Temporal Processing Abilities Research Articles

Trainable Reference Spikes Improve Temporal Information Processing of SNNs With Supervised Learning.

Spiking neural networks (SNNs) are the next-generation neural networks composed of biologically plausible neurons that communicate through trains of spikes. By modifying the plastic parameters of SNNs, including weights and time delays, SNNs can be trained to perform various AI tasks, although in general not at the same level of performance as typical artificial neural networks (ANNs). One possible solution to improve the performance of SNNs is to consider plastic parameters other than just weights and time delays drawn from the inherent complexity of the neural system of the brain, which may help SNNs improve their information processing ability and achieve brainlike functions. Here, we propose reference spikes as a new type of plastic parameters in a supervised learning scheme in SNNs. A neuron receives reference spikes through synapses providing reference information independent of input to help during learning, whose number of spikes and timings are trainable by error backpropagation. Theoretically, reference spikes improve the temporal information processing of SNNs by modulating the integration of incoming spikes at a detailed level. Through comparative computational experiments, we demonstrate using supervised learning that reference spikes improve the memory capacity of SNNs to map input spike patterns to target output spike patterns and increase classification accuracy on the MNIST, Fashion-MNIST, and SHD data sets, where both input and target output are temporally encoded. Our results demonstrate that applying reference spikes improves the performance of SNNs by enhancing their temporal information processing ability.

Degradation in Binaural and Spatial Hearing and Auditory Temporal Processing Abilities as a Function of Aging.

Sensorineural hearing loss is common with advancing age, but even with normal or near normal hearing in older persons, performance deficits are often seen for suprathreshold listening tasks such as understanding speech in background noise or localizing sound direction. This suggests there is also a more central source of the problem. Objectives of this study were to examine as a function of age (young adult to septuagenarian) performance on: 1) a spatial acuity task examining lateralization ability, and a spatial speech-in-noise (SSIN) recognition task, both measured in a hemi-anechoic sound field using a circular horizontal-plane loudspeaker array, and 2) a suprathreshold auditory temporal processing task and a spectro-temporal processing task, both measured under headphones. Further, we examined any correlations between the measures.DesignSubjects were 48 adults, aged 21 to 78, with either normal hearing or only a mild sensorineural hearing loss through 4000 Hz. The lateralization task measured minimum audible angle (MAA) for 500 and 4000 Hz narrowband noise (NBN) bursts in diffuse background noise for both an on-axis (subject facing 0°) and off-axis (facing 45°) listening condition at signal-to-noise ratios (SNRs) of -3, -6, -9, and -12 dB. For 42 of the subjects, SSIN testing was also completed for key word recognition in sentences in multi-talker babble noise; specifically, the separation between speech and noise loudspeakers was adaptively varied to determine the difference needed for 40% and 80% correct performance levels. Finally, auditory temporal processing ability was examined using the Temporal Fine Structure test (44 subjects), and the Spectro-Temporal Modulation test (46 subjects). Mean lateralization performances were poorer (larger MAAs) in older compared to younger subjects, particularly in the more adverse listening conditions (4000 Hz, off-axis, and poorer SNRs). Performance variability was notably higher for older subjects than for young adults. The 4000 Hz NBN bursts produced larger MAAs than did 500 Hz NBN bursts. The SSIN data also showed declining mean performance with age at both criterion levels, with greater variability again found for older subjects. Spearman rho analyses revealed some low to moderate, but significant correlation coefficients for age versus MAA and age versus SSIN results. A low but significant correlation was also observed between the most adverse MAA and SSIN conditions. Results from both the TFS and STM assessments showed decreased mean performance with aging, and revealed moderate, significant correlations, with the strongest relationship shown with the TFS test. Finally, of note, extended-high-frequency (EHF) hearing loss (measured between 9000 and 16,000 Hz) was found in older but not young subjects, and correlated with decreasing performance on several tasks. Particularly for more adverse listening conditions, age-related deficits were found on both of the spatial hearing tasks and in temporal and spectro-temporal processing abilities. It may be that deficits in temporal processing ability contribute to poorer spatial hearing performance in older subjects due to inaccurate coding of binaural/interaural timing information sent from the periphery to the brainstem. In addition, EHF hearing loss may be a coexisting factor in the reduced performance in older subjects.

