Central presbycusis: a review and evaluation of the evidence

On-beat rhythm and working memory are associated with better speech-in-noise perception for older adults with hearing loss

Even with the use of hearing aids (HAs), speech in noise perception remains challenging for older adults, impacting communication and quality of life outcomes. The association between music perception and speech-in-noise (SIN) outcomes is of interest, as there is evidence that professionally trained musicians are adept listeners in noisy environments. Thus, this study explored the association between music processing, cognitive factors, and the outcome variable of SIN perception, in older adults with hearing loss. Forty-two HA users aged between 57 and 90 years with a symmetrical, moderate-to-moderately severe hearing loss participated in this study. Our findings suggest that on-beat rhythm accuracy, pitch perception, and working memory all positively contribute to SIN perception for older adults with hearing loss. These findings provide key insights into the relationship between music, cognitive factors, and SIN perception, which may inform future interventions, rehabilitation, and the mechanisms that support better SIN perception.

Multidimensional relationships between sensory perception and cognitive aging

A growing literature suggests that declines in sensory/perceptual systems predate cognitive declines in aging, and furthermore, they are highly predictive for developing Alzheimer's disease and Alzheimer's related dementias (ADRD). While vision, hearing, olfaction, and vestibular function have each been shown to be related to ADRD, their causal relations to cognitive declines, how they interact with each other remains to be clarified. Currently, there is substantial debate whether sensory/perceptual systems that fail early in disease progression are causal in their contributions to cognitive load and/or social isolation or are simply coincident declines due to aging. At the same time, substantial declines in any of these senses requires compensation, can strain other neural processes and impact activities of daily living, including social engagement, quality of life, and the risk of falls. In this perspective piece, we review literature that illustrates the different relationships between sensory/perceptual systems, cognitive aging and ADRD. We suggest that broadly administered and precise assessment of sensory/perceptual functions could facilitate early detection of ADRD and pave the way for intervention strategies that could help reduce the multifaceted risk of developing ADRD and to improve everyday functioning as people age.

Auditory processing deficits in subacute stroke

BACKGROUND

Stroke is the second leading cause of disability worldwide. Stroke results in focal neurological deficit and often leads to auditory problems due to its impact on the auditory pathway. Altered connections in the auditory pathway, caused by stroke, can result in hearing difficulties ranging from impaired sound detection to altered auditory perception. A better understanding of how stroke affects these early sound processing mechanisms will provide valuable insights into stroke recovery and rehabilitation options.

METHODS

We recruited forty consecutive adult patients with stroke (30 males, 10 females) due to ischemic or intracerebral hemorrhage > 3 and up to 12 months after stroke (subacute stage). Brain MRIs were performed on all patients, and we calculated a central auditory nervous system stroke severity index (CANS SSI) according to number of CANS areas involved and an extended CANS definition of auditory responsive areas. All patients underwent cognitive screening assessment, basic audiological assessments, and a hierarchical central auditory processing assessment battery with the Queen Square Tests of Auditory Cognition (early perceptual processing, apperceptive processing, semantic Processing) and Gaps in Noise tests.

RESULTS

When comparing patients with auditory responsive cortical lesions and with versus without Heschl's gyrus involvement (primary auditory cortex), patients with Heschl's gyrus involvement exhibited worse early perceptual scores. The CANS SSI showed a significant negative correlation with early perceptual test scores.

CONCLUSION

This study demonstrates a correlation between stroke severity, characterized by a higher number of lesions involving auditory areas in patients with subacute stroke, and worse early perceptual scores. Heschl's gyrus involvement is associated with poorer early perceptual score.

Executive Function Associations With Audibility-Adjusted Speech Perception in Noise

PURPOSE

Speech recognition in noise is challenging for listeners and appears to require support from executive functions to focus attention on rapidly unfolding target speech, track misunderstanding, and sustain attention. The current study was designed to test the hypothesis that lower executive function abilities explain poorer speech recognition in noise, including among older participants with hearing loss who often exhibit diminished speech recognition in noise and cognitive abilities.

METHOD

A cross-sectional sample of 400 younger-to-older adult participants (19 to < 90 years of age) from the community-based Medical University of South CarolinaLongitudinal Cohort Study of Age-related Hearing Loss were administered tasks with executive control demands to assess individual variability in a card-sorting measure of set-shifting/performance monitoring, a dichotic listening measure of selective attention/working memory, sustained attention, and processing speed. Key word recognition in the high- and low-context speech perception-in-noise (SPIN) tests provided measures of speech recognition in noise. The SPIN scores were adjusted for audibility using the Articulation Index to characterize the impact of varied hearing sensitivity unrelated to reduced audibility on cognitive and speech recognition associations.

RESULTS

Set-shifting, dichotic listening, and processing speed each explained unique and significant variance in audibility-adjusted, low-context SPIN scores (ps < .001), including after controlling for age, pure-tone threshold average (PTA), sex, and education level. The dichotic listening and processing speed effect sizes were significantly diminished when controlling for PTA, indicating that participants with poorer hearing sensitivity were also likely to have lower executive function and lower audibility-adjusted speech recognition.

CONCLUSIONS

Poor set-shifting/performance monitoring, slow processing speed, and poor selective attention/working memory appeared to partially explain difficulties with speech recognition in noise after accounting for audibility. These results are consistent with the premise that distinct executive functions support speech recognition in noise.

Spatial selective auditory attention is preserved in older age but is degraded by peripheral hearing loss

Interest in how ageing affects attention is long-standing, although interactions between sensory and attentional processing in older age are not fully understood. Here, we examined interactions between peripheral hearing and selective attention in a spatialised cocktail party listening paradigm, in which three talkers spoke different sentences simultaneously and participants were asked to report the sentence spoken by a talker at a particular location. By comparing a sample of older (N = 61; age = 55-80 years) and younger (N = 58; age = 18-35 years) adults, we show that, as a group, older adults benefit as much as younger adults from preparatory spatial attention. Although, for older adults, this benefit significantly reduces with greater age-related hearing loss. These results demonstrate that older adults with excellent hearing retain the ability to direct spatial selective attention, but this ability deteriorates, in a graded manner, with age-related hearing loss. Thus, reductions in spatial selective attention likely contribute to difficulties communicating in social settings for older adults with age-related hearing loss. Overall, these findings demonstrate a relationship between mild perceptual decline and attention in older age.

The impact of age-related hearing loss on cognitive decline: The mediating role of brain age gap

In recent years, the relationship between age-related hearing loss, cognitive decline, and the risk of dementia has garnered significant attention. The significant variability in brain health and aging among individuals of the same chronological age suggests that a measure assessing how one's brain ages may better explain hearing-cognition links. The main aim of this study was to investigate the mediating role of Brain Age Gap (BAG) in the association between hearing impairment and cognitive function. This research included 185 participants aged 20-79 years. BAG was estimated based on the difference between participant's brain age (estimated based on their structural T1-weighted MRI scans) and chronological age. Cognitive performance was assessed using the Montreal Cognitive Assessment (MoCA) test while hearing ability was measured using pure-tone thresholds (PTT) and words-in-noise (WIN) perception. Mediation analyses were used to examine the mediating role of BAG in the relationship between age-related hearing loss as well as difficulties in WIN perception and cognition. Participants with poorer hearing sensitivity and WIN perception showed lower MoCA scores, but this was an indirect effect. Participants with poorer performance on PTT and WIN tests had larger BAG (accelerated brain aging), and this was associated with poorer performance on the MoCA test. Mediation analyses showed that BAG partially mediated the relationship between age-related hearing loss and cognitive decline. This study enhances our understanding of the interplay among hearing loss, cognition, and BAG, emphasizing the potential value of incorporating brain age assessments in clinical evaluations to gain insights beyond chronological age, thus advancing strategies for preserving cognitive health in aging populations.

