Temporal Processing Deficits Research Articles (Page 1)

IntroductionChildren with auditory processing disorder (APD) exhibit various auditory processing deficits, including temporal processing deficits. Temporal processing abilities are assessed by estimating the gap detection threshold (GDT) as the lowest perceivable gap duration identified by the subject.ObjectiveThe present study attempted to examine the performance of normal-hearing children and children with APD using adaptive within-channel and across-channel gap detection tests.MethodsTwo groups of children aged between 10 and 12 years participated in the study. Group 1 included children diagnosed with APD, and group 2 included normal hearing, typically developing children (TD), with 12 participants in each group. For each subject, the lowest detectable gap duration was obtained monoaurally, using broadband noise (BBN), within-channel (narrow bands of noise centered spectrally at 2 kHz on either side of the gap), and across-channel (narrow bands of noise leading marker spectrally centered at 2 kHz and trailer marker spectrally centered at 1 kHz) gap detection tests through the Psycon platform (free).ResultsThe results of the statistical analysis revealed significant group differences only in across-channel GDT measures between the two groups. In contrast, there were no statistically significant differences between the groups in terms of either within-channel GDT or BBN GDT.ConclusionThe results indicate that, compared to other stimuli, an across-channel gap detection test would be a better diagnostic test of temporal resolution to identify and assess children with APD.

Congenital amusia is a neurodevelopmental disorder resulting in impaired pitch perception and memory. Here we investigated whether participants with congenital amusia have deficits in temporal processing of auditory information, in addition to pitch processing deficits. Individuals with amusia (n = 19) and matched controls (n = 21) were presented with sequences of five tones in which one tone was sometimes shifted in pitch or in time, and we adaptively assessed psychophysical thresholds for detecting these shifts. Pitch thresholds of the amusia group were higher (i.e., worse) than those of the control group as expected, and, crucially, time thresholds were too, although the group difference for time thresholds was smaller. Across participants, time thresholds correlated with pitch thresholds. Principal component analysis revealed that all pitch- and time-related variables (thresholds and amusia battery scores) were correlated to one component that also distinguished between amusics and controls; whereas a second component captured additional variability on the time task. Simulations suggest that prior studies had not found these time processing deficits because they had less statistical power, likely due to smaller sample sizes. The observed time processing deficit is in agreement with amusic individuals' subjective reports about their difficulties following the rhythm of the music. These data suggest that amusia deficits are not restricted to pitch, but extend to the time domain, yet with a smaller effect size, and at least when the stimuli have a clear pitch content, such as for tone sequences or music.

In the present study, 43 Italian school-age children (age range = 7-14 years, 16 females) with (N = 19) and without DD (N = 24) were presented with pairs of visual displays separated by varying interstimulus intervals and performed either a temporal integration or segregation task despite an identical visual input. Children with DD had lower accuracy and slower RTs for longer temporal intervals. Additionally, efficiency (combined accuracy and speed trade-off) increased as a function of age only in the DD group, most markedly for the integration condition. Results suggest that visual temporal processing deficits in DD may depend on short-term/working memory liability as well as the existence of possibly differentiated developmental trajectories for integration and segregation abilities.

Cortical layer-specific abnormalities in auditory responses in a mouse model of Fragile X Syndrome.

The inferior olivary nuclei (ION), a key component of the olivo-cerebellar system, remain understudied in autism spectrum disorder (ASD) research despite evident cerebellar involvement. This perspective piece aims to elucidate the critical role of the ION in cerebellar microcircuitry and its potential implications in ASD pathophysiology. We review the olivo- cerebellar system and the structural and functional alterations of the ION in autism, highlighting findings from neuroanatomical, neuroimaging, and behavioral studies. ION disruptions, although underexplored, may have a major role in the symptomatology of ASD, particularly higher-order cognitive abilities, rapid stimuli processing, and motor coordination. Specifically, we highlight how anomalies in olivary neuron morphology and olivo-cerebellar connectivity patterns may underlie deficits in temporal processing and motor learning observed in ASD. Furthermore, we discuss the challenges in brainstem imaging and recent advancements in ultra-high field (UHF) 7T MRI technology, as standard neuroimaging techniques. As these neuroimaging techniques continue to evolve, further investigation of the functional territories of the ION holds promise for providing essential understandings into ASD processes and may lead to pioneering therapeutic options targeting this crucial brainstem area.