Comparison of Spectral and Temporal Processing Abilities between Adults with Stroke and Healthy Peers

Background and Aim: Perception of speech in noise (SIN) is based on the accurate extraction of spectral and temporal cues. Disruption of this process can reduce the productivity of the spectral and temporal features of the target stimulus and speech recognition in noise. Auditory processing disorder is one of the main challenges of people with stroke, which leads to social, mental, and even physical failures. This study aimed to investigate the spectral and temporal processing abilities of people with stroke compared to healthy peers. Methods: In this study, participants were 15 patients with stroke referred to the neurology clinic of Imam Khomeini Hospital and 30 healthy people aged 20–60 years. Spectral Modulation Detection Test (SMDT), Pitch Pattern Sequencing Test (PPST), Random Gap Detection Test (RGDT) and QuickSIN tests were performed for all participants. The mean scores of the two groups were compared. Results: Patients with stroke had poorer performance in SMDT, PPST, RGDT and QuickSIN tests (p<0.001) compared to healthy subjects. The results showed that there was a significant correlation between SIN test with temporal and spectral processing in the normal group, but the correlation pattern was different in people with stroke. The scores of all the tests were not significantly different between the right and left ears. Conclusion: The results showed that people with stroke have poorer performance in all tests compared to normal people and have more problems in speech perception in challenging areas. Keywords: Auditory processing disorder; speech perception in noise; spectral modulation; temporal processing; stroke

Temporal processing abilities in normal hearing individuals with tinnitus: a systematic review

PurposeTinnitus, characterized by the perception of auditory phantoms, is prevalent worldwide and can lead to a range of hearing-related issues. Understanding its influence on temporal processing helps to delineate the auditory manifestations of tinnitus. This systematic review aimed to identify the patterns of temporal processing difficulties in individuals with tinnitus and normal hearing abilities. Furthermore, this review evaluates the potential of specific measurement techniques as tools for diagnosing temporal processing deficits in tinnitus.MethodsA comprehensive search was conducted in multiple international databases, followed by rigorous screening of the titles, abstracts, and full-length content. The inclusion and exclusion criteria were formulated using the Population, intervention, compression, Outcome, and Study design (PICOS) format, and the study bias was determined. After excluding irrelevant articles, nine studies were selected for the analysis.ResultsOver 50% of the selected studies demonstrated a significant impact on temporal processing in individuals with tinnitus, especially with gap detection test (GDT) and gaps in noise (GIN) tests, indicating of the deficits in peripheral temporal process in tinnitus individuals with normal hearing. However, the other central auditory tests showed no major changes.ConclusionsThe findings from this review underscore the importance of understanding temporal processing impairments in tinnitus and hold promise for enhancing the diagnostic accuracy and treatment outcomes, ultimately improving the lives of those affected by tinnitus. This review highlights the potential of the GDT and GIN tests as sensitive tools for assessing temporal processing deficits in the peripheral auditory system, which in turn can manifest as central changes in temporal processing.Systematic review registrationhttp://www.crd.york.ac.uk/PROSPERO/display_record.asp?ID=CRD42021287194, Prospero [CRD42021287194].

Auditory Processing and Speech-Sound Disorders.