Central Auditory Changes Associated with Age-related Hearing Loss

Objective. This study aimed to investigate age-related changes in cortical auditory evoked potentials (CAEPs) while considering three crucial factors: aging, high-frequency hearing loss and sensation level of the CAEP stimulus. Method. The electrophysiological and audiometric data of 71 elderly participants were analyzed using multiple regression analysis to investigate the association of CAEPs with the factors of aging, high-frequency hearing loss and sensation level of the CAEP test stimulus. Results. Aging was significantly associated with prolonged N1 and P2 latencies and reduced P2 amplitude. Elevated thresholds related to the sensation level of the CAEP stimulus were significantly associated with increased N1 and P2 amplitudes and decreased N1 latency. A significant relationship was detected between high-frequency hearing thresholds and the shortening of P2 latencies and the reduction of P2 amplitudes. Conclusion. The results of this study highlight the complex interplay of aging, high-frequency hearing loss and the sensation level of the CAEP stimulus on CAEP components in elderly people. These factors should be considered in future research using CAEPs to enhance overall understanding of auditory processing in the aging population.

Development and Evaluation of the Italian Version of the Dichotic Digit Test: Insights from 39 Normal-Hearing Children Aged 11 to 13 years

BACKGROUND The dichotic digit test (DDT) is one of the tests for the behavioral assessment of central auditory processing. Dichotic listening tests are sensitive ways of assessing cortical structures, the corpus callossum, and binaural integration mechanisms, showing strong correlations with learning difficulties. The DDT is presently available in a number of languages, each appropriate for the subject's native language. However, there is presently no test in the Italian language. The goal of this study was to develop an Italian version of the one-pair dichotic digit test (DDT-IT) and analyze results in 39 normal-hearing Italian children 11 to 13 years old. We used 2 conditions of presentation: free recall and directed attention (left or right ear), and looked at possible effects of sex and ear side. MATERIAL AND METHODS This study involved 3 steps: creation of the stimuli, checking their quality with Italian speakers, and assessment of the DDT-IT in our subject pool. The study involved 39 children (26 girls and 13 boys), aged 11-13 years. All participants underwent basic audiological assessment, auditory brainstem response, and then DDT-IT. RESULTS Results under free recall and directed attention conditions were similar for right and left ears, and there were no sex or age effects. CONCLUSIONS The Italian version of DDT (DDT-IT) has been developed and its performance on 39 normal-hearing Italian children was assessed. We found there were no age or sex effects for either the free recall condition or the directed attention condition.

Age Impacts Speech-in-Noise Recognition Differently for Nonnative and Native Listeners

PURPOSE

The purpose of this study was to explore potential differences in suprathreshold auditory function among native and nonnative speakers of English as a function of age.

METHOD

Retrospective analyses were performed on three large data sets containing suprathreshold auditory tests completed by 5,572 participants who were self-identified native and nonnative speakers of English between the ages of 18-65 years, including a binaural tone detection test, a digit identification test, and a sentence recognition test.

RESULTS

The analyses show a significant interaction between increasing age and participant group on tests involving speech-based stimuli (digit strings, sentences) but not on the binaural tone detection test. For both speech tests, differences in speech recognition emerged between groups during early adulthood, and increasing age had a more negative impact on word recognition for nonnative compared to native participants. Age-related declines in performance were 2.9 times faster for digit strings and 3.3 times faster for sentences for nonnative participants compared to native participants.

CONCLUSIONS

This set of analyses extends the existing literature by examining interactions between aging and self-identified native English speaker status in several auditory domains in a cohort of adults spanning young adulthood through middle age. The finding that older nonnative English speakers in this age cohort may have greater-than-expected deficits on speech-in-noise perception may have clinical implications on how these individuals should be diagnosed and treated for hearing difficulties.

Age-related differences in auditory spatial processing revealed by acoustic change complex

Objectives

The auditory spatial processing abilities mature throughout childhood and degenerate in older adults. This study aimed to compare the differences in onset cortical auditory evoked potentials (CAEPs) and location-evoked acoustic change complex (ACC) responses among children, adults, and the elderly and to investigate the impact of aging and development on ACC responses.

Design

One hundred and seventeen people were recruited in the study, including 57 typically-developed children, 30 adults, and 30 elderlies. The onset-CAEP evoked by white noise and ACC by sequential changes in azimuths were recorded. Latencies and amplitudes as a function of azimuths were analyzed using the analysis of variance, Pearson correlation analysis, and multiple linear regression model.

Results

The ACC N1'-P2' amplitudes and latencies in adults, P1'-N1' amplitudes in children, and N1' amplitudes and latencies in the elderly were correlated with angles of shifts. The N1'-P2' and P2' amplitudes decreased in the elderly compared to adults. In Children, the ACC P1'-N1' responses gradually differentiated into the P1'-N1'-P2' complex. Multiple regression analysis showed that N1'-P2' amplitudes (R2 = 0.33) and P2' latencies (R2 = 0.18) were the two most variable predictors in adults, while in the elderly, N1' latencies (R2 = 0.26) explained most variances. Although the amplitudes of onset-CAEP differed at some angles, it could not predict angle changes as effectively as ACC responses.

Conclusion

The location-evoked ACC responses varied among children, adults, and the elderly. The N1'-P2' amplitudes and P2' latencies in adults and N1' latencies in the elderly explained most variances of changes in spatial position. The differentiation of the N1' waveform was observed in children. Further research should be conducted across all age groups, along with behavioral assessments, to confirm the relationship between aging and immaturity in objective ACC responses and poorer subjective spatial performance.

Significance

ACCs evoked by location changes were assessed in adults, children, and the elderly to explore the impact of aging and development on these differences.

rTMS of the auditory association cortex improves speech intelligibility in patients with sensorineural hearing loss

OBJECTIVE

Sensorineural hearing-loss (SHL) is accompanied by changes in the entire ear-brain pathway and its connected regions. While hearing-aid (HA) partially compensates for SHL, speech perception abilities often continue to remain poor, resulting in consequences in everyday activities. Repetitive transcranial magnetic stimulation (rTMS) promotes cortical network plasticity and may enhance language comprehension in SHL patients.

METHODS

27 patients using HA and with SHL were randomly assigned to a treatment protocol consisting of five consecutive days of either real (Active group: 13 patients) or placebo rTMS (Sham group: 14 patients). The stimulation parameters were as follows: 2-second trains at 10 Hz, 4-second inter-train-interval, and 1800 pulses. Neuronavigated rTMS was applied over the left superior temporal sulcus. Audiological tests were administered before (T0), immediately after (T1), and one week following treatment completion (T2) to evaluate the speech reception threshold (SRT) and the Pure Tone Average (PTA).

RESULTS

In the context of a general improvement likely due to learning, the treatment with real rTMS induced significant reduction of the SRT and PTA at T1 and T2 versus placebo.

CONCLUSIONS

The long-lasting effects on SRT and PTA observed in the Active group indicates that rTMS administered over the auditory cortex could promote sustained neuromodulatory-induced changes in the brain, improving the perception of complex sentences and pure tones reception skills.

SIGNIFICANCE

Five days of rTMS treatment enhances overall speech intelligibility and PTA in SHL patients.

Neural attentional filters and behavioural outcome follow independent individual trajectories over the adult lifespan

Preserved communication abilities promote healthy ageing. To this end, the age-typical loss of sensory acuity might in part be compensated for by an individual's preserved attentional neural filtering. Is such a compensatory brain-behaviour link longitudinally stable? Can it predict individual change in listening behaviour? We here show that individual listening behaviour and neural filtering ability follow largely independent developmental trajectories modelling electroencephalographic and behavioural data of N = 105 ageing individuals (39-82 y). First, despite the expected decline in hearing-threshold-derived sensory acuity, listening-task performance proved stable over 2 y. Second, neural filtering and behaviour were correlated only within each separate measurement timepoint (T1, T2). Longitudinally, however, our results raise caution on attention-guided neural filtering metrics as predictors of individual trajectories in listening behaviour: neither neural filtering at T1 nor its 2-year change could predict individual 2-year behavioural change, under a combination of modelling strategies.

A Central Auditory Test reveals differences between drug treatment regimens in adults living with HIV

OBJECTIVE

This exploratory study examined whether central auditory tests show differences between people living with HIV (PLWH) treated with two predominant antiretroviral drug therapy (ART) regimens.

DESIGN

Cross-sectional.

