Speech Comprehension Training and Auditory and Cognitive Processing in Older Adults

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

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

Eye Movements Decrease during Effortful Speech Listening

Hearing impairment affects many older adults but is often diagnosed decades after speech comprehension in noisy situations has become effortful. Accurate assessment of listening effort may thus help diagnose hearing impairment earlier. However, pupillometry-the most used approach to assess listening effort-has limitations that hinder its use in practice. The current study explores a novel way to assess listening effort through eye movements. Building on cognitive and neurophysiological work, we examine the hypothesis that eye movements decrease when speech listening becomes challenging. In three experiments with human participants from both sexes, we demonstrate, consistent with this hypothesis, that fixation duration increases and spatial gaze dispersion decreases with increasing speech masking. Eye movements decreased during effortful speech listening for different visual scenes (free viewing, object tracking) and speech materials (simple sentences, naturalistic stories). In contrast, pupillometry was less sensitive to speech masking during story listening, suggesting pupillometric measures may not be as effective for the assessments of listening effort in naturalistic speech-listening paradigms. Our results reveal a critical link between eye movements and cognitive load, suggesting that neural activity in the brain regions that support the regulation of eye movements, such as frontal eye field and superior colliculus, are modulated when listening is effortful.SIGNIFICANCE STATEMENT Assessment of listening effort is critical for early diagnosis of age-related hearing loss. Pupillometry is most used but has several disadvantages. The current study explores a novel way to assess listening effort through eye movements. We examine the hypothesis that eye movements decrease when speech listening becomes effortful. We demonstrate, consistent with this hypothesis, that fixation duration increases and gaze dispersion decreases with increasing speech masking. Eye movements decreased during effortful speech listening for different visual scenes (free viewing, object tracking) and speech materials (sentences, naturalistic stories). Our results reveal a critical link between eye movements and cognitive load, suggesting that neural activity in brain regions that support the regulation of eye movements are modulated when listening is effortful.

Comparing the Outcomes of a Personalized Versus Nonpersonalized Home-Based Auditory Training Program for Cochlear Implant Users

OBJECTIVES

Audiological rehabilitation includes sensory management, auditory training (AT), and counseling and can alleviate the negative consequences associated with (untreated) hearing impairment. AT aims at improving auditory skills through structured analytical (bottom-up) or synthetic (top-down) listening exercises. The evidence for AT to improve auditory outcomes of postlingually deafened adults with a cochlear implant (CI) remains a point of debate due to the relatively limited number of studies and methodological shortcomings. There is a general agreement that more rigorous scientific study designs are needed to determine the effectiveness, generalization, and consolidation of AT for CI users. The present study aimed to investigate the effectiveness of a personalized AT program compared to a nonpersonalized Active Control program with adult CI users in a stratified randomized controlled clinical trial.

DESIGN

Off-task outcomes were sentence understanding in noise, executive functioning, and health-related quality of life. Participants were tested before and after 16 weeks of training and after a further 8 months without training. Participant expectations of the training program were assessed before the start of training.

RESULTS

The personalized and nonpersonalized AT programs yielded similar results. Significant on-task improvements were observed. Moreover, AT generalized to improved speech understanding in noise for both programs. Half of the CI users reached a clinically relevant improvement in speech understanding in noise of at least 2 dB SNR post-training. These improvements were maintained 8 months after completion of the training. In addition, a significant improvement in quality of life was observed for participants in both treatment groups. Adherence to the training programs was high, and both programs were considered user-friendly.

CONCLUSIONS

Training in both treatments yielded similar results. For half of the CI users, AT transferred to better performance with generalization of learning for speech understanding in noise and quality of life. Our study supports the previous findings that AT can be beneficial for some CI users.

Auditory Perceptual Exercises in Adults Adapting to the Use of Hearing Aids

Older adults with age-related hearing loss often use hearing aids (HAs) to compensate. However, certain challenges in speech perception, especially in noise still exist, despite today's HA technology. The current study presents an evaluation of a home-based auditory exercises program that can be used during the adaptation process for HA use. The home-based program was developed at a time when telemedicine became prominent in part due to the COVID-19 pandemic. The study included 53 older adults with age-related symmetrical sensorineural hearing loss. They were divided into three groups depending on their experience using HAs. Group 1: Experienced users (participants who used bilateral HAs for at least 2 years). Group 2: New users (participants who were fitted with bilateral HAs for the first time). Group 3: Non-users. These three groups underwent auditory exercises for 3 weeks. The auditory tasks included auditory detection, auditory discrimination, and auditory identification, as well as comprehension with basic (syllables) and more complex (sentences) stimuli, presented in quiet and in noisy listening conditions. All participants completed self-assessment questionnaires before and after the auditory exercises program and underwent a cognitive test at the end. Self-assessed improvements in hearing ability were observed across the HA users groups, with significant changes described by new users. Overall, speech perception in noise was poorer than in quiet. Speech perception accuracy was poorer in the non-users group compared to the users in all tasks. In sessions where stimuli were presented in quiet, similar performance was observed among new and experienced uses. New users performed significantly better than non-users in all speech in noise tasks; however, compared to the experienced users, performance differences depended on task difficulty. The findings indicate that HA users, even new users, had better perceptual performance than their peers who did not receive hearing aids.

Listening-Based Communication Ability in Adults With Hearing Loss: A Scoping Review of Existing Measures

Introduction

Hearing loss in adults has a pervasive impact on health and well-being. Its effects on everyday listening and communication can directly influence participation across multiple spheres of life. These impacts, however, remain poorly assessed within clinical settings. Whilst various tests and questionnaires that measure listening and communication abilities are available, there is a lack of consensus about which measures assess the factors that are most relevant to optimising auditory rehabilitation. This study aimed to map current measures used in published studies to evaluate listening skills needed for oral communication in adults with hearing loss.