The purpose of this study was to measure sensitivity to interaurally in-phase and out-of-phase frequency modulation (FM) using parallel behavioral and electrophysiological approaches. The broader goal was to apply these approaches to the assessment of age-related deficits in temporal fine-structure processing. The hypothesis was that the range of modulation rates over which FM detection is superior for out-of-phase modulation, as well as the magnitude of benefit, diminishes with age due to reduced fidelity of temporal fine-structure processing. Participants were 63 adults with good audiometric hearing for their age divided equally into 3 age groups of young (mean = 23 years), middle-aged (mean = 47 years), and older (mean = 70 years) listeners. FM detection thresholds for stimuli carried by a nominally 500-Hz tone were measured for interaurally in-phase and out-of-phase modulators having rates ranging from 4 to 32 Hz. The rationale for restricting carrier and modulator frequencies to low rates was to focus on the benefit provided by interaurally out-of-phase modulators as a gauge of temporal fine-structure processing. The electrophysiological acoustic change complex (ACC) was also measured in the same participants for a subset of these modulation rates where the depth of modulation was fixed at 3 Hz. The ACC was quantified using an intertrial phase coherence metric. For in-phase modulation, there was minimal change in FM detection threshold across the range of modulation rates, and no effects of age. For out-of-phase modulation, thresholds were markedly lower for low rates and increased (became poorer) monotonically as rate increased. For the 2 older age groups, thresholds for the 2 modulator phases converged by 32 Hz. Young participants performed consistently better than the participants in the 2 older groups for the out-of-phase configurations. The ACC was most robust for low-rate, out-of-phase modulation and diminished systematically as rate increased in all participants. No ACC was observed for the highest rate of 32 Hz. The older listeners had consistently poorer ACC responses across all rates. Correlations between behavioral and electrophysiological metrics were small, but significant, for rates of 8, 16, and 24 Hz. The results support the hypothesis of diminishing temporal fine-structure processing as a function of age. For behavioral FM detection, middle-age and older adults had poorer thresholds for out-of-phase FM than young adults, with functions for in- and out-of-phase FM converging at a lower rate. For the ACC test, this was demonstrated by reduced intertrial phase coherences in the older participants. Although there were general similarities between the behavioral and electrophysiological data patterns, some differences were observed, and further study is required to clarify underlying mechanism(s). The study broadly demonstrates that objective measures can be used to gauge temporal processing, in parallel to behavioral measures, and so can be applied in situations where subjective assessment is challenging.

Contour integration, the process of combining local visual fragments into coherent paths or shapes, is essential for visual perception. Although prior research on amblyopia has focused primarily on spatial domain deficits in contour integration, this study investigates how amblyopia affects contour integration over time and examines the relationship between temporal contour integration deficits and visual functions. Nineteen amblyopic children (mean age, 10.9 ± 2.4 years; 17 anisometropic, 2 anisometropic/strabismic mixed) and 26 visually normal children (mean age, 10.5 ± 1.8 years) participated in this study. Temporal contour integration was assessed by measuring the accuracy of detecting tilted contour paths, formed by collinear Gabor elements with similar orientations, under slit-viewing conditions. Performance was evaluated for amblyopic eyes (AEs) and fellow eyes (FEs) at two spatial frequencies (1.5 cpd and 3 cpd). The slit width, orientation jitter of contour elements, and stimulus movement speed were systematically varied across separate runs. Visual acuity and Randot stereoacuity were assessed before testing. AEs exhibited significant deficits in temporal contour processing compared with FEs. Specifically, AEs required larger slit widths to achieve performance levels comparable to FEs, with more severe amblyopia (i.e., worse AE visual acuity) necessitating even larger slit widths for temporal contour integration. Temporal contour integration deficits in AEs were most pronounced under conditions of complete Gabor collinearity or moderate stimulus movement speeds (6.4°/s). No significant differences were observed between FEs and control eyes. Notably, the temporal contour integration ability between the two eyes quantified as the AE/FE ratio of slit width thresholds showed no correlation with interocular acuity differences, stereoacuity, or spatial contour integration deficits. Amblyopic children demonstrate significant deficits in temporal contour integration in AEs, which seem to be independent of spatial contour integration deficits. The severity of these temporal deficits increases with worse AE visual acuity. These findings suggest that amblyopia is associated with temporal deficits in visual integration, in addition to the well-documented spatial deficits, highlighting the need for a more comprehensive understanding of amblyopic visual processing.

