Speech-evoked Auditory Brainstem Response Research Articles

My Perspective: Auditory Evoked Potentials Using Speech

Purpose: The purpose of this tutorial is to clarify the use of speech sounds as stimuli for auditory evoked potentials and how these might contribute to our understanding of speech, language, learning, and hearing disorders. Speech-evoked auditory brainstem responses (ABRs), auditory steady-state responses, auditory middle latency responses, mismatch negativity, P300, cortical onset responses, and the acoustic change complex are reviewed. Method: The author drew upon her scholarship in this area from over 4 decades of research and teaching to summarize the major findings when using speech stimuli to evoke auditory potentials that have been used in clinical contexts. Results: Speech-evoked auditory potentials contribute to our understanding of how the brain processes the acoustic features of speech sounds, providing information that is complementary to psychophysical tests. When psychophysical tests cannot be performed owing to neurodevelopmental immaturity or disability, or cognitive disability, speech-evoked auditory potentials may be used to estimate the benefit of amplification or implantation for speech, language, and hearing. Conclusions: The benefit of using auditory evoked potentials for evaluation is that they provide insight into the brain mechanisms underlying hearing and listening disorders that audiologists aim to treat. While we can use the known correlations between perceptual and electrophysiological responses for “cross-checking” our evaluation results, examining when discrepancies occur is also especially meaningful. For example, the complex ABR reveals subcortical issues in temporal processing that would not be evident in ABRs to clicks or tone bursts, nor in behavioral testing. P300 can document slower neural processing of speech stimuli that may be relevant to the rehabilitation of older adults, even when word recognition scores appear to be congruent with the pure-tone audiogram. In these ways, auditory evoked potentials for speech provide audiologists with tools for demonstrating to clients how their brain responds to speech and opening the conversation for rehabilitation.

Can auditory evoked responses elicited to click and/or verbal sound identify children with or at risk of central auditory processing disorder: A scoping review.

(Central) auditory processing disorders, (C)APDs are clinically identified using behavioral tests. However, changes in attention and motivation may easily affect true identification. Although auditory electrophysiological tests, such as Auditory Brainstem Responses (ABR), are independent of most confounding cognitive factors, there is no consensus that click and/or speech-evoked ABR can be used to identify children with or at-risk of (C)APDs due to heterogeneity among studies. This study aimed to review the possibility of using ABR evoked by click and/or speech stimuli to identify children with or at risk of (C)APDs. The online databases of PubMed, Web of Science, Medline, Embase, and CINAHL were explored using combined keywords for all English and French articles published until April 2021. Additional gray literature was also included such as conference abstracts, dissertations, and editorials in ProQuest Dissertations. Thirteen papers met the eligibility criteria and were included in the scoping review. Fourteen papers were cross-sectional and two were interventional studies. Eleven papers used click stimuli to assess children with/at risk of (C)APDs, and speech stimuli were utilized in the remaining studies. Despite the diversity of the results, especially in click ABR assessments, most studies indicated increases in the wave latencies and/or decreases in the wave amplitudes of click ABR in children with/at risk of (C)APDs. The results of speech ABR assessments were more consistent, as prolongation of the transient components of speech ABR was observed in these children, while sustained components remained almost unchanged. Although both click and speech-evoked ABRs could be used to assess children with (C)APDs, it appears that speech-evoked ABR assessments yield more reliable findings. These findings, however, should be interpreted with caution given the heterogeneity among studies. Well-designed studies on children with confirmed (C)APDs using standard diagnostic and assessment protocols are recommended.

Features of Cognitive Ability and Central Auditory Processing of Preschool Children With Minimal and Mild Hearing Loss.

