Changes In Auditory Processing Research Articles

Age and masking effects on acoustic cues for vowel categorizationa).

Age-related changes in auditory processing may reduce physiological coding of acoustic cues, contributing to older adults' difficulty perceiving speech in background noise. This study investigated whether older adults differed from young adults in patterns of acoustic cue weighting for categorizing vowels in quiet and in noise. All participants relied primarily on spectral quality to categorize /ɛ/ and /æ/ sounds under both listening conditions. However, relative to young adults, older adults exhibited greater reliance on duration and less reliance on spectral quality. These results suggest that aging alters patterns of perceptual cue weights that may influence speech recognition abilities.

Turkish dichotic sentence mobile scan test results in young and elderly people

BackgroundThis study investigated the impact of age on dichotic listening performance by comparing results from the Turkish Dichotic Sentence Mobile Screening Test in young and elderly individuals with normal hearing. A total of 60 adults (30 young, 30 old) underwent otoscopic examination, audiological tests, and, for the elderly group, a mini-mental test. The Turkish Dichotic Sentence Mobile Screening Test was administered, and directed and undirected scores for the right and left ears were compared between age groups.ResultsIn the young group, the directed left ear mean (96.67% ± 8.02%), directed right ear mean (98.33% ± 3.79%), undirected left ear mean (97.67% ± 6.26%), and undirected right ear mean (98.67% ± 5.71%) were obtained. In the elderly group, corresponding values were lower: directed left ear mean (49.00% ± 36.33%), directed right ear mean (54.67% ± 40.66%), undirected left ear mean (64.00% ± 32.86%), and undirected right ear mean (65.00% ± 30.82%). Statistically significant differences were found between the young and elderly groups (p < 0.001), with the young group consistently outperforming the elderly group.ConclusionsThese results align with existing literature on dichotic listening tests, highlighting age-related declines in performance. The study contributes valuable insights into age-related changes in auditory processing and cognition, emphasizing the importance of considering dichotic listening as a marker of cognitive aging. Future research should explore potential interventions to mitigate age-related declines in dichotic listening performance.

Auditory Models for Formant Frequency Discrimination of Vowel Sounds

As formant frequencies of vowel sounds are critical acoustic cues for vowel perception, human listeners need to be sensitive to formant frequency change. Numerous studies have found that formant frequency discrimination is affected by many factors like formant frequency, speech level, and fundamental frequency. Theoretically, to perceive a formant frequency change, human listeners with normal hearing may need a relatively constant change in the excitation and loudness pattern, and this internal change in auditory processing is independent of vowel category. Thus, the present study examined whether such metrics could explain the effects of formant frequency and speech level on formant frequency discrimination thresholds. Moreover, a simulation model based on the auditory excitation-pattern and loudness-pattern models was developed to simulate the auditory processing of vowel signals and predict thresholds of vowel formant discrimination. The results showed that predicted thresholds based on auditory metrics incorporating auditory excitation or loudness patterns near the target formant showed high correlations and low root-mean-square errors with human behavioral thresholds in terms of the effects of formant frequency and speech level). In addition, the simulation model, which particularly simulates the spectral processing of acoustic signals in the human auditory system, may be used to evaluate the auditory perception of speech signals for listeners with hearing impairments and/or different language backgrounds.

Pairing with Enriched Sound Exposure Restores Auditory Processing Degraded by an Antidepressant.