STUDY SAMPLE

253 PLWH (mean age 39.8 years) from the Shanghai Public Health Clinical Centre, China.

METHODS

The Hearing in Noise Test speech reception threshold (SRT) assessed central auditory function and the Montreal Cognitive Assessment (MoCA) assessed cognition. The relationship between ART regimen and SRT was evaluated with multivariable linear regression incorporating age, HIV duration, and peripheral hearing ability. Multivariable logistic regression was used to ascertain if SRT and ART regimen predicted MoCA impairment.

RESULTS

The two predominant ART regimens differed by one drug (zidovudine or tenofovir). Participants taking the zidovudine-containing regimen had poorer SRT performance (p=.012) independent of age and hearing thresholds. MoCA scores did not differ between drug regimens, but a negative relationship was found between SRT and MoCA impairment (p=.048).

CONCLUSIONS

ART regimens differed in their association with central auditory test performance likely reflecting neurocognitive changes in PLWH taking the zidovudine-containing regimen. Central auditory test performance also marginally predicted cognitive impairment, supporting further assessment of central auditory tests to detect neurocognitive deficits in PLWH.

Asymmetries and hemispheric interaction in the auditory system of elderly people

Age-related changes of asymmetries in the auditory system and decreasing efficiency of hemispheric interaction have been discussed for some time. This mini-review discusses recent neuroimaging studies on alterations in lateralization of cortical processing and structural changes concerning the division of labor and interaction between hemispheres during auditory processing in elderly people with the focus on people without severe hearing loss. Several changes of asymmetries in anatomy, function and neurotransmitter concentration were observed in auditory cortical areas of older compared to younger adults. It was shown that connections between left and right auditory cortex are reduced during aging. Functionally, aging seems to lead to a reduction in asymmetry of auditory processing. However, the results do not always point into the same direction. Furthermore, correlations between function, anatomy and behavior in the left and right hemisphere appear to differ between younger and older adults. The changes in auditory cortex asymmetries with aging might be due to compensation of declining processing capacities, but at the same time these mechanisms could impair the balanced division of labor between the two hemispheres that is required for the processing of complex auditory stimuli such as speech. Neuroimaging studies are essential to follow the slow changes with aging as in the beginning no behavioral effects might be visible due to compensation. Future studies should control well for peripheral hearing loss and cognitive decline. Furthermore, for the interpretability of results it is necessary to use specific tasks with well-controlled task difficulty.

Processing of Visual Speech Cues in Speech-in-Noise Comprehension Depends on Working Memory Capacity and Enhances Neural Speech Tracking in Older Adults With Hearing Impairment

Comprehending speech in noise (SiN) poses a challenge for older hearing-impaired listeners, requiring auditory and working memory resources. Visual speech cues provide additional sensory information supporting speech understanding, while the extent of such visual benefit is characterized by large variability, which might be accounted for by individual differences in working memory capacity (WMC). In the current study, we investigated behavioral and neurofunctional (i.e., neural speech tracking) correlates of auditory and audio-visual speech comprehension in babble noise and the associations with WMC. Healthy older adults with hearing impairment quantified by pure-tone hearing loss (threshold average: 31.85-57 dB, N = 67) listened to sentences in babble noise in audio-only, visual-only and audio-visual speech modality and performed a pattern matching and a comprehension task, while electroencephalography (EEG) was recorded. Behaviorally, no significant difference in task performance was observed across modalities. However, we did find a significant association between individual working memory capacity and task performance, suggesting a more complex interplay between audio-visual speech cues, working memory capacity and real-world listening tasks. Furthermore, we found that the visual speech presentation was accompanied by increased cortical tracking of the speech envelope, particularly in a right-hemispheric auditory topographical cluster. Post-hoc, we investigated the potential relationships between the behavioral performance and neural speech tracking but were not able to establish a significant association. Overall, our results show an increase in neurofunctional correlates of speech associated with congruent visual speech cues, specifically in a right auditory cluster, suggesting multisensory integration.

A Perspective on Auditory Wellness: What It Is, Why It Is Important, and How It Can Be Managed

During the last decade, there has been a move towards consumer-centric hearing healthcare. This is a direct result of technological advancements (e.g., merger of consumer grade hearing aids with consumer grade earphones creating a wide range of hearing devices) as well as policy changes (e.g., the U.S. Food and Drug Administration creating a new over-the-counter [OTC] hearing aid category). In addition to various direct-to-consumer (DTC) hearing devices available on the market, there are also several validated tools for the self-assessment of auditory function and the detection of ear disease, as well as tools for education about hearing loss, hearing devices, and communication strategies. Further, all can be made easily available to a wide range of people. This perspective provides a framework and identifies tools to improve and maintain optimal auditory wellness across the adult life course. A broadly available and accessible set of tools that can be made available on a digital platform to aid adults in the assessment and as needed, the improvement, of auditory wellness is discussed.

Speech-Identification During Standing as a Multitasking Challenge for Young, Middle-Aged and Older Adults

While listening, we commonly participate in simultaneous activities. For instance, at receptions people often stand while engaging in conversation. It is known that listening and postural control are associated with each other. Previous studies focused on the interplay of listening and postural control when the speech identification task had rather high cognitive control demands. This study aimed to determine whether listening and postural control interact when the speech identification task requires minimal cognitive control, i.e., when words are presented without background noise, or a large memory load. This study included 22 young adults, 27 middle-aged adults, and 21 older adults. Participants performed a speech identification task (auditory single task), a postural control task (posture single task) and combined postural control and speech identification tasks (dual task) to assess the effects of multitasking. The difficulty levels of the listening and postural control tasks were manipulated by altering the level of the words (25 or 30 dB SPL) and the mobility of the platform (stable or moving). The sound level was increased for adults with a hearing impairment. In the dual-task, listening performance decreased, especially for middle-aged and older adults, while postural control improved. These results suggest that even when cognitive control demands for listening are minimal, interaction with postural control occurs. Correlational analysis revealed that hearing loss was a better predictor than age of speech identification and postural control.

Testing the Informativeness of Diverse Measures of Auditory Processing for Clinical Audiological Practice in Middle-Aged Adults in Mexico

PURPOSE

Standard clinical audiologic assessment is limited in its ability to capture variance in self-reported hearing difficulty. Additionally, the costs associated with clinical testing in audiology create financial barriers for hearing health care in developing countries like Mexico. This study used an open-source Spanish-language tool called PART (Portable Automated Rapid Testing) to test the hypothesis that a battery of assessments of auditory processing can complement standard clinical audiological assessment to better capture the variance of self-reported hearing difficulty.

METHOD

Forty-three adults between 40 and 69 years of age were tested in Mexico City using a traditional clinical pure-tone audiogram, cognitive screening, and a battery of PART-based auditory processing assessments including a speech-on-speech competition spatial release from masking task. Results were compared to self-reported hearing difficulty, assessed with a Spanish-language adaptation of the Hearing Handicap Inventory for the Elderly-Screening Version (HHIE-S).

RESULTS

Several measures from the PART battery exhibited stronger correlations with self-reported hearing difficulties than the pure-tone audiogram. The spatial release from masking task best captured variance in HHIE-S scores and remained significant after controlling for the effects of age, audibility, and cognitive score.

CONCLUSIONS

The spatial release from masking task can complement traditional clinical measures to better account for patient's self-reported hearing difficulty. Open-source access to this test in PART supports its implementation for Spanish speakers in clinical settings around the world at low cost.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.24470140.

A model incorporating clinicopathologic and liver imaging reporting and data system-based magnetic resonance imaging features to identify hepatocellular carcinoma in LR-M observations

PURPOSE

To evaluate the predictive value of a combination model of Liver Imaging Reporting and Data System (LI-RADS)-based magnetic resonance imaging (MRI) and clinicopathologic features to identify atypical hepatocellular carcinoma (HCC) in LI-RADS category M (LR-M) observations.

