Listening-Related Fatigue in New and Experienced Adult Cochlear Implant Users.

OBJECTIVES: Active listening in everyday settings is challenging and requires substantial mental effort, particularly in noisy settings. In some cases, effortful listening can lead to significant listening-related fatigue and negatively affect quality of life. However, our understanding of factors that affect the severity of fatigue is limited. Hearing aids and cochlear implants (CIs) can improve speech understanding and thus, potentially, reduce listening effort and fatigue. Some research supports this idea for adult hearing aid users with mild-to-moderate hearing loss, but similar work in CI users is very limited. This study examined (1) longitudinal changes in listening-related fatigue in new and established CI users, and (2) relationships between demographic and audiologic factors and preimplantation and postimplantation listening-related fatigue. DESIGN: Participants included an experimental group of 48 adult CI candidates receiving either a unilateral implant (n = 46) or simultaneous, bilateral implants (n = 2) and a control group of 96 experienced (>12 months experience) adult CI users (50 unilateral, 46 bilateral). Listening-related fatigue was evaluated using the 40-item version of the Vanderbilt Fatigue Scale for Adults. Experimental group ratings were obtained before implantation and again at 0.5-, 1-, 2-, 3-, 6-, and 12-month(s) postactivation. Control group participants completed the scale twice-upon study entry and approximately 3 months later. Additional measures, including a social isolation and disconnectedness questionnaire, hearing handicap inventory, and the Effort Assessment Scale, were also administered at multiple time points. The role of these measures and select demographic and audiologic factors on preimplant and postimplant fatigue ratings were examined. RESULTS: Adult CI candidates reported significantly more fatigue, greater self-perceived hearing handicap, greater listening effort, and more social isolation than experienced adult CI users. However, significant reductions in fatigue and effort were observed within 2 weeks postimplantation. By 3 months, there were no significant differences in fatigue, effort, hearing handicap, or social isolation between new CI recipients and experienced CI users. Secondary analyses revealed that age at onset of hearing loss (before or after 2 years of age) and subjective hearing handicap contributed significantly to the variance of preimplantation fatigue ratings (those with higher handicap reported higher fatigue). In contrast, variance in postimplantation fatigue ratings was not affected by age of hearing loss onset but was affected by gender (females reported more fatigue than males) and subjective ratings of effort, handicap, and isolation (those reporting more effort, handicap, and isolation reported more fatigue). CONCLUSIONS: Listening-related fatigue is a significant problem for many CI candidates, as well as for many experienced unilateral and bilateral CI users. Receipt of a CI significantly reduced listening-related fatigue (as well as listening effort, hearing handicap, and social isolation) as soon as 2 weeks post-CI activation. However, the magnitude of fatigue-related issues for both CI candidates and experienced CI users varies widely. Audiologic factors, such as hearing loss severity and aided speech recognition, were not predictive of individual differences in listening-related fatigue. In contrast, strong associations were observed between perceived hearing handicap and listening-related fatigue in all groups suggesting fatigue-related issues may be a component of perceived hearing handicap.

Development and Validation of a Brief Version of the Vanderbilt Fatigue Scale for Adults: The VFS-A-10.