Antidepressants, while effective in treating depression and anxiety disorders, also induce deficits in sensory (particularly auditory) processing, which in turn may exacerbate psychiatric symptoms. How antidepressants cause auditory signature deficits remains largely unknown. Here, we found that fluoxetine-treated adult female rats were significantly less accurate when performing a tone-frequency discrimination task compared with age-matched control rats. Their cortical neurons also responded less selectively to sound frequencies. The degraded behavioral and cortical processing was accompanied by decreased cortical perineuronal nets, particularly those wrapped around parvalbumin-expressing inhibitory interneurons. Furthermore, fluoxetine induced critical period-like plasticity in their already mature auditory cortices; therefore, a brief rearing of these drug-treated rats under an enriched acoustic environment renormalized auditory processing degraded by fluoxetine. The altered cortical expression of perineuronal nets was also reversed as a result of enriched sound exposure. These findings suggest that the adverse effects of antidepressants on auditory processing, possibly because of a reduction in intracortical inhibition, can be substantially alleviated by simply pairing drug treatment with passive, enriched sound exposure. They have important implications for understanding the neurobiological basis of antidepressant effects on hearing and for designing novel pharmacological treatment strategies for psychiatric disorders.SIGNIFICANCE STATEMENT Clinical experience suggests that antidepressants adversely affect sensory (particularly auditory) processing, which can exacerbate patients' psychiatric symptoms. Here, we show that the antidepressant fluoxetine reduces cortical inhibition in adult rats, leading to degraded behavioral and cortical spectral processing of sound. Importantly, fluoxetine induces a critical period-like state of plasticity in the mature cortex; therefore, a brief rearing under an enriched acoustic environment is sufficient to reverse the changes in auditory processing caused by the administration of fluoxetine. These results provide a putative neurobiological basis for the effects of antidepressants on hearing and indicate that antidepressant treatment combined with enriched sensory experiences could optimize clinical outcomes.

Differences in Startle and Prepulse Inhibition in Contactin-associated Protein-like 2 Knock-out Rats are Associated with Sex-specific Alterations in Brainstem Neural Activity

The contactin-associated protein-like 2 (CNTNAP2) gene encodes for the CASPR2 protein, which plays an essential role in neurodevelopment. Mutations in CNTNAP2 are associated with neurodevelopmental disorders, including autism spectrum disorder and schizophrenia. Rats with a loss of function mutation in the Cntnap2 gene show increased acoustic startle response (ASR) and decreased prepulse inhibition (PPI). The neural basis of this altered auditory processing in Cntnap2 knock-out rats is currently unknown. Auditory brainstem recordings previously revealed no differences between the genotypes. The next step is to investigate brainstem structures outside of the primary auditory pathway that mediate ASR and PPI, which are the pontine reticular nucleus (PnC) and pedunculopontine tegmentum (PPTg), respectively. Multi-unit responses from the PnC and PPTg in vivo of the same rats revealed sex-specific effects of loss of CASPR2 expression on PnC activity, but no effects on PPTg activity. Female Cntnap2−/− rats showed considerably increased PnC firing rates compared with female wildtypes, whereas the difference between the genotypes was modest in male rats. In contrast, for both females and males we found meager differences between the genotypes for PPTg firing rates and inhibition of PnC firing rates, indicating that altered firing rates of these brainstem structures are not responsible for decreased PPI in Cntnap2−/− rats. We conclude that the auditory processing changes seen in Cntnap2−/− rats are associated with, but cannot be fully explained by, differences in PnC firing rates, and that a loss of function mutation in the Cntnap2 gene has differential effects depending on sex.

Music and Visual Art Training Increase Auditory-Evoked Theta Oscillations in Older Adults.

Music training was shown to induce changes in auditory processing in older adults. However, most findings stem from correlational studies and fewer examine long-term sustainable benefits. Moreover, research shows small and variable changes in auditory event-related potential (ERP) amplitudes and/or latencies in older adults. Conventional time domain analysis methods, however, are susceptible to latency jitter in evoked responses and may miss important information of brain processing. Here, we used time-frequency analyses to examine training-related changes in auditory-evoked oscillatory activity in healthy older adults (N = 50) assigned to a music training (n = 16), visual art training (n = 17), or a no-treatment control (n = 17) group. All three groups were presented with oddball auditory paradigms with synthesized piano tones or vowels during the acquisition of high-density EEG. Neurophysiological measures were collected at three-time points: pre-training, post-training, and at a three-month follow-up. Training programs were administered for 12-weeks. Increased theta power was found pre and post- training for the music (p = 0.010) and visual art group (p = 0.010) as compared to controls (p = 0.776) and maintained at the three-month follow-up. Results showed training-related plasticity on auditory processing in aging adults. Neuroplastic changes were maintained three months post-training, suggesting music and visual art programs yield lasting benefits that might facilitate encoding, retention, and memory retrieval.