METHODS

A total of 105 patients with HCC based on surgery or biopsy who underwent preoperative MRI were retrospectively reviewed in the training group from hospital-1 between December 2016 and November 2020. The LI-RADS-based MRI features and clinicopathologic data were compared between LR-M HCC and non-HCC groups. Univariate and least absolute shrinkage and selection operator regression analyses were used to select the features. Binary logistic regression analysis was then conducted to estimate potential predictors of atypical HCC. A predictive nomogram was established based on the combination of MRI and clinicopathologic features and further validated using an independent external set of data from hospital-2.

RESULTS

Of 113 observations from 105 patients (mean age, 61 years; 77 men) in the training set, 47 (41.59%) were classified as LR-M HCC. Following multivariate analysis, aspartate aminotransferase >40 U/L [odds ratio (OR): 4.65], alpha-fetoprotein >20 ng/mL (OR: 13.04), surface retraction (OR: 0.16), enhancing capsule (OR: 5.24), blood products in mass (OR: 8.2), and iso/hypoenhancement on delayed phase (OR: 10.26) were found to be independently correlated with LR-M HCC. The corresponding area under the curve for a combined model-based nomogram was 0.95 in the training patients (n = 113) and 0.90 in the validation cohort (n = 53).

CONCLUSION

The combined model incorporating clinicopathologic and MRI features demonstrated a satisfactory prediction result for LR-M HCC.

Potential role of Bcl2 in lipid metabolism and synaptic dysfunction of age-related hearing loss

Age-related hearing loss (ARHL) is a prevalent condition affecting millions of individuals globally. This study investigated the role of the cell survival regulator Bcl2 in ARHL through in vitro and in vivo experiments and metabolomics analysis. The results showed that the lack of Bcl2 in the auditory cortex affects lipid metabolism, resulting in reduced synaptic function and neurodegeneration. Immunohistochemical analysis demonstrated enrichment of Bcl2 in specific areas of the auditory cortex, including the secondary auditory cortex, dorsal and ventral areas, and primary somatosensory cortex. In ARHL rats, a significant decrease in Bcl2 expression was observed in these areas. RNAseq analysis showed that the downregulation of Bcl2 altered lipid metabolism pathways within the auditory pathway, which was further confirmed by metabolomics analysis. These results suggest that Bcl2 plays a crucial role in regulating lipid metabolism, synaptic function, and neurodegeneration in ARHL; thereby, it could be a potential therapeutic target. We also revealed that Bcl2 probably has a close connection with lipid peroxidation and reactive oxygen species (ROS) production occurring in cochlear hair cells and cortical neurons in ARHL. The study also identified changes in hair cells, spiral ganglion cells, and nerve fiber density as consequences of Bcl2 deficiency, which could potentially contribute to the inner ear nerve blockage and subsequent hearing loss. Therefore, targeting Bcl2 may be a promising potential therapeutic intervention for ARHL. These findings provide valuable insights into the molecular mechanisms underlying ARHL and may pave the way for novel treatment approaches for this prevalent age-related disorder.

Improvements in naturalistic speech-in-noise comprehension in middle-aged and older adults after 3 weeks of computer-based speechreading training

Problems in understanding speech in noisy environments are characteristic for age-related hearing loss. Since hearing aids do not mitigate these communication problems in every case, potential alternatives in a clinical rehabilitation plan need to be explored. This study investigates whether a computer-based speechreading training improves audiovisual speech perception in noise in a sample of middle-aged and older adults (N = 62, 47-83 years) with 32 participants completing a speechreading training and 30 participants of an active control group completing a foreign language training. Before and after training participants performed a speech-in-noise task mimicking real-life communication settings with participants being required to answer a speaker's questions. Using generalized linear mixed-effects models we found a significant improvement in audiovisual speech perception in noise in the speechreading training group. This is of great relevance as these results highlight the potential of a low-cost and easy-to-implement intervention for a profound and widespread problem as speech-in-noise comprehension impairment.

Aging and Speech-in-Noise Perception

The objective was investigating the effect of age on speech-in-noise perception (SINP) using word perception score in white noise (WPS in WN). This cross-sectional study was conducted on 76 participants, including 30 elderly (older than 61 years) and 46 young adults (between 14 and 35 years) with normal levels of stress, night sleep and mini-mental states. Audiological evaluations included acoustic immittance testing, pure tone audiometry, determination of speech reception threshold and WPS in WN. Data analysis were performed using Mann-Whitney and Tukey HSD tests. Based on the results of the tests, the participants were divided into three groups: (1) young adults with normal hearing (n = 30), (2) elderly adults with normal hearing (n = 16), (3) elderly adults with mild to moderate high frequency hearing loss (n = 14). In both groups of old adults, the means WPS in WN differences were significant only in the left ears (Pv = 0.008, 0.033, 0.025 for SNR = 0, +5, +10 dB). In the three groups and in the right ears, there were the significant differences between the means of WPS in WN (Pv = 0.002, 0.000, 0.001 for SNR = 0, +5, +10 dB), and also the left ears (Pv = 0.000, 0.002, 0.002 for SNR = 0,+5, +10 dB).There is a relationship between increasing age and decreasing WPS in WN. The deleterious effects of aging on SINP decline are greater than that of hearing loss.

Effects of age on brainstem coding of speech glimpses in interrupted noise

Difficulty understanding speech in fluctuating backgrounds is common among older adults. Whereas younger adults are adept at interpreting speech based on brief moments when the signal-to-noise ratio is favorable, older adults use these glimpses of speech less effectively. Age-related declines in auditory brainstem function may degrade the fidelity of speech cues in fluctuating noise for older adults, such that brief glimpses of speech interrupted by noise segments are not faithfully represented in the neural code that reaches the cortex. This hypothesis was tested using electrophysiological recordings of the envelope following response (EFR) elicited by glimpses of speech-like stimuli varying in duration (42, 70, 210 ms) and interrupted by silence or intervening noise. Responses from adults aged 23-73 years indicated that both age and hearing sensitivity were associated with EFR temporal coherence and response magnitude. Age was better than hearing sensitivity for predicting temporal coherence, whereas hearing sensitivity was better than age for predicting response magnitude. Poorer-fidelity EFRs were observed with shorter glimpses and with the addition of intervening noise. However, losses of fidelity with glimpse duration and noise were not associated with participant age or hearing sensitivity. These results suggest that the EFR is sensitive to factors commonly associated with glimpsing but do not entirely account for age-related changes in speech recognition in fluctuating backgrounds.

Cognitive control in age-related hearing loss: A narrative review

Recent evidence suggests links between hearing loss and cognitive impairment in older adults with peripheral age-related hearing loss (ARHL). Earliest cognitive changes have been observed in cognitive control; however, a cohesive account of cognitive control alterations in older adults with peripheral ARHL is lacking. Cognitive control refers to cognitive processes that manage and regulate one's behavior to achieve desired goals. This review summarizes behavioral evidence on alterations in three cognitive control processes, including cognitive flexibility, inhibitory control, and working memory updating, in individuals with ARHL. Of the three processes, cognitive flexibility and working memory updating have been most extensively studied, with relatively fewer studies examining inhibitory control. Most consistent evidence is observed for long-term changes in cognitive flexibility, particularly in individuals with greater severity of ARHL. Equivocal evidence is seen for alterations in inhibitory control and working memory updating, with various factors contributing to inconsistencies across studies. Our review summarizes the emerging body of research on cognitive control in individuals with ARHL to guide future work in this area and considerations related to the management of cognitive issues in this population.

Listening with an Ageing Brain - a Cognitive Challenge

Hearing impairment has been recently identified as a major modifiable risk factor for cognitive decline in later life and has been becoming of increasing scientific interest. Sensory and cognitive decline are connected by complex bottom-up and top-down processes, a sharp distinction between sensation, perception, and cognition is impossible. This review provides a comprehensive overview on the effects of healthy and pathological aging on auditory as well as cognitive functioning on speech perception and comprehension, as well as specific auditory deficits in the 2 most common neurodegenerative diseases in old age: Alzheimer disease and Parkinson syndrome. Hypotheses linking hearing loss to cognitive decline are discussed, and current knowledge on the effect of hearing rehabilitation on cognitive functioning is presented. This article provides an overview of the complex relationship between hearing and cognition in old age.