Speech-sound disorders (SSD) have been linked to auditory processing difficulties, and auditory processing disorders (APD) have been related to phonological awareness and literacy development. To this date, there has not been a systematic literature review investigating the results of psychophysiology and language assessments related to SSD and APD in children. The literature search was conducted in PubMed, Medline EBSCO, and Scopus to identify studies with children diagnosed/suspected of having APDs and SSDs. The quality of methodology in the selected articles was evaluated with the Newcastle Ottawa Scale. Seven out of 378 relevant studies met the selection criteria. The findings were summarized for children with SSD and APD based on (a) metalinguistic and literacy skills, (b) cognitive abilities, and (c) temporal processing abilities. Three articles indicated that children with APD and SSD exhibit lower temporal task accuracy and reaction time. In two studies, children with SSD exhibited lower scores in discrimination, sequencing, and recall of brief stimuli in rapid succession. This review revealed associations between SSD severity and APD that may underline low performance in metalinguistic skills. Diagnostic assessments have been proposed based on the review to adequately identify children with SSD and APD and provide useful information for more suitable intervention.

A Step Toward Precision Audiology: Individual Differences and Characteristic Profiles From Auditory Perceptual and Cognitive Abilities.

Older adults with normal hearing or with age-related hearing loss face challenges when listening to speech in noisy environments. To better serve individuals with communication difficulties, precision diagnostics are needed to characterize individuals' auditory perceptual and cognitive abilities beyond pure tone thresholds. These abilities can be heterogenous across individuals within the same population. The goal of the present study is to consider the suprathreshold variability and develop characteristic profiles for older adults with normal hearing (ONH) and with hearing loss (OHL). Auditory perceptual and cognitive abilities were tested on ONH (n = 20) and OHL (n = 20) on an abbreviated test battery using portable automated rapid testing. Using cluster analyses, three main profiles were revealed for each group, showing differences in auditory perceptual and cognitive abilities despite similar audiometric thresholds. Analysis of variance showed that ONH profiles differed in spatial release from masking, speech-in-babble testing, cognition, tone-in-noise, and binaural temporal processing abilities. The OHL profiles differed in spatial release from masking, speech-in-babble testing, cognition, and tolerance to background noise performance. Correlation analyses showed significant relationships between auditory and cognitive abilities in both groups. This study showed that auditory perceptual and cognitive deficits can be present to varying degrees in the presence of audiometrically normal hearing and among listeners with similar degrees of hearing loss. The results of this study inform the need for taking individual differences into consideration and developing targeted intervention options beyond pure tone thresholds and speech testing.

Asynchronies in Auditory and Language Development Obscure Connections to Phonological Deficits in Children

Purpose: For half a century, psycholinguists have been exploring the idea that developmental language disorders may have their roots in suprathreshold auditory dysfunctions, but results are inconclusive. Typical studies focus on relationships between temporal processing abilities and measures of various language skills at the time of testing, a proximal account. This study expanded that focus by testing three novel hypotheses: (a) Spectral processing impairments may be more responsible for language-learning deficits than temporal processing impairments. (b) Phonological sensitivity is likely the specific language skill most strongly affected by auditory (dys)functions. (c) Poor auditory functioning observed at young ages may wholly or partly recover, reducing the magnitude of relationship between those recovered functions and persistent language skills at older ages. Method: Sixty-six children (31 boys, 35 girls) 7–10 years of age participated: 36 with typical language and 30 with reading or speech disorder; from this sample two subsamples were designated: younger (7–8 years) and older (9–10 years) children. Four auditory measures were obtained of spectral modulation detection (0.5 and 2.0 cycles per octave) and temporal modulation detection (16 and 64 Hz). Four language measures were obtained, two lexicosyntactic and two phonological. Results: Younger children showed deficits in all auditory skills, but most strongly for spectral modulation detection at 0.5 cycles per octave; that measure was the only one for which older children showed deficits. Spectral modulation detection was the auditory function most strongly correlated with a language skill, and that language skill was phonological sensitivity. Conclusions: Early impairments in suprathreshold auditory functions, especially spectral processing, interfere with language acquisition at early stages, especially phonological sensitivity. Although auditory functions can recover to some extent, impairments in language skills persist, indicating that a distal account may more appropriately explain the relationship. Supplemental Material: https://doi.org/10.23641/asha.24730128

Spiking Neural Network with plasticity in the time domain recovers temporal information from a noisy pattern using reference spikes