Methods

A scoping review was conducted using systematic searches in Medline, EMBASE, Web of Science and Google Scholar to retrieve peer-reviewed articles that used one or more linguistic-based measure necessary to oral communication in adults with hearing loss. The range of measures identified and their frequency where charted in relation to auditory hierarchies, linguistic domains, health status domains, and associated neuropsychological and cognitive domains.

Results

9121 articles were identified and 2579 articles that reported on 6714 discrete measures were included for further analysis. The predominant linguistic-based measure reported was word or sentence identification in quiet (65.9%). In contrast, discourse-based measures were used in 2.7% of the articles included. Of the included studies, 36.6% used a self-reported instrument purporting to measures of listening for communication. Consistent with previous studies, a large number of self-reported measures were identified (n = 139), but 60.4% of these measures were used in only one study and 80.7% were cited five times or fewer.

Discussion

Current measures used in published studies to assess listening abilities relevant to oral communication target a narrow set of domains. Concepts of communicative interaction have limited representation in current measurement. The lack of measurement consensus and heterogeneity amongst the assessments limit comparisons across studies. Furthermore, extracted measures rarely consider the broader linguistic, cognitive and interactive elements of communication. Consequently, existing measures may have limited clinical application if assessing the listening-related skills required for communication in daily life, as experienced by adults with hearing loss.

The effect of harmonic training on speech perception in noise in hearing-impaired children

OBJECTIVE

Speech perception in noise is a highly challenging situation experienced by hearing-impaired children (HIC). Despite advances in hearing aid technologies, speech perception in noise still poses challenges. Pitch-based training improves pitch discrimination and speech perception and may facilitate concurrent sound segregation. Considering the role of harmonics in the analysis of concurrent sounds, we performed a harmonic assessment, examined the role of harmonic training in the rehabilitation of moderate-to-severe HIC, and investigated its effect on their speech perception in noise.

METHODS

The participants were 57 normally hearing children (NHC) with a mean age of 7.73 ± 1.57 years and 18 HIC with a mean age of 7.94 ± 1.47 years. The two groups were compared in terms of harmonic assessment, the Pitch Pattern Sequence Test (PPST), the Consonant-Vowel in Noise (CV in noise) test, and the Bamford-Kowal Bench (BKB) test. Subsequently, the HIC underwent harmonic training, and the results of the pre- and post-harmonic training assessments were compared.

RESULTS

HIC displayed poorer harmonic discrimination than NHC at all harmonics (P < 0.05). They also showed lower scores in PPST, CV in noise, and BKB tests compared to NHC (P < 0.05). Harmonic training led to HIC's better performance in harmonic assessment, PPST, and CV in noise test (P < 0.05). However, the BKB test results pre- and post-training did not significantly differ (P > 0.05).

CONCLUSION

Harmonic training plays a significant role in improving the HIC's temporal processing of the PPST and CV in noise test; therefore, it can serve as a rehabilitation method to enhance temporal processing and auditory scene analysis.

Neural circuits and behavioral pathways linking hearing loss to affective dysregulation in older adults

Substantial evidence now links age-related hearing loss to incident major depressive disorder in older adults. However, research examining the neural circuits and behavioral mechanisms by which age-related hearing loss leads to depression is at an early phase. It is known that hearing loss has adverse structural and functional brain consequences, is associated with reduced social engagement and loneliness, and often results in tinnitus, which can independently affect cognitive control and emotion processing circuits. While pathways leading from these sequelae of hearing loss to affective dysregulation and depression are intuitive to hypothesize, few studies have yet been designed to provide conclusive evidence for specific pathophysiological mechanisms. Here we review the neurobiological and behavioral consequences of age-related hearing loss, present a model linking them to increased risk for major depressive disorder and suggest how future studies may facilitate the development of rationally designed therapeutic interventions for older adults with impaired hearing to reduce risk for depression and/or ameliorate depressive symptoms.

The effects of a temporal processing-based auditory training program on the auditory skills of elderly users of hearing aids: a study protocol for a randomized clinical trial

Background: One of the most important effects of age-related declines in neural processing speed is the impairment of temporal resolution, which leads to difficulty hearing in noisy environments. Since the central auditory system is highly plastic, by designing and implementing a temporal processing-based auditory training program, we can help the elderly improve their listening skills and speech understanding in noisy environments.

Methods: In the first phase of this research, based on the theoretical framework of temporal processing, an auditory training solution was developed as a software program. In the second phase, which will be described in the present study, the effects of the designed program on the listening skills of the elderly users of hearing aids (age: 60-75 years) will be studied in the control and intervention groups. In the intervention group, the auditory training program will be implemented for three months (36 sessions), and the results of central tests (GIN, DPT, QuickSIN) and the electrophysiological speech-ABR test will be compared in both groups before, immediately and one month after the intervention.

Discussion: Since temporal processing is not sufficient in auditory training programs for the elderly with hearing impairments, implementation of a temporal processing-based auditory training program can reduce hearing problems in noisy environments among elderly users of hearing aids.

Trial registration: This study was registered as a clinical trial in the Iranian Registry of Clinical Trials ( IRCT20190921044838N1) on December 25, 2019.

Effects of aging on spatial hearing

BACKGROUND

Aging has several effects on auditory processing with the most important effect known as speech perception impairment in noise.

AIMS

The aim of the present study was to investigate the effects of aging on spatial hearing using quick speech in noise (QSIN) and binaural masking level difference (BMLD) tests and speech, spatial, and qualities of hearing scale (SSQ) questionnaire.

METHODS

The study was carried out on 34 elderly people, aged 60-75 years, with normal peripheral hearing and 34 young participants, aged 18-25 years. Using SSQ questionnaire and QSIN and BMLD tests, the spatial auditory processing ability was compared between the two groups.