Stability of neural representations in the auditory midbrain across the lifespan despite age-related brainstem delays

The extent to which aging of the central auditory pathway impairs auditory perception in the elderly independent of peripheral cochlear decline is debated. To cause auditory deficits in normal hearing elderly, central aging needs to degrade neural sound representations at some point along the auditory pathway. However, inaccessible to psychophysical methods, the level of the auditory pathway at which aging starts to effectively degrade neural sound representations remains poorly differentiated. Here we tested how potential age-related changes in the auditory brainstem affect the stability of spatiotemporal multiunit complex speech-like sound representations in the auditory midbrain of old normal hearing CBA/J mice. Although brainstem conduction speed slowed down in old mice, the change was limited to the sub-millisecond range and only minimally affected temporal processing in the midbrain (i.e. gaps-in-noise sensitivity). Importantly, besides the small delay, multiunit complex temporal sound representations in the auditory midbrain did not differ between young and old mice. This shows that although small age-related neural effects in simple sound parameters in the lower brainstem may be present in aging they do not effectively deteriorate complex neural population representations at the level of the auditory midbrain when peripheral hearing remains normal. This result challenges the widespread belief of 'pure' central auditory decline as an automatic consequence of aging, at least up to the inferior colliculus. However, the stability of midbrain processing in aging emphasizes the role of undetected 'hidden' peripheral damage and accumulating effects in higher cortical auditory-cognitive processing explaining perception deficits in 'normal hearing' elderly.

Effect of Age and Hearing Loss on Auditory Processing Skills

Background: The present study aimed to evaluate the effect of age and hearing loss on auditory processing abilities. For this purpose, auditory processing abilities were compared among young and older adults with normal hearing sensitivity and older adults with and without hearing loss. Method: The study comprised 20 normal-hearing young adults (18-25 years), 20 older adults with normal hearing sensitivity (50-70 years), and 20 older adults with mild to moderate sensorineural hearing impairment (50-70 years). All 60 participants underwent gap detection (GDT), dichotic consonant-vowe (DCV)l, speech in noise (SPIN), duration pattern (DPT), and working memory (forward and backward span) tests in a sound treated test room. Results: Results showed that young normal-hearing adults performed significantly better than normal-hearing older adults in SPIN, GDT, DCV, working memory, and DPT. Futher, normal-hearing older individuals performed better than older individuals with hearing impairment on all the auditory processing tests except on the forward span test and DPT. Conclusion: Auditory processing abilities deteriorate with age and hearing loss also has a pronounced effect on most auditory processing abilities.

Non-linguistic auditory speech processing

OBJECTIVES

A method for testing auditory processing of non-linguistic speech-like stimuli was developed and evaluated.

DESIGN

Monosyllabic words were temporally reversed and distorted. Stimuli were matched for spectrum and level. Listeners discriminated between distorted and undistorted stimuli.

STUDY SAMPLE

Three groups were tested. The Normal group was comprised of 12 normal-hearing participants. The Senior group was comprised of 12 seniors. The Hearing Loss group was comprised of 12 participants with thresholds of at least 35 dB HL at one or more frequencies.

RESULTS

The Senior group scored lower than the Normal group, and the Hearing Loss group scored lower than the Senior group. Scores for forward compressed speech were slightly higher than backward compressed speech but the difference was not statistically significant. Retest scores were slightly higher than scores on the first test, but the difference was not statistically significant.

CONCLUSIONS

Large differences in discrimination of distorted speech were observed among the three groups. Age and hearing loss separately affected performance. The depressed performance of the Senior group may be a result of "hidden hearing loss" that is attributed to cochlear synaptopathy. The backward-distorted speech task may be a useful non-linguistic test of speech processing that is language independent.

Functional Hearing Difficulties in Veterans: Retrospective Chart Review of Auditory Processing Assessments in the VA Health Care System

PURPOSE

Approximately 23 million Americans might have functional hearing difficulties (FHDs) that are not well explained by their audiometric thresholds. Clinical management of patients with FHDs is the subject of considerable debate, with few evidence-based guidelines to direct patient care. A better understanding of the characteristics of patients who seek help for FHDs, as well as current audiological management practices, is needed to direct research efforts to the areas greatest opportunity for advancement of clinical care.

METHOD

A retrospective chart review was conducted examining the medical records of a random sample of 100 Veterans who underwent auditory processing assessments across the VA Health Care System between 2008 and 2020.

RESULTS

Patients were young to middle-age, often with previous traumatic brain injury or blast exposure. Mental health, sleep, and pain disorders were common. No consistent relationships emerged between specific patient factors and domains of auditory processing deficits. Low-gain hearing aids were provided to 35 patients, 69% of whom continued wearing their hearing aids for at least 2 years.

CONCLUSION

Future research should address the potential overlap in symptoms and treatment for comorbid health conditions and FHDs, as well as the conditions underlying successful hearing aid use in this patient population.

Different neuroanatomical correlates for temporal and spectral supra-threshold auditory tasks and speech in noise recognition in older adults with hearing impairment

Varying degrees of pure-tone hearing loss in older adults are differentially associated with cortical volume (CV) and thickness (CT) within and outside of the auditory pathway. This study addressed the question to what degree supra-threshold auditory performance (i.e., temporal compression and frequency selectivity) as well as speech in noise (SiN) recognition are associated with neurostructural correlates in a sample of 59 healthy older adults with mild to moderate pure-tone hearing loss. Using surface-based morphometry on T1-weighted MRI images, CT, CV, and surface area (CSA) of several regions-of-interest were obtained. The results showed distinct neurostructural patterns for the different tasks in terms of involved regions as well as morphometric parameters. While pure-tone averages (PTAs) positively correlated with CT in a right hemisphere superior temporal sulcus and gyrus cluster, supra-threshold auditory perception additionally extended significantly to CV and CT in left and right superior temporal clusters including Heschl's gyrus and sulcus, the planum polare and temporale. For SiN recognition, we found significant correlations with an auditory-related CT cluster and furthermore with language-related areas in the prefrontal cortex. Taken together, our results show that different auditory abilities are differently associated with cortical morphology in older adults with hearing impairment. Still, a common pattern is that greater PTAs and poorer supra-threshold auditory performance as well as poorer SiN recognition are all related to cortical thinning and volume loss but not to changes in CSA. These results support the hypothesis that mostly CT undergoes alterations in the context of auditory decline, while CSA remains stable.

Relationships between behavioural and self-report measures in speech recognition in noise

OBJECTIVE

Using data from the n200-study, we aimed to investigate the relationship between behavioural (the Swedish HINT and Hagerman speech-in-noise tests) and self-report (Speech, Spatial and Qualities of Hearing Questionnaire (SSQ)) measures of listening under adverse conditions.

DESIGN

The Swedish HINT was masked with a speech-shaped noise (SSN), the Hagerman was masked with a SSN and a four-talker babble, and the subscales from the SSQ were used as a self-report measure. The HINT and Hagerman were administered through an experimental hearing aid.

STUDY SAMPLE

This study included 191 hearing aid users with hearing loss (mean PTA4 = 37.6, SD = 10.8) and 195 normally hearing adults (mean PTA4 = 10.0, SD = 6.0).

RESULTS

The present study found correlations between behavioural measures of speech-in-noise and self-report scores of the SSQ in normally hearing individuals, but not in hearing aid users.

CONCLUSION

The present study may help identify relationships between clinically used behavioural measures, and a self-report measure of speech recognition. The results from the present study suggest that use of a self-report measure as a complement to behavioural speech in noise tests might help to further our understanding of how self-report, and behavioural results can be generalised to everyday functioning.

