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Journal of Visualized Experiments : JoVE Apr 2022The auditory brainstem response (ABR) is an invaluable assay in clinical audiology, non-human animals, and human research. Despite the widespread use of ABRs in...
The auditory brainstem response (ABR) is an invaluable assay in clinical audiology, non-human animals, and human research. Despite the widespread use of ABRs in measuring auditory neural synchrony and estimating hearing sensitivity in other vertebrate model systems, methods for recording ABRs in the chicken have not been reported in nearly four decades. Chickens provide a robust animal research model because their auditory system is near functional maturation during late embryonic and early hatchling stages. We have demonstrated methods used to elicit one or two-channel ABR recordings using subdermal needle electrode arrays in chicken hatchlings. Regardless of electrode recording configuration (i.e., montage), ABR recordings included 3-4 positive-going peak waveforms within the first 6 ms of a suprathreshold click stimulus. Peak-to-trough waveform amplitudes ranged from 2-11 µV at high-intensity levels, with positive peaks exhibiting expected latency-intensity functions (i.e., increase in latency as a function of decreased intensity). Standardized earphone position was critical for optimal recordings as loose skin can occlude the ear canal, and animal movement can dislodge the stimulus transducer. Peak amplitudes were smaller, and latencies were longer as animal body temperature lowered, supporting the need for maintaining physiological body temperature. For young hatchlings (<3 h post-hatch day 1), thresholds were elevated by ~5 dB, peak latencies increased ~1-2 ms, and peak to trough amplitudes were decreased ~1 µV compared to older hatchlings. This suggests a potential conductive-related issue (i.e., fluid in the middle ear cavity) and should be considered for young hatchlings. Overall, the ABR methods outlined here permit accurate and reproducible recording of in-vivo auditory function in chicken hatchlings that could be applied to different stages of development. Such findings are easily compared to human and mammalian models of hearing loss, aging, or other auditory-related manipulations.
Topics: Acoustic Stimulation; Animals; Auditory Threshold; Chickens; Cochlear Nerve; Evoked Potentials, Auditory, Brain Stem; Hearing; Mammals
PubMed: 35435914
DOI: 10.3791/63477 -
American Journal of Otolaryngology 2022This study compared distortion product otoacoustic emissions (DPOAEs) and click-evoked auditory brainstem responses (ABRs) recorded from infants whose mother had...
BACKGROUND
This study compared distortion product otoacoustic emissions (DPOAEs) and click-evoked auditory brainstem responses (ABRs) recorded from infants whose mother had Covid-19 during pregnancy (Covid-19 group) to infants whose mother did not have Covid-19 (Control group) during pregnancy.
METHODS
This study retrospectively examined records of infants in the Covid-19 group (n = 15) and control group (n = 46) who had distortion product otoacoustic emissions (DPOAEs) and click-evoked auditory brainstem responses (ABRs) recorded as part of their clinical assessment. DPOAE amplitudes, absolute latencies (I, III, and V), and I-V interpeak intervals were examined.
RESULTS
DPOAE amplitudes were similar between the Covid-19 group and the control group. The absolute latency of wave I was similar between groups. But absolute latencies III and V and I-V interpeak intervals of the Covid-19 group were significantly prolonged compared to the control group.
CONCLUSION
Covid-19 infection and its complications during pregnancy may not affect the cochlear function but may affect the functioning of the auditory brainstem.
Topics: Auditory Threshold; COVID-19; Evoked Potentials, Auditory, Brain Stem; Female; Humans; Infant; Otoacoustic Emissions, Spontaneous; Pregnancy; Retrospective Studies
PubMed: 35533437
DOI: 10.1016/j.amjoto.2022.103484 -
Journal of the American Academy of... Oct 2021Numerous cardiometabolic factors may underlie risk of hearing loss. Modifiable risk factors such as non-optimal blood pressure (BP) are of interest.