Temporal processing abilities are crucial for encoding auditory information. These abilities decline with age, particularly impacting the ability to perceive brief temporal cues. Furthermore, age-related temporal processing deficits appear to be particularly detrimental for speech processing with degraded auditory input, such as that experienced by cochlear implant users. First, we hypothesized that reducing spectral information in speech would negatively impact temporal processing, with older listeners showing greater deficits. Twenty-two normal-hearing listeners, aged 20–70 years, completed temporal cue discrimination tasks involving silent interval duration using the stimuli dish versus ditch and gap detection tasks using vocoded speech. Results showed that the 50% crossover point for vocoded speech was about 5 ms later for older compared to younger listeners. Second, we hypothesized the individual variability in speech discrimination performance would correlate with gap detection thresholds. Results showed listeners with steeper word discrimination slopes also had better gap detection thresholds for the vocoded stimuli. These results emphasize the role of temporal processing in understanding speech with degraded spectral cues.

This study examined how age, stimulus degradation, and sentence context affect sensitivity to speech temporal cues. Adults aged 20-72 with self-reported normal hearing completed a phonemic categorization task using unprocessed and 8-channel vocoded (simulating stimulus degradation in cochlear implants) versions of a dent/tent contrast with varying voice-onset times. Target words were embedded in sentences biased toward "dent" or "tent," or presented in a neutral context. Advancing age reduced voice-onset time sensitivity regardless of sentence context, although this effect was less pronounced for vocoded stimuli. These results suggest that age-related temporal processing deficits may be unaffected by top-down linguistic influences.

BackgroundFragile X syndrome (FXS) is a leading known genetic cause of intellectual disability and autism spectrum disorders (ASD)-associated behaviors. A consistent and debilitating phenotype of FXS is auditory hypersensitivity that may lead to delayed language and high anxiety. Consistent with findings in FXS human studies, the mouse model of FXS, the Fmr1 knock out (KO) mouse, shows auditory hypersensitivity and temporal processing deficits. In electroencephalograph (EEG) recordings from humans and mice, these deficits manifest as increased N1 amplitudes in event-related potentials (ERP), increased gamma band single trial power (STP) and reduced phase locking to rapid temporal modulations of sound. In our previous study, we found that administration of the selective serotonin-1 A (5-HT1A)receptor biased agonist, NLX-101, protected Fmr1 KO mice from auditory hypersensitivity-associated seizures. Here we tested the hypothesis that NLX-101 will normalize EEG phenotypes in developing Fmr1 KO mice.MethodsTo test this hypothesis, we examined the effect of NLX-101 on EEG phenotypes in male and female wildtype (WT) and Fmr1 KO mice. Using epidural electrodes, we recorded auditory event related potentials (ERP) and auditory temporal processing with a gap-in-noise auditory steady state response (ASSR) paradigm at two ages, postnatal (P) 21 and 30 days, from both auditory and frontal cortices of awake, freely moving mice, following NLX-101 (at 1.8 mg/kg i.p.) or saline administration.ResultsSaline-injected Fmr1 KO mice showed increased N1 amplitudes, increased STP and reduced phase locking to auditory gap-in-noise stimuli versus wild-type mice, reproducing previously published EEG phenotypes. An acute injection of NLX-101 did not alter ERP amplitudes at either P21 or P30, but significantly reduces STP at P30. Inter-trial phase clustering was significantly increased in both age groups with NLX-101, indicating improved temporal processing. The differential effects of serotonin modulation on ERP, background power and temporal processing suggest different developmental mechanisms leading to these phenotypes.ConclusionsThese results suggest that NLX-101 could constitute a promising treatment option for targeting post-synaptic 5-HT1A receptors to improve auditory temporal processing, which in turn may improve speech and language function in FXS.

Atypical oscillatory and aperiodic signatures of visual sampling in developmental dyslexia

Children with temporal processing deficits struggle to detect and discriminate syllables, phonemes, and stress patterns in speech. To overcome these deficits, computer-based auditory training programs have been widely used as one of the rehabilitation alternatives in recent years. The present study aimed to examine the usefulness of one such computer-based temporal processing training (CBTPT) module on children with temporal processing deficits. Sixteen children (8-15years) with temporal processing deficits were enrolled in the study, further divided into active (CBTPT) and placebo (placebo training) groups. Further, 8 typically developing children (no training) were enrolled as a comparison group. The auditory outcome measures included Duration Pattern Test (DPT), Gap Detection Test (GDT), Dichotic CV (DCV), and Speech-in-Noise-Indian English (SPIN-IE) assessed before and after training for all three groups. Wilcoxon-sign rank test showed a statically significant difference between pre and post-test scores of DPT, GDT, and SPIN (p < 0.001) except DCV among the active group. However, no significant differences were noted in the pre and post-test scores among the placebo and TD groups. Mann Whitney U test showed a significant difference in DPT and SPIN post-training scores between active and placebo groups; active and TD group; placebo and TD group. From the above finding, it is inferred that the CBTPT module is useful among children having temporal processing deficits.

