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American Journal of Audiology Dec 2022Normative auditory brainstem response (ABR) data for infants and young children are available for 0.25-4 kHz, limiting clinical assessment to this range. As such, the...
PURPOSE
Normative auditory brainstem response (ABR) data for infants and young children are available for 0.25-4 kHz, limiting clinical assessment to this range. As such, the high-frequency hearing sensitivity of infants and young children remains unknown until behavioral testing can be completed, often not until late preschool or early school ages. The purpose of this study was to obtain normative ABR data at 6 and 8 kHz in young infants.
METHOD
Participants were 173 full-term infants seen clinically for ABR testing at 0.4-6.7 months chronological age ( = 1.4 months, = 1.0), 97% of whom were ≤ 12 weeks chronological age. Stimuli included 6 and 8 kHz tone bursts presented at a rate of 27.7/s or 30.7/s using Blackman window gating with six cycles (6 kHz) or eight cycles (8 kHz) rise/fall time and no plateau. Presentation levels included 20, 40, and 60 dB nHL. The ABR threshold was estimated in 5- to 10-dB steps.
RESULTS
As previously observed with lower frequency stimuli, ABR waveforms obtained in response to 6 and 8 kHz tone bursts decreased in latency with increasing intensity and increasing age. Latency was shorter for 8-kHz tone bursts than 6-kHz tone bursts. Data tables are presented for clinical reference for infants ≤ 4 weeks, 4.1-8 weeks, and 8.1-12 weeks chronological age including median ABR latency for Waves I, III, and V and the upper and lower boundaries of the 90% prediction interval. Interpeak Latencies I-III, III-V, and I-V are also reported.
CONCLUSION
The results from this study demonstrate that ABR assessment at 6 and 8 kHz is feasible for young infants within a standard clinical appointment and provide reference data for clinical interpretation of ABR waveforms for frequencies above 4 kHz.
Topics: Infant; Child; Humans; Child, Preschool; Evoked Potentials, Auditory, Brain Stem; Audiometry, Pure-Tone; Auditory Threshold; Hearing; Acoustic Stimulation
PubMed: 36442042
DOI: 10.1044/2022_AJA-22-00100 -
Journal of Neurophysiology Apr 2021Permanent threshold elevation after noise exposure or aging is caused by loss of sensory cells; however, animal studies show that hair cell loss is often preceded by...
Permanent threshold elevation after noise exposure or aging is caused by loss of sensory cells; however, animal studies show that hair cell loss is often preceded by degeneration of the synapses between sensory cells and auditory nerve fibers. Silencing these neurons is likely to degrade auditory processing and may contribute to difficulties understanding speech in noisy backgrounds. Reduction of suprathreshold ABR amplitudes can be used to quantify synaptopathy in inbred mice. However, ABR amplitudes are highly variable in humans, and thus more challenging to use. Since noise-induced neuropathy preferentially targets fibers with high thresholds and low spontaneous rate and because phase locking to temporal envelopes is particularly strong in these fibers, measuring envelope following responses (EFRs) might be a more robust measure of cochlear synaptopathy. A recent auditory model further suggests that modulation of carrier tones with rectangular envelopes should be less sensitive to cochlear amplifier dysfunction and, therefore, a better metric of cochlear neural damage than sinusoidal amplitude modulation. In this study, we measure performance scores on a variety of difficult word-recognition tasks among listeners with normal audiograms and assess correlations with EFR magnitudes to rectangular versus sinusoidal modulation. Higher harmonics of EFR magnitudes evoked by a rectangular-envelope stimulus were significantly correlated with word scores, whereas those evoked by sinusoidally modulated tones did not. These results support previous reports that individual differences in synaptopathy may be a source of speech recognition variability despite the presence of normal thresholds at standard audiometric frequencies. Recent studies suggest that millions of people may be at risk of permanent impairment from cochlear synaptopathy, the age-related and noise-induced degeneration of neural connections in the inner ear. This study examines electrophysiological responses to stimuli designed to improve detection of neural damage in subjects with normal hearing sensitivity. The resultant correlations with word recognition performance are consistent with a contribution of cochlear neural damage to deficits in hearing in noise abilities.