This study aimed to investigate the current status of cognitive development and central auditory processing development of preschool children with minimal and mild hearing loss (MMHL) in Nanjing, China. We recruited 34 children with MMHL and 45 children with normal hearing (NH). They completed a series of tests, including cognitive tests (i.e., Wechsler Preschool and Primary Scale of Intelligence and Continuous Performance Test), behavioral auditory tests (speech-in-noise [SIN] test and frequency pattern test), and objective electrophysiological audiometry (speech-evoked auditory brainstem response and cortical auditory evoked potential). In addition, teacher evaluations and demographic information and questionnaires completed by parents were collected. Regarding cognitive ability, statistical differences in the verbal comprehensive index, full-scale intelligence quotient, and abnormal rate of attention test score were found between the MMHL group and the NH group. The children with MMHL performed poorer on the SIN test than the children with NH. As for the auditory electrophysiology of the two groups, the latency and amplitude of some waves of the speech-evoked auditory brainstem response and cortical auditory evoked potential were statistically different between the two groups. We attempted to explore the relationship between some key indicators of auditory processing and some key indicators of cognitive development. Children with MMHL are already at increased developmental risk as early as preschool. They are more likely to have problems with attention and verbal comprehension than children with NH. This condition is not compensated with increasing age during the preschool years. The results suggest a possible relationship between the risk of cognitive deficit and divergence of auditory processing. https://doi.org/10.23641/asha.22670473.

Effects of Unilateral Hearing Loss on Speech-Evoked Auditory Brainstem Responses and Reading: A Preliminary Study.

The purpose of this study was to determine whether the speech-evoked auditory brainstem responses (sABRs) obtained by stimulating the ear with normal sensitivity in children with unilateral hearing loss (UHL) were different from that of children with normal hearing (NH), and to explore correlations between the sABR findings and measures of reading. Eleven children with UHL and 11 children with NH were tested via the BioMARK sABR protocol using the syllable /da/; latency and amplitudes of Waves V, A, C, D, E, F, and O were measured. Participants also were tested on the Phonemic Synthesis Test (PST) and the Woodcock Reading Mastery Test-Revised (WRMT-R), particularly the Reading Readiness, Basic Skills, and Comprehension subtests. Multivariate analysis of variance testing showed a significantly higher amplitude for Wave A for the NH group as compared to the UHL group. Separate ANOVAs also found significantly lower scores for the UHL group compared to the NH group on Basic Skills and Comprehension subtests of the Woodcock. Significant positive Spearman rho correlations were found for the UHL group between wave amplitudes for V, A, and O and the Reading Readiness score, and between wave amplitudes for V, A, D, and O and the Reading Comprehension score. A significant correlation also was found between the Total Reading score and wave amplitudes for V and A. No such correlations were found between wave amplitude and Woodcock scores for the NH group. Further testing of the UHL data found significant relationships between the pure-tone average of the hearing loss ear and the Basic Skills, Comprehension, and Total Reading scores from the WRMT-R. There was also a significant correlation between the PST score and Wave C amplitude. There may be a connection between speech encoding and measures of reading in children with UHL.

The Relationship between Contralateral Suppression of Transient Evoked Otoacoustic Emission and Unmasking of Speech Evoked Auditory Brainstem Response

Introduction Several studies have shown that efferent pathways of the auditory system improve perception of speech-in-noise. But, the majority of investigations assessing the role of efferent pathways on speech perception have used contralateral suppression of otoacoustic emissions as a measure of efferent activity. By studying the effect of efferent activity on the speech-evoked auditory brainstem response (ABR), some more light could be shed on the effect of efferent pathways on the encoding of speech in the auditory pathway. Objectives To investigate the relationship between contralateral suppression of transient evoked otoacoustic emission (CSTEOAE) and unmasking of speech ABR. Methods A total of 23 young adults participated in the study. The CSTEOAE was measured using linear clicks at 60 dB peSPL and white noise at 60 dB sound pressure level (SPL). The speech ABR was recorded using the syllable /da/ at 80 dB SPL in quiet, ipsilateral noise, and binaural noise conditions. In the ipsilateral noise condition, white noise was presented to the test ear at 60 dB SPL, and, in the binaural noise condition, two separate white noises were presented to both ears. Results The F0 amplitude of speech ABR was higher in quiet condition; however, the mean amplitude of F0 was not significantly different across conditions. Correlation analysis showed a significant positive correlation between the CSTEOAE and the magnitude of unmasking of F0 amplitude of speech ABR. Conclusions The findings of the present study suggests that the efferent pathways are involved in speech-in-noise processing.

Effects of Spectral Shaping on Speech Auditory Brainstem Responses to Stop Consonant-Vowel Syllables.