Small molecule modulation of the large-conductance calcium-activated potassium channel suppresses salicylate-induced tinnitus in mice

Tinnitus is the phantom perception of sound that has no external source. A neurological signature of tinnitus, and the frequently associated hyperacusis, is an imbalance between excitatory and inhibitory activity in the central auditory system (CAS), leading to dysregulated network excitability. The large conductance, calcium-activated potassium (BK) channel is a key player in pre- and post-synaptic excitability through its mediation of K+ currents. Changes in BK channel activity are associated with aberrant network activity in sensory regions of the CNS, raising the possibility that BK channel modulation could regulate activity associated with tinnitus and hyperacusis. To test whether BK channel openers are able to suppress biomarkers of drug-induced tinnitus and hyperacusis, the 1,3,4 oxadiazole BMS-191011 was given to young adult CBA mice that had been administered 250 mg/kg sodium salicylate (SS). Systemic treatment with BMS-191011 reduced behavioral manifestations of SS-induced tinnitus, but not hyperacusis, probed via the gap-in-noise startle response method. Systemic BMS-191011 treatment did not influence SS-induced increases in auditory brainstem response functions, but local application at the inferior colliculus did reverse SS-suppressed spontaneous activity, particularly in the frequency region of the tinnitus percept. Thus, action of BMS-191011 in the inferior colliculus may contribute to the reduction in behaviorally measured tinnitus. Together, these findings support the utility of BK channel openers in reducing central auditory processing changes associated with the formation of the tinnitus percept.

The Influence of Male- and Female-Spoken Vowel Acoustics on Envelope-Following Responses.

The influence of male and female vowel characteristics on the envelope-following responses (EFRs) is not well understood. This study explored the role of vowel characteristics on the EFR at the fundamental frequency (f0) in response to the vowel /ε/ (as in "head"). Vowel tokens were spoken by five males and five females and EFRs were measured in 25 young adults (21 females). An auditory model was used to estimate changes in auditory processing that might account for talker effects on EFR amplitude. There were several differences between male and female vowels in relation to the EFR. For male talkers, EFR amplitudes were correlated with the bandwidth and harmonic count of the first formant, and the amplitude of the trough below the second formant. For female talkers, EFR amplitudes were correlated with the range of f0 frequencies and the amplitude of the trough above the second formant. The model suggested that the f0 EFR reflects a wide distribution of energy in speech, with primary contributions from high-frequency harmonics mediated from cochlear regions basal to the peaks of the first and second formants, not from low-frequency harmonics with energy near f0. Vowels produced by female talkers tend to produce lower-amplitude EFR, likely because they depend on higher-frequency harmonics where speech sound levels tend to be lower. This work advances auditory electrophysiology by showing how the EFR evoked by speech relates to the acoustics of speech, for both male and female voices.

Aging effects on listening effort in cochlear-implant users

Cochlear-implant (CI) users often report that listening to speech can be exhausting. Greater listening effort can occur with a degraded acoustic signal even in individuals with normal hearing, but age-related changes in auditory processing and individual differences in cognitive abilities may exacerbate the effort required to process a degraded signal. Therefore, we examined the effects of aging and individual differences in cognitive abilities on listening effort (measured with pupillometry) in two experiments. In the first experiment, we measured how changes in signal degradation (spectral resolution) affect listening effort in younger and older adults with normal hearing recalling CI-simulated (vocoded) sentences. In the second experiment, we examined how memory load and cognitive abilities (individual differences in working memory scores) affect listening effort in CI users recalling digit strings. It was hypothesized that increased effort would be observed with greater signal degradation, memory load, and age, and that individual differences would relate to working memory scores. Preliminary results are consistent with the hypothesized effects. These results support the clinical relevance of listening effort in older CI users and provide motivation for development of clinical practices to reduce listening effort in this population.