Topics: Acoustic Stimulation; Adolescent; Adult; Age Factors; Aging; Audiometry; Auditory Threshold; Cochlea; Cochlear Nerve; Female; Humans; Male; Middle Aged; Noise; Recognition, Psychology; Speech Perception; Young Adult
PubMed: 33656936
DOI: 10.1152/jn.00620.2020 -
Proceedings of the National Academy of... Aug 2017Our sense of hearing boasts exquisite sensitivity, precise frequency discrimination, and a broad dynamic range. Experiments and modeling imply, however, that the...
Our sense of hearing boasts exquisite sensitivity, precise frequency discrimination, and a broad dynamic range. Experiments and modeling imply, however, that the auditory system achieves this performance for only a narrow range of parameter values. Small changes in these values could compromise hair cells' ability to detect stimuli. We propose that, rather than exerting tight control over parameters, the auditory system uses a homeostatic mechanism that increases the robustness of its operation to variation in parameter values. To slowly adjust the response to sinusoidal stimulation, the homeostatic mechanism feeds back a rectified version of the hair bundle's displacement to its adaptation process. When homeostasis is enforced, the range of parameter values for which the sensitivity, tuning sharpness, and dynamic range exceed specified thresholds can increase by more than an order of magnitude. Signatures in the hair cell's behavior provide a means to determine through experiment whether such a mechanism operates in the auditory system. Robustness of function through homeostasis may be ensured in any system through mechanisms similar to those that we describe here.
Topics: Algorithms; Animals; Auditory Threshold; Hair Cells, Auditory; Hearing; Homeostasis; Mechanotransduction, Cellular; Models, Biological; Rana catesbeiana; Saccule and Utricle
PubMed: 28760949
DOI: 10.1073/pnas.1706242114 -
Acta Clinica Croatica Dec 2019Current recommendations proposed by pediatric audiologists are to commence with hearing amplification in children aged 6 months and above, after previous determination... (Comparative Study)
Comparative Study
Current recommendations proposed by pediatric audiologists are to commence with hearing amplification in children aged 6 months and above, after previous determination of the type and degree of hearing impairment and audiometric configuration. The goal of this study was to compare results obtained by click-evoked auditory brainstem response (c-ABR) and auditory steady state response (ASSR) in a group of children. This study included 68 children with different degrees of hearing impairment evaluated by c-ABR and ASSR. It is well-known that the c-ABR threshold highly correlates with behavioral hearing level at 2 kHz. In our study, the correlation between the c-ABR and ASSR thresholds in the whole sample was 0.58, 0.73, 0.97, 0.96, 0.95, 0.97; in the group of children with c-ABR thresholds up to 40 dBHL, it was 0.42, 0.73, 0.86, 0.74, 0.81, 0.81; and in the group with c-ABR thresholds worse than 40 dBHL, it was 0.46, 0.56, 0.89, 0.83, 0.85, 0.89 at 0.5, 1, 2, 4, 1-4, 2-4 kHz, respectively. Individual differences between the c-ABR and ASSR thresholds in the whole sample were up to 95, 90, 20, 25 dB at 0.5, 1, 2, 4 kHz, respectively. Study results indicated that there was strong correlation between the c-ABR and ASSR thresholds at 2, 4, 1-4, 2-4 kHz. The ASSR can be used as a valuable clinical tool and an excellent complementary method which, along with other audiologic techniques, provides more accurate hearing threshold estimation at an early age in children.
Topics: Acoustic Stimulation; Audiology; Auditory Threshold; Child; Child, Preschool; Evoked Potentials, Auditory, Brain Stem; Female; Hearing Loss; Humans; Infant; Male; Practice Guidelines as Topic
PubMed: 32595255
DOI: 10.20471/acc.2019.58.04.17 -
Fa Yi Xue Za Zhi Feb 2024To study the application of CE-Chirp in the evaluation of hearing impairment in forensic medicine by testing the auditory brainstem response (ABR) in adults using...
OBJECTIVES
To study the application of CE-Chirp in the evaluation of hearing impairment in forensic medicine by testing the auditory brainstem response (ABR) in adults using CE-Chirp to analyze the relationship between the V-wave response threshold of CE-Chirp ABR test and the pure tone hearing threshold.