Spectral shaping is employed by hearing aids to make consonantal information, such as formant transitions, audible for listeners with hearing loss. How manipulations of the stimuli, such as spectral shaping, may alter encoding in the auditory brainstem has not been thoroughly studied. The aim of this study was to determine how spectral shaping of synthetic consonant-vowel (CV) syllables, varying in their second formant (F2) onset frequency, may affect encoding of the syllables in the auditory brainstem. We employed a repeated measure design. Sixteen young adults (mean = 20.94 years, 6 males) and 11 older adults (mean = 58.60 years, 4 males) participated in this study. Speech-evoked auditory brainstem responses (speech-ABRs) were obtained from each participant using three CV exemplars selected from synthetic stimuli generated for a /ba-da-ga/ continuum. Brainstem responses were also recorded to corresponding three CV exemplars that were spectrally shaped to decrease low-frequency information and provide gain for middle and high frequencies according to a Desired Sensation Level function. In total, six grand average waveforms (3 phonemes [/ba/, /da/, /ga/] X 2 shaping conditions [unshaped, shaped]) were produced for each participant. Peak latencies and amplitudes, referenced to prestimulus baseline, were identified for 15 speech-ABR peaks. Peaks were marked manually using the program cursor on each individual waveform. Repeated-measures analysis of variances were used to determine the effects of shaping on the latencies and amplitudes of the speech-ABR peaks. Shaping effects produced changes within participants in ABR latencies and amplitudes involving onset and major peaks of the speech-ABR waveform for certain phonemes. Specifically, data from onset peaks showed that shaping decreased latency for /ga/ in older listeners, and decreased amplitude onset for /ba/ in younger listeners. Shaping also increased the amplitudes of major peaks for /ga/ stimuli in both groups. Encoding of speech in the ABR waveform may be more complex and multidimensional than a simple demarcation of source and filter information, and may also be influenced by cue intensity and age. These results suggest a more complex subcortical encoding of vocal tract filter information in the ABR waveform, which may also be influenced by cue intensity and age.

Exosomes derived from cochlear spiral ganglion progenitor cells prevent cochlea damage from ischemia-reperfusion injury via inhibiting the inflammatory process.

Ischemia-reperfusion injury (I/R)-induced inflammatory process can mediate cochlea damage-related hearing loss; whether cochlear spiral ganglion progenitor cell-derived exosomes (CSGPC-exos) play a protective role by carrying functional microRNAs into recipient cells is unknown. Different doses of CSGPC-exos (0.1μg/μl, 0.2μg/μl, 0.5μg/μl, 1.0μg/μl) were administrated into the cochleae of the I/R group induced with 30-min occlusion of the bilateral vertebral arteries and sham surgery group. The speech-evoked auditory brainstem response (ABR) test was utilized to estimate the auditory threshold shift. The relative expression of proinflammatory cytokines was detected with RT-PCR and Western blot, while parvalbumin and caspase-3 expression were detected by immunofluorescence staining in the cochleae. The relative expression of microRNAs (miR-21-5p, miR-26a-5p, and miR-181a-5p) was detected in the cochleae. I/R significantly up-regulated ABR threshold shift and promoted hair cell apoptosis indicated by parvalbumin and caspase-3 staining, while CSGPC-exos (0.5μg/μl, 1.0μg/μl) could diminish such damages with downregulated proinflammatory factors (IL-6, IL-1β, TNF-α, and Cox-2) and upregulated anti-inflammatory miRNAs (miR-21-5p, miR-26a-5p, and miR-181a-5p) expression in the cochleae. CSGPC-exos could protect cochleae damage from I/R, probably via inhibiting the inflammatory process.

Dysfunction of the Auditory Brainstem as a Neurophysiology Subtype of Autism Spectrum Disorder.