Effectiveness of Auditory Training in Experienced Hearing-Aid Users, and an Exploration of Their Health-Related Quality of Life and Coping Strategies

Hearing aids (HA) are a fundamental component in restoring auditory function; however, they cannot completely alleviate all problems encountered by adults with hearing impairment. The aim of this study is twofold. Firstly, we assess the health-related quality of life and coping strategies of experienced HA users. Secondly, we assess whether HA users can benefit from auditory training. To this end, 40 participants who had worn HAs for more than 6 months participated in this study. Half of the participants received auditory training, while the other half served as a passive control. The training consisted of a personalized training scheme, with outcome measures including speech in noise perception in free-field and via direct streaming to the HA, phoneme identification, cognitive control, and health-related quality of life. Results showed that experienced HA users reported a relatively good quality of life. Health-related quality of life was correlated with aided speech perception in noise, but not with aided pure tone audiometry. Coping strategies were adaptive, leading to improved communication. Participants showed improvements in trained tasks, consonant identification, and speech in noise perception. While both groups yielded improved speech in noise perception at the end, post hoc analysis following a three-way interaction showed a significantly larger pre-post difference for the trained group in the streaming condition. Although training showed some improvements, the study suggests that the training paradigm was not sufficiently challenging for HA users. To optimize daily life listening, we recommend that future training should incorporate more exercises in noise and focus on cognitive control.

Age effects on cognitive functions and speech-in-noise processing: An event-related potential study with cochlear-implant users and normal-hearing listeners

A cochlear implant (CI) can partially restore hearing in individuals with profound sensorineural hearing loss. However, electrical hearing with a CI is limited and highly variable. The current study aimed to better understand the different factors contributing to this variability by examining how age affects cognitive functions and cortical speech processing in CI users. Electroencephalography (EEG) was applied while two groups of CI users (young and elderly; N = 13 each) and normal-hearing (NH) listeners (young and elderly; N = 13 each) performed an auditory sentence categorization task, including semantically correct and incorrect sentences presented either with or without background noise. Event-related potentials (ERPs) representing earlier, sensory-driven processes (N1-P2 complex to sentence onset) and later, cognitive-linguistic integration processes (N400 to semantically correct/incorrect sentence-final words) were compared between the different groups and speech conditions. The results revealed reduced amplitudes and prolonged latencies of auditory ERPs in CI users compared to NH listeners, both at earlier (N1, P2) and later processing stages (N400 effect). In addition to this hearing-group effect, CI users and NH listeners showed a comparable background-noise effect, as indicated by reduced hit rates and reduced (P2) and delayed (N1/P2) ERPs in conditions with background noise. Moreover, we observed an age effect in CI users and NH listeners, with young individuals showing improved specific cognitive functions (working memory capacity, cognitive flexibility and verbal learning/retrieval), reduced latencies (N1/P2), decreased N1 amplitudes and an increased N400 effect when compared to the elderly. In sum, our findings extend previous research by showing that the CI users' speech processing is impaired not only at earlier (sensory) but also at later (semantic integration) processing stages, both in conditions with and without background noise. Using objective ERP measures, our study provides further evidence of strong age effects on cortical speech processing, which can be observed in both the NH listeners and the CI users. We conclude that elderly individuals require more effortful processing at sensory stages of speech processing, which however seems to be at the cost of the limited resources available for the later semantic integration processes.

Causal Contributions of the Domain-General (Multiple Demand) and the Language-Selective Brain Networks to Perceptual and Semantic Challenges in Speech Comprehension

Listening to spoken language engages domain-general multiple demand (MD; frontoparietal) regions of the human brain, in addition to domain-selective (frontotemporal) language regions, particularly when comprehension is challenging. However, there is limited evidence that the MD network makes a functional contribution to core aspects of understanding language. In a behavioural study of volunteers (n = 19) with chronic brain lesions, but without aphasia, we assessed the causal role of these networks in perceiving, comprehending, and adapting to spoken sentences made more challenging by acoustic-degradation or lexico-semantic ambiguity. We measured perception of and adaptation to acoustically degraded (noise-vocoded) sentences with a word report task before and after training. Participants with greater damage to MD but not language regions required more vocoder channels to achieve 50% word report, indicating impaired perception. Perception improved following training, reflecting adaptation to acoustic degradation, but adaptation was unrelated to lesion location or extent. Comprehension of spoken sentences with semantically ambiguous words was measured with a sentence coherence judgement task. Accuracy was high and unaffected by lesion location or extent. Adaptation to semantic ambiguity was measured in a subsequent word association task, which showed that availability of lower-frequency meanings of ambiguous words increased following their comprehension (word-meaning priming). Word-meaning priming was reduced for participants with greater damage to language but not MD regions. Language and MD networks make dissociable contributions to challenging speech comprehension: Using recent experience to update word meaning preferences depends on language-selective regions, whereas the domain-general MD network plays a causal role in reporting words from degraded speech.

Adaptive Syllable Training Improves Phoneme Identification in Older Listeners with and without Hearing Loss

Acoustic-phonetic speech training mitigates confusion between consonants and improves phoneme identification in noise. A novel training paradigm addressed two principles of perceptual learning. First, training benefits are often specific to the trained material; therefore, stimulus variability was reduced by training small sets of phonetically similar consonant-vowel-consonant syllables. Second, the training is most efficient at an optimal difficulty level; accordingly, the noise level was adapted to the participant's competency. Fifty-two adults aged between sixty and ninety years with normal hearing or moderate hearing loss participated in five training sessions within two weeks. Training sets of phonetically similar syllables contained voiced and voiceless stop and fricative consonants, as well as voiced nasals and liquids. Listeners identified consonants at the onset or the coda syllable position by matching the syllables with their orthographic equivalent within a closed set of three alternative symbols. The noise level was adjusted in a staircase procedure. Pre-post-training benefits were quantified as increased accuracy and a decrease in the required signal-to-noise ratio (SNR) and analyzed with regard to the stimulus sets and the participant's hearing abilities. The adaptive training was feasible for older adults with various degrees of hearing loss. Normal-hearing listeners performed with high accuracy at lower SNR after the training. Participants with hearing loss improved consonant accuracy but still required a high SNR. Phoneme identification improved for all stimulus sets. However, syllables within a set required noticeably different SNRs. Most significant gains occurred for voiced and voiceless stop and (af)fricative consonants. The training was beneficial for difficult consonants, but the easiest to identify consonants improved most prominently. The training enabled older listeners with different capabilities to train and improve at an individual 'edge of competence'.

The recognition of time-compressed speech as a function of age in listeners with cochlear implants or normal hearing

Speech recognition is diminished when a listener has an auditory temporal processing deficit. Such deficits occur in listeners over 65 years old with normal hearing (NH) and with age-related hearing loss, but their source is still unclear. These deficits may be especially apparent when speech occurs at a rapid rate and when a listener is mostly reliant on temporal information to recognize speech, such as when listening with a cochlear implant (CI) or to vocoded speech (a CI simulation). Assessment of the auditory temporal processing abilities of adults with CIs across a wide range of ages should better reveal central or cognitive sources of age-related deficits with rapid speech because CI stimulation bypasses much of the cochlear encoding that is affected by age-related peripheral hearing loss. This study used time-compressed speech at four different degrees of time compression (0, 20, 40, and 60%) to challenge the auditory temporal processing abilities of younger, middle-aged, and older listeners with CIs or with NH. Listeners with NH were presented vocoded speech at four degrees of spectral resolution (unprocessed, 16, 8, and 4 channels). Results showed an interaction between age and degree of time compression. The reduction in speech recognition associated with faster rates of speech was greater for older adults than younger adults. The performance of the middle-aged listeners was more similar to that of the older listeners than to that of the younger listeners, especially at higher degrees of time compression. A measure of cognitive processing speed did not predict the effects of time compression. These results suggest that central auditory changes related to the aging process are at least partially responsible for the auditory temporal processing deficits seen in older listeners, rather than solely peripheral age-related changes.

The Influence of Noise Type and Semantic Predictability on Word Recall in Older Listeners and Listeners With Hearing Impairment

PURPOSE

A dual-task paradigm was implemented to investigate how noise type and sentence context may interact with age and hearing loss to impact word recall during speech recognition.

METHOD

Three noise types with varying degrees of temporal/spectrotemporal modulation were used: speech-shaped noise, speech-modulated noise, and three-talker babble. Participant groups included younger listeners with normal hearing (NH), older listeners with near-normal hearing, and older listeners with sensorineural hearing loss. An adaptive measure was used to establish the signal-to-noise ratio approximating 70% sentence recognition for each participant in each noise type. A word-recall task was then implemented while matching speech-recognition performance across noise types and participant groups. Random-intercept linear mixed-effects models were used to determine the effects of and interactions between noise type, sentence context, and participant group on word recall.

