noise test, pupil measurement during speech tests, and questionnaires (Sound-Spatial-Qualities of Hearing Scale; subjective listening effort rating) were performed before and 6 months after surgery.

RESULTS

Of 30 consecutive patients who initially enrolled, only 18 patients (12 males and 6 females) were included in the analysis. When the improvement of the air-bone gap and interaural difference of air conduction within 30 dB was defined as a successful hearing outcome, successful hearing improvement was achieved in 50% of the 18 patients. In pupil measurement, the success group had a significantly smaller mean pupil dilation response than the nonsuccess group at 0 and -3 dB signal to noise ratio (SNR) (all p < 0.01). In addition, significant differences were identified between the two groups for peak dilation and peak latency at all noise levels (all p < 0.01). When analyzing the change in pupil response before and after surgery, the difference in relative mean pupil dilation in the success group was significantly greater than that in the nonsuccess group at -3 dB SNR ( p = 0.02). In addition, the success group showed a significantly greater change in peak latency than the nonsuccess group at the -3 dB SNR ( p < 0.01). The difference in peak dilation tended to be greater in the success group than in the nonsuccess group, but the difference was not statistically significant.

CONCLUSIONS

Patients with unilateral CAA who achieved surgically improved hearing had a smaller pupil dilation response than those who did not. These results suggest that successful hearing outcomes after surgery in patients with unilateral CAA may reduce the cognitive effort required to understand speech under difficult listening conditions.

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

OBJECTIVES

The Framework for Effortful Listening (FUEL) suggests five input-related demands can alter listening effort: source, transmission, listener, message and context factors. We hypothesised that vocoded sentences represented a source factor degradation and sentences in speech-shaped noise represented a transmission factor degradation. We used pupillometry and a subjective scale to examine our hypothesis.

DESIGN

Participants listened to vocoded sentences and sentences in speech-shaped noise at several difficulty levels designed to produce similar word recognition abilities; they also listened to unprocessed sentences. Within-participant pupillometrics and subjective listening effort were analysed. Post-hoc analyses were performed to examine if word recognition accuracy differentially influenced pupil responses.

STUDY SAMPLES

Twenty young adults with normal hearing.

RESULTS

Baseline pupil diameter was significantly smaller, peak pupil dilation was significantly larger, peak pupil dilation latency was significantly shorter, and subjective listening effort was significantly greater for the vocoded sentences than the sentences-in-noise. Word recognition ability also affected pupillometrics, but only for the vocoded sentences.

CONCLUSIONS

Our findings suggest that source factor degradations result in greater listening effort than transmission factor degradations. Future research should address how clinical interventions tailored towards different input-related demands may lead to reduced listening effort and improve patient outcomes.

Discrimination of Second Language Vowel Contrasts and the Role of Phonological Short-Term Memory and Nonverbal Intelligence

Although extensive research has focused on the perceptual abilities of second language (L2) learners, a significant gap persists in understanding how cognitive functions like phonological short-term memory (PSTM) and nonverbal intelligence (IQ) impact L2 speech perception. This study sets out to investigate the discrimination of L2 English monophthongal vowel contrasts and to assess the effect of PSTM and nonverbal IQ on L2 speech perception. The participants consisted of adult monolingually-raised Greek speakers, who completed an AX discrimination test, a digit span test, and a nonverbal intelligence test. A control group of English speakers also completed the AX test. Data were analyzed using Bayesian regression models. The results revealed that Greek speakers exhibited below chance discrimination for the majority of L2 vowel contrasts, consistently underperforming in comparison to the control group. Intriguingly, the study did not provide substantial evidence in favor of more accurate discrimination of L2 contrasts by Greek participants with high PSTM compared to those with low PSTM. However, the study yielded compelling evidence indicating that Greek participants with higher IQ demonstrated superior accuracy in discriminating most L2 contrasts compared to their lower IQ counterparts. The limited influence of PSTM on speech perception suggests the need for further exploration, considering the potential impact of test methodologies and the intricate interplay of other confounding factors. Furthermore, the study uncovers a noteworthy relationship between nonverbal IQ and L2 speech perception, likely linked with the association of high IQ with enhanced attentional capacities, information processing abilities, and learning skills-all of which are pivotal for accurate speech perception.

Remote Cochlear Implant Assessments: Validity and Stability in Self-Administered Smartphone-Based Testing

OBJECTIVES

The stability of remote testing in cochlear implant care was studied by testing the influence of time-of-day, listener fatigue, and motivation on the outcomes of the aided threshold test (ATT) and digit triplets test (DTT) in cochlear implant (CI) recipients using self-tests at-home on a smartphone or tablet.

DESIGN

A single-center repeated measures cohort study design (n = 50 adult CI recipients). The ATT and DTT were tested at-home ten times, with nine of these sessions planned within a period of eight days. Outcomes were modeled as a function of time-of-day, momentary motivation, listeners' task-related fatigue, and chronotype (i.e., someone's preference for morning or evening due to the sleep-wake cycle) using linear mixed models. Additional factors included aided monosyllabic word recognition in quiet, daily-life fatigue, age, and CI experience.

RESULTS

Out of 500 planned measurements, 407 ATTs and 476 DTTs were completed. The ATT determined thresholds and impedances were stable across sessions. The factors in the DTT model explained 75% of the total variance. Forty-nine percent of the total variance was explained by individual differences in the participants' DTT performance. For each 10% increase in word recognition in quiet, the DTT speech reception threshold improved by an average of 1.6 dB. DTT speech reception threshold improved, on average by 0.1 dB per repeated session and correlated with the number of successful DTTs per participant. There was no significant time-of-day effect on auditory performance in at-home administered tests.

CONCLUSIONS

This study is one of the first to report on the validity and stability of remote assessments in CI recipients and reveals relevant factors. CI recipients can be self-tested at any waking hour to monitor performance via smartphone or tablet. Motivation, task-related fatigue, and chronotype did not affect the outcomes of ATT or DTT in the studied cohort. Word recognition in quiet is a good predictor for deciding whether the DTT should be included in an individual's remote test battery. At-home testing is reliable for cochlear implant recipients and offers an opportunity to provide care in a virtual hearing clinic setting.

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.

The Influence of Hearing Loss on the Pupil Response to Degraded Speech

PURPOSE

Current evidence regarding the influence of hearing loss on the pupil response elicited by speech perception is inconsistent. This might be partially due to confounding effects of age. This study aimed to compare pupil responses in age-matched groups of normal-hearing (NH) and hard of hearing (HH) listeners during listening to speech.

METHOD

We tested the baseline pupil size and mean and peak pupil dilation response of 17 NH participants (Mage = 46 years; age range: 20-62 years) and 17 HH participants (Mage = 45 years; age range: 20-63 years) who were pairwise matched on age and educational level. Participants performed three speech perception tasks at a 50% intelligibility level: noise-vocoded speech and speech masked with either stationary noise or interfering speech. They also listened to speech presented in quiet.

RESULTS

Hearing loss was associated with poorer speech perception, except for noise-vocoded speech. In contrast to NH participants, performance of HH participants did not improve across trials for the interfering speech condition, and it decreased for speech in stationary noise. HH participants had a smaller mean pupil dilation in degraded speech conditions compared to NH participants, but not for speech in quiet. They also had a steeper decline in the baseline pupil size across trials. The baseline pupil size was smaller for noise-vocoded speech as compared to the other conditions. The normalized data showed an additional group effect on the baseline pupil response.

CONCLUSIONS

Hearing loss is associated with a smaller pupil response and steeper decline in baseline pupil size during the perception of degraded speech. This suggests difficulties of the HH participants to sustain their effort investment and performance across the test session.

Auditory-Perceptual and Pupillometric Evaluation of Vocal Roughness and Listening Effort in Tracheoesophageal Speech

OBJECTIVES

This study evaluated auditory-perceptual judgments of perceived vocal roughness (VR) and listening effort (LE) along with pupillometric responses in response to speech samples produced by tracheoesophageal (TE) talkers.