Going Beyond Rote Auditory Learning: Neural Patterns of Generalized Auditory Learning.

The ability to generalize across specific experiences is vital for the recognition of new patterns, especially in speech perception considering acoustic-phonetic pattern variability. Indeed, behavioral research has demonstrated that listeners are able via a process of generalized learning to leverage their experiences of past words said by difficult-to-understand talker to improve their understanding for new words said by that talker. Here, we examine differences in neural responses to generalized versus rote learning in auditory cortical processing by training listeners to understand a novel synthetic talker. Using a pretest-posttest design with EEG, participants were trained using either (1) a large inventory of words where no words were repeated across the experiment (generalized learning) or (2) a small inventory of words where words were repeated (rote learning). Analysis of long-latency auditory evoked potentials at pretest and posttest revealed that rote and generalized learning both produced rapid changes in auditory processing, yet the nature of these changes differed. Generalized learning was marked by an amplitude reduction in the N1-P2 complex and by the presence of a late negativity wave in the auditory evoked potential following training; rote learning was marked only by temporally later scalp topography differences. The early N1-P2 change, found only for generalized learning, is consistent with an active processing account of speech perception, which proposes that the ability to rapidly adjust to the specific vocal characteristics of a new talker (for which rote learning is rare) relies on attentional mechanisms to selectively modify early auditory processing sensitivity.

Age-related changes in event related potentials, steady state responses and temporal processing in the auditory cortex of mice with severe or mild hearing loss

Age-related changes in auditory processing affect the quality of life of older adults with and without hearing loss. To distinguish between the effects of sensorineural hearing loss and aging on cortical processing, the main goal of the present study was to compare cortical responses using the same stimulus paradigms and recording conditions in two strains of mice (C57BL/6J and FVB) that differ in the degree of age-related hearing loss. Electroencephalogram (EEG) recordings were obtained from freely moving young and old mice using epidural screw electrodes. We measured event related potentials (ERP) and 40 Hz auditory steady-state responses (ASSR). We used a novel stimulus, termed the gap-ASSR stimulus, which elicits an ASSR by rapidly presenting short gaps in continuous noise. By varying the gap widths and modulation depths, we probed the limits of temporal processing in young and old mice. Temporal fidelity of ASSR and gap-ASSR responses were measured as phase consistency across trials (inter-trial phase clustering; ITPC). The old C57 mice, which show severe hearing loss, produced larger ERP amplitudes compared to young mice. Despite robust ERPs, the old C57 mice showed significantly diminished ITPC in the ASSR and gap-ASSR responses, even with 100% modulation depth. The FVB mice, which show mild hearing loss with age, generated similar ERP amplitudes and ASSR ITPC across the age groups tested. However, the old FVB mice showed decreased gap-ASSR responses compared to young mice, particularly for modulation depths <100%. The C57 mice data suggest that severe presbycusis leads to increased gain in the auditory cortex, but with reduced temporal fidelity. The FVB mice data suggest that with mild hearing loss, age-related changes in temporal processing become apparent only when tested with more challenging sounds (shorter gaps and shallower modulation).

Changes in Auditory Processing After Completing The Listening Program Training

ABSTRACT Professionals may recommend listening therapies for people identified with auditory processing problems. A concern arises whether the therapies have evidence supporting changes that occur after completing such training. The authors looked at a large sample of people over a wide age range who completed TLP training. Using each individual as his/her own control, the following study was undertaken. Files of people ranging in age from 5-year to 50-year old for people who had completed TLP training were evaluated. Assessment was completed via results of the SCAN test of auditory processing both before and after completing training. Analyses of changes on the SCAN were computed via paired samples t-tests. Measures found significant improvements with large effect size improvements. Findings support a conclusion that one should expect improvements in auditory processing abilities in people completing TLP training.