Autism spectrum disorder (ASD) is very heterogeneous, particularly in language. Studies have suggested that language impairment is linked to auditory-brainstem dysfunction in ASD. However, not all ASD children have these deficits, which suggests potential subtypes of ASD. We classified ASD children into two subtypes according to their speech-evoked auditory brainstem response (speech-ABR) and explored the neural substrates for possible subtypes. Twenty-nine children with ASD and 25 typically developing (TD) peers were enrolled to undergo speech-ABR testing and structural magnetic resonance imaging (sMRI). There were significant differences between the ASD group and TD group in surface area, cortical volume and cortical thickness. According to speech-ABR results, ASD participants were divided into the ASD-typical (ASD-T) group and ASD-atypical (ASD-A) group. Compared with the ASD-T group, the ASD-A group had a lower score in language of the Gesell Developmental Diagnosis Scale (GDDS), increased left rostral middle frontal gyrus (lRMFG) area and decreased local gyrification index of the right superior temporal gyrus. GDDS-language and surface area of lRMFG were correlated to the wave-A amplitude in ASD. Surface area of lRMFG had an indirect effect on language performance via alteration of the wave-V amplitude. Thus, cortical deficits may impair language ability in children with ASD by causing subcortical dysfunction at preschool age. These evidences support dysfunction of the auditory brainstem as a potential subtype of ASD. Besides, this subtype-based method may be useful for various clinical applications.

Speech in Noise Ability in Patients with Central Auditory Processing Disorders (CAPDs)

Background: Central auditory processing disorders (CAPDs) tend to affect an individual’s ability to understand speech, especially in difficult listening conditions.Objective: To study speech-in-noise (SIN) ability in cases of central auditory processing disorders (CAPDs) subjectively by Arabic Hearing in Noise Test (A-HINT) and objectively by Speech-evoked auditory brainstem response (S-ABR) with ipsilateral noise.Patients and Methods: Subjects included in this study will be divided into 2 groups: a control group which included 30 normal hearing subjects (17 males and 13 females). Their age ranged from 6 to 17 years. All subjects had normal developmental milestones and normal speech development. The Study group included 30 normal hearing subjects (18 males and 12 females). Their age ranged from 7 to 16 years. These subjects had central auditory processing disorders (CAPDs) diagnosed by central auditory screening tests. Both groups were tested using Arabic HINT and Speech-evoked auditory brainstem response (S-ABR) with ipsilateral noise.Results: Comparison between control and study groups as regards the Arabic HINT revealed statistically significant differences in noise conditions. Using S-ABR significant difference was found in onset and offset response waves latency in noise conditions also.Conclusion: Patients with CAPDs have speech in noise ability affection proved by affected HINT in noise conditions and by delayed S- ABR with ipsilateral noise latencies in onset- offset responses.

Comparisons of Auditory Brainstem Responses Between a Laboratory and Simulated Home Environment.

Purpose Miniaturization of digital technologies has created new opportunities for remote health care and neuroscientific fieldwork. The current study assesses comparisons between in-home auditory brainstem response (ABR) recordings and recordings obtained in a traditional lab setting. Method Click-evoked and speech-evoked ABRs were recorded in 12 normal-hearing, young adult participants over three test sessions in (a) a shielded sound booth within a research lab, (b) a simulated home environment, and (c) the research lab once more. The same single-family house was used for all home testing. Results Analyses of ABR latencies, a common clinical metric, showed high repeatability between the home and lab environments across both the click-evoked and speech-evoked ABRs. Like ABR latencies, response consistency and signal-to-noise ratio (SNR) were robust both in the lab and in the home and did not show significant differences between locations, although variability between the home and lab was higher than latencies, with two participants influencing this lower repeatability between locations. Response consistency and SNR also patterned together, with a trend for higher SNRs to pair with more consistent responses in both the home and lab environments. Conclusions Our findings demonstrate the feasibility of obtaining high-quality ABR recordings within a simulated home environment that closely approximate those recorded in a more traditional recording environment. This line of work may open doors to greater accessibility to underserved clinical and research populations.