METHODS

Twenty normal-hearing, naive young adults (eight men and twelve women) served as listeners. Listeners were divided into two groups: (1) a with-anchor (WA) group (four men and six women) and (2) a no-anchor (NA) group (four men and six women). All were presented with speech samples produced by twenty TE talkers; listeners evaluated two auditory-perceptual dimensions-VR and LE-using visual analog scales. Anchors were provided to the WA group as an external referent for their ratings. In addition, during the auditory-perceptual task, each listener's pupil reactions also were recorded with peak pupil dilation (PPD) measures extracted as a physiologic indicator associated with the listening task.

RESULTS

High interrater reliability was obtained for both the WA and NA groups. High correlations also were observed between auditory-perceptual ratings of roughness and LE, and between PPD values and ratings of both dimensions for the WA group. The inclusion of an anchor during the auditory-perceptual task improved interrater reliability ratings, but it also imposed an increased demand on listeners.

CONCLUSIONS

Data obtained offer insights into the relationship between subjective indices of voice quality (ie, auditory-perceptual evaluation) and physiologic responses (PPD) to the abnormal voice quality that characterizes TE talkers. Furthermore, these data provide information on the inclusion/exclusion of audio anchors and potential increases in listener demand in response to abnormal voice quality.

Speech recognition in noise task among children and young-adults: a pupillometry study

Introduction

Children experience unique challenges when listening to speech in noisy environments. The present study used pupillometry, an established method for quantifying listening and cognitive effort, to detect temporal changes in pupil dilation during a speech-recognition-in-noise task among school-aged children and young adults.

Methods

Thirty school-aged children and 31 young adults listened to sentences amidst four-talker babble noise in two signal-to-noise ratios (SNR) conditions: high accuracy condition (+10 dB and  + 6 dB, for children and adults, respectively) and low accuracy condition (+5 dB and + 2 dB, for children and adults, respectively). They were asked to repeat the sentences while pupil size was measured continuously during the task.

Results

During the auditory processing phase, both groups displayed pupil dilation; however, adults exhibited greater dilation than children, particularly in the low accuracy condition. In the second phase (retention), only children demonstrated increased pupil dilation, whereas adults consistently exhibited a decrease in pupil size. Additionally, the children's group showed increased pupil dilation during the response phase.

Discussion

Although adults and school-aged children produce similar behavioural scores, group differences in dilation patterns point that their underlying auditory processing differs. A second peak of pupil dilation among the children suggests that their cognitive effort during speech recognition in noise lasts longer than in adults, continuing past the first auditory processing peak dilation. These findings support effortful listening among children and highlight the need to identify and alleviate listening difficulties in school-aged children, to provide proper intervention strategies.

Time Scales and Moments of Listening Effort Revealed in Pupillometry

This article offers a collection of observations that highlight the value of time course data in pupillometry and points out ways in which these observations create deeper understanding of listening effort. The main message is that listening effort should be considered on a moment-to-moment basis rather than as a singular amount. A review of various studies and the reanalysis of data reveal distinct signatures of effort before a stimulus, during a stimulus, in the moments after a stimulus, and changes over whole experimental testing sessions. Collectively these observations motivate questions that extend beyond the "amount" of effort, toward understanding how long the effort lasts, and how precisely someone can allocate effort at specific points in time or reduce effort at other times. Apparent disagreements between studies are reconsidered as informative lessons about stimulus selection and the nature of pupil dilation as a reflection of decision making rather than the difficulty of sensory encoding.

Dual-Task Paradigm Measures of Listening Effort: To Include or Not to Include Secondary Task Responses with Incorrect Primary Task Responses

Response time–based dual-task paradigms are commonly adopted to measure behavioral listening effort. Most extant studies used an all-response approach that included secondary task responses under both correct and incorrect primary task responses during analysis. However, evidence supporting this strategy is limited. Therefore, the current study investigated the potential differences between including all responses versus only including correct responses. Data from two previous studies were reanalyzed. Experiment 1 included 16 listeners and used a dual-task paradigm to examine the effect of introducing background noise on listening effort. Experiment 2 included 19 participants and used a different dual-task paradigm to examine the effect of reverberation and loudspeaker-to-listener distance on listening effort. ANOVA results obtained using both analysis approaches were compared. The all-response and correct-only approaches revealed similar results. However, larger effect sizes and an additional main effect were found with the all-response approach. The current study supports the use of an all-response approach due to its greater sensitivity to changes in behavioral listening effort. However, a correct-only approach could be utilized to suit specific study purposes.

Impact of hearing impairment and cochlear implantation on productivity and social well-being in a professionally active but severely hearing-impaired group: protocol of the 'Hear again, work again' longitudinal prospective cohort study

INTRODUCTION

Severe hearing loss is a sensory deficit with considerable impact on the patient's daily life and on society. Previous research has established occupational obstacles in professionally active patients with hearing loss. However, studies investigating the impact of severe hearing loss and cochlear implantation (CI) on work performance using a quantitative and longitudinal study design and validated questionnaires are lacking. This study aims to answer the following research question: 'What is the impact of unilateral and bilateral severe hearing loss and CI on the cost for society, health state, employment, productivity and social well-being?'. We hypothesise hearing impairment to influence work performance. After establishing the impact, we will be able to enhance the support of hearing impaired patients to maintain employed.

METHODS AND ANALYSIS

A total of 200 professionally active adults between 18 and 65 years old with severe hearing loss will be included for assessment at baseline and reassessment at 3, 6 and 12 months. The following four study groups are included: bilateral severely hearing impaired participants without CI (1) and with CI (2) and unilateral severely hearing impaired participants in acute (3) and chronic (4) setting. The primary outcome of this study is the change in index score on the Work Limitations Questionnaire, which evaluates the degree of limitations and health-related productivity loss. Secondary outcome measures include audiometric and cognitive evaluations and validated questionnaires evaluating employment, work productivity, quality of life and direct healthcare costs. Linear mixed models will assess the evolution in time and the difference in evolution between groups.

ETHICS AND DISSEMINATION

This study protocol (project ID 2021-0306) received ethical approval from the ethics committee of the Antwerp University Hospital on 22 November 2021. Our findings will be disseminated by peer-reviewed publications and conference presentations.

TRIAL REGISTRATION NUMBER

NCT05196022.

Quality of Life Impact of Cochlear Implantation for Single-Sided Deafness: Assessing the Interrelationship of Objective and Subjective Measures

OBJECTIVE

To determine the effect on quality of life (QOL) of cochlear implantation (CI) for single-sided deafness (SSD) and asymmetric hearing loss (AHL) using the first psychometrically developed CI-specific QOL tool for English-speaking patients and to assess its relationship to objective perceptual measures.

STUDY DESIGN

Retrospective cohort study.

SETTING

Tertiary-care medical center.

PATIENTS

English-speaking adults with SSD or AHL.

INTERVENTIONS

Unilateral CI.

MAIN OUTCOME MEASURES

Cochlear Implant Quality of Life (CIQOL) score, CI-alone speech-in-quiet (SIQ) score (CNC and AzBio), binaural speech-in-noise (SIN) threshold, binaural azimuthal sound localization (SL) error.

RESULTS

At the most recent postoperative evaluation (median, 9.3 months postimplantation), 25 of 28 subjects (89%) had a CIQOL improvement, with the improvement considered clinically beneficial (>3 points) for 18 of 28 subjects (64%). Group-mean CIQOL improvement was observed at the first postoperative visit and did not change significantly thereafter. Objective perceptual measures (SL, SIQ, SIN) continued to improve over 12 months after implantation. Linear mixed-model regression analyses showed a moderate positive correlation between SIN and SIQ improvements (r = 0.50 to 0.59, p < 0.0001) and a strong positive correlation between the improvement in the two SIQ measures (r = 0.89, p < 0.0001). No significant relationships were observed ( p > 0.05) among QOL or the objective perceptual measures.