HABILIDADES HABILIDADES AUDITIVAS POR MEIO DA AVALIAÇÃO SIMPLIFICADA DO PROCESSAMENTO AUDITIVO EM ESCOLARES

Introdução: Os primeiros anos da vida de uma criança são críticos para o desenvolvimento da fala e da linguagem, sendo fundamentais para a sociabilidade do ser humano. Neste período desenvolvem-se as habilidades auditivas devido à grande maturação e a plasticidade auditiva do sistema nervoso central. Desta forma, um bom desenvolvimento das habilidades auditivas será favorável no processo de aprendizagem em pré-escolares e escolares. Objetivo: Investigar as habilidades auditivas dos escolares do primeiro e segundo ano do Ensino Fundamental de nove anos por meio do desempenho nos testes da ASPA. Metodologia: A casuística foi composta por 67 escolares matriculados regularmente nos anos iniciais na Escola Municipal Hermes Vezzaro no Município de Cascavel-PR, divididos em dois grupos. O grupo 1 (G1), formado por 51 escolares do primeiro ano, sendo 30 do gênero feminino e 21 do gênero masculino, com 6 anos de idade. O grupo 2 (G2), composto por 16 escolares do segundo ano, sendo 10 do gênero feminino e 6 do gênero masculino, com 7 anos de idade. Todos foram submetidos aos seguintes procedimentos: anamnese, inspeção visual do Meato Acústico Externo, triagem audiométrica e os testes que compõem a Avaliação Simplificada do Processamento Auditivo (ASPA). Resultado: Os escolares de ambos os grupos apresentaram desempenho satisfatório em todos os testes mostrando, em sua maioria, habilidades de atenção, localização sonora e memória sequencial. No entanto, o G1 ofereceu respostas inferiores quando comparados ao G2. As crianças mais jovens tiveram maior ocorrência de alterações no teste de Memória Sequencial para Sons Não Verbais. Conclusão: A maioria dos escolares estudados apresentou as habilidades de atenção, localização sonora e memória sequencial adequadas para a faixa etária. A ASPA pode ser um instrumento de rastreio sensível às alterações do processamento auditivo, embora não avalie as demais habilidades auditivas

Neural correlates of sound-learning experiences in the auditory system: Translational candidates for hearing rehabilitation

A major disconnect between traditional auditory perception research and recent neuroscience is the high propensity in the auditory system for neuroplasticity. Altered processing of reward-associated sound stimuli can contribute to adaptive behavior, such as hearing, listening, and attending appropriately to sound cues. I will the present work from animal models of learning-induced neuroplasticity in the cortical and subcortical auditory system. The data show how receptive fields and tonotopic maps in primary auditory cortex (A1) as well as the auditory brainstem response (ABR) can change when adult animals trained by pairing a tone with the availability to obtain reward alters sound coding in the auditory system. Over the course of conditioning, increases and reductions, respectively, in ABR amplitude and peak latencies predict how well animals can pick out the learned sound-frequency acoustic cue from other frequencies following conditioning. Furthermore, receptive fields in A1 have narrower tuning for a remembered sound frequency—and only in animals who successfully remember that frequency over others assessed by behavioral test. Therefore, learned sounds are preferentially processed over novel and distractor sounds following conditioning. Significant behavioral preferences for learned tones may be due, in part, to the observed changes in auditory processing across the auditory system.