Click-evoked and speech-evoked auditory brainstem responses from individuals with multiple sclerosis

PurposeTo determine whether speech-evoked auditory brainstem response (ABR) is more sensitive to the effects of multiple sclerosis (MS) than click-evoked ABR. Materials and MethodsEleven previously-confirmed MS patients (8 females, 3 males) and nine controls (7 females, 2 males), matched in age and gender, participated in a repeated-measures design. Stimuli were presented monaurally to the right ear via insert earphone. All evoked potential responses were collected by a single-channel montage where three electrodes were placed on the center of the head (Cz: non-inverting/ active), the ipsilateral earlobe (inverting/ reference) and the contralateral earlobe (ground). Rarefaction clicks of 0.1 ms duration were presented at rates of 13.30 and 91.1 clicks per second. Speech-evoked ABRs were obtained using the BioMARK software and the Bio-Logic Navigator PRO hardware. A synthesized /da/ syllable of 40-ms duration was presented via alternating polarity and at a rate of 10.9 stimuli per second. Stimuli were presented at 80 dB SPL. Speech-evoked ABR responses were obtained in quiet and in noise. ResultsConventional click ABR responses were absent more often at high presentation rates in control subjects than in MS patients. Speech-evoked ABR peak amplitudes, wave E latency and VA complex slope variables separated the MS patients from controls. Group differences were also found in speech-evoked ABR response correlations in quiet versus noise conditions. ConclusionsThe speech-evoked ABR is as or more sensitive to MS than conventional ABR measures without resort to simply noting missing peaks. Comparison of speech-evoked ABR responses in quiet and in noise highlight loss of neural synchrony in MS.

Auditory Processing in Children with Specific Language Impairment: A FFR Based Study.

Specific language impairment (SLI) is diagnosed when a child has difficulty in producing or understanding spoken language for no apparent reason. The study attempted to assess the sub-cortical encoding in children with SLI using speech-evoked auditory brainstem response (ABR). The objective of the study was to compare the amplitude and latency of the frequency following response (FFR) parameters between the children with SLI and typically developing children. The frequency following response was recorded using/da/stimuli from ten ears of children diagnosed with SLI. The amplitude and the latencies of the different peaks of FFR in children with SLI were compared with those of typically developing children. The results of the study showed that the latencies of wave C and D were significantly prolonged in children with SLI compared to typically developing children. The waveforms obtained from the typically developing (TD) children were clearer and easily identifiable, with larger negativity observed in the troughs. The waveform morphology was poorer in children with SLI with shallower peaks. Thus, it can be concluded that speech evoked ABR gives an insight into the auditory processing ability of children with SLI. It indicates that signal processing in the auditory pathway of children with SLI is temporally distorted and which might affect the development of language.

Effects of Aging on the Subcortical Encoding of Stop Consonants.

Purpose The main purpose of this study was to evaluate aging effects on the predominantly subcortical (brainstem) encoding of the second-formant frequency transition, an essential acoustic cue for perceiving place of articulation. Method Synthetic consonant-vowel syllables varying in second-formant onset frequency (i.e., /ba/, /da/, and /ga/ stimuli) were used to elicit speech-evoked auditory brainstem responses (speech-ABRs) in 16 young adults (M age = 21 years) and 11 older adults (M age = 59 years). Repeated-measures mixed-model analyses of variance were performed on the latencies and amplitudes of the speech-ABR peaks. Fixed factors were phoneme (repeated measures on three levels: /b/ vs. /d/ vs. /g/) and age (two levels: young vs. older). Results Speech-ABR differences were observed between the two groups (young vs. older adults). Specifically, older listeners showed generalized amplitude reductions for onset and major peaks. Significant Phoneme × Group interactions were not observed. Conclusions Results showed aging effects in speech-ABR amplitudes that may reflect diminished subcortical encoding of consonants in older listeners. These aging effects were not phoneme dependent as observed using the statistical methods of this study.

Impact of hearing aid noise reduction algorithms on the speech-evoked auditory brainstem response

The purposes of this study are to investigate the neural representation of a speech stimulus in the auditory system of individuals with normal hearing (NH) and those with hearing aids (HAs) and to explore the impact of noise reduction algorithms (NR) on auditory brainstem response to complex sounds (cABR). Twenty NH individuals and 28 HA users completed puretone audiometry, the Korean version of the Hearing in Noise Test (K-HINT), and cABR. In 0 and +5 dB signal-to-noise ratios (SNRs), the NH group was tested in /da/ only (quiet) and /da/ with white noise (WN) conditions while the HA group was tested in /da/ only, /da/ WN, /da/ WN NR ON, and /da/ WN NR OFF conditions. Significant differences were observed between /da/ only and /da/ WN conditions for F0 in both groups, but no SNR effect was observed for both groups. Findings of this study are consistent with previous literature that diminished cABR amplitudes indicate reduced representation of sounds in the auditory system. This is the first to examine the effect of a specific HA feature on cABR responses.