CONCLUSIONS

QOL improved for the majority of subjects implanted for SSD and AHL. Different time courses for improvement in QOL and audiologic tests, combined with the lack of significant relationships among them, suggest that QOL outcomes reflect different aspects of the CI experience than those captured by speech-understanding and localization measures. SIQ may substitute for SIN when clinical constraints exist.

Exploring the Correlations Between Measures of Listening Effort in Adults and Children: A Systematic Review with Narrative Synthesis

Listening effort (LE) describes the cognitive resources needed to process an auditory message. Our understanding of this notion remains in its infancy, hindering our ability to appreciate how it impacts individuals with hearing impairment effectively. Despite the myriad of proposed measurement tools, a validated method remains elusive. This is complicated by the seeming lack of association between tools demonstrated via correlational analyses. This review aims to systematically review the literature relating to the correlational analyses between different measures of LE. Five databases were used- PubMed, Cochrane, EMBASE, PsychINFO, and CINAHL. The quality of the evidence was assessed using the GRADE criteria and risk of bias with ROBINS-I/GRADE tools. Each statistically significant analysis was classified using an approved system for medical correlations. The final analyses included 48 papers, equating to 274 correlational analyses, of which 99 reached statistical significance (36.1%). Within these results, the most prevalent classifications were poor or fair. Moreover, when moderate or very strong correlations were observed, they tended to be dependent on experimental conditions. The quality of evidence was graded as very low. These results show that measures of LE are poorly correlated and supports the multi-dimensional concept of LE. The lack of association may be explained by considering where each measure operates along the effort perception pathway. Moreover, the fragility of significant correlations to specific conditions further diminishes the hope of finding an all-encompassing tool. Therefore, it may be prudent to focus on capturing the consequences of LE rather than the notion itself.

Factors associated with change in the need for recovery and subjective listening effort in employees with hearing loss receiving aural rehabilitation

OBJECTIVE

Compared to normally-hearing employees, those with hearing loss suffer from higher Need For Recovery (NFR) after work. The aims of this study are to assess the NFR of employees with hearing loss before and after aural rehabilitation and to examine to what extent change in the NFR can be explained by changes in subjective listening effort, personal adjustments, communication strategies, auditory work demands, and self-reported hearing ability.

METHODS

We included patients who received aural rehabilitation in two audiological centers in the Netherlands because of hearing complaints in their work situation. Outcomes were measured by questionnaires at baseline and 3 month follow-up. The NFR before and after the rehabilitation was compared with a t test. Hierarchical multiple analyses were performed.

RESULTS

In total, 60 patients (aged 22-63, working hours ≥8 per week) participated in the study, of which 50 completed the follow-up questionnaires. The NFR was significantly lower after the aural rehabilitation (M = 45.03) compared to before the aural rehabilitation (M = 51.89), t = -3.43, p < 0.01). Change in NFR could best be explained by the change in personal adjustments (R² = 0.45, B = -1.23, p < 0.01).

CONCLUSION

The NFR of employees with hearing loss can be improved by aural rehabilitation, but this study shows that current practices reduce the NFR only in part of the employees. Therefore, improving current practices should be considered and evaluated, for example by applying a different combination of rehabilitation components. Especially, interventions that affect personal adjustments may be promising to further reduce the NFR in employees with hearing loss.

Previous Mental Load and Incentives Influence Anticipatory Arousal as Indexed by the Baseline Pupil Diameter in a Speech-in-Noise Task

Listening effort and fatigue are common experiences when conversing in noisy environments. Much research has investigated listening effort in relation to listening demand using the speech-in-noise paradigm. Recent conceptualizations of listening effort postulate that mental fatigue should result in decreased arousal and a reluctance to invest further effort, particularly when the effort is not worthwhile. The aim of the study was to investigate the influence of fatigue on listening effort, in interaction with listening demands and motivation. To induce fatigue 30 adults with normal hearing completed a 40-minute long speech-in-noise task ("load sequence"). Pre- and post-load sequence listening effort was probed in easy and hard listening demands (individually adjusted signal-to-noise ratios); with high and low motivation (manipulated with monetary incentives). Subjective effort, estimated performance, and tendency to quit listening were collected using rating scales. Baseline pupil diameter and mean pupil dilation were recorded as indices of anticipatory arousal and objective effort. Self-reported effort and mean pupil dilation were overall larger during hard SNR as compared to easy SNR. Baseline pupil diameter declined from pre- to post-load sequence, suggesting an overall decrease in arousal. Monetary incentives had no influence on the baseline pupil diameter for the easy SNR condition, but for the hard SNR condition larger incentives led to larger baseline pupil diameter. These results suggest that anticipatory arousal may be influenced by fatigue and motivation effects. Models of listening effort should account for the independent influence of motivation and previous load on anticipatory arousal and effort in distinct parameters.

Study protocol for a randomised controlled trial evaluating the benefits from bimodal solution with cochlear implant and hearing aid versus bilateral hearing aids in patients with asymmetric speech identification scores

INTRODUCTION

Cochlear implant (CI) and hearing aid (HA) in a bimodal solution (CI+HA) is compared with bilateral HAs (HA+HA) to test if the bimodal solution results in better speech intelligibility and self-reported quality of life.

METHODS AND ANALYSIS

This randomised controlled trial is conducted in Odense University Hospital, Denmark. Sixty adult bilateral HA users referred for CI surgery are enrolled if eligible and undergo: audiometry, speech perception in noise (HINT: Hearing in Noise Test), Speech Identification Scores and video head impulse test. All participants will receive new replacement HAs. After 1 month they will be randomly assigned (1:1) to the intervention group (CI+HA) or to the delayed intervention control group (HA+HA). The intervention group (CI+HA) will receive a CI on the ear with a poorer speech recognition score and continue using the HA on the other ear. The control group (HA+HA) will receive a CI after a total of 4 months of bilateral HA use.The primary outcome measures are speech intelligibility measured objectively with HINT (sentences in noise) and DANTALE I (words) and subjectively with the Speech, Spatial and Qualities of Hearing scale questionnaire. Secondary outcomes are patient reported Health-Related Quality of Life scores assessed with the Nijmegen Cochlear Implant Questionnaire, the Tinnitus Handicap Inventory and Dizziness Handicap Inventory. Third outcome is listening effort assessed with pupil dilation during HINT.In conclusion, the purpose is to improve the clinical decision-making for CI candidacy and optimise bimodal solutions.

ETHICS AND DISSEMINATION

This study protocol was approved by the Ethics Committee Southern Denmark project ID S-20200074G. All participants are required to sign an informed consent form.This study will be published on completion in peer-reviewed publications and scientific conferences.

TRIAL REGISTRATION NUMBER

NCT04919928.

Speech to noise ratio improvement induces nonlinear parietal phase synchrony in hearing aid users

Objectives

Comprehension of speech in adverse listening conditions is challenging for hearing-impaired (HI) individuals. Noise reduction (NR) schemes in hearing aids (HAs) have demonstrated the capability to help HI to overcome these challenges. The objective of this study was to investigate the effect of NR processing (inactive, where the NR feature was switched off, vs. active, where the NR feature was switched on) on correlates of listening effort across two different background noise levels [+3 dB signal-to-noise ratio (SNR) and +8 dB SNR] by using a phase synchrony analysis of electroencephalogram (EEG) signals.

Design

The EEG was recorded while 22 HI participants fitted with HAs performed a continuous speech in noise (SiN) task in the presence of background noise and a competing talker. The phase synchrony within eight regions of interest (ROIs) and four conventional EEG bands was computed by using a multivariate phase synchrony measure.

Results

The results demonstrated that the activation of NR in HAs affects the EEG phase synchrony in the parietal ROI at low SNR differently than that at high SNR. The relationship between conditions of the listening task and phase synchrony in the parietal ROI was nonlinear.