OBJECTIVES: Listening-related fatigue can be a significant problem for adults who struggle to hear and understand, particularly adults with hearing loss. However, valid, sensitive, and clinically useful measures for listening-related fatigue do not currently exist. The purpose of this study was to develop and validate a brief clinical tool for measuring listening-related fatigue in adults. DESIGN: The clinical scale was derived from the 40-item version of the Vanderbilt Fatigue Scale for Adults (VFS-A-40), an existing, reliable, and valid research tool for measuring listening-related fatigue. The study consisted of two phases. Phase 1 ( N = 580) and Phase 2 ( N = 607) participants consisted of convenience samples of adults recruited via online advertisements, clinical records review, and a pool of prior research participants. In Phase 1, results from item response theory (IRT) analyses of VFS-A-40 items were used to identify high-quality items for the brief (10-item) clinical scale: the VFS-A-10. In Phase 2, the characteristics and quality of the VFS-A-10 were evaluated in a separate sample of respondents. Dimensionality was evaluated using exploratory factor analyses (EFAs) and item quality and characteristics were evaluated using IRT. VFS-A-10 reliability and validity were assessed in multiple ways. IRT reliability analysis was used to examine VFS-A-10 measurement fidelity. In addition, test-retest reliability was assessed in a subset of Phase 2 participants ( n = 145) who completed the VFS-A-10 a second time approximately one month after their initial measure (range 5 to 90 days). IRT differential item functioning (DIF) was used to assess item bias across different age, gender, and hearing loss subgroups. Convergent construct validity was evaluated by comparing VFS-A-10 responses to two other generic fatigue scales and a measure of hearing disability. Known-groups validity was assessed by comparing VFS-A-10 scores between adults with and without self-reported hearing loss. RESULTS: EFA suggested a unidimensional structure for the VFS-A-10. IRT analyses confirmed all test items were high quality. IRT reliability analysis revealed good measurement fidelity over a wide range of fatigue severities. Test-retest reliability was excellent ( rs = 0.88, collapsed across participants). IRT DIF analyses confirmed the VFS-A-10 provided a valid measure of listening-related fatigue regardless of respondent age, gender, or hearing status. An examination of associations between VFS-A-10 scores and generic fatigue/vigor measures revealed only weak-to-moderate correlations (Spearman's correlation coefficient, rs = -0.36 to 0.57). Stronger associations were seen between VFS-A-10 scores and a measure of perceived hearing difficulties ( rs = 0.79 to 0.81) providing evidence of convergent construct validity. In addition, the VFS-A-10 was more sensitive to fatigue associated with self-reported hearing difficulties than generic measures. It was also more sensitive than generic measures to variations in fatigue as a function of degree of hearing impairment. CONCLUSIONS: These findings suggest that the VFS-A-10 is a reliable, valid, and sensitive tool for measuring listening-related fatigue in adults. Its brevity, high sensitivity, and good reliability make it appropriate for clinical use. The scale will be useful for identifying those most affected by listening-related fatigue and for assessing benefits of interventions designed to reduce its negative effects.

Predictors of Listening-Related Fatigue Across the Adult Life Span.

Listening-related fatigue is a potentially serious negative consequence of an aging auditory and cognitive system. However, the impact of age on listening-related fatigue and the factors underpinning any such effect remain unexplored. Using data from a large sample of adults (N = 281), we conducted a conditional process analysis to examine potential mediators and moderators of age-related changes in listening-related fatigue. Mediation analyses revealed opposing effects of age on listening-related fatigue: Older adults with greater perceived hearing impairment tended to report increased listening-related fatigue. However, aging was otherwise associated with decreased listening-related fatigue via reductions in both mood disturbance and sensory-processing sensitivity. Results suggested that the effect of auditory attention ability on listening-related fatigue was moderated by sensory-processing sensitivity; for individuals with high sensory-processing sensitivity, better auditory attention ability was associated with increased fatigue. These findings shed light on the perceptual, cognitive, and psychological factors underlying age-related changes in listening-related fatigue.

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.

Understanding Listening-Related Fatigue: Perspectives of Adults with Hearing Loss.

OBJECTIVE: Adults with hearing loss (AHL) often report feeling fatigued after being in situations that require prolonged listening, an experience referred to as listening-related fatigue. We conducted focus groups to identify key domains and constructs of listening-related fatigue. Our goal was to create a theoretical framework for understanding listening-related fatigue that could guide the development of a reliable and valid assessment tool. DESIGN: Eight focus group discussions were conducted using a moderator's guide. Discussions were recorded, transcribed, coded, and analysed to identify common themes related to listening-related fatigue. A hierarchical coding manual was developed iteratively as new themes and subcategories were identified during the analysis process. STUDY SAMPLE: Forty-three adults (11 males; aged 20 to 77 years) with varying degrees of hearing loss participated in the focus groups. Participants included primarily hearing aid users (n = 34), hearing aid candidates (n = 6), and a small group of cochlear implant users (n = 3). RESULTS: Qualitative analyses revealed the multidimensional nature of listening-related fatigue for AHL, including physical, mental, emotional, and social domains. These varied experiences were influenced by the external (acoustic/environmental) characteristics of the listening situation, the internal state of the listener (cognitive/motivational), and coping strategies implemented to modify the listening experience. The use of amplification had both positive and negative effects on listening-related fatigue. CONCLUSIONS: For some AHL, the consequences of listening-related fatigue can be significant, negatively impacting their quality of life. Data from these focus groups provides a framework for understanding the experience of listening-related fatigue among AHL. This is a critical first step in the development of a tool for measuring listening-related fatigue in this at-risk group.