Presbycusis: Comparison between the Auditory Brainstem Response (ABR) and the Pure Tone Audiometry (PTA) in Presbycusis Patient

Background: Presbycusis is a complex phenomenon resulting from an elevation hearing levels as well as changes in auditory processing. Chronic diseases such as diabetes (D), arterial hypertension (H) may act as an accelerating factor in agerelated degeneration of the auditory system. The most used diagnostic test is PTA, ABR is recorded when the pure tone audiometry cannot be access. Objective: to compare the relation between ABR and PTA threshold in presbycusis patients and evaluate the influence of diabetes and/or hypertension on the relationship between ABR and PTA threshold. Material and methods: This is a prospective hospital-based study on the comparison between ABR and PTA of presbycusis patients (≥ 50 years old) composed of 35 females and 21 males. The participants were divided into groups, set as follows group 1 composed of 21 patients, group 2 comprising 12 patients, group 3 made of 14 patients and group 4 composed of 9 patients. Results: The comparison between the mean threshold difference of ABR and PTA in group I and II was significant at each frequency with the mean difference in decibel was 20 dB at 0.5 and 1 kHz in group 2,while in group 2 a mean difference 20 dB at 0.5, 1, and 2 kHz. However, group IV showed no significant difference between ABR and PTA thresholds, the mean threshold difference was>20 dB at each frequency. Conclusion: it was found that there is a positive relationship between ABR and PTA, threshold, which appear to be insignificant in presbycusis patients with both hypertension and diabetes; this may be probably related to synergic effects of the two chronic illnesses on the cochlea.

Development of electrophysiological and behavioural measures of electrode discrimination in adult cochlear implant users

The plasticity of the auditory system enables it to adjust to electrical stimulation from cochlear implants (CI). Whilst speech perception may develop for many years after implant activation, very little is known about the changes in auditory processing that underpin these improvements. Such an understanding could help guide interventions that improve hearing performance. In this longitudinal study, we examine how electrode discrimination ability changes over time in newly implanted adult CI users. Electrode discrimination was measured with a behavioural task as well as the spatial auditory change complex (ACC), which is a cortical response to a change in place of stimulation. We show that there was significant improvement in electrode discrimination ability over time, though in certain individuals the process of accommodation was slower and more limited. We found a strong relationship between objective and behavioural measures of electrode discrimination using pass-fail rules. In several cases, the development of the spatial ACC preceded accurate behavioural discrimination. These data provide evidence for plasticity of auditory processing in adult CI users. Behavioural electrode discrimination score but not spatial ACC amplitude was found to be a significant predictor of speech perception. We suggest that it would be beneficial to measure electrode discrimination in CI users and that interventions that exploit the plastic capacity of the auditory system to improve basic auditory processing, could be used to optimize performance in CI users.

Decrease of Auditory Evoked Delta, Alpha and Beta Oscillatory Responses in d-galactose Induced Aging Model: Effects of Rosmarinic Acid

Summary Background Age-related hearing impairment is one of the most common complaints among older people. It was reported that central neural processing deficits contribute this deficit and improving central auditory function might be beneficial for cognitive functions in elderly. In the present study, we examined the effect of rosmarinic acid (RA) on auditory evoked oscillations and lipid peroxidation in d -galactose induced rat aging model. Methods Wistar rats were randomly divided into four groups: sham (S); RA-treated (R); d -galactose-treated (DG); d -galactose + RA-treated (DGR). After eight weeks period, central auditory functions were evaluated by measuring the auditory evoked oscillations over temporal cortex. Thiobarbituric acid reactive substances (TBARS) assay was used to quantify lipid peroxidation levels of the temporal cortex. Results d -galactose treated rats exhibited attenuated auditory evoked delta, alpha and beta responses. Moreover, increased lipid peroxidation levels were detected in the d -galactose treated rats. Eight weeks RA (50 mg/kg) treatment significantly improved oscillatory alterations and lipid peroxidation as compared to DG group. Conclusion Thus, present study shows d -galactose induced oscillatory changes in auditory processing and highlights the protective effect of RA against d -galactose induced changes in auditory evoked oscillations and lipid peroxidation.