RESULTS

Comparison of mean scores using independent t test showed that there was a significant difference in the mean scores of QSIN, BMLD tests and SSQ questionnaire between the two groups (p < 0.001). Sex was not found to have any effect on the results (p > 0.05).

DISCUSSION

Structural and neurochemical changes that occur in different parts of the central nervous system by aging affect various aspects of spatial auditory processing, such as localization, the precedence effect, and speech perception in noise.

CONCLUSIONS

Lower scores of older adults with normal hearing in SSQ questionnaire and behavioral tests, compared with younger participants, may be considered as their weak performance in spatial auditory processing. The results of the present study reconfirm the effects of aging on spatial auditory processing, such as localization and speech perception in noise.

Auditory-frontal Channeling in α and β Bands is Altered by Age-related Hearing Loss and Relates to Speech Perception in Noise

Difficulty understanding speech-in-noise (SIN) is a pervasive problem faced by older adults particularly those with hearing loss. Previous studies have identified structural and functional changes in the brain that contribute to older adults' speech perception difficulties. Yet, many of these studies use neuroimaging techniques that evaluate only gross activation in isolated brain regions. Neural oscillations may provide further insight into the processes underlying SIN perception as well as the interaction between auditory cortex and prefrontal linguistic brain regions that mediate complex behaviors. We examined frequency-specific neural oscillations and functional connectivity of the EEG in older adults with and without hearing loss during an active SIN perception task. Brain-behavior correlations revealed listeners who were more resistant to the detrimental effects of noise also demonstrated greater modulation of α phase coherence between clean and noise-degraded speech, suggesting α desynchronization reflects release from inhibition and more flexible allocation of neural resources. Additionally, we found top-down β connectivity between prefrontal and auditory cortices strengthened with poorer hearing thresholds despite minimal behavioral differences. This is consistent with the proposal that linguistic brain areas may be recruited to compensate for impoverished auditory inputs through increased top-down predictions to assist SIN perception. Overall, these results emphasize the importance of top-down signaling in low-frequency brain rhythms that help compensate for hearing-related declines and facilitate efficient SIN processing.

Efficacy of a newly developed auditory-cognitive training system on speech recognition, central auditory processing and cognitive ability among older adults with normal cognition and with neurocognitive impairment

AIM

To evaluate the efficacy of a newly developed auditory-cognitive training system on speech recognition, central auditory processing and cognition among older adults with normal cognition (NC) and with neurocognitive impairment (NCI).

METHODS

A double-blind quasi-experiment was carried out on NC (n = 43) and NCI (n = 33) groups. Participants in each group were randomly assigned into treatment and control programs groups. The treatment group underwent auditory-cognitive training, whereas the control group was assigned to watch documentary videos, three times per week, for 8 consecutive weeks. Study outcomes that included Montreal Cognitive Assessment, Malay Hearing in Noise Test, Dichotic Digit Test, Gaps in Noise Test and Pitch Pattern Sequence Test were measured at 4-week intervals at baseline, and weeks 4, 8 and 12.

RESULTS

Mixed design anova showed significant training effects in total Montreal Cognitive Assessment and Dichotic Digit Test in both groups, NC (P < 0.001) and NCI (P < 0.01). The NC group also showed significant training effects in the Malay Hearing in Noise Test (quiet) (P < 0.01), Gaps in Noise Test (P < 0.001) and Pitch Pattern Sequence Test (humming) (P < 0.05). All training effects were sustained up to 4 weeks after the training ended.

CONCLUSIONS

The present study suggests that the newly developed auditory-cognitive training system has the potential to improve general cognition and some of the auditory processing abilities in both the NC and NCI groups. Because of the short test-retest intervals used in the present study, it is possible that the training effects were influenced by learning effect and, therefore, should be considered cautiously. Geriatr Gerontol Int 2019; 19: 768-773.

Auditory and Cognitive Training for Cognition in Adults With Hearing Loss: A Systematic Review and Meta-Analysis

This systematic review and meta-analysis examined the efficacy of auditory training and cognitive training to improve cognitive function in adults with hearing loss. A literature search of academic databases (e.g., MEDLINE, Scopus) and gray literature (e.g., OpenGrey) identified relevant articles published up to January 25, 2018. Randomized controlled trials (RCTs) or repeated measures designs were included. Outcome effects were computed as Hedge’s g and pooled using random-effects meta-analysis (PROSPERO: CRD42017076680). Nine studies, five auditory training, and four cognitive training met the inclusion criteria. Following auditory training, the pooled effect was small and statistically significant for both working memory (g = 0.21; 95% CI [0.05, 0.36]) and overall cognition (g = 0.19; 95% CI [0.07, 0.31]). Following cognitive training, the pooled effect for working memory was small and statistically significant (g = 0.34; 95% CI [0.16, 0.53]), and the pooled effect for overall cognition was large and significant (g = 1.03; 95% CI [0.41, 1.66]). However, this was dependent on the classification of training approach. Sensitivity analyses revealed no statistical difference between the effectiveness of auditory and cognitive training for improving cognition upon removal of a study that used a combined auditory–cognitive approach, which showed a very large effect. Overall certainty in the estimation of effect was “low” for auditory training and “very low” for cognitive training. High-quality RCTs are needed to determine which training stimuli will provide optimal conditions to improve cognition in adults with hearing loss.