Neurons in the brain communicate with each other by sending trains of spikes that can encode information using the timings of the spikes. Spiking Neural Networks (SNNs) are biologically plausible neural networks that can model this transfer of information and that, by incorporating plasticity, can detect repeating patterns that may be embedded in a train of spikes with a noisy background. Although existing model networks are capable of learning to detect the occurrence of repeated patterns, they are not tailored to recover the entirety of the time sequence of the spikes in the pattern. Here we present a network that, in addition to typical parameters of plasticity such as weights and time delays, uses a new plasticity on the time domain that can recover most of the spikes in a pattern. This new plasticity acts by modifying the timings of reference spikes that come from a hypothesized upstream network that could potentially encode preexisting memories. The model is shown to be robust under several noise perturbation scenarios, and its overall performance demonstrates the benefits of using reference spikes to improve the temporal information processing ability of SNNs.

The Effect of Hemodialysis on Spectral and Temporal Processing Abilities and Speech Perception in Noise among Individuals with Chronic Kidney Disease

Introduction: The effect of chronic kidney disease (CKD) on hearing is well documented in the literature. Several studies have investigated the effect of hemodialysis on the peripheral auditory system among individuals with CKD. However, studies investigating the effect of hemodialysis on speech perception and auditory processing abilities are limited. The present study investigated the effect of hemodialysis on few auditory processing abilities and speech perception in noise among adults with CKD. Methods: A total of 25 adults with CKD undergoing hemodialysis regularly participated in the study. Spectral ripple discrimination threshold (SRDT), gap detection threshold (GDT), amplitude-modulation detection threshold (AMDT), and speech recognition threshold in noise (SRTn) were measured before and after hemodialysis. Paired samples “t” test was carried out to investigate the effect of hemodialysis on thresholds. Results: Results showed a significant improvement for SRDT, GDT, AMDT, and SRTn after hemodialysis among individuals with CKD. Discussion: Hemodialysis showed a positive effect on speech perception in noise and auditory processing abilities among individuals with CKD.

Does Binaural Stimulation Enhance Temporal Processing in Young Children?

Background and objective Temporal processing abilities help perceive signal changes over time. Efficient temporal processing is necessary for pitch perception, voice identification, and speech perception. It plays a significant role in language development. Internal redundancy of the central auditory nervous plays a role in processing sensory information. There is a need to gain more insights into the maturation of neural hardwiring that supports binaural temporal processing at a young age. The purpose of the present study was to evaluate the difference between monaural and binaural temporal processing in children aged 7-11 years. Methods Temporal processing was assessed using gap detection and temporal modulation transfer function (TMTF) tests. The tests were administered in 40 typically developing children with normal clinical auditory sensitivity. The maximum likelihood procedure (MLP), a MATLAB toolbox, was employed to deliver the stimulus. A multivariate analysis followed by post hoc analysis was performed to analyze the data. Results There was a significant difference between binaural and monoaural stimulation in children aged 7-11 years. However, there was no statistically significant difference between the right and left ears for gap detection threshold (GDT) and TMTF across all test frequencies. Conclusion Based on our findings, binaural stimulation enhances temporal processing in young children.

Age-related rollover for spectrally degraded temporal speech contrasts

Some speech sounds, or phonemes, are primarily distinguished acoustically from other phonemes by temporal cues. A decline in temporal-processing abilities is a common consequence of aging that might cause a listener to have difficulty differentiating between sounds, especially when the speech is degraded. One type of signal degradation occurs in a cochlear-implant vocoder simulation, which eliminates most of the spectral information in speech while maintaining the temporal envelope. In addition, temporal processing abilities may be challenged at higher presentation levels causing a decrease in performance (i.e., rollover), particularly in older listeners. This study measures the phoneme classification of younger and older listeners of four spectro-temporal contrasts when presented in quiet with and without vocoding at a range of presentation levels. We hypothesized that, due to declines in temporal processing abilities, older listeners would be more susceptible to rollover, measured by a decrease in phoneme classification performance for degraded temporal contrasts as presentation levels increase. We further hypothesized that performance rollover would occur more often for vocoded speech than for unprocessed speech, especially in older listeners. Preliminary data show interactions between speech contrasts, presentation levels, and vocoding. Our results will help facilitate understanding speech perception difficulties in older cochlear-implant users.