RESULTS

The results suggest that noise type does not significantly impact word recall when word-recognition performance is controlled. When data from noise types were pooled and compared with quiet, and recall was assessed: older listeners with near-normal hearing performed well when either quiet backgrounds or high sentence context (or both) were present, but older listeners with hearing loss performed well only when both quiet backgrounds and high sentence context were present. Younger listeners with NH were robust to the detrimental effects of noise and low context.

CONCLUSIONS

The general presence of noise has the potential to decrease word recall, but type of noise does not appear to significantly impact this observation when overall task difficulty is controlled. The presence of noise as well as deficits related to age and/or hearing loss appear to limit the availability of cognitive processing resources available for working memory during conversation in difficult listening environments. The conversation environments that impact these resources appear to differ depending on age and/or hearing status.

Understanding the Relationship Between Age-Related Hearing Loss and Alzheimer’s Disease: A Narrative Review

Evidence suggests that hearing loss (HL), even at mild levels, increases the long-term risk of cognitive decline and incident dementia. Hearing loss is one of the modifiable risk factors for dementia, with approximately 4 million of the 50 million cases of dementia worldwide possibly attributed to untreated HL. This paper describes four possible mechanisms that have been suggested for the relationship between age-related hearing loss (ARHL) and Alzheimer’s disease (AD), which is the most common form of dementia. The first mechanism suggests mitochondrial dysfunction and altered signal pathways due to aging as a possible link between ARHL and AD. The second mechanism proposes that sensory degradation in hearing impaired people could explain the relationship between ARHL and AD. The occupation of cognitive resource (third) mechanism indicates that the association between ARHL and AD is a result of increased cognitive processing that is required to compensate for the degraded sensory input. The fourth mechanism is an expansion of the third mechanism, i.e., the function and structure interaction involves both cognitive resource occupation (neural activity) and AD pathology as the link between ARHL and AD. Exploring the specific mechanisms that provide the link between ARHL and AD has the potential to lead to innovative ideas for the diagnosis, prevention, and/or treatment of AD. This paper also provides insight into the current evidence for the use of hearing treatments as a possible treatment/prevention for AD, and if auditory assessments could provide an avenue for early detection of cognitive impairment associated with AD.

Relationship between hearing, cognitive function, and quality of life in aging companion dogs

Background

Elderly people with presbycusis are at higher risk for dementia and depression than the general population. There is no information regarding consequences of presbycusis in dogs.

Objective

Evaluate the relationship between cognitive function, quality of life, and hearing loss in aging companion dogs.

Animals

Thirty‐nine elderly companion dogs.

Methods

Prospective study. Hearing was evaluated using brainstem auditory evoked response (BAER) testing. Dogs were grouped by hearing ability. Owners completed the canine dementia scale (CADES) and canine owner‐reported quality of life (CORQ) questionnaire. Cognitive testing was performed, and cognitive testing outcomes, CADES and CORQ scores and age were compared between hearing groups.

Results

Nineteen dogs could hear at 50 dB, 12 at 70 dB, and 8 at 90 dB with mean ages (months) of 141 ± 14, 160 ± 16, and 172 ± 15 for each group respectively (P = .0002). Vitality and companionship CORQ scores were significantly lower as hearing deteriorated (6.6‐5.4, 50‐90 dB group, P = .03 and 6.9‐6.2, 50‐90 dB group, P = .02, respectively). Cognitive classification by CADES was abnormal in all 90 dB group dogs and normal in 3/12 70 dB group and 11/19 50 dB group dogs (P = .0004). Performance on inhibitory control, detour and sustained gaze tasks decreased significantly with hearing loss (P = .001, P = .008, P = .002, respectively). In multivariate analysis, higher CADES score was associated with worse hearing (P = .01).

Conclusions and Clinical Importance

Presbycusis negatively alters owner‐pet interactions and is associated with poor executive performance and owner‐assessed dementia severity.

Animal-to-Human Translation Difficulties and Problems With Proposed Coding-in-Noise Deficits in Noise-Induced Synaptopathy and Hidden Hearing Loss

Noise induced synaptopathy (NIS) and hidden hearing loss (NIHHL) have been hot topic in hearing research since a massive synaptic loss was identified in CBA mice after a brief noise exposure that did not cause permanent threshold shift (PTS) in 2009. Based upon the amount of synaptic loss and the bias of it to synapses with a group of auditory nerve fibers (ANFs) with low spontaneous rate (LSR), coding-in-noise deficit (CIND) has been speculated as the major difficult of hearing in subjects with NIS and NIHHL. This speculation is based upon the idea that the coding of sound at high level against background noise relies mainly on the LSR ANFs. However, the translation from animal data to humans for NIS remains to be justified due to the difference in noise exposure between laboratory animals and human subjects in real life, the lack of morphological data and reliable functional methods to quantify or estimate the loss of the afferent synapses by noise. Moreover, there is no clear, robust data revealing the CIND even in animals with the synaptic loss but no PTS. In humans, both positive and negative reports are available. The difficulty in verifying CINDs has led a re-examination of the hypothesis that CIND is the major deficit associated with NIS and NIHHL, and the theoretical basis of this idea on the role of LSR ANFs. This review summarized the current status of research in NIS and NIHHL, with focus on the translational difficulty from animal data to human clinicals, the technical difficulties in quantifying NIS in humans, and the problems with the SR theory on signal coding. Temporal fluctuation profile model was discussed as a potential alternative for signal coding at high sound level against background noise, in association with the mechanisms of efferent control on the cochlea gain.

The electrophysiological masking level difference: effects of age and mediation of hearing and cognition

OBJECTIVE

Evaluate the conceptual framework that age effects on the electrophysiological binaural masking level difference (MLD) are partially mediated by age-related hearing loss and/or global cognitive function via mediation analysis.

DESIGN

Participants underwent a series of audiometric tests. The MLD was measured via cortical auditory evoked potentials using a speech stimulus (/ɑ/) in speech-weighted background noise. We used mediation analyses to determine the total effect, natural direct effects, and natural indirect effects, which are displayed as regression coefficients ([95% CI]; p value).

STUDY SAMPLE

Twenty-eight individuals aged 19-87 years (mean [SD]: 53.3 [25.2]), recruited from the community.

RESULTS

Older age had a significant total effect on the MLD (-0.69 [95% CI: -0.96, -0.45]; p < 0.01). Neither pure tone average (-0.11 [95% CI: -0.43, 0.24; p = 0.54] nor global cognitive function (-0.02 [95% CI: -0.13, 0.02]; p = 0.55) mediated the relationship of age and the MLD and effect sizes were small. Results were insensitive to use of alternative hearing measures or inclusion of interaction terms.

CONCLUSIONS

The electrophysiological MLD may be an age-sensitive measure of binaural temporal processing that is minimally affected by age-related hearing loss and global cognitive function.

The Associations of Hearing Sensitivity and Different Cognitive Functions with Perception of Speech-in-Noise

OBJECTIVES

Impaired speech-in-noise perception affects individuals' daily lives and is a frequent symptom of age-related hearing loss, which is a common disabling condition and a health concern in aging populations. The relative impact of hearing sensitivity loss and different cognitive functions on speech-in-noise perception is not well understood. We aimed to assess to what extent hearing sensitivity and different cognitive functions were associated with sentence-in-noise performance across the adult lifespan.

DESIGN

This study is based on data of 2585 participants of the Rhineland Study, which is a German community-based cohort study of persons of age 30 years and older. We assessed speech-in-noise with a sentence-in-noise test (Göttinger Satztest), hearing sensitivity thresholds (air conduction pure-tone audiometry [PTA] average of 0.5, 1, 2, and 4 kHz), and the following cognitive domains: crystallized intelligence (German Mehrfachwahl-Wortschatz-Intelligenztest, MWT-B), executive functioning (Trail Making Test B, TMT), working memory (Digit Span forward, DS), and long-term memory (Verbal Learning and Memory Test delayed recall; VLMT). We examined the association between hearing sensitivity and cognitive functions with sentence-in-noise perception using a multivariable linear regression model adjusted for age, sex, and multiple potential confounders.