Age, Hearing, and the Perceptual Learning of Rapid Speech

The effects of aging and age-related hearing loss on the ability to learn degraded speech are not well understood. This study was designed to compare the perceptual learning of time-compressed speech and its generalization to natural-fast speech across young adults with normal hearing, older adults with normal hearing, and older adults with age-related hearing loss. Early learning (following brief exposure to time-compressed speech) and later learning (following further training) were compared across groups. Age and age-related hearing loss were both associated with declines in early learning. Although the two groups of older adults improved during the training session, when compared to untrained control groups (matched for age and hearing), learning was weaker in older than in young adults. Especially, the transfer of learning to untrained time-compressed sentences was reduced in both groups of older adults. Transfer of learning to natural-fast speech occurred regardless of age and hearing, but it was limited to sentences encountered during training. Findings are discussed within the framework of dynamic models of speech perception and learning. Based on this framework, we tentatively suggest that age-related declines in learning may stem from age differences in the use of high- and low-level speech cues. These age differences result in weaker early learning in older adults, which may further contribute to the difficulty to perceive speech in daily conversational settings in this population.

Time-Compressed Speech Identification Is Predicted by Auditory Neural Processing, Perceptuomotor Speed, and Executive Functioning in Younger and Older Listeners

Older adults typically have difficulty identifying speech that is temporally distorted, such as reverberant, accented, time-compressed, or interrupted speech. These difficulties occur even when hearing thresholds fall within a normal range. Auditory neural processing speed, which we have previously found to predict auditory temporal processing (auditory gap detection), may interfere with the ability to recognize phonetic features as they rapidly unfold over time in spoken speech. Further, declines in perceptuomotor processing speed and executive functioning may interfere with the ability to track, access, and process information. The current investigation examined the extent to which age-related differences in time-compressed speech identification were predicted by auditory neural processing speed, perceptuomotor processing speed, and executive functioning. Groups of normal-hearing (up to 3000 Hz) younger and older adults identified 40, 50, and 60 % time-compressed sentences. Auditory neural processing speed was defined as the P1 and N1 latencies of click-induced auditory-evoked potentials. Perceptuomotor processing speed and executive functioning were measured behaviorally using the Connections Test. Compared to younger adults, older adults exhibited poorer time-compressed speech identification and slower perceptuomotor processing. Executive functioning, P1 latency, and N1 latency did not differ between age groups. Time-compressed speech identification was independently predicted by P1 latency, perceptuomotor processing speed, and executive functioning in younger and older listeners. Results of model testing suggested that declines in perceptuomotor processing speed mediated age-group differences in time-compressed speech identification. The current investigation joins a growing body of literature suggesting that the processing of temporally distorted speech is impacted by lower-level auditory neural processing and higher-level perceptuomotor and executive processes.

Amplification and aural rehabilitation in resource-constrained environments

Objectives

This article attempts to highlight the challenges and possibilities for hearing healthcare through technology and aural rehabilitation in a resource-constrained setting, using South Africa as an example.

Results and conclusion

The authors argue that it is possible to enhance service delivery by using free resources and maximising the limited existing resources. In order to provide a sustainable hearing healthcare service in developing countries, it is pertinent to understand the context where the services are needed, and not just adopt an approach developed for a different context. Audiologists in such settings need to employ strategies to develop context-specific tools, and adapt existing tools to serve the needs of the local population. Some examples, although not exhaustive, are provided in the article.

Neural Correlates of Selective Attention With Hearing Aid Use Followed by ReadMyQuips Auditory Training Program

OBJECTIVES

The objectives of this study were to investigate the effects of hearing aid use and the effectiveness of ReadMyQuips (RMQ), an auditory training program, on speech perception performance and auditory selective attention using electrophysiological measures. RMQ is an audiovisual training program designed to improve speech perception in everyday noisy listening environments.

DESIGN

Participants were adults with mild to moderate hearing loss who were first-time hearing aid users. After 4 weeks of hearing aid use, the experimental group completed RMQ training in 4 weeks, and the control group received listening practice on audiobooks during the same period. Cortical late event-related potentials (ERPs) and the Hearing in Noise Test (HINT) were administered at prefitting, pretraining, and post-training to assess effects of hearing aid use and RMQ training. An oddball paradigm allowed tracking of changes in P3a and P3b ERPs to distractors and targets, respectively. Behavioral measures were also obtained while ERPs were recorded from participants.

RESULTS

After 4 weeks of hearing aid use but before auditory training, HINT results did not show a statistically significant change, but there was a significant P3a reduction. This reduction in P3a was correlated with improvement in d prime (d') in the selective attention task. Increased P3b amplitudes were also correlated with improvement in d' in the selective attention task. After training, this correlation between P3b and d' remained in the experimental group, but not in the control group. Similarly, HINT testing showed improved speech perception post training only in the experimental group. The criterion calculated in the auditory selective attention task showed a reduction only in the experimental group after training. ERP measures in the auditory selective attention task did not show any changes related to training.

CONCLUSIONS

Hearing aid use was associated with a decrement in involuntary attention switch to distractors in the auditory selective attention task. RMQ training led to gains in speech perception in noise and improved listener confidence in the auditory selective attention task.

Connected Audiological Rehabilitation: 21st Century Innovations

BACKGROUND

Tele-audiology provides a means to offer audiologic rehabilitation (AR) in a cost-, resource-, and time-effective manner. If designed appropriately, it also has the capability of personalizing rehabilitation to the user in terms of content, depth of detail, etc., thus permitting selection of the best content for a particular individual. Synchronous/real-time data collection, store and forward telehealth, remote monitoring and mobile health using smartphone applications have each been applied to components of audiologic rehabilitation intervention (sensory management, instruction in the use of technology and control of the listening environment, perceptual and communication strategies training, and counseling). In this article, the current state of tele-audiological rehabilitation interventions are described and discussed.