Conclusion

We showed that the activation of NR schemes in HAs can non-linearly reduce correlates of listening effort as estimated by EEG-based phase synchrony. We contend that investigation of the phase synchrony within ROIs can reflect the effects of HAs in HI individuals in ecological listening conditions.

Listening Over Time: Single-Trial Tonic and Phasic Oscillatory Alpha-and Theta-Band Indicators of Listening-Related Fatigue

Objectives

Listening effort engages cognitive resources to support speech understanding in adverse listening conditions, and leads to fatigue over the longer term for people with hearing loss. Direct, neural measures of listening-related fatigue have not been developed. Here, event-related or phasic changes in alpha and theta oscillatory power during listening were used as measures of listening effort, and longer-term or tonic changes over the course of the listening task were assessed as measures of listening-related fatigue. In addition, influences of self-reported fatigue and degree of hearing loss on tonic changes in oscillatory power were examined.

Design

Participants were middle-aged adults (age 37–65 years; n = 12) with age-appropriate hearing. Sentences were presented in a background of multi-talker babble at a range of signal-to-noise ratios (SNRs) varying around the 80 percent threshold of individual listeners. Single-trial oscillatory power during both sentence and baseline intervals was analyzed with linear mixed-effect models that included as predictors trial number, SNR, subjective fatigue, and hearing loss.

Results

Alpha and theta power in both sentence presentation and baseline intervals increased as a function of trial, indicating listening-related fatigue. Further, tonic power increases across trials were affected by hearing loss and/or subjective fatigue, particularly in the alpha-band. Phasic changes in alpha and theta power generally tracked with SNR, with decreased alpha power and increased theta power at less favorable SNRs. However, for the alpha-band, the linear effect of SNR emerged only at later trials.

Conclusion

Tonic increases in oscillatory power in alpha- and theta-bands over the course of a listening task may be biomarkers for the development of listening-related fatigue. In addition, alpha-band power as an index of listening-related fatigue may be sensitive to individual differences attributable to level of hearing loss and the subjective experience of listening-related fatigue. Finally, phasic effects of SNR on alpha power emerged only after a period of listening, suggesting that this measure of listening effort could depend on the development of listening-related fatigue.

Assessment methods for determining small changes in hearing performance over time

Although the behavioral pure-tone threshold audiogram is considered the gold standard for quantifying hearing loss, assessment of speech understanding, especially in noise, is more relevant to quality of life but is only partly related to the audiogram. Metrics of speech understanding in noise are therefore an attractive target for assessing hearing over time. However, speech-in-noise assessments have more potential sources of variability than pure-tone threshold measures, making it a challenge to obtain results reliable enough to detect small changes in performance. This review examines the benefits and limitations of speech-understanding metrics and their application to longitudinal hearing assessment, and identifies potential sources of variability, including learning effects, differences in item difficulty, and between- and within-individual variations in effort and motivation. We conclude by recommending the integration of non-speech auditory tests, which provide information about aspects of auditory health that have reduced variability and fewer central influences than speech tests, in parallel with the traditional audiogram and speech-based assessments.

Repetition of anchor stimuli and nature of vocal samples in the perceptual auditory judgment performed by speech-language pathology students

PURPOSE

Verify the effect of anchor repetition in the perceptual auditory judgement of the type of vocal deviation performed by speech-language pathology (SLP) students; analyze the correlation between the amount of different vocal dimensions in the same stimuli and accuracy; investigate the correlation between type of vocal deviation and accuracy.

METHODS

54 SLP students were divided in two groups: Group with repetition (GwR), 28 students; and, Group with no repetition (GnR), 26 students. The analyzed sample counted with 220 dysphonic human voices, vowel /ε/. The GwR heard three anchor stimuli before the judgement and every 20 voices during the assessment. The GnR heard the anchor only before beginning the judgement. The anchor stimuli counted with one rough, one breathy and one strain voice. These classifications were compared with reference judgements from three expert SLPs. The intra and inter-rater reliability, the correlation between the amount of different vocal dimensions in the same stimuli and type of vocal deviation with accuracy were assessed.

RESULTS

The accuracy between type of deviation was similar among groups. The GwR presented slightly higher intra and inter-rater reliability. The student's accuracy was inversely proportional to the amount of different vocal dimensions in the stimuli. Breathiness presented the highest accuracy and strain presented the lowest accuracy.

CONCLUSION

The repetition of anchor stimuli improved intra and inter-rater reliability. However, it was not effective in the accuracy of the type of vocal deviation. The amount of different vocal dimensions in the stimuli have influence in the students' accuracy.

Quantifying the Effect of Noise on Cognitive Processes: A Review of Psychophysiological Correlates of Workload

Noise is present in most work environments, including emissions from machines and devices, irrelevant speech from colleagues, and traffic noise. Although it is generally accepted that noise below the permissible exposure limits does not pose a considerable risk for auditory effects like hearing impairments. Yet, noise can have a direct adverse effect on cognitive performance (non-auditory effects like workload or stress). Under certain circumstances, the observable performance for a task carried out in silence compared to noisy surroundings may not differ. One possible explanation for this phenomenon needs further investigation: individuals may invest additional cognitive resources to overcome the distraction from irrelevant auditory stimulation. Recent developments in measurements of psychophysiological correlates and analysis methods of load-related parameters can shed light on this complex interaction. These objective measurements complement subjective self-report of perceived effort by quantifying unnoticed noise-related cognitive workload. In this review, literature databases were searched for peer-reviewed journal articles that deal with an at least partially irrelevant "auditory stimulation" during an ongoing "cognitive task" that is accompanied by "psychophysiological correlates" to quantify the "momentary workload." The spectrum of assessed types of "auditory stimulations" extended from speech stimuli (varying intelligibility), oddball sounds (repeating short tone sequences), and auditory stressors (white noise, task-irrelevant real-life sounds). The type of "auditory stimulation" was related (speech stimuli) or unrelated (oddball, auditory stressor) to the type of primary "cognitive task." The types of "cognitive tasks" include speech-related tasks, fundamental psychological assessment tasks, and real-world/simulated tasks. The "psychophysiological correlates" include pupillometry and eye-tracking, recordings of brain activity (hemodynamic, potentials), cardiovascular markers, skin conductance, endocrinological markers, and behavioral markers. The prevention of negative effects on health by unexpected stressful soundscapes during mental work starts with the continuous estimation of cognitive workload triggered by auditory noise. This review gives a comprehensive overview of methods that were tested for their sensitivity as markers of workload in various auditory settings during cognitive processing.

Perceived Listening Difficulty in the Classroom, Not Measured Noise Levels, Is Associated With Fatigue in Children With and Without Hearing Loss

PURPOSE

The purpose of this study was to examine if classroom noise levels and perceived listening difficulty were related to fatigue reported by children with and without hearing loss.

METHOD

Measures of classroom noise and reports of classroom listening difficulty were obtained from 79 children (ages 6-12 years) at two time points on two different school days. Forty-four children had mild to moderately severe hearing loss in at least one ear. Multiple regression analyses were conducted to evaluate if measured noise levels, perceived listening difficulty, hearing status, language abilities, or grade level would predict self-reported fatigue ratings measured using the Pediatric Quality of Life Inventory Multidimensional Fatigue Scale.

RESULTS

Higher perceived listening difficulty was the only predictor variable that was associated with greater self-reported fatigue.

CONCLUSIONS

Measured classroom noise levels showed no systematic relationship with fatigue ratings, suggesting that actual classroom noise levels do not contribute to increased reports of subjective fatigue. Instead, perceived challenges with listening appears to be an important factor for consideration in future work examining listening-related fatigue in children with and without hearing loss.