METHODS
Subjects (aged 20-77 with a total of 100 ears) who underwent CE-Chirp ABR test in Changzhou De'an Hospital from January 2018 to June 2019 were selected to obtain the V-wave response threshold, and pure tone air conduction hearing threshold tests were conducted at 0.5, 1.0, 2.0 and 4.0 kHz, respectively, to obtain pure tone listening threshold. The differences and statistical differences between the average pure tone hearing threshold and V-wave response threshold were compared in different hearing levels and different age groups. The correlation, differences and statistical differences between the two tests at each frequency were analyzed for all subjects. The linear regression equation for estimating pure tone hearing threshold for all subjects CE-Chirp ABR V-wave response threshold was established, and the feasibility of the equation was tested.
RESULTS
There was no statistical significance in the CE-Chirp ABR response threshold and pure tone hearing threshold difference between different hearing level groups and different age groups (0.05). There was a good correlation between adult CE-Chirp ABR V-wave response threshold and pure tone hearing threshold with statistical significance (<0.05), and linear regression analysis showed a significant linear correlation between the two (<0.05).
CONCLUSIONS
The use of CE-Chirp ABR V-wave response threshold can be used to evaluate subjects' pure tone hearing threshold under certain conditions, and can be used as an audiological test method for forensic hearing impairment assessment.
Topics: Adult; Humans; Acoustic Stimulation; Auditory Threshold; Hearing; Hearing Loss; Audiometry, Pure-Tone; Evoked Potentials, Auditory, Brain Stem
PubMed: 38500456
DOI: 10.12116/j.issn.1004-5619.2021.210101 -
Hearing Research Feb 2023Beyond reduced audibility, there is convincing evidence that the auditory system adapts according to the principles of homeostatic plasticity in response to a hearing...
Beyond reduced audibility, there is convincing evidence that the auditory system adapts according to the principles of homeostatic plasticity in response to a hearing loss. Such compensatory changes include modulation of central auditory gain mechanisms. Earplugging is a common experimental method that has been used to introduce a temporary, reversible hearing loss that induces changes consistent with central gain modulation. In the present study, young, normal-hearing adult participants wore a unilateral earplug for two weeks, during which we measured changes in the acoustic reflex threshold (ART), loudness perception, and cortically-evoked (40 Hz) auditory steady-state response (ASSR) to assess potential modulation in central gain with reduced peripheral input. The ART decreased on average by 8 to 10 dB during the treatment period, with modest increases in loudness perception after one week but not after two weeks of earplug use. Significant changes in both the magnitude and hemispheric laterality of source-localized cortical ASSR measures revealed asymmetrical changes in stimulus-driven cortical activity over time. The ART results following unilateral earplugging are consistent with the literature and suggest that homeostatic plasticity is evident in the brainstem. The novel findings from the cortical ASSR in the present study indicates that reduced peripheral input induces adaptive homeostatic plasticity reflected as both an increase in central gain in the auditory brainstem and reduced cortical activity ipsilateral to the deprived ear. Both the ART and the novel use of the 40-Hz ASSR provide sensitive measures of central gain modulation in the brainstem and cortex of young, normal hearing listeners, and thus may be useful in future studies with other clinical populations.
Topics: Adult; Humans; Auditory Threshold; Acoustic Stimulation; Brain Stem; Hearing Loss; Deafness; Acoustics; Auditory Cortex
PubMed: 36599259
DOI: 10.1016/j.heares.2022.108683 -
The Journal of Neuroscience : the... Oct 2015Although cochlear damage is believed to trigger the perception of tinnitus in the central auditory system, its pathophysiological mechanism is still unclear. We aimed to...