RESULTS

The provision of AR via tele-audiology potentially provides a cost-effective mechanism for addressing barriers to the routine provision of AR beyond provisions of hearing technology. Furthermore, if designed appropriately, it has the capability of personalizing rehabilitation to the user in terms of content, depth of detail, etc., thus permitting selection of the best content for a particular individual. However, effective widespread implementation of tele-audiology will be dependent on good education of patients and clinician alike, and researchers must continue to examine the effectiveness of these new approaches to AR in order to ensure clinicians provide effective evidence-based rehabilitation to their patients.

CONCLUSIONS

While several barriers to the widespread use of tele-audiology for audiologic rehabilitation currently exist, it is concluded that through education of patients and clinicians alike, it will gain greater support from practitioners and patients over time and will become successfully and widely implemented.

Neuromodulatory Effects of Auditory Training and Hearing Aid Use on Audiovisual Speech Perception in Elderly Individuals

Although audiovisual (AV) training has been shown to improve overall speech perception in hearing-impaired listeners, there has been a lack of direct brain imaging data to help elucidate the neural networks and neural plasticity associated with hearing aid (HA) use and auditory training targeting speechreading. For this purpose, the current clinical case study reports functional magnetic resonance imaging (fMRI) data from two hearing-impaired patients who were first-time HA users. During the study period, both patients used HAs for 8 weeks; only one received a training program named ReadMyQuips^TM (RMQ) targeting speechreading during the second half of the study period for 4 weeks. Identical fMRI tests were administered at pre-fitting and at the end of the 8 weeks. Regions of interest (ROI) including auditory cortex and visual cortex for uni-sensory processing, and superior temporal sulcus (STS) for AV integration, were identified for each person through independent functional localizer task. The results showed experience-dependent changes involving ROIs of auditory cortex, STS and functional connectivity between uni-sensory ROIs and STS from pretest to posttest in both cases. These data provide initial evidence for the malleable experience-driven cortical functionality for AV speech perception in elderly hearing-impaired people and call for further studies with a much larger subject sample and systematic control to fill in the knowledge gap to understand brain plasticity associated with auditory rehabilitation in the aging population.

Evidence and evidence gaps in tinnitus therapy

A nearly endless number of procedures has been tried and in particular sold for the treatment of tinnitus, unfortunately they have not been evaluated appropriately in an evidence-based way. A causal therapy, omitting the tinnitus still does not exist, actually it cannot exist because of the various mechanisms of its origin. However or perhaps because of that, medical interventions appear and reappear like fashion trends that can never be proven by stable and reliable treatment success. This contribution will discuss and acknowledge all current therapeutic procedures and the existing or non-existing evidence will be assessed. Beside external evidence, the term of evidence also encompasses the internal evidence, i.e. the experience of the treating physician and the patient's needs shall be included. While there is no evidence for nearly all direct procedures that intend modulating or stimulating either the cochlea or specific cervical regions such as the auditory cortex, there are therapeutic procedures that are acknowledged in clinical practice and have achieved at least a certain degree of evidence and generate measurable effect sizes. Those are in particular habituation therapy and psychotherapeutic measures, especially if they are combined with concrete measures for improved audio perception (hearing aids, CI, hearing therapies).

Listening and Learning: Cognitive Contributions to the Rehabilitation of Older Adults With and Without Audiometrically Defined Hearing Loss

Here, we describe some of the ways in which aging negatively affects the way sensory input is transduced and processed within the aging brain and how cognitive work is involved when listening to a less-than-perfect signal. We also describe how audiologic rehabilitation, including hearing aid amplification and listening training, is used to reduce the amount of cognitive resources required for effective auditory communication and conclude with an example of how listening effort is being studied in research laboratories for the purpose(s) of informing clinical practice.

Impact of peripheral hearing loss on top-down auditory processing

The auditory system consists of an intricate set of connections interposed between hierarchically arranged nuclei. The ascending pathways carrying sound information from the cochlea to the auditory cortex are, predictably, altered in instances of hearing loss resulting from blockage or damage to peripheral auditory structures. However, hearing loss-induced changes in descending connections that emanate from higher auditory centers and project back toward the periphery are still poorly understood. These pathways, which are the hypothesized substrate of high-level contextual and plasticity cues, are intimately linked to the ascending stream, and are thereby also likely to be influenced by auditory deprivation. In the current report, we review both the human and animal literature regarding changes in top-down modulation after peripheral hearing loss. Both aged humans and cochlear implant users are able to harness the power of top-down cues to disambiguate corrupted sounds and, in the case of aged listeners, may rely more heavily on these cues than non-aged listeners. The animal literature also reveals a plethora of structural and functional changes occurring in multiple descending projection systems after peripheral deafferentation. These data suggest that peripheral deafferentation induces a rebalancing of bottom-up and top-down controls, and that it will be necessary to understand the mechanisms underlying this rebalancing to develop better rehabilitation strategies for individuals with peripheral hearing loss.

Effects of Aging and Adult-Onset Hearing Loss on Cortical Auditory Regions

Hearing loss is a common feature in human aging. It has been argued that dysfunctions in central processing are important contributing factors to hearing loss during older age. Aging also has well documented consequences for neural structure and function, but it is not clear how these effects interact with those that arise as a consequence of hearing loss. This paper reviews the effects of aging and adult-onset hearing loss in the structure and function of cortical auditory regions. The evidence reviewed suggests that aging and hearing loss result in atrophy of cortical auditory regions and stronger engagement of networks involved in the detection of salient events, adaptive control and re-allocation of attention. These cortical mechanisms are engaged during listening in effortful conditions in normal hearing individuals. Therefore, as a consequence of aging and hearing loss, all listening becomes effortful and cognitive load is constantly high, reducing the amount of available cognitive resources. This constant effortful listening and reduced cognitive spare capacity could be what accelerates cognitive decline in older adults with hearing loss.