Influence of Gender on Auditory Temporal Processing: A Cross-sectional study in Security Personnel in Puducherry, India

ABSTRACT Introduction: It is no wonder that men and women have their fair share of differences. Scientific evidences are scarce to justify the clear-cut role of gender differences on the human brain. It is a well-known fact that perception and accurate processing of sound stimuli in the auditory pathway is a necessary skill for efficient learning and language development. This study aimed to investigate the role of gender on auditory processing by comparing the temporal resolution ability of healthy, adult males and females. Methods: Forty-three apparently healthy individuals (F = 18; M = 25) in the age group of 25–60 years with a normal hearing threshold on audiometry participated in this study. Audiometry and random gap detection test (RGDT) were used to assess hearing threshold and auditory temporal processing ability. In RGDT, a pair of pure tones was presented to participants’ ears at different frequencies (500–4000 Hz) and they were instructed to identify a silent-gap (in milliseconds) between each pair of tones. Values were compared using an unpaired student “t” test. Results: The mean age of participants was 40.5 ± 8.45 years. The average hearing threshold levels (in dB) of male and female participants were 15.6 ± 2.5 and 14.5 ± 2.8, respectively (P-value = 0.1293). Temporal processing values of males and females were 10.48 ± 0.49 and 10.67 ± 0.51, respectively (P-value = 0.2338). Conclusion: The temporal processing ability was slightly higher in males than the females. However, the difference was insignificant. Therefore, it can be concluded that gender does not affect auditory temporal processing ability in middle-aged adults.

Auditory Temporal Processing Abilities in Patients with Diabetes Mellitus Type 1 and Type 2

Auditory Temporal Processing Abilities in Patients with Diabetes Mellitus Type 1 and Type 2

Effect of Contralateral Acoustic Stimulation on Temporal Processing Abilities in Individuals with Normal Hearing.

The aim of the article was to compare the conditions of silent and contralateral noise on the temporal processing parameters. A total of 40 participants (20 males and 20 females) were enrolled in the study with a mean age of 21.7years, participants with normal hearing thresholds and no history of middle ear pathology were enrolled for the study. The temporal processing tests such as duration discrimination test, gap detection test, and temporal modulation transfer function tests were carried out in these 40 individuals in the two conditions of silent and contralateral noise using MATLAB. Statistical analysis was carried out using the SPSS version 25.0 were descriptive and inferential statistics were carried out. Data was normally distributed on the Shapiro-Wilk's test of normality due to which a paired t test was carried out to establish the nature of significance between the silent and contralateral noise condition. Results reveal the presence of significant difference (p < 0.01) between the groups for all the parameters of temporal resolution with contralateral noise condition performing better than silent condition for the parameters. There is a positive effect of the efferent auditory pathway on the temporal resolution parameters thus implying that speech perception in noise is improved in the presence of background noise for normal hearing individuals due to this effect.

Within- and across-frequency temporal processing and speech perception in cochlear implant users.