UNLABELLED
Although cochlear damage is believed to trigger the perception of tinnitus in the central auditory system, its pathophysiological mechanism is still unclear. We aimed to investigate the pathophysiology of tinnitus using psychoacoustic assessments of auditory spectral and temporal resolution and speech perception in noise. Human subjects with tinnitus and symmetric hearing thresholds were divided into three groups: nine unilateral tinnitus subjects with normal hearing thresholds (Group 1), 12 unilateral tinnitus subjects with hearing loss (HL; Group 2), and nine bilateral tinnitus subjects with HL. Fifteen normal-hearing subjects without tinnitus were also tested as a control group. Four different tests were administered: (1) the spectral-ripple discrimination (SRD) test, (2) the temporal modulation detection (TMD) test, (3) the Schroeder-phase discrimination (SPD) test, and (4) the speech recognition threshold (SRT) in noise test. There were no significant differences in SRD, TMD, and SPD between the tinnitus-affected ears (TEs) and non-tinnitus ears (NTEs) in Groups 1 and 2 (p > 0.05). In contrast, the TEs showed poorer SRTs than the NTEs in these two subject groups (p = 0.022 and 0.049). No inferiority of spectral/temporal resolution in TEs compared with NTEs suggests that there may be no more outer hair cell (OHC) damage on the tinnitus side given that damaged OHCs are associated with broadening the auditory filters. The decoupling of the SRT results from the spectral/temporal resolution data could imply that the occurrence of tinnitus does not depend upon the degree of damage to the OHCs, but rather upon different plastic changes in the central auditory system after cochlear damage.
SIGNIFICANCE STATEMENT
We can easily find unilateral tinnitus patients who have symmetric hearing thresholds. Our research question was what kind of difference would be responsible for the tinnitus in the tinnitus-affected ears but not in the non-tinnitus ears of subjects with symmetric hearing thresholds. The answer to this fundamental question could help us to understand the pathophysiology of tinnitus. We evaluated the potential influence of tinnitus upon the subjects' auditory spectral and temporal resolution and speech perception in noise by comparing these psychoacoustic performances between tinnitus-affected ears and non-tinnitus ears in the same subjects.
Topics: Acoustic Stimulation; Adult; Auditory Perceptual Disorders; Auditory Threshold; Discrimination, Psychological; Female; Functional Laterality; Humans; Male; Middle Aged; Psychoacoustics; Regression Analysis; Speech Perception; Tinnitus
PubMed: 26490865
DOI: 10.1523/JNEUROSCI.5091-14.2015 -
Journal of the Association For Research... Dec 2023External-ear amplification (EEA) has been shown to vary from 5-19 dB-A in large datasets of pediatric, adolescent, and adult human participants. However, variable EEA...
BACKGROUND
External-ear amplification (EEA) has been shown to vary from 5-19 dB-A in large datasets of pediatric, adolescent, and adult human participants. However, variable EEA is an overlooked characteristic that likely plays a role in individual noise-induced hearing loss (NIHL) susceptibility. A noise exposure varying 5-19 dB-A translates to high-EEA individuals theoretically experiencing 3-4 times greater NIHL risk than low-EEA individuals.
OBJECTIVE
The purpose of this preliminary analysis was to test the hypothesis that higher EEA is correlated with increased noise-induced threshold shift susceptibility.
DESIGN
Nine chinchillas were exposed to 4-kHz octave-band noise at 89 dB-SPL for 24 h. Auditory brainstem response thresholds were obtained pre-exposure, 24-h post-exposure, and 4-week post-exposure. Relationships between EEA and threshold shift were analyzed.
RESULTS
Open-ear EEA ranged 11-19 dB-SPL, and occluded-ear EEA ranged 10-21 dB-SPL. Higher occluded-ear EEA was correlated with increased NIHL susceptibility (p = 0.04), as was lower body weight (p = 0.01). Male animals exhibited more threshold shift than female animals (p = 0.02), lower body weight than female animals (p = 0.02), and higher occluded-ear EEA (male mean = 18 dB; female mean = 15 dB).
CONCLUSIONS
Taken together, increased threshold shift susceptibility was observed in the smallest animals, animals with the highest occluded-ear EEA, and in male animals (which tended to have higher occluded-ear EEA). Given the established relationship between smaller body size and higher occluded-ear EEA, these preliminary results suggest that body size (and occluded-ear EEA; a function of body size) could be a potential, underlying driver of NIHL susceptibility differences, rather than true sex differences.