The Challenge of Listening at Home: Speech and Noise Levels in Homes of Young Children With Hearing Loss.

OBJECTIVES: The objective of this study was to characterize the acoustics of the home environment of young children with hearing loss. Specifically, we aimed to quantify the range of speech levels, noise levels, and signal-to-noise ratios (SNRs) encountered by children with hearing loss in their homes. DESIGN: Nine families participated in the study. The children with hearing loss in these families were between 2 and 5 years of age. Acoustic recordings were made in the children's homes over one weekend (Saturday and Sunday) using Language ENvironmental Analysis (LENA) recorders. These recordings were analyzed using LENA's proprietary software to determine the range of speech and noise levels in the child's home. A custom Matlab program analyzed the LENA output to estimate the SNRs in the children's homes. RESULTS: The average SNR encountered by children with hearing loss in our sample was approximately +7.9 dB SNR. It is important to note that our analyses revealed that approximately 84% of the SNRs experienced by these children with hearing loss were below the +15 dB SNR recommended by the American Speech-Language Hearing Association. Averaged across families, speech and noise levels were 70.1 and 62.2 C-weighted decibels, respectively. CONCLUSIONS: These data show that, for much of the time, young children with hearing loss are forced to listen under suboptimal conditions in their home environments. This has important implications as listening under these conditions could negatively affect learning opportunities for young children with hearing loss. To mitigate these potential negative effects, the use of assistive listening devices that improve the SNR (e.g., remote microphone systems) should be considered for use at home by young children with hearing loss.

Binaural spatial adaptation as a mechanism for asymmetric trading of interaural time and level differences.

A classic paradigm used to quantify the perceptual weighting of binaural spatial cues requires a listener to adjust the value of one cue, while the complementary cue is held constant. Adjustments are made until the auditory percept appears centered in the head, and the values of both cues are recorded as a trading relation (TR), most commonly in µs interaural time difference per dB interaural level difference. Interestingly, existing literature has shown that TRs differ according to the cue being adjusted. The current study investigated whether cue-specific adaptation, which might arise due to the continuous, alternating presentation of signals during adjustment tasks, could account for this poorly understood phenomenon. Three experiments measured TRs via adjustment and via lateralization of single targets in virtual reality (VR). Targets were 500 Hz pure tones preceded by silence or by adapting trains that held one of the cues constant. VR removed visual anchors and provided an intuitive response technique during lateralization. The pattern of results suggests that adaptation can account for cue-dependent TRs. In addition, VR seems to be a viable tool for psychophysical tasks.

Behavioral Measures of Listening Effort in School-Age Children: Examining the Effects of Signal-to-Noise Ratio, Hearing Loss, and Amplification.

OBJECTIVES: Increased listening effort in school-age children with hearing loss (CHL) could compromise learning and academic achievement. Identifying a sensitive behavioral measure of listening effort for this group could have both clinical and research value. This study examined the effects of signal-to-noise ratio (SNR), hearing loss, and personal amplification on 2 commonly used behavioral measures of listening effort: dual-task visual response times (visual RTs) and verbal response times (verbal RTs). DESIGN: A total of 82 children (aged 6-13 years) took part in this study; 37 children with normal hearing (CNH) and 45 CHL. All children performed a dual-task paradigm from which both measures of listening effort (dual-task visual RT and verbal RT) were derived. The primary task was word recognition in multi-talker babble in three individually selected SNR conditions: Easy, Moderate, and Hard. The secondary task was a visual monitoring task. Listening effort during the dual-task was quantified as the change in secondary task RT from baseline (single-task visual RT) to the dual-task condition. Listening effort based on verbal RT was quantified as the time elapsed from the onset of the auditory stimulus to the onset of the verbal response when performing the primary (word recognition) task in isolation. CHL completed the task aided and/or unaided to examine the effect of amplification on listening effort. RESULTS: Verbal RTs were generally slower in the more challenging SNR conditions. However, there was no effect of SNR on dual-task visual RT. Overall, verbal RTs were significantly slower in CHL versus CNH. No group difference in dual-task visual RTs was found between CNH and CHL. No effect of amplification was found on either dual-task visual RTs or verbal RTs. CONCLUSIONS: This study compared dual-task visual RT and verbal RT measures of listening effort in the child population. Overall, verbal RTs appear more sensitive than dual-task visual RTs to the negative effects of SNR and hearing loss. The current findings extend the literature on listening effort in the pediatric population by demonstrating that, even for speech that is accurately recognized, school-age CHL show a greater processing speed decrement than their normal-hearing counterparts, a decrement that could have a negative impact on learning and academic achievement in the classroom.