Cochlear implant (CI) recipient's speech perception performance is highly variable and is influenced by temporal processing abilities. Temporal processing is commonly assessed using a behavioral task that requires the participant to detect a silent gap with the pre- and post-gap stimuli of the same frequency (within-frequency gap detection) or of different frequencies (across-frequency gap detection). The purpose of the study was to evaluate behavioral and electrophysiological measures of within- and across-frequency temporal processing and their correlations with speech perception performance in CI users. Participants included 11 post-lingually deafened adult CI users (n = 15 ears; Mean Age = 50.2 yrs) and 11 age- and gender-matched normal hearing (NH) individuals (n = 15 ears; Mean Age = 49.0 yrs). Speech perception was assessed with Consonant-Nucleus-Consonant Word Recognition (CNC), Arizona Biomedical Sentence Recognition (AzBio), and Bamford-Kowal-Bench Speech-in-Noise Test (BKB-SIN) tests. Within- and across-frequency behavioral gap detection thresholds (referred to as the GDTwithin and GDTacross) were measured using an adaptive, two-alternative, forced-choice procedure. Cortical auditory evoked potentials (CAEPs) were elicited using within- and across-frequency gap stimuli under four gap duration conditions (no gap, GDT, sub-threshold GDT, and supra-threshold GDT). Correlations among speech perception, GDTs, and CAEPs were examined. CI users had poorer speech perception scores compared to NH listeners (p < 0.05), but the GDTs were not different between groups (p > 0.05). Compared to NH peers, CI users showed increased N1 latency in the CAEPs evoked by the across-frequency gap stimuli (p < 0.05). No group difference was observed for the CAEPs evoked by the within-frequency gap (p > 0.05). Three CI ears showing the longest GDTwithin also showed the poorest performance in speech in noise. The within-frequency CAEP increased in amplitude with the increase of gap duration; while the across-frequency CAEP displayed a similar amplitude for all gap durations. There was a significant correlation between speech scores and within-frequency CAEP measures for the supra-threshold GDT condition, with CI users with poorer speech performance having a smaller N1-P2 amplitude and longer N1 latency. No correlations were found among GDTacross, speech perception, and across-frequency CAEP measures. Within- and across-frequency gap detection may involve different neural mechanisms. The within-frequency gap detection task can help identify CI users with poor speech performance for rehabilitation. The within-frequency CAEP is a better predictor for speech perception performance than the across-frequency CAEP.

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.

Audiovisual temporal processing in adult patients with first-episode schizophrenia and high-functioning autism

Schizophrenia and autism spectrum disorder (ASD) are both neurodevelopmental disorders with altered sensory processing. Widened temporal binding window (TBW) signifies reduced sensitivity to detect stimulus asynchrony, and may be a shared feature in schizophrenia and ASD. Few studies directly compared audiovisual temporal processing ability in the two disorders. We recruited 43 adult patients with first-episode schizophrenia (FES), 35 average intelligent and verbally-fluent adult patients with high-functioning ASD and 48 controls. We employed two unisensory Temporal Order Judgement (TOJ) tasks within visual or auditory modalities, and two audiovisual Simultaneity Judgement (SJ) tasks with flash-beeps and videos of syllable utterance as stimuli. Participants with FES exhibited widened TBW affecting both speech and non-speech processing, which were not attributable to altered unisensory sensory acuity because they had normal visual and auditory TOJ thresholds. However, adults with ASD exhibited intact unisensory and audiovisual temporal processing. Lower non-verbal IQ was correlated with larger TBW width across the three groups. Taking our findings with earlier evidence in chronic samples, widened TBW is associated with schizophrenia regardless illness stage. The altered audiovisual temporal processing in ASD may ameliorate after reaching adulthood.

Rate Discrimination Training May Partially Restore Temporal Processing Abilities from Age-Related Deficits.