Speech-evoked auditory brainstem response; electrophysiological evidence of upper brainstem facilitative role on sound lateralization in noise.

Sound lateralization/localization is one of the most important auditory processing abilities, which plays approved role in auditory streaming and speech perception in challenging situations like noisy places. In addition to the main role of lower brainstem centers like superior olivary complex in sound lateralization, efferent auditory system effects on improving auditory skills in everyday auditory challenging positions were revealed. This study evaluated noise effects on lateralization scores in correlation with an objective electrophysiologic test (Speech-ABR in noise), which objectively shows cumulative effects of the afferent and efferent auditory systems at the inferior colliculus and upper brainstem pathway. Fourteen normal-hearing subjects in the age range of 18 to 25 participated in this study. Lateralization scores in the quiet and noisy modes were evaluated. Speech-ABR in both ears for quiet mode and three different contralateral noise levels (SNR = + 5, 0, - 5) were recorded, too. Correlation of lateralization scores and Speech-ABR changes in noise was studied. Significant decrease of lateralization scores with latency increase and amplitude decrease of Speech-ABR transient peaks (V, A, O) was seen with noise presentation. A high positive correlation between lateralization decrease with latency increase of onset peaks (V, A) and amplitude decrease of transient peaks (V, A, O) was found in low signal-to-noise ratios. The study revealed that in high challenging auditory situations like auditory lateralization in noise, upper brainstem centers and pathways play a facilitative role for main auditory lateralization centers in lower levels.

The Role of Cognition in Common Measures of Peripheral Synaptopathy and Hidden Hearing Loss

Purpose The aim of this study was to quantify the portion of variance in several measures suggested to be indicative of peripheral noise-induced cochlear synaptopathy and hidden hearing disorder that can be attributed to individual cognitive capacity. Method Regression and relative importance analysis was used to model several behavioral and physiological measures of hearing in 32 adults ranging in age from 20 to 74 years. Predictors for the model were hearing sensitivity and performance on a number of cognitive tasks. Results There was a significant influence of cognitive capacity on several measures of cochlear synaptopathy and hidden hearing disorder. These measures include frequency modulation detection threshold, time-compressed word recognition in quiet and reverberation, and the strength of the frequency-following response of the speech-evoked auditory brainstem response. Conclusions Measures of hearing that involve temporal processing are significantly influenced by cognitive abilities, specifically, short-term and working memory capacity, executive function, and attention. Research using measures of temporal processing to diagnose peripheral disorders, such as noise-induced synaptopathy, need to consider cognitive influence even in a young, healthy population.

Speech-ABR in contralateral noise: A potential tool to evaluate rostral part of the auditory efferent system

In parallel with the auditory afferent system, the auditory efferent system is active in all parts of the auditory pathways from auditory cortex to the cochlea. The auditory efferent system has two main segments: the rostral and the caudal parts. The rostral part, which starts from the cortical centers to thalamic nuclei and continues into collicular pathways in rostral brainstem, which sends its neural fibers to the main collicular nuclei especially inferior colliculus. The caudal part includes the olivocochlear bundle, which originates from the superior olivary complex and terminates on the cochlear hair cells. Most studies about the auditory efferent system have focused only on the caudal part using otoacoustic emission suppression test. Speech-evoked auditory brainstem response (S-ABR) as an electrophysiologic test that uses speech stimuli to simulate real-life auditory conditions, reflects the performance of rostral brainstem centers, so structurally seems to be an appropriate candidate to examine the rostral part of the auditory efferent system. Our hypothesis is that S-ABR in noisy condition, a typical condition for stimulating the auditory efferent system, has the potential to be used as an objective noninvasive electrophysiologic test for studying the rostral auditory efferent system in diagnosis and treatment/rehabilitation follow-ups. In addition, S-ABR can potentially reflect higher-order auditory functions and the effects of their dysfunctions on the lower brainstem. This characteristic makes S-ABR even more suitable tool for evaluation of the efferent system. To evaluate our hypothesis, Eighteen normal hearing subjects in the age range of 18–25 were tested in a pilot study for S-ABR in quiet mode and three signal to noise ratios of +10,0 and −10 for both ears. Then we checked the correlation between the results of S-ABR in different conditions and scores of auditory behavioral tests that auditory efferent system is involved in them: Consonant-Vowel perception in noise, dichotic Consonant-Vowel-Consonant and sound lateralization in noise. The results of our pilot study showed a significant correlation between S-ABR changes in noise with the scores of the behavioral tests in noisy or dichotic situations. Findings of the current study suggest that S-ABR with specific contralateral noise can be an appropriate option for evaluating the performance of rostral part of the auditory efferent system and may be suitable for top-down auditory training follow-ups, although the generalization of these results needs further studies in different groups with different auditory processing abnormalities or skills.