A Taxonomy of Fatigue Concepts and Their Relation to Hearing Loss.

Fatigue is common in individuals with a variety of chronic health conditions and can have significant negative effects on quality of life. Although limited in scope, recent work suggests persons with hearing loss may be at increased risk for fatigue, in part due to effortful listening that is exacerbated by their hearing impairment. However, the mechanisms responsible for hearing loss-related fatigue, and the efficacy of audiologic interventions for reducing fatigue, remain unclear. To improve our understanding of hearing loss-related fatigue, as a field it is important to develop a common conceptual understanding of this construct. In this article, the broader fatigue literature is reviewed to identify and describe core constructs, consequences, and methods for assessing fatigue and related constructs. Finally, the current knowledge linking hearing loss and fatigue is described and may be summarized as follows: Hearing impairment may increase the risk of subjective fatigue and vigor deficits; adults with hearing loss require more time to recover from fatigue after work and have more work absences; sustained, effortful, listening can be fatiguing; optimal methods for eliciting and measuring fatigue in persons with hearing loss remain unclear and may vary with listening condition; and amplification may minimize decrements in cognitive processing speed during sustained effortful listening. Future research is needed to develop reliable measurement methods to quantify hearing loss-related fatigue, explore factors responsible for modulating fatigue in people with hearing loss, and identify and evaluate potential interventions for reducing hearing loss-related fatigue.

Subjective Ratings of Fatigue and Vigor in Adults With Hearing Loss Are Driven by Perceived Hearing Difficulties Not Degree of Hearing Loss.

OBJECTIVES: Anecdotal reports and qualitative research suggests that fatigue is a common, but often overlooked, accompaniment of hearing loss which negatively affects quality of life. However, systematic research examining the relationship between hearing loss and fatigue is limited. In this study, the authors examined relationships between hearing loss and various domains of fatigue and vigor using standardized and validated measures. Relationships between subjective ratings of multidimensional fatigue and vigor and the social and emotional consequences of hearing loss were also explored. DESIGN: Subjective ratings of fatigue and vigor were assessed using the profile of mood states and the multidimensional fatigue symptom inventory-short form. To assess the social and emotional impact of hearing loss participants also completed, depending on their age, the hearing handicap inventory for the elderly or adults. Responses were obtained from 149 adults (mean age = 66.1 years, range 22 to 94 years), who had scheduled a hearing test and/or a hearing aid selection at the Vanderbilt Bill Wilkerson Center Audiology clinic. These data were used to explore relationships between audiometric and demographic (i.e., age and gender) factors, fatigue, and hearing handicap scores. RESULTS: Compared with normative data, adults seeking help for their hearing difficulties in this study reported significantly less vigor and more fatigue. Reports of severe vigor/fatigue problems (ratings exceeding normative means by ±1.5 standard deviations) were also increased in the study sample compared with that of normative data. Regression analyses, with adjustments for age and gender, revealed that the subjective percepts of fatigue, regardless of domain, and vigor were not strongly associated with degree of hearing loss. However, similar analyses controlling for age, gender, and degree of hearing loss showed a strong association between measures of fatigue and vigor (multidimensional fatigue symptom inventory-short form scores) and the social and emotional consequences of hearing loss (hearing handicap inventory for the elderly/adults scores). CONCLUSIONS: Adults seeking help for hearing difficulties are more likely to experience severe fatigue and vigor problems; surprisingly, this increased risk appears unrelated to degree of hearing loss. However, the negative psychosocial consequences of hearing loss are strongly associated with subjective ratings of fatigue, across all domains, and vigor. Additional research is needed to define the pathogenesis of hearing loss-related fatigue and to identify factors that may modulate and mediate (e.g., hearing aid or cochlear implant use) its impact.