BACKGROUND
Numerous cardiometabolic factors may underlie risk of hearing loss. Modifiable risk factors such as non-optimal blood pressure (BP) are of interest.
PURPOSE
To investigate early auditory evoked potentials (AEPs) in persons with nonoptimal BP.
RESEARCH DESIGN
A cross-sectional nonexperimental study was performed.
STUDY SAMPLE
Fifty-two adults (18-55 years) served as subjects. Individuals were classified as having optimal (systolic [S] BP < 120 and diastolic [D] BP < 80 mm Hg, = 25) or non-optimal BP (SBP ≥=120 or DBP ≥=80 mm Hg or antihypertensive use, = 27). Thirteen subjects had hypertension (HTN) (SBP ≥130 or DBP ≥80 mm Hg or use of antihypertensives).
DATA COLLECTION AND ANALYSIS
Behavioral thresholds from 0.25 to 16 kHz were collected. Threshold auditory brain stem responses (ABRs) were recorded using rarefaction clicks (17.7/second) from 80 dB nHL to wave V threshold. Electrocochleograms were obtained with 90 dB nHL 7.1/second alternating clicks and assessed for summating and compound action potentials (APs). Outcomes were compared via independent samples tests. Linear mixed effects models for behavioral thresholds and ABR wave latencies were constructed to account for potential confounders.
RESULTS
Wave I and III latencies were comparable between optimal and non-optimal BP groups. Wave I was prolonged in hypertensive versus optimal BP subjects at stimulus level 70 dB nHL ( = 0.016). ABR wave V latencies were prolonged in non-optimal BP at stimulus level 80 dB nHL ( = 0.048) and in HTN at levels of 80, 50, and 30 dB nHL (all < 0.050). DBP was significantly correlated with wave V latency ( = 0.295; = 0.039). No differences in ABR amplitudes were observed between optimal and non-optimal BP subjects. Electrocochleographic study showed statistically comparable action and summating potential amplitudes between optimal and non-optimal BP subjects. AP latencies were also similar between the groups. Analysis using a set baseline amplitude of 0 μV showed that hypertensive subjects had higher summating ( = 0.038) and AP ( = 0.047) amplitudes versus optimal BP subjects; AP latencies were comparable.
CONCLUSION
Elevated BP and more specifically, HTN was associated with subtle AEP abnormalities. This study provides preliminary evidence that nonoptimal BP, and more specifically HTN, may be related to auditory neural dysfunction; larger confirmatory studies are warranted.
Topics: Acoustic Stimulation; Adult; Audiometry, Evoked Response; Auditory Threshold; Blood Pressure; Cross-Sectional Studies; Evoked Potentials, Auditory, Brain Stem; Humans
PubMed: 35176801
DOI: 10.1055/s-0041-1733970 -
Hearing Research Sep 2022Auditory Brainstem Responses (ABRs) are a reliably robust measure of auditory thresholds in the mammalian hearing system and can be used to determine deficits in the...
Auditory Brainstem Responses (ABRs) are a reliably robust measure of auditory thresholds in the mammalian hearing system and can be used to determine deficits in the auditory periphery. However, because these measures are limited to the lower stages of the auditory pathway, they are insensitive to changes or deficits that occur in the thalamic and cortical regions. Cortical Auditory Evoked Potentials (CAEPs), as longer latency responses, capture information from these regions. However they are less frequently used as a diagnostic tool, particularly in rodent models, due to their inherent variability and subsequent difficult interpretation. The purpose of this study was to develop a consistent measure of subcutaneous CAEPs to auditory stimuli in mice and to determine their origin. To this end, we investigated the effect on the CAEPs recorded in response to different stimuli (noise, click, and tone (16 kHz) bursts), stimulus presentation rates (2/s, 6/s, 10/s) and electrode placements. Recordings were examined for robust CAEP components to determine the optimal experimental paradigm. We argue that CAEPs can measure robust and replicable cortical responses. Furthermore, by deactivating the auditory cortex with lidocaine we demonstrated that the contralateral cortex is the main contributor to the CAEP. Thus CAEP measurements could prove to be of value diagnostically in future for deficits in higher auditory areas.