Social observation increases the cardiovascular response of hearing-impaired listeners during a speech reception task

Certain cardiovascular measures allow for distinction between sympathetic and parasympathetic nervous system activity. Applied during listening, these measures may provide a novel and complementary insight into listening effort. To date, few studies have implemented cardiovascular measures of listening effort and seldom have these included hearing-impaired participants. These studies have generally measured changes in cardiovascular parameters while manipulating environmental factors, such as listening difficulty. Yet, listening effort is also known to be moderated by individual factors, including the importance of performing successfully. In this study, we aimed to manipulate success importance by adding observers to the traditional laboratory set-up. Twenty-nine hearing-impaired participants performed a speech reception task both alone and in the presence of two observers. Auditory stimuli consisted of Danish Hearing in Noise Test (HINT) sentences masked by four-talker babble. Sentences were delivered at two individually adapted signal-to-noise ratios, corresponding to 50 and 80% of sentences correct. We measured change scores, relative to baseline, of pre-ejection period, two indices of heart rate variability, heart rate and blood pressure (systolic, diastolic, and mean arterial pressure). After each condition, participants rated their effort investment, stress, tendency to give up and preference to change the situation to improve audibility. A multivariate analysis revealed that cardiovascular reactivity increased in the presence of the observers, compared to when the task was performed alone. More specifically, systolic, diastolic, and mean arterial blood pressure increased while observed. Interestingly, participants' subjective ratings were sensitive only to intelligibility level, not the observation state. This study was the first to report results from a range of different cardiovascular variables measured from hearing-impaired participants during a speech reception task. Due to the timing of the observers' presence, we were not able to conclusively attribute these physiological changes to being task related. Therefore, instead of representing listening effort, we suggest that the increased cardiovascular response detected during observation reveals increased physiological stress associated with potential evaluation.

Increased pupil dilation to happy faces in children with hyperactive/impulsive symptoms of ADHD

Attention-deficit/hyperactivity disorder (ADHD) is associated with disrupted emotional processes including impaired regulation of approach behavior and positive affect, irritability, and anger. Enhanced reactivity to emotional cues may be an underlying process. Pupil dilation is an indirect index of arousal, modulated by the autonomic nervous system and activity in the locus coeruleus-noradrenergic system. In the current study, pupil dilation was recorded while 8- to 12- year old children (n = 71, 26 with a diagnosis of ADHD and 45 typically developing), viewed images of emotional faces. Parent-rated hyperactive/impulsive symptoms were uniquely linked to higher pupil dilation to happy, but not fearful, angry, or neutral faces. This was not explained by comorbid externalizing symptoms. Together, these results suggest that hyperactive/impulsive symptoms are associated with hyperresponsiveness to approach-related emotional cues across a wide range of symptom severity.

The Effect of Hearing Loss and Hearing Device Fitting on Fatigue in Adults: A Systematic Review

OBJECTIVES

To conduct a systematic review to address two research questions: (Q1) Does hearing loss have an effect on fatigue? (Q2) Does hearing device fitting have an effect on fatigue? It was hypothesized that hearing loss would increase fatigue (H1), and hearing device fitting would reduce fatigue (H2).

DESIGN

Systematic searches were undertaken of five bibliographic databases: Embase, MedLine, Web of Science, Psychinfo, and the Cochrane Library. English language peer-reviewed research articles were included from inception until present. Inclusion and exclusion criteria were formulated using the Population, Intervention, Comparison, Outcomes and Study design strategy.

RESULTS

Initial searches for both research questions produced 1,227 unique articles, after removal of duplicates. After screening, the full text of 61 studies was checked, resulting in 12 articles with content relevant to the research questions. The reference lists of these studies were examined, and a final updated search was conducted on October 16, 2019. This resulted in a final total of 20 studies being selected for the review. For each study, the information relating to the Population, Intervention, Comparison, Outcomes and Study design criteria and the statistical outcomes relating to both questions (Q1 and Q2) were extracted. Evidence relating to Q1 was provided by 15 studies, reporting 24 findings. Evidence relating to Q2 was provided by six studies, reporting eight findings. One study provided evidence for both. Using the Grading of Recommendations Assessment, Development and Evaluation guidelines, the quality of evidence on both research questions was deemed to be "very low." It was impossible to perform a meta-analysis of the results due to a lack of homogeneity.

CONCLUSIONS

As the studies were too heterogeneous to support a meta-analysis, it was not possible to provide statistically significant evidence to support the hypotheses that hearing loss results in increased fatigue (H1) or that hearing device fitting results in decreased fatigue (H2). Despite this, the comparative volume of positive results and the lack of any negative findings are promising for future research (particularly in respect of Q1). There was a very small number of studies deemed eligible for the review, and there was large variability between studies in terms of population, and quantification of hearing loss and fatigue. The review highlights the need for consistency when measuring fatigue, particularly when using self-report questionnaires, where the majority of the current evidence was generated.

Listening effort and fatigue in native and non-native primary school children

Background noise makes listening effortful and may lead to fatigue. This may compromise classroom learning, especially for children with a non-native background. In the current study, we used pupillometry to investigate listening effort and fatigue during listening comprehension under typical (0 dB signal-to-noise ratio [SNR]) and favorable (+10 dB SNR) listening conditions in 63 Swedish primary school children (7-9 years of age) performing a narrative speech-picture verification task. Our sample comprised both native (n = 25) and non-native (n = 38) speakers of Swedish. Results revealed greater pupil dilation, indicating more listening effort, in the typical listening condition compared with the favorable listening condition, and it was primarily the non-native speakers who contributed to this effect (and who also had lower performance accuracy than the native speakers). Furthermore, the native speakers had greater pupil dilation during successful trials, whereas the non-native speakers showed greatest pupil dilation during unsuccessful trials, especially in the typical listening condition. This set of results indicates that whereas native speakers can apply listening effort to good effect, non-native speakers may have reached their effort ceiling, resulting in poorer listening comprehension. Finally, we found that baseline pupil size decreased over trials, which potentially indicates more listening-related fatigue, and this effect was greater in the typical listening condition compared with the favorable listening condition. Collectively, these results provide novel insight into the underlying dynamics of listening effort, fatigue, and listening comprehension in typical classroom conditions compared with favorable classroom conditions, and they demonstrate for the first time how sensitive this interplay is to language experience.

Pupil Dilation Is Sensitive to Semantic Ambiguity and Acoustic Degradation

Speech comprehension is challenged by background noise, acoustic interference, and linguistic factors, such as the presence of words with more than one meaning (homonyms and homophones). Previous work suggests that homophony in spoken language increases cognitive demand. Here, we measured pupil dilation—a physiological index of cognitive demand—while listeners heard high-ambiguity sentences, containing words with more than one meaning, or well-matched low-ambiguity sentences without ambiguous words. This semantic-ambiguity manipulation was crossed with an acoustic manipulation in two experiments. In Experiment 1, sentences were masked with 30-talker babble at 0 and +6 dB signal-to-noise ratio (SNR), and in Experiment 2, sentences were heard with or without a pink noise masker at –2 dB SNR. Speech comprehension was measured by asking listeners to judge the semantic relatedness of a visual probe word to the previous sentence. In both experiments, comprehension was lower for high- than for low-ambiguity sentences when SNRs were low. Pupils dilated more when sentences included ambiguous words, even when no noise was added (Experiment 2). Pupil also dilated more when SNRs were low. The effect of masking was larger than the effect of ambiguity for performance and pupil responses. This work demonstrates that the presence of homophones, a condition that is ubiquitous in natural language, increases cognitive demand and reduces intelligibility of speech heard with a noisy background.