Salivary Cortisol Profiles of Children with Hearing Loss.

OBJECTIVES: It has long been speculated that effortful listening places children with hearing loss at risk for fatigue. School-age children with hearing loss experiencing cumulative stress and listening fatigue on a daily basis might undergo dysregulation of hypothalamic-pituitary-adrenal (HPA) axis activity resulting in elevated or flattened cortisol profiles. The purpose of this study was to examine whether school-age children with hearing loss show different diurnal salivary cortisol patterns than children with normal hearing. DESIGN: Participants included 32 children with mild to moderate hearing loss (14 males; 18 females) and 28 children with normal hearing (19 males; 9 females) ranging in age from 6 to 12 years. Saliva samples were obtained six times per day on two separate school days. Cortisol levels were measured by mass spectrometric detection after liquid-liquid extraction. Salivary cortisol levels between children with hearing loss and children with no hearing loss over the course of the day were examined with hierarchical linear modeling using mixed model statistical analysis. Between-group comparisons were also computed for the area under the curve, an analytical approach for calculating overall cortisol secretion throughout the day. RESULTS: Significant differences in the cortisol awakening response (CAR) were observed between children with hearing loss and children with normal hearing; however, no differences were observed between the two groups subsequent to the cortisol awakening response (60-min postawakening, 10:00 A.M., 2:00 P.M., and 8:00 P.M.). Compared with children with normal hearing, children with hearing loss displayed elevated cortisol levels at awakening and a reduced growth in cortisol secretion from awakening to 30-min postawakening. No significant differences in overall cortisol secretion throughout the day were found between groups (area under the curve). Finally, cortisol levels increased with increasing age for children with hearing loss but not for children with normal hearing. CONCLUSIONS: Results of this preliminary study indicate a possible dysregulation in HPA axis activity in children with hearing loss characterized by elevated salivary cortisol levels at awakening and a diminished increase in cortisol from awakening to 30-min postawakening. The pattern of elevated cortisol levels at awakening is consistent with some studies on adults with burnout, a condition characterized by fatigue, loss of energy, and poor coping skills. These findings support the idea that children with hearing loss may experience increased vigilance and need to mobilize energy promptly in preparation for the new day.

Hearing Impairment and Cognitive Energy: The Framework for Understanding Effortful Listening (FUEL).

The Fifth Eriksholm Workshop on "Hearing Impairment and Cognitive Energy" was convened to develop a consensus among interdisciplinary experts about what is known on the topic, gaps in knowledge, the use of terminology, priorities for future research, and implications for practice. The general term cognitive energy was chosen to facilitate the broadest possible discussion of the topic. It goes back to who described the effects of attention on perception; he used the term psychic energy for the notion that limited mental resources can be flexibly allocated among perceptual and mental activities. The workshop focused on three main areas: (1) theories, models, concepts, definitions, and frameworks; (2) methods and measures; and (3) knowledge translation. We defined effort as the deliberate allocation of mental resources to overcome obstacles in goal pursuit when carrying out a task, with listening effort applying more specifically when tasks involve listening. We adapted Kahneman's seminal (1973) Capacity Model of Attention to listening and proposed a heuristically useful Framework for Understanding Effortful Listening (FUEL). Our FUEL incorporates the well-known relationship between cognitive demand and the supply of cognitive capacity that is the foundation of cognitive theories of attention. Our FUEL also incorporates a motivation dimension based on complementary theories of motivational intensity, adaptive gain control, and optimal performance, fatigue, and pleasure. Using a three-dimensional illustration, we highlight how listening effort depends not only on hearing difficulties and task demands but also on the listener's motivation to expend mental effort in the challenging situations of everyday life.

Commentary: listening can be exhausting--fatigue in children and adults with hearing loss.