The Auditory-Visual Speech Benefit on Working Memory in Older Adults with Hearing Impairment

This study examined the effect of auditory-visual (AV) speech stimuli on working memory in older adults with poorer-hearing (PH) in comparison to age- and education-matched older adults with better hearing (BH). Participants completed a working memory n-back task (0- to 2-back) in which sequences of digits were presented in visual-only (i.e., speech-reading), auditory-only (A-only), and AV conditions. Auditory event-related potentials (ERP) were collected to assess the relationship between perceptual and working memory processing. The behavioral results showed that both groups were faster in the AV condition in comparison to the unisensory conditions. The ERP data showed perceptual facilitation in the AV condition, in the form of reduced amplitudes and latencies of the auditory N1 and/or P1 components, in the PH group. Furthermore, a working memory ERP component, the P3, peaked earlier for both groups in the AV condition compared to the A-only condition. In general, the PH group showed a more robust AV benefit; however, the BH group showed a dose-response relationship between perceptual facilitation and working memory improvement, especially for facilitation of processing speed. Two measures, reaction time and P3 amplitude, suggested that the presence of visual speech cues may have helped the PH group to counteract the demanding auditory processing, to the level that no group differences were evident during the AV modality despite lower performance during the A-only condition. Overall, this study provides support for the theory of an integrated perceptual-cognitive system. The practical significance of these findings is also discussed.

Auditory Perceptual Learning in Adults with and without Age-Related Hearing Loss

Introduction : Speech recognition in adverse listening conditions becomes more difficult as we age, particularly for individuals with age-related hearing loss (ARHL). Whether these difficulties can be eased with training remains debated, because it is not clear whether the outcomes are sufficiently general to be of use outside of the training context. The aim of the current study was to compare training-induced learning and generalization between normal-hearing older adults and those with ARHL. Methods : Fifty-six listeners (60-72 y/o), 35 participants with ARHL, and 21 normal hearing adults participated in the study. The study design was a cross over design with three groups (immediate-training, delayed-training, and no-training group). Trained participants received 13 sessions of home-based auditory training over the course of 4 weeks. Three adverse listening conditions were targeted: (1) Speech-in-noise, (2) time compressed speech, and (3) competing speakers, and the outcomes of training were compared between normal and ARHL groups. Pre- and post-test sessions were completed by all participants. Outcome measures included tests on all of the trained conditions as well as on a series of untrained conditions designed to assess the transfer of learning to other speech and non-speech conditions. Results : Significant improvements on all trained conditions were observed in both ARHL and normal-hearing groups over the course of training. Normal hearing participants learned more than participants with ARHL in the speech-in-noise condition, but showed similar patterns of learning in the other conditions. Greater pre- to post-test changes were observed in trained than in untrained listeners on all trained conditions. In addition, the ability of trained listeners from the ARHL group to discriminate minimally different pseudowords in noise also improved with training. Conclusions : ARHL did not preclude auditory perceptual learning but there was little generalization to untrained conditions. We suggest that most training-related changes occurred at higher level task-specific cognitive processes in both groups. However, these were enhanced by high quality perceptual representations in the normal-hearing group. In contrast, some training-related changes have also occurred at the level of phonemic representations in the ARHL group, consistent with an interaction between bottom-up and top-down processes.

Electrophysiologic Assessment of Auditory Training Benefits in Older Adults

Older adults often exhibit speech perception deficits in difficult listening environments. At present, hearing aids or cochlear implants are the main options for therapeutic remediation; however, they only address audibility and do not compensate for central processing changes that may accompany aging and hearing loss or declines in cognitive function. It is unknown whether long-term hearing aid or cochlear implant use can restore changes in central encoding of temporal and spectral components of speech or improve cognitive function. Therefore, consideration should be given to auditory/cognitive training that targets auditory processing and cognitive declines, taking advantage of the plastic nature of the central auditory system. The demonstration of treatment efficacy is an important component of any training strategy. Electrophysiologic measures can be used to assess training-related benefits. This article will review the evidence for neuroplasticity in the auditory system and the use of evoked potentials to document treatment efficacy.

How Does Auditory Training Work? Joined-Up Thinking and Listening

Auditory training aims to compensate for degradation in the auditory signal and is offered as an intervention to help alleviate the most common complaint in people with hearing loss, understanding speech in a background noise. Yet there remain many unanswered questions. This article reviews some of the key pieces of evidence that assess the evidence for whether, and how, auditory training benefits adults with hearing loss. The evidence supports that improvements occur on the trained task; however, transfer of that learning to generalized real-world benefit is much less robust. For more than a decade, there has been an increasing awareness of the role that cognition plays in listening. But more recently in the auditory training literature, there has been an increased focus on assessing how cognitive performance relevant for listening may improve with training. We argue that this is specifically the case for measures that index executive processes, such as monitoring, attention switching, and updating of working memory, all of which are required for successful listening and communication in challenging or adverse listening conditions. We propose combined auditory-cognitive training approaches, where training interventions develop cognition embedded within auditory tasks, which are most likely to offer generalized benefits to the real-world listening abilities of people with hearing loss.

Hearing Aid-Induced Plasticity in the Auditory System of Older Adults: Evidence From Speech Perception

PURPOSE

We tested whether using hearing aids can improve unaided performance in speech perception tasks in older adults with hearing impairment.

METHOD

Unaided performance was evaluated in dichotic listening and speech-in-noise tests in 47 older adults with hearing impairment; 36 participants in 3 study groups were tested before hearing aid fitting and after 4, 8, and 14 weeks of hearing-aid use. The remaining 11 participants served as a control group and were similarly evaluated but were not fitted with hearing aids. Three protocols were compared in the study groups: amplification for the nondominant ear, amplification for the dominant ear, and bilateral amplification. Subsequently, after 4 weeks, all participants were afforded bilateral amplification.