Topics: Animals; Mice; Acoustic Stimulation; Evoked Potentials, Auditory; Hearing; Evoked Potentials, Auditory, Brain Stem; Auditory Threshold; Auditory Cortex; Mammals
PubMed: 35863162
DOI: 10.1016/j.heares.2022.108566 -
Hearing Research Mar 2023Repeated exposures to blast overpressure (BOP) introduce hearing complaints in military service members even with the use of hearing protection devices (HPDs). Although... (Review)
Review
Repeated exposures to blast overpressure (BOP) introduce hearing complaints in military service members even with the use of hearing protection devices (HPDs). Although epidemiology and animal studies have been performed to investigate the damage formation mechanism of blast-induced hearing damage, there is still a lack of understanding and therapeutic solutions, especially for HPD-protected ears. Recent studies revealed the potential therapeutic function of liraglutide, a glucagon-like peptide-1 receptor agonist, to facilitate post-blast hearing restoration in chinchillas. This study is a continuation and summary of the previous studies performed by Jiang et al. (2021, 2022) to investigate the damage mitigation function of liraglutide treatment in chinchillas with open and protected ears after repeated low-intensity blast exposures within 28 days of observation. Chinchillas were divided into six experimental groups: pre-blast treatment, post-blast treatment, and blast control with ears open or protected by earplug (EP). All animals were exposed to six consecutive blasts at the level of 3-5 psi (21-35 kPa) on Day 1. Hearing function tests including auditory brainstem response (ABR), distortion product otoacoustic emission (DPOAE), and middle latency response (MLR) were performed on Day 1 (pre- and post-blast) and Days 4, 7, 14, and 28 after blast exposure. Results indicated that the damage mitigation function of the liraglutide treatment in the open-ear chinchillas was reflected by the significantly lower ABR threshold shifts in the drug treatment groups than in the blast controls. In EP groups, the higher ABR wave I/V ratio and lower MLR amplitude observed in the drug-treated chinchillas suggested that the post-blast hyperactivities in the auditory system might be potentially ameliorated by the liraglutide treatment. The 28-day-long experiment showed the effect of liraglutide treatment increased with time in both open and EP groups. This study demonstrated that the use of HPDs prevented the blast-induced complications in the middle ear and reduced the damage caused in the central auditory system. The liraglutide treatment showed an effect increasing with time and different outcomes in open and EP chinchillas. This innovation in the animal model of chinchilla provides insights to investigate subtle changes in the higher-level structures of the auditory system.
Topics: Animals; Chinchilla; Cochlea; Liraglutide; Hearing; Otoacoustic Emissions, Spontaneous; Evoked Potentials, Auditory, Brain Stem; Auditory Threshold
PubMed: 36680874
DOI: 10.1016/j.heares.2023.108703 -
Otology & Neurotology : Official... Dec 2017: Auditory evoked potentials (AEP) are highly demanded during the whole process of equipping patients with cochlear implants (CI). They play an essential role in... (Review)
Review
: Auditory evoked potentials (AEP) are highly demanded during the whole process of equipping patients with cochlear implants (CI). They play an essential role in preoperative diagnostics, intraoperative testing, and postoperative monitoring of auditory performance and success. The versatility of AEP's is essentially enhanced by their property to be evokable by acoustic as well as electric stimuli. Thus, the electric responses of the auditory system following acoustic stimulation and recorded by the conventional surface technique as well as by transtympanic derivation from the promontory (Electrocochleography [ECochG]) are used for the quantitative determination of hearing loss and, additionally, electrically evoked compound actions potentials (ECAP) can be recorded with the intracochlear electrodes of the implant just adjacent to the stimulation electrode to check the functional integrity of the device and its coupling to the auditory system. The profile of ECAP thresholds is used as basis for speech processor fitting, the spread of excitation (SOE) allows the identification of electrode mislocations such as array foldover, and recovery functions may serve to optimize stimulus pulse rate. These techniques as well as those relying on scalp surface activity originating in the brainstem or the auditory cortex accompany the CI recipient during its whole life span and they offer valuable insights into functioning and possible adverse effects of the CI for clinical and scientific purposes.
