scholarly journals Temporal Alterations to Central Auditory Processing without Synaptopathy after Lifetime Exposure to Environmental Noise

2021 ◽  
Author(s):  
Florian Occelli ◽  
Florian Hasselmann ◽  
Jérôme Bourien ◽  
Jean-Luc Puel ◽  
Nathalie Desvignes ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Auditory Cortex ◽  
Auditory Processing ◽  
Noise Exposure ◽  
Sound Intensity ◽  
Environmental Noise ◽  
Central Auditory Processing ◽  
Adult Rats ◽  
Cochlear Hair Cells ◽  
Lifetime Exposure

Abstract People are increasingly exposed to environmental noise through the cumulation of occupational and recreational activities, which is considered harmless to the auditory system, if the sound intensity remains <80 dB. However, recent evidence of noise-induced peripheral synaptic damage and central reorganizations in the auditory cortex, despite normal audiometry results, has cast doubt on the innocuousness of lifetime exposure to environmental noise. We addressed this issue by exposing adult rats to realistic and nontraumatic environmental noise, within the daily permissible noise exposure limit for humans (80 dB sound pressure level, 8 h/day) for between 3 and 18 months. We found that temporary hearing loss could be detected after 6 months of daily exposure, without leading to permanent hearing loss or to missing synaptic ribbons in cochlear hair cells. The degraded temporal representation of sounds in the auditory cortex after 18 months of exposure was very different from the effects observed after only 3 months of exposure, suggesting that modifications to the neural code continue throughout a lifetime of exposure to noise.

Central Auditory Processing

2021 ◽  
Author(s):  
Josef P. Rauschecker
Keyword(s):  
Auditory Cortex ◽  
Auditory Processing ◽  
Cognitive Abilities ◽  
Auditory Perception ◽  
Auditory Brainstem ◽  
Central Auditory Processing ◽  
Visible Part ◽  
Auditory Object ◽  
Mother’S Voice ◽  
The Brain

When one talks about hearing, some may first imagine the auricle (or external ear), which is the only visible part of the auditory system in humans and other mammals. Its shape and size vary among people, but it does not tell us much about a person’s abilities to hear (except perhaps their ability to localize sounds in space, where the shape of the auricle plays a certain role). Most of what is used for hearing is inside the head, particularly in the brain. The inner ear transforms mechanical vibrations into electrical signals; then the auditory nerve sends these signals into the brainstem, where intricate preprocessing occurs. Although auditory brainstem mechanisms are an important part of central auditory processing, it is the processing taking place in the cerebral cortex (with the thalamus as the mediator), which enables auditory perception and cognition. Human speech and the appreciation of music can hardly be imagined without a complex cortical network of specialized regions, each contributing different aspects of auditory cognitive abilities. During the evolution of these abilities in higher vertebrates, especially birds and mammals, the cortex played a crucial role, so a great deal of what is referred to as central auditory processing happens there. Whether it is the recognition of one’s mother’s voice, listening to Pavarotti singing or Yo-Yo Ma playing the cello, hearing or reading Shakespeare’s sonnets, it will evoke electrical vibrations in the auditory cortex, but it does not end there. Large parts of frontal and parietal cortex receive auditory signals originating in auditory cortex, forming processing streams for auditory object recognition and auditory-motor control, before being channeled into other parts of the brain for comprehension and enjoyment.

scholarly journals Effects of cochlear hair cell ablation on spatial learning/memory

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Z. Jason Qian ◽  
Anthony J. Ricci
Keyword(s):  
Hearing Loss ◽  
Hair Cell ◽  
Spatial Learning ◽  
Hair Cells ◽  
Noise Exposure ◽  
Memory Errors ◽  
Cochlear Hair Cells ◽  
Cochlear Hair Cell ◽  
Cell Ablation ◽  
Spatial Learning Memory

AbstractCurrent clinical interest lies in the relationship between hearing loss and cognitive impairment. Previous work demonstrated that noise exposure, a common cause of sensorineural hearing loss (SNHL), leads to cognitive impairments in mice. However, in noise-induced models, it is difficult to distinguish the effects of noise trauma from subsequent SNHL on central processes. Here, we use cochlear hair cell ablation to isolate the effects of SNHL. Cochlear hair cells were conditionally and selectively ablated in mature, transgenic mice where the human diphtheria toxin (DT) receptor was expressed behind the hair-cell specific Pou4f3 promoter. Due to higher Pou4f3 expression in cochlear hair cells than vestibular hair cells, administration of a low dose of DT caused profound SNHL without vestibular dysfunction and had no effect on wild-type (WT) littermates. Spatial learning/memory was assayed using an automated radial 8-arm maze (RAM), where mice were trained to find food rewards over a 14-day period. The number of working memory errors (WME) and reference memory errors (RME) per training day were recorded. All animals were injected with DT during P30–60 and underwent the RAM assay during P90–120. SNHL animals committed more WME and RME than WT animals, demonstrating that isolated SNHL affected cognitive function. Duration of SNHL (60 versus 90 days post DT injection) had no effect on RAM performance. However, younger age of acquired SNHL (DT on P30 versus P60) was associated with fewer WME. This describes the previously undocumented effect of isolated SNHL on cognitive processes that do not directly rely on auditory sensory input.

scholarly journals Hormones and Hearing: Central Auditory Processing in Women

2019 ◽  
Vol 30 (06) ◽  
pp. 493-501
Author(s):  
Skylar Trott ◽  
Trey Cline ◽  
Jeffrey Weihing ◽  
Deidra Beshear ◽  
Matthew Bush ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Auditory Processing ◽  
Auditory Brainstem ◽  
Human Model ◽  
Central Auditory Processing ◽  
Hormonal Changes ◽  
Hearing Sensitivity ◽  
Organ Systems ◽  
Significant Difference ◽  
Brainstem Response