RESULTS

In the study groups, unaided dichotic listening scores improved significantly in the nondominant ear by 8 weeks and onward. Significant improvements were also observed for unaided speech identification in noise, with some gains apparent after 4 weeks of hearing-aid use. No gains were observed in the control group.

CONCLUSIONS

Using hearing aids for a relatively short period can induce changes in the way older adults process auditory inputs in perceptual tasks such as speech identification in noise and dichotic listening. These changes suggest that the central auditory system of older adults retains the potential for behaviorally relevant plasticity.

Intrinsic and extrinsic motivation is associated with computer-based auditory training uptake, engagement, and adherence for people with hearing loss

Hearing aid intervention typically occurs after significant delay, or not at all, resulting in an unmet need for many people with hearing loss. Computer-based auditory training (CBAT) may provide generalized benefits to real-world listening, particularly in adverse listening conditions, and can be conveniently delivered in the home environment. Yet as with any intervention, adherence to CBAT is critical to its success. The main aim of this investigation was to explore motivations for uptake, engagement and adherence with home-delivered CBAT in a randomized controlled trial of adults with mild sensorineural hearing loss (SNHL), with a view to informing future CBAT development. A secondary aim examined perceived benefits of CBAT. Participants (n = 44, 50–74 years olds with mild SNHL who did not have hearing aids) completed a 4-week program of phoneme discrimination CBAT at home. Participants' experiences of CBAT were captured using a post-training questionnaire (n = 44) and two focus groups (n = 5 per group). A mixed-methods approach examined participants' experiences with the intervention, the usability and desirability of the CBAT software, and participants' motivations for CBAT uptake, engagement and adherence. Self-Determination Theory (SDT) was used as a theoretical framework for the interpretation of results. Participants found the CBAT intervention easy to use, interesting and enjoyable. Initial participation in the study was associated with extrinsic motivation (e.g., hearing difficulties). Engagement and adherence with CBAT was influenced by intrinsic (e.g., a desire to achieve higher scores), and extrinsic (e.g., to help others with hearing loss) motivations. Perceived post-training benefits included better concentration and attention leading to improved listening. CBAT also prompted further help-seeking behaviors for some individuals. We see this as an important first-step for informing future theory-driven development of effective CBAT interventions.

Auditory training can improve working memory, attention, and communication in adverse conditions for adults with hearing loss

Auditory training (AT) helps compensate for degradation in the auditory signal. A series of three high-quality training studies are discussed, which include, (i) a randomized controlled trial (RCT) of phoneme discrimination in quiet that trained adults with mild hearing loss (n = 44), (ii) a repeated measures study that trained phoneme discrimination in noise in hearing aid (HA) users (n = 30), and (iii) a double-blind RCT that directly trained working memory (WM) in HA users (n = 57). AT resulted in generalized improvements in measures of self-reported hearing, competing speech, and complex cognitive tasks that all index executive functions. This suggests that for AT related benefits, the development of complex cognitive skills may be more important than the refinement of sensory processing. Furthermore, outcome measures should be sensitive to the functional benefits of AT. For WM training, lack of far-transfer to untrained outcomes suggests no generalized benefits to real-world listening abilities. We propose that combined auditory-cognitive training approaches, where cognitive enhancement is embedded within auditory tasks, are most likely to offer generalized benefits to the real-world listening abilities of adults with hearing loss.

Efficacy of auditory training in elderly subjects

Auditory training (AT) has been used for auditory rehabilitation in elderly individuals and is an effective tool for optimizing speech processing in this population. However, it is necessary to distinguish training-related improvements from placebo and test-retest effects. Thus, we investigated the efficacy of short-term AT [acoustically controlled auditory training (ACAT)] in elderly subjects through behavioral measures and P300. Sixteen elderly individuals with auditory processing disorder (APD) received an initial evaluation (evaluation 1 - E1) consisting of behavioral and electrophysiological tests (P300 evoked by tone burst and speech sounds) to evaluate their auditory processing. The individuals were divided into two groups. The Active Control Group (n = 8) underwent placebo training. The Passive Control Group (n = 8) did not receive any intervention. After 12 weeks, the subjects were revaluated (evaluation 2 - E2). Then, all of the subjects underwent ACAT. Following another 12 weeks (eight training sessions), they underwent the final evaluation (evaluation 3 - E3). There was no significant difference between E1 and E2 in the behavioral test [F(9.6) = 0.06, p = 0.92, λ de Wilks = 0.65)] or P300 [F(8.7) = 2.11, p = 0.17, λ de Wilks = 0.29] (discarding the presence of placebo effects and test-retest). A significant improvement was observed between the pre- and post-ACAT conditions (E2 and E3) for all auditory skills according to the behavioral methods [F(4.27) = 0.18, p = 0.94, λ de Wilks = 0.97]. However, the same result was not observed for P300 in any condition. There was no significant difference between P300 stimuli. The ACAT improved the behavioral performance of the elderly for all auditory skills and was an effective method for hearing rehabilitation.