Altered sensory processing especially in the auditory system is considered a typical observation in children with autism spectrum disorder (ASD). Auditory temporal processing is known to be impaired in ASD children. Although research suggests that auditory temporal processing abnormalities could be responsible for the core aspects of ASD, few studies have examined early time processing and their results have been conflicting. The present event-related potential (ERP) study investigated the early neural responses to duration and inter-stimulus interval (ISI) deviants in nonspeech contexts in children with ASD and a control group of typically developing (TD) children matched in terms of age and IQ. A passive auditory oddball paradigm was employed to elicit the mismatch negativity (MMN) for change detection considering both the duration and ISI-based stimulus. The MMN results showed that the ASD group had a relatively diminished amplitude and significant delayed latency in response to duration deviants. The findings are finally discussed in terms of hyper-hyposensitivity of auditory processing and the fact that the observed patterns may potentially act as risk factors for ASD development within the research domain criteria (RDoC) framework.

Developmental trajectory and sex differences in auditory processing in a PTEN-deletion model of autism spectrum disorders

This study aimed to investigate the effects of amateur choir experience on “forced-attention” dichotic listening performance in older adults. Twenty older adults with choir experience and 20 without such experience were recruited, along with a group of 20 younger adults as the baseline. Participants were instructed to complete the dichotic listening task based on consonant-vowel (CV) syllables in four attentional conditions, that is, non-forced, forced-left, forced-right, and divided attention conditions. The results showed that choir experience may offset age-related deficits in temporal processing, inhibitory control, and divided attention in the non-forced, forced-left, and divided attention conditions, respectively. But in the forced-right condition where the orienting process was required, two groups of older adults performed similarly, comparable with the younger group. Our findings support the OPERA-e hypothesis and underscore the effects of amateur musical activities against declines in temporal processing, inhibitory control, and divided attention in aging populations.

Loss of synapses between spiral ganglion neurons and inner hair cells (IHC synaptopathy) leads to an auditory neuropathy called hidden hearing loss (HHL) characterized by normal auditory thresholds but reduced amplitude of sound-evoked auditory potentials. It has been proposed that synaptopathy and HHL result in poor performance in challenging hearing tasks despite a normal audiogram. However, this has only been tested in animals after exposure to noise or ototoxic drugs, which can cause deficits beyond synaptopathy. Furthermore, the impact of supernumerary synapses on auditory processing has not been evaluated. Here, we studied mice in which IHC synapse counts were increased or decreased by altering neurotrophin 3 (Ntf3) expression in IHC supporting cells. As we previously showed, postnatal Ntf3 knockdown or overexpression reduces or increases, respectively, IHC synapse density and suprathreshold amplitude of sound-evoked auditory potentials without changing cochlear thresholds. We now show that IHC synapse density does not influence the magnitude of the acoustic startle reflex or its prepulse inhibition. In contrast, gap-prepulse inhibition, a behavioral test for auditory temporal processing, is reduced or enhanced according to Ntf3 expression levels. These results indicate that IHC synaptopathy causes temporal processing deficits predicted in HHL. Furthermore, the improvement in temporal acuity achieved by increasing Ntf3 expression and synapse density suggests a therapeutic strategy for improving hearing in noise for individuals with synaptopathy of various etiologies.