Mental fatigue measurement using eye metrics: A systematic literature review

Mental fatigue measurement techniques utilize one or a combination of the cognitive, affective, and behavioral responses of the body. Eye-tracking and electrooculography, which are used to compute eye-based features, have gained momentum with increases in accuracy and robustness of the lightweight equipment emerging in the markets and can be used for objective and continuous assessment of mental fatigue. The main goal of this systematic review was to summarize the various eye-based features that have been used to measure mental fatigue and explore the relation of eye-based features to mental fatigue. The review process, following the preferred reporting items for systematic reviews and meta-analyses, used the electronic databases Web of Science, Scopus, ACM digital library, IEEE Xplore, and PubMed. Of the 1,385 retrieved documents, 34 studies met the inclusion criteria, resulting in 21 useful eye-based features. Categorizing these into eight groups revealed saccades as the most promising category, with saccade mean and peak velocity providing quick access to the cognitive states within 30 min of fatiguing activity. Complex brain networks involving sympathetic and parasympathetic nervous systems control the relation of mental fatigue to tonic pupil size and have the potential to indicate mental fatigue in controlled experimental conditions. Other categories, like blinks, are derived from the field of sleep research and should be used with caution. Several limitations emerged in the analysis, including varied experimental methods, use of dim lighting during the experiment (that could possibly also induce sleepiness), and use of unclear data analysis techniques, thereby complicating comparisons between studies.

Associations between pre-stimulus alpha power, hearing level and performance in a digits-in-noise task

OBJECTIVE

Baseline electroencephalography (EEG) alpha power, i.e. that measured prior to stimulus presentation, is a potential objective predictor of task performance. Here we assessed the predictive power of EEG alpha on performance accuracy in a digits-in-noise recognition task, factoring in hearing thresholds and age.

DESIGN

EEG alpha power, recorded while participants listened to target digits presented in a noise background, was analysed during two different baseline periods: i) a pre-stimulus baseline (pre-STIM) free from any acoustic stimulus, and ii) a pre-target baseline (pre-TARG) recorded in background noise only.

STUDY SAMPLE

Eighty-five participants with either normal hearing or aided hearing impairment (age range: 55-85 years old, 42 male).

RESULTS

Hierarchical multiple regression analyses indicated that i) lower hearing thresholds and, to a lesser extent, higher pre-STIM alpha power were associated with improved performance accuracy ii) alpha power in pre-STIM and pre-TARG were highly correlated across individuals but pre-TARG alpha power was not a significant predictor of performance accuracy.

CONCLUSION

Investigations of baseline EEG alpha power as a predictor of speech-in-noise performance accuracy should control for associations between hearing thresholds and measures of EEG baseline periods.

The Principle of Least Effort and Comprehension of Spoken Sentences by Younger and Older Adults

There is considerable evidence that listeners' understanding of a spoken sentence need not always follow from a full analysis of the words and syntax of the utterance. Rather, listeners may instead conduct a superficial analysis, sampling some words and using presumed plausibility to arrive at an understanding of the sentence meaning. Because this latter strategy occurs more often for sentences with complex syntax that place a heavier processing burden on the listener than sentences with simpler syntax, shallow processing may represent a resource conserving strategy reflected in reduced processing effort. This factor may be even more important for older adults who as a group are known to have more limited working memory resources. In the present experiment, 40 older adults (M age = 75.5 years) and 20 younger adults (M age = 20.7) were tested for comprehension of plausible and implausible sentences with a simpler subject-relative embedded clause structure or a more complex object-relative embedded clause structure. Dilation of the pupil of the eye was recorded as an index of processing effort. Results confirmed greater comprehension accuracy for plausible than implausible sentences, and for sentences with simpler than more complex syntax, with both effects amplified for the older adults. Analysis of peak pupil dilations for implausible sentences revealed a complex three-way interaction between age, syntactic complexity, and plausibility. Results are discussed in terms of models of sentence comprehension, and pupillometry as an index of intentional task engagement.

Disentangling listening effort and memory load beyond behavioural evidence: Pupillary response to listening effort during a concurrent memory task

Recent research has demonstrated that pupillometry is a robust measure for quantifying listening effort. However, pupillary responses in listening situations where multiple cognitive functions are engaged and sustained over a period of time remain hard to interpret. This limits our conceptualisation and understanding of listening effort in realistic situations, because rarely in everyday life are people challenged by one task at a time. Therefore, the purpose of this experiment was to reveal the dynamics of listening effort in a sustained listening condition using a word repeat and recall task. Words were presented in quiet and speech-shaped noise at different signal-to-noise ratios (SNR): 0dB, 7dB, 14dB and quiet. Participants were presented with lists of 10 words, and required to repeat each word after its presentation. At the end of the list, participants either recalled as many words as possible or moved on to the next list. Simultaneously, their pupil dilation was recorded throughout the whole experiment. When only word repeating was required, peak pupil dilation (PPD) was bigger in 0dB versus other conditions; whereas when recall was required, PPD showed no difference among SNR levels and PPD in 0dB was smaller than repeat-only condition. Baseline pupil diameter and PPD followed different variation patterns across the 10 serial positions within a block for conditions requiring recall: baseline pupil diameter built up progressively and plateaued in the later positions (but shot up when listeners were recalling the previously heard words from memory); PPD decreased at a pace quicker than in repeat-only condition. The current findings demonstrate that additional cognitive load during a speech intelligibility task could disturb the well-established relation between pupillary response and listening effort. Both the magnitude and temporal pattern of task-evoked pupillary response differ greatly in complex listening conditions, urging for more listening effort studies in complex and realistic listening situations.

Effects of Noise and Serial Position on Free Recall of Spoken Words and Pupil Dilation during Encoding in Normal-Hearing Adults

This preliminary study assessed the effects of noise and stimulus presentation order on recall of spoken words and recorded pupil sizes while normal-hearing listeners were trying to encode a series of words for a subsequent recall task. In three listening conditions (stationary noise in Experiment 1; quiet versus four-talker babble in Experiment 2), participants were assigned to remember as many words as possible to recall them in any order after each list of seven sentences. In the two noise conditions, lists of sentences fixed at 65 dB SPL were presented at an easily audible level via a loudspeaker. Reading span (RS) scores were used as a grouping variable, based on a median split. The primacy effect was present apart from the noise interference, and the high-RS group significantly outperformed the low-RS group at free recall measured in the quiet and four-talker babble noise conditions. RS scores were positively correlated with free-recall scores. In both quiet and four-talker babble noise conditions, sentence baselines after correction to the initial stimulus baseline increased significantly with increasing memory load. Larger sentence baselines but smaller peak pupil dilations seemed to be associated with noise interruption. The analysis method of pupil dilation used in this study is likely to provide a more thorough understanding of how listeners respond to a later recall task in comparison with previously used methods. Further studies are needed to confirm the applicability of our method in people with impaired hearing using multiple repetitions to estimate the allocation of relevant cognitive resources.

Can listening-related fatigue influence well-being? Examining associations between hearing loss, fatigue, activity levels and well-being

Objective

Well-being is influenced by the activities we undertake. Hearing loss may reduce well-being directly through increased listening-related fatigue due to cognitive and emotional strain in challenging situations. Hearing loss and hearing device use may also indirectly impact fatigue and well-being by altering the frequency and type of daily-life activities. This review examines the available literature to help understand the relationships.

Design

We provide (i) a summary of the extant literature regarding hearing loss, hearing device use and fatigue in adults, as well as regarding fatigue and daily-life activity (work, social and physical) and (ii) a systematic search and narrative review of the relationships between hearing loss, hearing device use and activity.

Study sample

The systematic search resulted in 66 eligible texts.

Results

Data examining well-being in persons with hearing loss are limited. Our literature review suggests that well-being can be related directly and indirectly to hearing loss, hearing device use, activity level and listening-related fatigue.

Conclusions

Variations and interactions between hearing loss, hearing device use, fatigue and activity levels can be expected to impact well-being in persons with hearing loss in direct and indirect ways. Future research linking hearing and daily-life fatigue should take account of activity levels.