Anecdotal reports of fatigue after sustained speech-processing demands are common among adults with hearing loss; however, systematic research examining hearing loss-related fatigue is limited, particularly with regard to fatigue among children with hearing loss (CHL). Many audiologists, educators, and parents have long suspected that CHL experience stress and fatigue as a result of the difficult listening demands they encounter throughout the day at school. Recent research in this area provides support for these intuitive suggestions. In this article, the authors provide a framework for understanding the construct of fatigue and its relation to hearing loss, particularly in children. Although empirical evidence is limited, preliminary data from recent studies suggest that some CHL experience significant fatigue-and such fatigue has the potential to compromise a child's performance in the classroom. In this commentary, the authors discuss several aspects of fatigue including its importance, definitions, prevalence, consequences, and potential linkage to increased listening effort in persons with hearing loss. The authors also provide a brief synopsis of subjective and objective methods to quantify listening effort and fatigue. Finally, the authors suggest a common-sense approach for identification of fatigue in CHL; and, the authors briefly comment on the use of amplification as a management strategy for reducing hearing-related fatigue.

Estimates of cochlear compression using distortion product otoacoustic emissions and growth of forward masking.

OBJECTIVE: The authors investigated the relationship between behavioral and physiologic estimates of cochlear compression. DESIGN: Cochlear compression was estimated in distortion product otoacoustic emission (DPOAE) fine structure minima and maxima near 4 kHz. The composite DPOAE response and separated generator and reflection components yielded three estimates in four young adults with normal hearing. DPOAE estimates were compared to behavioral compression estimates derived using a growth of forward masking (GOFM) paradigm. The DPOAE primary tone f2 and GOFM signal were identical and selected individually based on placement in a DPOAE fine structure minimum. RESULTS: Across participants, DPOAE compression estimates derived from the generator component were most similar to estimates derived from the GOFM paradigm and did not vary with DPOAE fine structure. CONCLUSIONS: These results suggest that the generator component may provide a quick, reliable estimate of cochlear compression in humans. This may prove useful in populations that cannot give behavioral responses.

Reliability and Validity of the Turkish Version of the Vanderbilt Fatigue Scale for Adults.

PURPOSE: Listening-related fatigue (LRF) is a prominent topic of research interest. The purpose of this study is to investigate the reliability and validity of the Turkish version of the 40-item Vanderbilt Fatigue Scale for Adults (TR-VFS-A-40). METHOD: This study included 317 adults with no hearing loss and 260 adults with hearing loss in the study group, totaling 577 adults aged 18-75 years. While 31 adults in the study group did not use any hearing technology, there were 96 hearing aid users and 123 cochlear implant (CI) users. A subset of 80 CI users completed the TR-VFS-A-40 a second time, 2 weeks later, to assess test-retest reliability. Intraclass correlation coefficients were used to assess test-retest reliability. Cronbach's alpha was used to evaluate internal consistency. To examine construct validity, a confirmatory factor analysis (CFA) was performed. For concurrent validity analysis, the Checklist Individual Strength (CIS) and TR-VFS-A-40 scores were analyzed using the Spearman correlation test. RESULTS: Cronbach's alpha values were excellent for the total scale of .987 and the cognitive, emotional, physical, and social subscales (.953, .954, .955, and .946, respectively). Analyses of concurrent validity revealed strong and significant correlations between CIS and TR-VFS-A-40 scores, indicating a good concurrent validity. The CFA determined that the construct validity of the TR-VFS-A-40 was satisfactory. CONCLUSION: The TR-VFS-A-40 is a valid and reliable measure of LRF. SUPPLEMENTAL MATERIAL: https://doi.org/10.23641/asha.25457752.

The effects of hearing aid use on listening effort and mental fatigue associated with sustained speech processing demands.