Sonification of scalp-recorded frequency-following responses (FFRs) offers improved response detection over conventional statistical metrics

BackgroundThe human frequency-following response (FFR) is a neurophonic potential used to examine the brain’s encoding of complex sounds (e.g., speech) and monitor neuroplastic changes in auditory processing. Given the FFR’s low amplitude (order of nanovolts), current conventions in literature recommend collecting several thousand trials to obtain a robust evoked response with adequate signal-to-noise ratio. New methodBy exploiting the spectrotemporal fidelity of the response, we examined whether auditory playbacks (i.e., “sonifications”) of the neural FFR could be used to assess the quality of running recordings and provide a stopping rule for signal averaging. Results and comparison with existing methodIn a listening task over headphones, naïve listeners detected speech-evoked FFRs within ∼500 sweeps based solely on their perception of the presence/absence of a tonal quality to the response. Moreover, response detection based on aural sonifications offered similar and in some cases a 2–3× improvement over objective statistical techniques proposed in the literature (i.e., MI, SNR, MSC, F-test, Corr). ConclusionsOur findings suggest that simply listening to FFR responses (sonifications) might offer a rapid technique to monitor real-time EEG recordings and provide a stopping rule to terminate signal averaging that performs comparably or better than current approaches.

An Integrated Assessment of Changes in Brain Structure and Function of the Insula Resulting from an Intensive Mindfulness-Based Intervention

Mindfulness training is thought to alter both brain function and structure, yet these effects are almost always investigated and reported independently. In the present study, we combine these two approaches to provide a more complete description of the effects of a 6-week mindfulness-based health and wellness intervention. Region-of-interest analysis of brain structure revealed a significant increase in cortical thickness within the left-hemisphere posterior insula, a region that plays a role in auditory perception and interoception. We then examined changes in the resting-state functional connectivity (rs-FC) of this insula cluster and found two regions with which it displayed increased functional connectivity: one in the right-hemisphere ventrolateral prefrontal cortex (vlPFC) and another spanning parts of the left-hemisphere middle and superior temporal gyri (MTG/STG). Individuals with the greatest improvements in dispositional mindfulness showed the greatest increases in insular thickness as well as greater increases in rs-FC of the posterior insula with vlPFC and MTG/STG. The insula, vlPFC, and MTG/STG comprise a structurally connected network involved in, respectively, early auditory perception, the allocation of attention to changes in sounds, and the detailed analysis of fluctuations in sounds. Accordingly, these findings suggest a mechanistic account of the alterations in brain structure and function that underlie changes in auditory processing following a mindfulness-based intervention.

Age-related changes in auditory processing and speech perception: cross-sectional and longitudinal analyses.

Age-related differences in speech perception have been shown in previous cross-sectional studies to be related to auditory temporal processing. We examined this association in both cross-sectional and longitudinal designs, controlling for age-related changes in hearing sensitivity and cognitive ability. Fifty-eight participants were tested in two phases. In phase 1, ages ranged between 22 and 82years. Phase 2 occurred seven years later. In both phases, participants performed auditory processing tasks, speech perception tests, and cognitive tasks. In both phases, age correlated with hearing level, auditory temporal processing thresholds, word recognition accuracy in noise, and compressed speech. Auditory temporal processing thresholds were correlated with word recognition accuracy in narrowband noise and compressed speech. Longitudinal analysis showed significant decreases in performance from phase 1 to phase 2 in hearing level, dichotic TOJ thresholds, and word recognition accuracy. Steeper slopes were observed in phase 2 than in phase 1 for correlations between age, hearing level, and word recognition accuracy in narrowband noise, but not for age and dichotic TOJ thresholds. Generalized estimating equations revealed an overall decrease in word recognition accuracy from phase 1 to phase 2; this decrease was larger for older participants. Increases in dichotic TOJ and gap detection thresholds were associated with a decrease over time in speech in narrowband and broadband noise, and compressed speech, even when adjusted for age, hearing level, and cognitive ability. These results show that both cross-sectional and longitudinal designs yield similar significant associations between temporal processing and speech perception, even when adjusted for hearing level and cognitive ability.