Effect of Speech-to-Noise Ratio and Luminance on a Range of Current and Potential Pupil Response Measures to Assess Listening Effort

In hearing research, pupillometry is an established method of studying listening effort. The focus of this study was to evaluate several pupil measures extracted from the Task-Evoked Pupil Responses (TEPRs) in speech-in-noise test. A range of analysis approaches was applied to extract these pupil measures, namely (a) pupil peak dilation (PPD); (b) mean pupil dilation (MPD); (c) index of pupillary activity; (d) growth curve analysis (GCA); and (e) principal component analysis (PCA). The effect of signal-to-noise ratio (SNR; Data Set A: -20 dB, -10 dB, +5 dB SNR) and luminance (Data Set B: 0.1 cd/m2, 360 cd/m2) on the TEPRs were investigated. Data Sets A and B were recorded during a speech-in-noise test and included TEPRs from 33 and 27 normal-hearing native Dutch speakers, respectively. The main results were as follows: (a) A significant effect of SNR was revealed for all pupil measures extracted in the time domain (PPD, MPD, GCA, PCA); (b) Two time series analysis approaches (GCA, PCA) provided modeled temporal profiles of TEPRs (GCA); and time windows spanning subtasks performed in a speech-in-noise test (PCA); and (c) All pupil measures revealed a significant effect of luminance. In conclusion, multiple pupil measures showed similar effects of SNR, suggesting that effort may be reflected in multiple aspects of TEPR. Moreover, a direct analysis of the pupil time course seems to provide a more holistic view of TEPRs, yet further research is needed to understand and interpret its measures. Further research is also required to find pupil measures less sensitive to changes in luminance.

Dimensions of self-reported listening effort and fatigue on a digits-in-noise task, and association with baseline pupil size and performance accuracy

OBJECTIVE

Pupillometry is sensitive to cognitive resource allocation and has been used as a potential measure of listening-related effort and fatigue. We investigated associations between peak pupil diameter, pre-stimulus pupil diameter, performance on a listening task, and the dimensionality of self-reported outcomes (task-related listening effort and fatigue).

DESIGN

Pupillometry was recorded while participants performed a speech-in-noise task. Participants rated their experience of listening effort and fatigue using the NASA-Task Load Index (NASA-TLX) and the Visual Analogue Scale of Fatigue (VAS-F), respectively. The dimensionality of the NASA-TLX and the VAS-F was investigated using factor analysis.

STUDY SAMPLE

82 participants with either normal hearing or aided hearing impairment (age range: 55-85 years old, 43 male).

RESULTS

Hierarchal linear regression analyses suggested that pre-stimulus pupil diameter predicts a dimension of self-reported fatigue, which we interpreted as tiredness/drowsiness, and listening task performance when controlling for hearing level and age: Larger pre-stimulus pupil diameter was associated with less tiredness/drowsiness and better task performance.

CONCLUSION

Pre-stimulus pupil diameter is a potential index of listening fatigue associated with speech processing in challenging listening conditions. To our knowledge, this is the first investigation of the associations between pre-stimulus pupil diameter and self-reported ratings of listening effort and fatigue.

Investigating the Influences of Task Demand and Reward on Cardiac Pre-Ejection Period Reactivity During a Speech-in-Noise Task

OBJECTIVES

Effort investment during listening varies as a function of task demand and motivation. Several studies have manipulated both these factors to elicit and measure changes in effort associated with listening. The cardiac pre-ejection period (PEP) is a relatively novel measure in the field of cognitive hearing science. This measure, which reflects sympathetic nervous system activity on the heart, has previously been implemented during a tone discrimination task but not during a speech-in-noise task. Therefore, the primary goal of this study was to explore the influences of signal to noise ratio (SNR) and monetary reward level on PEP reactivity during a speech-in-noise task.

DESIGN

Thirty-two participants with normal hearing (mean age = 22.22 years, SD = 3.03) were recruited at VU University Medical Center. Participants completed a Dutch speech-in-noise test with a single-interfering-talker masking noise. Six fixed SNRs, selected to span the entire psychometric performance curve, were presented in a block-wise fashion. Participants could earn a low (€0.20) or high (€5.00) reward by obtaining a score of ≥70% of words correct in each block. The authors analyzed PEP reactivity: the change in PEP measured during the task, relative to the baseline during rest. Two separate methods of PEP analysis were used, one including data from the whole task block and the other including data obtained during presentation of the target sentences only. After each block, participants rated their effort investment, performance, tendency to give up, and the perceived difficulty of the task. They also completed the need for recovery questionnaire and the reading span test, which are indices of additional factors (fatigue and working memory capacity, respectively) that are known to influence listening effort.

RESULTS

Average sentence perception scores ranged from 2.73 to 91.62%, revealing a significant effect of SNR. In addition, an improvement in performance was elicited by the high, compared to the low reward level. A linear relationship between SNR and PEP reactivity was demonstrated: at the lower SNRs PEP reactivity was the most negative, indicating greater effort investment compared to the higher SNRs. The target stimuli method of PEP analysis was more sensitive to this effect than the block-wise method. Contrary to expectations, no significant impact of reward on PEP reactivity was found in the present dataset. Also, there was no physiological evidence that participants were disengaged, even when performance was poor. A significant correlation between need for recovery scores and average PEP reactivity was demonstrated, indicating that a lower need for recovery was associated with less effort investment.

CONCLUSIONS

This study successfully implemented the measurement of PEP during a standard speech-in-noise test and included two distinct methods of PEP analysis. The results revealed for the first time that PEP reactivity varies linearly with task demand during a speech-in-noise task, although the effect size was small. No effect of reward on PEP was demonstrated. Finally, participants with a higher need for recovery score invested more effort, as shown by average PEP reactivity, than those with a lower need for recovery score.

Pupillometry Assessment of Speech Recognition and Listening Experience in Adult Cochlear Implant Patients

Objective

The aim of the present study was to investigate the pupillary response to word identification in cochlear implant (CI) patients. Authors hypothesized that when task difficulty (i.e., addition of background noise) increased, pupil dilation markers such as the peak dilation or the latency of the peak dilation would increase in CI users, as already observed in normal-hearing and hearing-impaired subjects.

Methods

Pupillometric measures in 10 CI patients were combined to standard speech recognition scores used to evaluate CI outcomes, namely, speech audiometry in quiet and in noise at +10 dB signal-to-noise ratio (SNR). The main outcome measures of pupillometry were mean pupil dilation, maximal pupil dilation, dilation latency, and mean dilation during return to baseline or retention interval. Subjective hearing quality was evaluated by means of one self-reported fatigue questionnaire, and the Speech, Spatial, and Qualities (SSQ) of Hearing scale.

Results

All pupil dilation data were transformed to percent change in event-related pupil dilation (ERPD, %). Analyses show that the peak amplitudes for both mean pupil dilation and maximal pupil dilation were higher during the speech-in-noise test. Mean peak dilation was measured at 3.47 ± 2.29% noise vs. 2.19 ± 2.46 in quiet and maximal peak value was detected at 9.17 ± 3.25% in noise vs. 8.72 ± 2.93% in quiet. Concerning the questionnaires, the mean pupil dilation during the retention interval was significantly correlated with the spatial subscale score of the SSQ Hearing scale [r(8) = −0.84, p = 0.0023], and with the global score [r(8) = −0.78, p = 0.0018].

Conclusion

The analysis of pupillometric traces, obtained during speech audiometry in quiet and in noise in CI users, provided interesting information about the different processes engaged in this task. Pupillometric measures could be indicative of listening difficulty, phoneme intelligibility, and were correlated with general hearing experience as evaluated by the SSQ of Hearing scale. These preliminary results show that pupillometry constitutes a promising tool to improve objective quantification of CI performance in clinical settings.