The ability to understand speech in complex environments depends on the brain’s ability to preserve the precise timing characteristics of the speech signal. Age-related declines in temporal processing may contribute to the older adult’s experience of communication difficulty in challenging listening conditions. This study’s purpose was to evaluate the effects of rate discrimination training on auditory temporal processing. A double-blind, randomized control design assigned 77 young normal-hearing, older normal-hearing, and older hearing-impaired listeners to one of two treatment groups: experimental (rate discrimination for 100- and 300-Hz pulse trains) and active control (tone detection in noise). All listeners were evaluated during pre- and post-training sessions using perceptual rate discrimination of 100-, 200-, 300-, and 400-Hz band-limited pulse trains and auditory steady-state responses (ASSRs) to the same stimuli. Training generalization was evaluated using several temporal processing measures and sentence recognition tests that included time-compressed and reverberant speech stimuli. Results demonstrated a session × training group interaction for perceptual and ASSR testing to the trained frequencies (100 and 300 Hz), driven by greater improvements in the training group than in the active control group. Further, post-test rate discrimination of the older listeners reached levels that were equivalent to those of the younger listeners at pre-test. Generalization was observed in significant improvement in rate discrimination of untrained frequencies (200 and 400 Hz) and in correlations between performance changes in rate discrimination and sentence recognition of reverberant speech. Further, non-auditory inhibition/attention performance predicted training-related improvement in rate discrimination. Overall, the results demonstrate the potential for auditory training to partially restore temporal processing in older listeners and highlight the role of cognitive function in these gains.

Evaluation of phase-locking to parameterized speech envelopes.

Humans rely on the temporal processing ability of the auditory system to perceive speech during everyday communication. The temporal envelope of speech is essential for speech perception, particularly envelope modulations below 20 Hz. In the literature, the neural representation of this speech envelope is usually investigated by recording neural phase-locked responses to speech stimuli. However, these phase-locked responses are not only associated with envelope modulation processing, but also with processing of linguistic information at a higher-order level when speech is comprehended. It is thus difficult to disentangle the responses into components from the acoustic envelope itself and the linguistic structures in speech (such as words, phrases and sentences). Another way to investigate neural modulation processing is to use sinusoidal amplitude-modulated stimuli at different modulation frequencies to obtain the temporal modulation transfer function. However, these transfer functions are considerably variable across modulation frequencies and individual listeners. To tackle the issues of both speech and sinusoidal amplitude-modulated stimuli, the recently introduced Temporal Speech Envelope Tracking (TEMPEST) framework proposed the use of stimuli with a distribution of envelope modulations. The framework aims to assess the brain's capability to process temporal envelopes in different frequency bands using stimuli with speech-like envelope modulations. In this study, we provide a proof-of-concept of the framework using stimuli with modulation frequency bands around the syllable and phoneme rate in natural speech. We evaluated whether the evoked phase-locked neural activity correlates with the speech-weighted modulation transfer function measured using sinusoidal amplitude-modulated stimuli in normal-hearing listeners. Since many studies on modulation processing employ different metrics and comparing their results is difficult, we included different power- and phase-based metrics and investigate how these metrics relate to each other. Results reveal a strong correspondence across listeners between the neural activity evoked by the speech-like stimuli and the activity evoked by the sinusoidal amplitude-modulated stimuli. Furthermore, strong correspondence was also apparent between each metric, facilitating comparisons between studies using different metrics. These findings indicate the potential of the TEMPEST framework to efficiently assess the neural capability to process temporal envelope modulations within a frequency band that is important for speech perception.

Spatial and temporal processing difficulties in Chinese children with developmental dyslexia: An ERP study.

Magnocellular (M) deficit theory indicates that individuals with developmental dyslexia (DD) have low sensitivity to stimuli with high temporal frequencies (HTF) and low spatial frequencies (LSF). However, some studies found that temporal processing and spatial processing were correlated with different reading-related skills. Chinese is a logographic language, and visual skills are particularly important for reading in Chinese. It is necessary to investigate the temporal and spatial processing abilities in the M pathway of Chinese children with DD. Using electrophysiological recordings, the present study examined the mean amplitude and latency of P1 during a grating direction judgment task in 13 children with DD and 13 age-matched normal children. Dyslexic children showed a low amplitude and long latency of P1 in the HTF condition and LSF condition compared with age-matched children. In the HTF condition, the amplitude of P1 correlated with phonological awareness, and the latency of P1 correlated with reading fluency and rapid naming of digits. The amplitude of P1 in the LSF condition correlated with reading accuracy. This result suggested that Chinese children with DD had difficulties in both temporal and spatial processing in the M pathway. However, temporal processing and spatial processing played different roles in Chinese reading.