RESULTS

Better hearing sensitivity was associated with better speech-in-noise perception (0.25 signal noise ratio [SNR] dB HL decrease per 5 dB HL decrease in PTA; 95% confidence interval [CI]: 0.20 to 0.25; p < 0.001). Better cognitive performance was also associated with better speech-in-noise perception, but to a lesser extent. Crystallized intelligence (MWT-B) showed an effect size of -0.10 SNR dB HL decrease per SD (95% CI: -0.14 to -0.06; p < 0.001), executive functioning (TMT) of -0.08 SNR dB HL decrease per SD (95% CI: -0.13 to -0.03; p = 0.002), working memory (DS) of -0.04 SNR dB HL decrease per SD (95% CI: -0.08 to -0.003; p = 0.03), and long-term memory (VLMT) of -0.03 SNR dB HL decrease per SD (95% CI: -0.07 to 0.01; p = 0.12). The standardized effect of hearing sensitivity (ß = 0.34) on speech-in-noise perception was four to five times larger than the effects of crystallized intelligence (ß = -0.08) and executive functioning (ß = -0.06).

CONCLUSIONS

Hearing sensitivity was the strongest determinant of sentence-in-noise perception in adults above the age of 30. We determined the relative effect of different cognitive functions on sentence-in-noise perception. Crystallized intelligence and executive functions showed stronger associations while working and long-term memory functions had much smaller independent effects. Our results contribute to the understanding of determinants of speech-in-noise perception in aging adults.

Difficulties Experienced by Older Listeners in Utilizing Voice Cues for Speaker Discrimination

Human listeners are assumed to apply different strategies to improve speech recognition in background noise. Young listeners with normal hearing (NH), e.g., have been shown to follow the voice of a particular speaker based on the fundamental (F0) and formant frequencies, which are both influenced by the gender, age, and size of the speaker. However, the auditory and cognitive processes that underlie the extraction and discrimination of these voice cues across speakers may be subject to age-related decline. The present study aimed to examine the utilization of F0 and formant cues for voice discrimination (VD) in older adults with hearing expected for their age. Difference limens (DLs) for VD were estimated in 15 healthy older adults (65–78 years old) and 35 young adults (18–35 years old) using only F0 cues, only formant frequency cues, and a combination of F0 + formant frequencies. A three-alternative forced-choice paradigm with an adaptive-tracking threshold-seeking procedure was used. Wechsler backward digit span test was used as a measure of auditory working memory. Trail Making Test (TMT) was used to provide cognitive information reflecting a combined effect of processing speed, mental flexibility, and executive control abilities. The results showed that (a) the mean VD thresholds of the older adults were poorer than those of the young adults for all voice cues, although larger variability was observed among the older listeners; (b) both age groups found the formant cues more beneficial for VD, compared to the F0 cues, and the combined (F0 + formant) cues resulted in better thresholds, compared to each cue separately; (c) significant associations were found for the older adults in the combined F0 + formant condition between VD and TMT scores, and between VD and hearing sensitivity, supporting the notion that a decline with age in both top-down and bottom-up mechanisms may hamper the ability of older adults to discriminate between voices. The present findings suggest that older listeners may have difficulty following the voice of a specific speaker and thus implementing doing so as a strategy for listening amid noise. This may contribute to understanding their reported difficulty listening in adverse conditions.

Hearing Loss and Cognition: What We Know and Where We Need to Go

Although a causal association remains to be determined, epidemiologic evidence suggests an association between hearing loss and increased risk of dementia. If we determine the association is causal, opportunity for targeted intervention for hearing loss may play a fundamental role in dementia prevention. In this discussion, we summarize current research on the association between hearing loss and dementia and review potential casual mechanisms behind the association (e.g., sensory-deprivation hypothesis, information-degradation hypothesis, common cause). We emphasize key areas of research which might best inform our investigation of this potential casual association. These selected research priorities include examination of the causal mechanism, measurement of co-existing hearing loss and cognitive impairment and determination of any bias in testing, potential for managing hearing loss for prevention of dementia and cognitive decline, or the potential to reduce dementia-related symptoms through the management of hearing loss. Addressing these research gaps and how results are then translated for clinical use may prove paramount for dementia prevention, management, and overall health of older adults.

Central Auditory Functions of Alzheimer's Disease and Its Preclinical Stages: A Systematic Review and Meta-Analysis

In 2020, 55 million people worldwide were living with dementia, and this number is projected to reach 139 million in 2050. However, approximately 75% of people living with dementia have not received a formal diagnosis. Hence, they do not have access to treatment and care. Without effective treatment in the foreseeable future, it is essential to focus on modifiable risk factors and early intervention. Central auditory processing is impaired in people diagnosed with Alzheimer's disease (AD) and its preclinical stages and may manifest many years before clinical diagnosis. This study systematically reviewed central auditory processing function in AD and its preclinical stages using behavioural central auditory processing tests. Eleven studies met the full inclusion criteria, and seven were included in the meta-analyses. The results revealed that those with mild cognitive impairment perform significantly worse than healthy controls within channel adaptive tests of temporal response (ATTR), time-compressed speech test (TCS), Dichotic Digits Test (DDT), Dichotic Sentence Identification (DSI), Speech in Noise (SPIN), and Synthetic Sentence Identification-Ipsilateral Competing Message (SSI-ICM) central auditory processing tests. In addition, this analysis indicates that participants with AD performed significantly worse than healthy controls in DDT, DSI, and SSI-ICM tasks. Clinical implications are discussed in detail.

The Effect of the Use of Hearing Aids in Elders: Perspectives

Older adults with hearing loss have difficulties during conversation with others because an elevated auditory threshold reduces speech intelligibility, especially in noisy environments. Listening and comprehension often become exhausting tasks for hearing-impaired elders, resulting in social isolation and depression. The aim of the present study was to investigate the advantages of hearing aid use in relation to relief from listening-related fatigue, which is still controversial. Participants included a sample of 49 hearing-impaired elders affected by presbycusis for whom hearing aids were prescribed. The Modified Fatigue Impact Scale was used to assess cognitive, physical and psychosocial fatigue. The vitality subscale of the Short Form Health Survey 36 and a single item of the multi-dimensional Speech, Spatial and Quality Hearing Scale (“Do you have to put a lot of effort to hear what is being said in conversation with others?”) were also used. The Cognitive Failures Questionnaire was used to investigate daily errors related to lack of memory and reduced mindedness. Hearing aids rehabilitation resulted in improved speech intelligibility in competing noise, and a significant reduction in cognitive and psychosocial fatigue and listening effort in conversation. Vitality was also improved and a significant reduction in the Cognitive Failures Questionnaire scores was observed. Findings from the study indicate that the use of hearing aids in older impaired-listeners provide them not only with an increased auditory function but also with a reduction in listening-related fatigue and mindedness.

Effects of aging and hearing loss on perceptual and electrophysiological measures of pulse-rate discrimination

Auditory temporal processing declines with age, leading to potential deleterious effects on communication. In young normal-hearing listeners, perceptual rate discrimination is rate limited around 300 Hz. It is not known whether this rate limitation is similar in older listeners with hearing loss. The purpose of this study was to investigate age- and hearing-loss-related rate limitations on perceptual rate discrimination, and age- and hearing-loss-related effects on neural representation of these stimuli. Younger normal-hearing, older normal-hearing, and older hearing-impaired listeners performed a pulse-rate discrimination task at rates of 100, 200, 300, and 400 Hz. Neural phase locking was assessed using the auditory steady-state response. Finally, a battery of non-auditory cognitive tests was administered. Younger listeners had better rate discrimination, higher phase locking, and higher cognitive scores compared to both groups of older listeners. Aging, but not hearing loss, diminished neural-rate encoding and perceptual performance; however, there was no relationship between the perceptual and neural measures. Higher cognitive scores were correlated with improved perceptual performance, but not with neural phase locking. This study shows that aging, rather than hearing loss, may be a stronger contributor to poorer temporal processing, and cognitive factors such as processing speed and inhibitory control may be related to these declines.