Effortful listening under the microscope: Examining relations between pupillometric and subjective markers of effort and tiredness from listening

Effort during listening is commonly measured using the task-evoked pupil response (TEPR); a pupillometric marker of physiological arousal. However, studies to date report no association between TEPR and perceived effort. One possible reason for this is the way in which self-report effort measures are typically administered, namely as a single data point collected at the end of a testing session. Another possible reason is that TEPR might relate more closely to the experience of tiredness from listening than to effort per se. To examine these possibilities, we conducted two preregistered experiments that recorded subjective ratings of effort and tiredness from listening at multiple time points and examined their covariance with TEPR over the course of listening tasks varying in levels of acoustic and attentional demand. In both experiments, we showed a within-subject association between TEPR and tiredness from listening, but no association between TEPR and effort. The data also suggest that the effect of task difficulty on the experience of tiredness from listening may go undetected using the traditional approach of collecting a single data point at the end of a listening block. Finally, this study demonstrates the utility of a novel correlation analysis technique ("rmcorr"), which can be used to overcome statistical power constraints commonly found in the literature. Teasing apart the subjective and physiological mechanisms that underpin effortful listening is a crucial step toward addressing these difficulties in older and/or hearing-impaired individuals.

The Influence of Hearing Loss on Cognitive Control in an Auditory Conflict Task: Behavioral and Pupillometry Findings

Purpose The pupil dilation response is sensitive not only to auditory task demand but also to cognitive conflict. Conflict is induced by incompatible trials in auditory Stroop tasks in which participants have to identify the presentation location (left or right ear) of the words "left" or "right." Previous studies demonstrated that the compatibility effect is reduced if the trial is preceded by another incompatible trial (conflict adaptation). Here, we investigated the influence of hearing status on cognitive conflict and conflict adaptation in an auditory Stroop task. Method Two age-matched groups consisting of 32 normal-hearing participants (M _age = 52 years, age range: 25-67 years) and 28 participants with hearing impairment (M _age = 52 years, age range: 23-64 years) performed an auditory Stroop task. We assessed the effects of hearing status and stimulus compatibility on reaction times (RTs) and pupil dilation responses. We furthermore analyzed the Pearson correlation coefficients between age, degree of hearing loss, and the compatibility effects on the RT and pupil response data across all participants. Results As expected, the RTs were longer and pupil dilation was larger for incompatible relative to compatible trials. Furthermore, these effects were reduced for trials following incompatible (as compared to compatible) trials (conflict adaptation). No general effect of hearing status was observed, but the correlations suggested that higher age and a larger degree of hearing loss were associated with more interference of current incompatibility on RTs. Conclusions Conflict processing and adaptation effects were observed on the RTs and pupil dilation responses in an auditory Stroop task. No general effects of hearing status were observed, but the correlations suggested that higher age and a greater degree of hearing loss were related to reduced conflict processing ability. The current study underlines the relevance of taking into account cognitive control and conflict adaptation processes.

An exploratory Study of EEG Alpha Oscillation and Pupil Dilation in Hearing-Aid Users During Effortful listening to Continuous Speech

Individuals with hearing loss allocate cognitive resources to comprehend noisy speech in everyday life scenarios. Such a scenario could be when they are exposed to ongoing speech and need to sustain their attention for a rather long period of time, which requires listening effort. Two well-established physiological methods that have been found to be sensitive to identify changes in listening effort are pupillometry and electroencephalography (EEG). However, these measurements have been used mainly for momentary, evoked or episodic effort. The aim of this study was to investigate how sustained effort manifests in pupillometry and EEG, using continuous speech with varying signal-to-noise ratio (SNR). Eight hearing-aid users participated in this exploratory study and performed a continuous speech-in-noise task. The speech material consisted of 30-second continuous streams that were presented from loudspeakers to the right and left side of the listener (±30° azimuth) in the presence of 4-talker background noise (+180° azimuth). The participants were instructed to attend either to the right or left speaker and ignore the other in a randomized order with two different SNR conditions: 0 dB and -5 dB (the difference between the target and the competing talker). The effects of SNR on listening effort were explored objectively using pupillometry and EEG. The results showed larger mean pupil dilation and decreased EEG alpha power in the parietal lobe during the more effortful condition. This study demonstrates that both measures are sensitive to changes in SNR during continuous speech.

Measures of Listening Effort Are Multidimensional

OBJECTIVES

Listening effort can be defined as the cognitive resources required to perform a listening task. The literature on listening effort is as confusing as it is voluminous: measures of listening effort rarely correlate with each other and sometimes result in contradictory findings. Here, we directly compared simultaneously recorded multimodal measures of listening effort. After establishing the reliability of the measures, we investigated validity by quantifying correlations between measures and then grouping-related measures through factor analysis.

DESIGN

One hundred and sixteen participants with audiometric thresholds ranging from normal to severe hearing loss took part in the study (age range: 55 to 85 years old, 50.3% male). We simultaneously measured pupil size, electroencephalographic alpha power, skin conductance, and self-report listening effort. One self-report measure of fatigue was also included. The signal to noise ratio (SNR) was adjusted at 71% criterion performance using sequences of 3 digits. The main listening task involved correct recall of a random digit from a sequence of six presented at a SNR where performance was around 82 to 93%. Test-retest reliability of the measures was established by retesting 30 participants 7 days after the initial session.

RESULTS

With the exception of skin conductance and the self-report measure of fatigue, interclass correlation coefficients (ICC) revealed good test-retest reliability (minimum ICC: 0.71). Weak or nonsignificant correlations were identified between measures. Factor analysis, using only the reliable measures, revealed four underlying dimensions: factor 1 included SNR, hearing level, baseline alpha power, and performance accuracy; factor 2 included pupillometry; factor 3 included alpha power (during speech presentation and during retention); factor 4 included self-reported listening effort and baseline alpha power.

CONCLUSIONS

The good ICC suggests that poor test reliability is not the reason for the lack of correlation between measures. We have demonstrated that measures traditionally used as indicators of listening effort tap into multiple underlying dimensions. We therefore propose that there is no "gold standard" measure of listening effort and that different measures of listening effort should not be used interchangeably. When choosing method(s) to measure listening effort, the nature of the task and aspects of increased listening demands that are of interest should be taken into account. The findings of this study provide a framework for understanding and interpreting listening effort measures.

Bottom-up and top-down neural signatures of disordered multi-talker speech perception in adults with normal hearing

In social settings, speech waveforms from nearby speakers mix together in our ear canals. Normally, the brain unmixes the attended speech stream from the chorus of background speakers using a combination of fast temporal processing and cognitive active listening mechanisms. Of >100,000 patient records,~10% of adults visited our clinic because of reduced hearing, only to learn that their hearing was clinically normal and should not cause communication difficulties. We found that multi-talker speech intelligibility thresholds varied widely in normal hearing adults, but could be predicted from neural phase-locking to frequency modulation (FM) cues measured with ear canal EEG recordings. Combining neural temporal fine structure processing, pupil-indexed listening effort, and behavioral FM thresholds accounted for 78% of the variability in multi-talker speech intelligibility. The disordered bottom-up and top-down markers of poor multi-talker speech perception identified here could inform the design of next-generation clinical tests for hidden hearing disorders.

Anticipatory Baseline Pupil Diameter Is Sensitive to Differences in Hearing Thresholds

Task-evoked changes in pupil dilation have long been used as a physiological index of cognitive effort. Unlike this response, that is measured during or after an experimental trial, the baseline pupil dilation (BPD) is a measure taken prior to an experimental trial. As such, it is considered to reflect an individual’s arousal level in anticipation of an experimental trial. We report data for 68 participants, ages 18 to 89, whose hearing acuity ranged from normal hearing to a moderate hearing loss, tested over a series 160 trials on an auditory sentence comprehension task. Results showed that BPDs progressively declined over the course of the experimental trials, with participants with poorer pure tone detection thresholds showing a steeper rate of decline than those with better thresholds. Data showed this slope difference to be due to participants with poorer hearing having larger BPDs than those with better hearing at the start of the experiment, but with their BPDs approaching that of the better hearing participants by the end of the 160 trials. A finding of increasing response accuracy over trials was seen as inconsistent with a fatigue or reduced task engagement account of the diminishing BPDs. Rather, the present results imply BPD as reflecting a heightened arousal level in poorer-hearing participants in anticipation of a task that demands accurate speech perception, a concern that dissipates over trials with task success. These data taken with others suggest that the baseline pupillary response may not reflect a single construct.