Topics: Acoustic Stimulation; Auditory Cortex; Auditory Threshold; Cochlear Implantation; Cochlear Implants; Evoked Potentials, Auditory; Hearing Loss; Humans
PubMed: 29135872
DOI: 10.1097/MAO.0000000000001480 -
Molecular and Cellular Neurosciences Jan 2022Afferent innervation of the cochlea by the auditory nerve declines during aging and potentially after sound overexposure, producing the common pathology known as... (Review)
Review
Afferent innervation of the cochlea by the auditory nerve declines during aging and potentially after sound overexposure, producing the common pathology known as cochlear synaptopathy. Auditory-nerve-fiber loss is difficult to detect with the clinical audiogram and has been proposed to cause 'hidden hearing loss' including impaired speech-in-noise perception. While evidence that auditory-nerve-fiber loss causes hidden hearing loss in humans is controversial, behavioral animal models hold promise to rigorously test this hypothesis because neural lesions can be induced and histologically validated. Here, we review recent animal behavioral studies on the impact of auditory-nerve-fiber loss on perception in a range of species. We first consider studies of tinnitus and hyperacusis inferred from acoustic startle reflexes, followed by a review of operant-conditioning studies of the audiogram, temporal integration for tones of varying duration, temporal resolution of gaps in noise, and tone-in-noise detection. Studies quantifying the audiogram show that tone-in-quiet sensitivity is unaffected by auditory-nerve-fiber loss unless neural lesions exceed 80%, at which point large deficits are possible. Changes in other aspects of perception, which were typically investigated for moderate-to-severe auditory-nerve-fiber loss of 50-70%, appear heterogeneous across studies and might be small compared to impairment caused by hair-cell pathologies. Future studies should pursue recent findings that behavioral sensitivity to brief tones and silent gaps in noise may be particularly vulnerable to auditory-nerve-fiber loss. Furthermore, aspects of auditory perception linked to central inhibition and fine neural response timing, such as modulation masking release and spatial hearing, may be productive directions for further animal behavioral research.
Topics: Animals; Auditory Perception; Auditory Threshold; Cochlear Nerve; Evoked Potentials, Auditory, Brain Stem; Hearing Loss; Models, Animal
PubMed: 34883241
DOI: 10.1016/j.mcn.2021.103692 -
Scientific Reports Nov 2023Tinnitus, reduced sound-level tolerance, and difficulties hearing in noisy environments are the most common complaints associated with sensorineural hearing loss in...
Tinnitus, reduced sound-level tolerance, and difficulties hearing in noisy environments are the most common complaints associated with sensorineural hearing loss in adult populations. This study aims to clarify if cochlear neural degeneration estimated in a large pool of participants with normal audiograms is associated with self-report of tinnitus using a test battery probing the different stages of the auditory processing from hair cell responses to the auditory reflexes of the brainstem. Self-report of chronic tinnitus was significantly associated with (1) reduced cochlear nerve responses, (2) weaker middle-ear muscle reflexes, (3) stronger medial olivocochlear efferent reflexes and (4) hyperactivity in the central auditory pathways. These results support the model of tinnitus generation whereby decreased neural activity from a damaged cochlea can elicit hyperactivity from decreased inhibition in the central nervous system.