OBJECTIVES: To maintain optimal understanding, persons with sensorineural hearing loss (SNHL) often report a need for increased attention, concentration, and "listening effort" compared with persons without hearing loss. It is generally assumed that this increased effort is related to subjective reports of mental fatigue in persons with hearing loss. Although the benefits of hearing aids for improving intelligibility are well documented, their impact on listening effort and mental fatigue are less clear. This study used subjective and objective measures to examine the effects of hearing aid use and advanced hearing aid features on listening effort and mental fatigue in adults with SNHL. DESIGN: Sixteen adults (aged 47-69 years) with mild to severe sloping SNHL participated. A dual-task paradigm assessed word recognition, word recall, and visual reaction times (RTs) to objectively quantify listening effort and fatigue. Mental fatigue was operationally defined as a decrement in performance over the duration of the experiment (approximately 1 hr). Participants were fitted with study hearing aids and tested unaided and in two aided conditions (omnidirectional and with directional processing and digital noise reduction active). Subjective ratings of listening effort experienced during the day and ratings of fatigue and attentiveness immediately before and after the dual-task were also obtained. RESULTS: Word recall was better and dual-task RTs were significantly faster in the aided compared with unaided conditions, suggesting a decrease in listening effort when listening aided. Word recognition and recall in unaided and aided conditions remained relatively stable over the duration of the dual-task, suggesting these processes were resistant to mental fatigue. In contrast, dual-task RTs systematically increased over the duration of the speech task when listening unaided, consistent with development of mental fatigue. However, dual-task RTs remained stable over time in both aided conditions suggesting that hearing aid use reduced susceptibility to mental fatigue. Subjective ratings of fatigue and attentiveness also increased significantly after completion of the dual-task; however, no differences between unaided and aided subjective ratings were observed. Correlation analyses between subjective and objective measures of listening effort and mental fatigue showed no strong or consistent relationship. Likewise, subject variables such as age and degree of hearing loss showed no strong or consistent relationship to either subjective or objective measures of listening effort or mental fatigue. CONCLUSIONS: Results from subjective and select objective measures suggest sustained speech-processing demands can lead to mental fatigue in persons with hearing loss. It is important to note that the use of clinically fit hearing aids may reduce listening effort and susceptibility to mental fatigue associated with sustained speech-processing demands. The present study design did not reveal additional benefits, in terms of reduced listening effort or fatigue, from use of directional processing and digital noise-reduction algorithms. However, experimental design limitations suggest further work in this area is needed. Finally, subjective and objective measures of listening effort and mental fatigue due to sustained speech-processing demands, were not strongly associated, suggesting that these measures may assess different aspects of listening effort and mental fatigue.

How hearing aids, background noise, and visual cues influence objective listening effort.

OBJECTIVES: The purpose of this article was to evaluate factors that influence the listening effort experienced when processing speech for people with hearing loss. Specifically, the change in listening effort resulting from introducing hearing aids, visual cues, and background noise was evaluated. An additional exploratory aim was to investigate the possible relationships between the magnitude of listening effort change and individual listeners' working memory capacity, verbal processing speed, or lipreading skill. DESIGN: Twenty-seven participants with bilateral sensorineural hearing loss were fitted with linear behind-the-ear hearing aids and tested using a dual-task paradigm designed to evaluate listening effort. The primary task was monosyllable word recognition and the secondary task was a visual reaction time task. The test conditions varied by hearing aids (unaided, aided), visual cues (auditory-only, auditory-visual), and background noise (present, absent). For all participants, the signal to noise ratio was set individually so that speech recognition performance in noise was approximately 60% in both the auditory-only and auditory-visual conditions. In addition to measures of listening effort, working memory capacity, verbal processing speed, and lipreading ability were measured using the Automated Operational Span Task, a Lexical Decision Task, and the Revised Shortened Utley Lipreading Test, respectively. RESULTS: In general, the effects measured using the objective measure of listening effort were small (~10 msec). Results indicated that background noise increased listening effort, and hearing aids reduced listening effort, while visual cues did not influence listening effort. With regard to the individual variables, verbal processing speed was negatively correlated with hearing aid benefit for listening effort; faster processors were less likely to derive benefit. Working memory capacity, verbal processing speed, and lipreading ability were related to benefit from visual cues. No variables were related to changes in listening effort resulting from the addition of background noise. CONCLUSIONS: The results of this study suggest that, on the average, hearing aids can reduce objectively measured listening effort. Furthermore, people who are slow verbal processors are more likely to derive hearing aid benefit for listening effort, perhaps because hearing aids improve the auditory input. Although background noise increased objective listening effort, no listener characteristic predicted susceptibility to noise. With regard to visual cues, while there was no effect on average of providing visual cues, there were some listener characteristics that were related to changes in listening effort with vision. Although these relationships are exploratory, they do suggest that these inherent listener characteristics like working memory capacity, verbal processing speed, and lipreading ability may influence susceptibility to changes in listening effort and thus warrant further study.