Speech-Evoked Auditory Brainstem Response in Children with Sensorineural Hearing Loss

Speech-Evoked Auditory Brainstem Response in Children with Sensorineural Hearing Loss

Perceptual sensitivity to, and electrophysiological encoding of, a complex periodic signal: effects of age

Objective: The purpose of this study was to investigate perceptual and electrophysiological encoding of complex periodic signals as a function of age.Design: Two groups of adults completed three listening tasks: a behavioural task of detection of a mistuned harmonic component in a complex tone, an electrophysiological measure of speech-evoked auditory brainstem response (sABR), and a speech-in-noise measure. Between group comparisons were undertaken for each task as well as pairwise correlation analyses for all tasks.Study sample: One group of younger adults (n = 20) and one group of older adults (n = 20) participated. All listeners had relatively normal audiometric thresholds (≤20 dB HL) from 250–4000 Hz.Results: Younger adults had better results than the older adults on all three tasks: sensitivity for detecting a mistuned harmonic, spectral encoding for sABR, and release from masking for the speech-in-noise test. There were no significant correlations between measures when evaluating the older adults in isolation.Conclusions: The results are consistent with the body of literature that demonstrates reduced temporal processing abilities for older adults. The combined method approach undertaken in this investigation did not result in correlations between the perceptual and electrophysiological measures of temporal processing.

Atypical longitudinal development of speech-evoked auditory brainstem response in preschool children with autism spectrum disorders.

Language impairment is common in children with autism spectrum disorders (ASDs). Previous research has shown that this disability may be, in part, due to atypical auditory processing of speech stimuli. However, how speech sounds are processed in children with ASD remains largely unknown. The present study assessed the developmental pattern of auditory information processing at the level of the brainstem in preschool children with ASD using speech-evoked auditory brainstem response (speech-ABR). Children with ASD (N = 15) and of typical developing (TD) (N = 20), both of preschool age, were enrolled. The speech-ABRs recorded at two different time points (T1 and T2; 9.68 months apart on average) were virtually identical in the TD group. However, in the ASD group, the wave V latency of speech-ABR was significantly shortened and the amplitudes of wave A and C were significantly larger at T2, compared to those recorded at T1 (10.78 months apart on average). Compared to the TD group, the wave V and A latencies were prolonged at T1, whereas the wave E amplitude decreased and wave F latency prolonged at T2. There was a positive partial correlation between the language performance and the wave A amplitude in the ASD group. These results indicate that auditory processing at the subcortical level is well-developed in the TD preschool children, but is immature and abnormal in the children with ASD at the same ages. Thus, aberrant speech processing at the brainstem level may contribute significantly to the language impairment in children with ASD at preschool ages. Autism Res 2019, 12: 1022-1031. © 2019 International Society for Autism Research, Wiley Periodicals, Inc. LAY SUMMARY: Language impairment is common in children with autism spectrum disorders (ASDs). We investigated the developmental pattern of subcortical auditory processing by monitoring changes in the speech-evoked auditory brainstem response (speech-ABR) over a period of 10 months in preschool children. Our results show that subcortical auditory processing is impaired and immature in children with ASD compared with age-matched, typically developing children. The results suggest that speech-ABR may be used as an objective measure in evaluating the language performance of children with ASD. The results also suggest that aberrant speech processing at the level of the brainstem may contribute significantly to the language impairment in preschool children with ASD.