Topics: Adult; Humans; Tinnitus; Auditory Threshold; Hearing; Cochlea; Auditory Perception; Vestibulocochlear Nerve Diseases
PubMed: 38036538
DOI: 10.1038/s41598-023-46741-5 -
International Journal of Pediatric... Jun 2019Hearing loss is a serious problem in infants and children because it may interfere with the development of typical speech, verbal language, and auditory and...
OBJECTIVES
Hearing loss is a serious problem in infants and children because it may interfere with the development of typical speech, verbal language, and auditory and communication skills. By measuring hearing ability (thresholds) as early as possible, even as early as during infancy, effective treatment can be administered. These treatments may significantly reduce the handicap associated with hearing loss. However, at times during behavioral auditory tests, observers cannot determine whether or not an accurate threshold was obtained. To support the use of infant audiometry for accurate diagnosis, audiologic behavioral responses may be obtained by selecting stimuli that interest infants, e.g., their mothers' voices.
METHODS
We evaluated 30 infants who were presented to our hospital for behavioral auditory assessment in 2016. The infants' ages ranged from 4 months to 3 years and 6 months. The mean age was 1 year and 10 months ±10 months (±standard deviation). The infants' hearing thresholds for their mothers' voices and warble tones at 250-4000 Hz were measured. Auditory brainstem response (ABR) had already been evaluated in 24 infants. Relationships between mother's voice and warble tone or ABR thresholds as well as responses to the initial stimuli and stimuli at the threshold were investigated. These responses were classified into four grades (no response, uncertain response, possible positive response, and positive response), and the response to mother's voice and warble tone were subsequently compared.
RESULTS
Mother's voice thresholds significantly correlated with all warble tone thresholds. In the relationship between the mother's voice threshold and average hearing levels of 500, 1000, and 2000 Hz, two infants were outliers. In these infants, the average hearing levels were relatively higher than the mother's voice thresholds. Judging from their ABR thresholds, the mother's voice thresholds were valid and the average hearing levels were worse than their original assessed hearing ability. The responses to mothers' voices were more distinct than those to warble tones, both for initial stimuli presentation and the determined threshold.
CONCLUSIONS
Audiologic behavioral responses to mothers' voices were clearer than those for warble tones. Evaluations that use the mother's voice threshold are useful for estimating hearing levels in infants.
Topics: Audiometry; Auditory Threshold; Child; Child, Preschool; Evoked Potentials, Auditory, Brain Stem; Female; Hearing; Hearing Loss; Humans; Infant; Male; Mothers; Voice
PubMed: 30877980
DOI: 10.1016/j.ijporl.2019.03.005 -
International Journal of Audiology Mar 2024The clinical audiology test battery often involves playing physically simple sounds with questionable ecological value to the listener. In this technical report, we...
OBJECTIVE
The clinical audiology test battery often involves playing physically simple sounds with questionable ecological value to the listener. In this technical report, we revisit how valid this approach is using an automated, involuntary auditory response; the acoustic reflex threshold (ART).
DESIGN
The ART was estimated four times in each individual in a quasi-random ordering of task conditions. The baseline condition (referred to as measured the ART following a standard clinical practice. Three experimental conditions were then used in which a secondary task was performed whilst the reflex was measured: , and tasks.
STUDY SAMPLE
Thirty-eight participants (27 males) with a mean age of 23 years were tested. All participants were audiometrically healthy.
RESULTS
The ART was elevated when a visual task was performed at the same time as the measurements were taken. Performing an auditory task did not affect the ART.
CONCLUSIONS
These data indicate that simple audiometric measures widely used in the clinic, can be affected by central, non-auditory processes even in healthy, normal-hearing volunteers. The role of cognition and attention on auditory responses will become ever more important in the coming years.
Topics: Adult; Humans; Male; Young Adult; Acoustic Stimulation; Acoustics; Audiometry; Auditory Threshold; Hearing Tests; Reflex, Acoustic; Female
PubMed: 36811451
DOI: 10.1080/14992027.2023.2174455