Horizontal plane localization in single-sided deaf adults fitted with a bone-anchored hearing aid (Baha).

OBJECTIVES: : One purpose of this investigation was to evaluate the effect of a unilateral bone-anchored hearing aid (Baha) on horizontal plane localization performance in single-sided deaf adults who had either a conductive or sensorineural hearing loss in their impaired ear. The use of a 33-loudspeaker array allowed for a finer response measure than has previously been used to investigate localization in this population. In addition, a detailed analysis of error patterns allowed an evaluation of the contribution of random error and bias error to the total rms error computed in the various conditions studied. A second purpose was to investigate the effect of stimulus duration and head-turning on localization performance. DESIGN: : Two groups of single-sided deaf adults were tested in a localization task in which they had to identify the direction of a spoken phrase on each trial. One group had a sensorineural hearing loss (SNHL group; N = 7), and the other group had a conductive hearing loss (CHL group; N = 5). In addition, a control group of four normal-hearing adults was tested. The spoken phrase was either 1250 msec in duration (a male saying "Where am I coming from now?") or 341 msec in duration (the same male saying "Where?"). For the longer-duration phrase, subjects were tested in conditions in which they either were or were not allowed to move their heads before the termination of the phrase. The source came from one of nine positions in the front horizontal plane (from -79° to +79°). The response range included 33 choices (from -90° to +90°, separated by 5.6°). Subjects were tested in all stimulus conditions, both with and without the Baha device. Overall rms error was computed for each condition. Contributions of random error and bias error to the overall error were also computed. RESULTS: : There was considerable intersubject variability in all conditions. However, for the CHL group, the average overall error was significantly smaller when the Baha was on than when it was off. Further analysis of error patterns indicated that this improvement was primarily based on reduced response bias when the device was on; that is, the average response azimuth was nearer to the source azimuth when the device was on than when it was off. The SNHL group, on the other hand, had significantly greater overall error when the Baha was on than when it was off. Collapsed across listening conditions and groups, localization performance was significantly better with the 1250 msec stimulus than with the 341 msec stimulus. However, for the longer-duration stimulus, there was no significant beneficial effect of head-turning. Error scores in all conditions for both groups were considerably larger than those in the normal-hearing control group. CONCLUSIONS: : On average, single-sided deaf adults with CHL showed improved localization ability when using the Baha, whereas single-sided deaf adults with SNHL showed a decrement in performance when using the device. These results may have implications for clinical counseling for patients with unilateral hearing impairment.

Is It Okay to Use Compressed NU-6 Files for Clinical Word Recognition Testing?

PURPOSE: The purpose of this study was to evaluate the impact of file compression on clinically measured word recognition scores obtained using the Northwestern University Test Number Six (NU-6; Auditec recording) materials. METHOD: Participants were 86 adults (N = 170 ears; M age = 65.5). The 25 most difficult words from each of four NU-6 test lists were used to measure word recognition. Two lists were compressed using a freely available Advanced Audio Coding compression algorithm and two were not. Word recognition was measured in each ear using one compressed file and one uncompressed file. Percent correct scores were calculated in each test condition and log transformed for analyses. Clinically meaningful differences between uncompressed and compressed scores were examined using 95% critical difference ranges. The effects of file compression on word recognition scores were examined in the context of multiple potential confounding effects, including age and degree of hearing loss, using linear mixed-effects models (LMMs). RESULTS: Differences between compressed and uncompressed scores in a given ear exceeded the 95% critical difference range in about 7% of cases, approximating the 5% of expected cases occurring due to chance. Likewise, LMM results revealed no significant effect of file compression on clinically measured NU-6 word recognition scores and no significant interactions between compression effects and age or degree of hearing loss. CONCLUSIONS: While the original uncompressed audio files are clearly the most appropriate stimuli for clinical purposes, our study results suggest that file compression, even at an aggressive 64 kilobits per second, does not have a statistically significant, or clinically meaningful, effect on word recognition scores when measured using these Auditec materials.