Topics: Animals; Female; Male; Humans; Child; Adolescent; Chinchilla; Auditory Threshold; Noise; Hearing; Hearing Loss, Noise-Induced; Body Weight
PubMed: 38010580
DOI: 10.1007/s10162-023-00913-2 -
The Journal of the Acoustical Society... Jan 2023The detectability of target amplitude modulation (AM) can be reduced by masker AM in the same carrier-frequency region. It can be reduced even further, however, if the...
The detectability of target amplitude modulation (AM) can be reduced by masker AM in the same carrier-frequency region. It can be reduced even further, however, if the masker-AM rate is uncertain [Conroy and Kidd, J. Acoust. Soc. Am. 149, 3665-3673 (2021)]. This study examined the effectiveness of contextual cues in reducing this latter, uncertainty-related effect (modulation informational masking). Observers were tasked with detecting fixed-rate target sinusoidal amplitude modulation (SAM) in the presence of masker SAM applied simultaneously to the same broadband-noise carrier. A single-interval, two-alternative forced-choice detection procedure was used to measure sensitivity for the target SAM; masker-AM-rate uncertainty was created by randomly selecting the AM rate of the masker SAM on each trial. Relative to an uncued condition, a pretrial cue to the masker SAM significantly improved sensitivity for the target SAM; a cue to the target SAM, however, did not. The delay between the cue-interval offset and trial-interval onset did not affect the size of the masker-cue benefit, suggesting that adaptation of the masker SAM was not responsible. A simple model of within-AM-channel masking captured important trends in the psychophysical data, suggesting that reduced masker-AM-rate uncertainty may have played a relatively minor role in the masker-cue benefit.
Topics: Auditory Threshold; Perceptual Masking; Cues; Uncertainty
PubMed: 36732267
DOI: 10.1121/10.0016867 -
Hearing Research Jan 2024Auditory complaints are frequently reported by individuals with mild traumatic brain injury (mTBI) yet remain difficult to detect in the absence of clinically...
Auditory complaints are frequently reported by individuals with mild traumatic brain injury (mTBI) yet remain difficult to detect in the absence of clinically significant hearing loss. This highlights a growing need to identify sensitive indices of auditory-related mTBI pathophysiology beyond pure-tone thresholds for improved hearing healthcare diagnosis and treatment. Given the heterogeneity of mTBI etiology and the diverse peripheral and central processes required for normal auditory function, the present study sought to determine the audiologic assessments sensitive to mTBI pathophysiology at the group level using a well-rounded test battery of both peripheral and central auditory system function. This test battery included pure-tone detection thresholds, word understanding in quiet, sentence understanding in noise, distortion product otoacoustic emissions (DPOAEs), middle-ear muscle reflexes (MEMRs), and auditory evoked potentials (AEPs), including auditory brainstem responses (ABRs), middle latency responses (MLRs), and late latency responses (LLRs). Each participant also received magnetic resonance imaging (MRI). Compared to the control group, we found that individuals with mTBI had reduced DPOAE amplitudes that revealed a compound effect of age, elevated MEMR thresholds for an ipsilateral broadband noise elicitor, longer ABR Wave I latencies for click and 4 kHz tone burst elicitors, longer ABR Wave III latencies for 4 kHz tone bursts, larger MLR Na and Nb amplitudes, smaller MLR Pb amplitudes, longer MLR Pa latencies, and smaller LLR N1 amplitudes for older individuals with mTBI. Further, mTBI individuals with combined hearing difficulty and noise sensitivity had a greater number of deficits on thalamic and cortical AEP measures compared to those with only one/no self-reported auditory symptoms. This finding was corroborated with MRI, which revealed significant structural differences in the auditory cortical areas of mTBI participants who reported combined hearing difficulty and noise sensitivity, including an enlargement of left transverse temporal gyrus (TTG) and bilateral planum polare (PP). These findings highlight the need for continued investigations toward identifying individualized audiologic assessments and treatments that are sensitive to mTBI pathophysiology.
Topics: Humans; Brain Concussion; Auditory Threshold; Hearing; Noise; Evoked Potentials, Auditory; Hearing Loss; Evoked Potentials, Auditory, Brain Stem; Otoacoustic Emissions, Spontaneous
PubMed: 38086151
DOI: 10.1016/j.heares.2023.108928