Objective:Children with hearing loss experience greater difficulty understanding speech in the presence of noise and reverberation relative to their normal hearing peers despite provision of appropriate amplification. The fidelity of fundamental frequency of voice (f0) encoding—a salient temporal cue for understanding speech in noise—could play a significant role in explaining the variance in abilities among children. However, the nature of deficits in f0 encoding and its relationship with speech understanding are poorly understood. To this end, we evaluated the influence of frequency-specific f0 encoding on speech perception abilities of children with and without hearing loss in the presence of noise and/or reverberation.Methods:In 14 school-aged children with sensorineural hearing loss fitted with hearing aids and 29 normal hearing peers, envelope following responses (EFRs) were elicited by the vowel /i/, modified to estimate f0 encoding in low (<1.1 kHz) and higher frequencies simultaneously. EFRs to /i/ were elicited in quiet, in the presence of speech-shaped noise at +5 dB signal to noise ratio, with simulated reverberation time of 0.62 sec, as well as both noise and reverberation. EFRs were recorded using single-channel electroencephalogram between the vertex and the nape while children watched a silent movie with captions. Speech discrimination accuracy was measured using the University of Western Ontario Distinctive Features Differences test in each of the four acoustic conditions. Stimuli for EFR recordings and speech discrimination were presented monaurally.Results:Both groups of children demonstrated a frequency-dependent dichotomy in the disruption of f0 encoding, as reflected in EFR amplitude and phase coherence. Greater disruption (i.e., lower EFR amplitudes and phase coherence) was evident in EFRs elicited by low frequencies due to noise and greater disruption was evident in EFRs elicited by higher frequencies due to reverberation. Relative to normal hearing peers, children with hearing loss demonstrated: (a) greater disruption of f0 encoding at low frequencies, particularly in the presence of reverberation, and (b) a positive relationship between f0 encoding at low frequencies and speech discrimination in the hardest listening condition (i.e., when both noise and reverberation were present).Conclusions:Together, these results provide new evidence for the persistence of suprathreshold temporal processing deficits related to f0 encoding in children despite the provision of appropriate amplification to compensate for hearing loss. These objectively measurable deficits may underlie the greater difficulty experienced by children with hearing loss.

Advancing age is associated with decreased sensitivity to temporal cues in word segments, particularly when target words follow non-informative carrier sentences or are spectrally degraded (e.g., vocoded to simulate cochlear-implant stimulation). This study investigated whether age, carrier sentences, and spectral degradation interacted to cause undue difficulty in processing speech temporal cues. Younger and older adults with normal hearing performed phonemic categorization tasks on two continua: a Buy/Pie contrast with voice onset time changes for the word-initial stop and a Dish/Ditch contrast with silent interval changes preceding the word-final fricative. Target words were presented in isolation or after non-informative carrier sentences, and were unprocessed or degraded via sinewave vocoding (2, 4, and 8 channels). Older listeners exhibited reduced sensitivity to both temporal cues compared to younger listeners. For the Buy/Pie contrast, age, carrier sentence, and spectral degradation interacted such that the largest age effects were seen for unprocessed words in the carrier sentence condition. This pattern differed from the Dish/Ditch contrast, where reducing spectral resolution exaggerated age effects, but introducing carrier sentences largely left the patterns unchanged. These results suggest that certain temporal cues are particularly susceptible to aging when placed in sentences, likely contributing to the difficulties of older cochlear-implant users in everyday environments.

BackgroundAutism spectrum disorder (ASD) is currently diagnosed in approximately 1 in 44 children in the United States, based on a wide array of symptoms, including sensory dysfunction and abnormal language development. Boys are diagnosed ~ 3.8 times more frequently than girls. Auditory temporal processing is crucial for speech recognition and language development. Abnormal development of temporal processing may account for ASD language impairments. Sex differences in the development of temporal processing may underlie the differences in language outcomes in male and female children with ASD. To understand mechanisms of potential sex differences in temporal processing requires a preclinical model. However, there are no studies that have addressed sex differences in temporal processing across development in any animal model of ASD.MethodsTo fill this major gap, we compared the development of auditory temporal processing in male and female wildtype (WT) and Fmr1 knock-out (KO) mice, a model of Fragile X Syndrome (FXS), a leading genetic cause of ASD-associated behaviors. Using epidural screw electrodes, we recorded auditory event related potentials (ERP) and auditory temporal processing with a gap-in-noise auditory steady state response (ASSR) paradigm at young (postnatal (p)21 and p30) and adult (p60) ages from both auditory and frontal cortices of awake, freely moving mice.ResultsThe results show that ERP amplitudes were enhanced in both sexes of Fmr1 KO mice across development compared to WT counterparts, with greater enhancement in adult female than adult male KO mice. Gap-ASSR deficits were seen in the frontal, but not auditory, cortex in early development (p21) in female KO mice. Unlike male KO mice, female KO mice show WT-like temporal processing at p30. There were no temporal processing deficits in the adult mice of both sexes.ConclusionsThese results show a sex difference in the developmental trajectories of temporal processing and hypersensitive responses in Fmr1 KO mice. Male KO mice show slower maturation of temporal processing than females. Female KO mice show stronger hypersensitive responses than males later in development. The differences in maturation rates of temporal processing and hypersensitive responses during various critical periods of development may lead to sex differences in language function, arousal and anxiety in FXS.

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].