Speech perception in older hearing impaired listeners: benefits of perceptual training

Hearing aids (HAs) only partially restore the ability of older hearing impaired (OHI) listeners to understand speech in noise, due in large part to persistent deficits in consonant identification. Here, we investigated whether adaptive perceptual training would improve consonant-identification in noise in sixteen aided OHI listeners who underwent 40 hours of computer-based training in their homes. Listeners identified 20 onset and 20 coda consonants in 9,600 consonant-vowel-consonant (CVC) syllables containing different vowels (/ɑ/, /i/, or /u/) and spoken by four different talkers. Consonants were presented at three consonant-specific signal-to-noise ratios (SNRs) spanning a 12 dB range. Noise levels were adjusted over training sessions based on d’ measures. Listeners were tested before and after training to measure (1) changes in consonant-identification thresholds using syllables spoken by familiar and unfamiliar talkers, and (2) sentence reception thresholds (SeRTs) using two different sentence tests. Consonant-identification thresholds improved gradually during training. Laboratory tests of d’ thresholds showed an average improvement of 9.1 dB, with 94% of listeners showing statistically significant training benefit. Training normalized consonant confusions and improved the thresholds of some consonants into the normal range. Benefits were equivalent for onset and coda consonants, syllables containing different vowels, and syllables presented at different SNRs. Greater training benefits were found for hard-to-identify consonants and for consonants spoken by familiar than unfamiliar talkers. SeRTs, tested with simple sentences, showed less elevation than consonant-identification thresholds prior to training and failed to show significant training benefit, although SeRT improvements did correlate with improvements in consonant thresholds. We argue that the lack of SeRT improvement reflects the dominant role of top-down semantic processing in processing simple sentences and that greater transfer of benefit would be evident in the comprehension of more unpredictable speech material.

Partial maintenance of auditory-based cognitive training benefits in older adults

The potential for short-term training to improve cognitive and sensory functions in older adults has captured the public's interest. Initial results have been promising. For example, eight weeks of auditory-based cognitive training decreases peak latencies and peak variability in neural responses to speech presented in a background of noise and instills gains in speed of processing, speech-in-noise recognition, and short-term memory in older adults. But while previous studies have demonstrated short-term plasticity in older adults, we must consider the long-term maintenance of training gains. To evaluate training maintenance, we invited participants from an earlier training study to return for follow-up testing six months after the completion of training. We found that improvements in response peak timing to speech in noise and speed of processing were maintained, but the participants did not maintain speech-in-noise recognition or memory gains. Future studies should consider factors that are important for training maintenance, including the nature of the training, compliance with the training schedule, and the need for booster sessions after the completion of primary training.

Benefits of auditory training for aided listening by older adults

PURPOSE

In this article, the authors provide an overview of auditory training programs for aided listening by older adults, review criteria for evaluating effectiveness, summarize results of published studies, report on 2 training programs currently undergoing assessment, and discuss directions and needs for future research.

METHOD

Experiments are ongoing to evaluate 2 individual, computer-based speech-perception training programs: Indiana University (IU) word-based training and the Speech Perception Assessment and Training System (SPATS). Training and control subjects are older adults with mild-to-severe hearing loss. Subjects train for about 30 hr with monaurally presented, spectrally shaped stimuli (IU) or through loudspeakers with their own hearing aids (SPATS). Displays and feedback use auditory and visual/orthographic cues. Outcome measures include objective measures of speech recognition in noise and other training benefits.

RESULTS

Significant improvements were observed in open-set recognition of trained sounds, words, phrases, and sentences. Large individual differences in training benefit were apparent. Generalization varied with the speech-perception task, competing noise, listening strategy, and pretraining scores.

CONCLUSIONS

High-level evidence is needed to support the effectiveness of auditory training for older adults as a supplement to aided listening. Studies are needed to predict who will benefit from specific types of training, to assess compliance and engagement, and to discover benefits beyond communication.

A preliminary study on the relationship between central auditory processing and childhood primary headaches in the intercritical phase

BACKGROUND

Recently, an increasing number of articles have appeared on central auditory processing disorders, but in the literature there is only one study that evaluated the possible correlation between migraine in the critical phase and central auditory processing. The aim of our study was to assess the correlation between auditory processing information and childhood primary headaches in the intercritical phase.

METHODS

This is an observational study. We enrolled 54 patients, 30 with primary headache (migraine and tension headache) and 24 normal controls, matched for sex and age. The mean age at first observation was 9 years 10 months; the duration of observational follow-up was 2 years. Both groups had normal audiological and neurological profiles, normal peripheral hearing acuity and normal cognitive and behavioral skills. We excluded patients who had undergone pharmacological prophylactic treatment for headaches in the 6 months preceding the study and subjects with a frequency of headache lower than one every two months. After enrolment, both groups were analyzed with a computerized test battery for Speech Perception Tests in silence and in noise background to assess speech perception disabilities. In addition, with a test battery of Speech Perception Tests, we compared patients with migraines and tension-type headaches. The non-parametric χ2 test, the Mann-Whitney U-test and the Wilcoxon signed ranks test were used for statistical analysis. P-values <0.05 were considered significant and STATA 10 software was used for statistical analyses.

RESULTS

Our results showed that patients with primary headache (migraine and tension-type headache), had a deficit of auditory processing in noisy background compared to control cases, but we found no significant differences when we compared patients with migraine and tension-type headache.

CONCLUSIONS

This is a work in progress and further studies are needed to assess the relationship between the impairment of auditory processing and primary headache, not only to improve the diagnostic approach to primary headache, but also to improve therapeutic intervention.

Hearing Technology and Cognition

Purpose

To summarize existing data on the interactions of cognitive function and hearing technology in older adults.

Method

A narrative review was used to summarize previous data for the short-term interactions of cognition and hearing technology on measured outcomes. For long-term outcomes, typically for 3–24 months of hearing aid use, a computerized database search was conducted.

Results

There is accumulating evidence that cognitive function can impact outcomes following immediate or short-term use of hearing aids and that hearing aids can impact immediate cognitive function. There is limited evidence regarding the long-term impact of hearing aids on cognition, and the most rigorous studies in this area have not observed a positive effect.

Conclusions

Although interactions have been observed between cognition and use of hearing aids for measures obtained following immediate or short-term usage of hearing technology, limited evidence is available following long-term usage, and that evidence that is available does not support an effect of hearing aids on cognitive function. More research is needed, however, including rigorous studies of older adults following longer periods of hearing aid usage.