AbstractEstrogen has been identified as playing a key role in many organ systems. Recently, estrogen has been found to be produced in the human brain and is believed contribute to central auditory processing. After menopause, a low estrogen state, many women report hearing loss but demonstrate no deficits in peripheral hearing sensitivity, which support the notion that estrogen plays an effect on central auditory processing. Although animal research on estrogen and hearing loss is extensive, there is little in the literature on the human model.The aim of this study was to evaluate relationships between hormonal changes and hearing as it relates to higher auditory function in pre- and postmenopausal (Post-M) females.A prospective, group comparison study.Twenty eight women between the ages of 18 and 70 at the University of Kentucky were recruited.Participants were separated into premenopausal and peri-/Post-M groups. Participants had normal peripheral hearing sensitivity and underwent a behavioral auditory processing battery and electrophysiological evaluation. An analysis of variance was performed to address the aims of the study.Results from the study demonstrated statistically significant difference between groups, where Post-M females had difficulties in spatial hearing abilities as reflected on the Listening in Spatialized Noise Test–Sentences test. In addition, measures on the auditory brainstem response and the middle latency response reflected statistically significant differences between groups with Post-M females having longer latencies.Results from the present study demonstrated significant differences between groups, particularly listening in noise. Females who present with auditory complaints in spite of normal hearing thresholds should have a more extensive audiological evaluation to further evaluate possible central deficits.

Audiological Correlates to a Rupture of a Pontine Arteriovenous Malformation

2004 ◽  
Vol 15 (02) ◽  
pp. 161-171 ◽  
Author(s):  
Frank E. Musiek ◽  
Jane A. Baran
Keyword(s):  
Hearing Loss ◽  
Arteriovenous Malformation ◽  
Auditory Processing ◽  
Rehabilitation Program ◽  
Central Auditory Processing ◽  
Central Auditory Processing Disorder ◽  
Auditory Rehabilitation ◽  
Initial Symptoms ◽  
Recovery Mechanisms

This is a report of a female patient in her midthirties who sustained a hemorrhage secondary to an arteriovenous malformation in the region of the pons. The patient's initial symptoms included hearing loss and tinnitus, which were followed by the more characteristic symptoms of headache and loss of consciousness. Results of audiological testing at three months postaccident documented the presence of a hearing loss and a central auditory processing disorder, and the patient was provided an auditory rehabilitation program. Follow-up testing over the course of an additional year documented improvement in both pure-tone threshold and central test results; however, at 15 months postaccident, some auditory deficits remained, especially in the ear ipsilateral to the primary site of lesion. The anatomical correlates of these deficits are discussed, as are the potential contributions of both the auditory rehabilitation program and spontaneous recovery mechanisms to the documented improvements in auditory function.

scholarly journals Hearing Characteristics of Stroke Patients: Prevalence and Characteristics of Hearing Impairment and Auditory Processing Disorders in Stroke Patients

2017 ◽  
Vol 28 (06) ◽  
pp. 491-505 ◽  
Author(s):  
Nehzat Koohi ◽  
Deborah A. Vickers ◽  
Rahul Lakshmanan ◽  
Hoskote Chandrashekar ◽  
David J. Werring ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Hearing Impairment ◽  
Auditory Processing ◽  
Otoacoustic Emissions ◽  
Pure Tone Audiometry ◽  
Stroke Survivors ◽  
Central Auditory Processing ◽  
Hearing Impairments ◽  
Stroke Patients ◽  
Brainstem Response

Background: Stroke survivors may suffer from a range of hearing impairments that may restrict their participation in postacute rehabilitation programs. Hearing impairment may have a significant impact on listening, linguistic skills, and overall communication of the affected stroke patient. However, no studies sought to systematically characterize auditory function of stroke patients in detail, to establish the different types of hearing impairments in this cohort of patients. Such information would be clinically useful in understanding and addressing the hearing needs of stroke survivors. Purpose: The present study aimed to characterize and classify the hearing impairments, using a detailed audiological assessment test battery, in order to determine the level of clinical need and inform appropriate rehabilitation for this patient population. Research Design: A case–control study. Study Sample: Forty-two recruited stroke patients who were discharged from a stroke unit and 40 control participants matched for age. Data Collection and Analysis: All participants underwent pure-tone audiometry and immittance measurements including acoustic reflex threshold, transient-evoked otoacoustic emissions, auditory-evoked brainstem response, and a central auditory processing assessment battery, performed in a single session. Hearing impairments were classified as peripheral hearing loss (cochlear and neural type), central auditory processing disorder (CAPD), and as a combination of CAPD and peripheral hearing loss. Results: Overall mean hearing thresholds were not significantly different between the control and stroke groups. The most common type of hearing impairment in stroke patients was the combination type, “peripheral and CAPD,” in the 61- to 80-yr-old subgroup (in 55%), and auditory processing deficits in 18- to 60-yr-olds (in 40%), which were both significantly higher than in controls. Conclusions: This is the first study to examine hearing function in detail in stroke patients. Given the importance of hearing for the efficiency of communication, it is essential to identify hearing impairments and differentiate peripheral and central deficits to define an appropriate intervention plan.

scholarly journals Development and Initial Validation of the Lifetime Exposure to Noise and Solvents Questionnaire in U.S. Service Members and Veterans

2021 ◽  
pp. 1-15
Author(s):  
Susan E. Griest-Hines ◽  
Naomi F. Bramhall ◽  
Kelly M. Reavis ◽  
Sarah M. Theodoroff ◽  
James A. Henry
Keyword(s):  
Hearing Loss ◽  
Military Service ◽  
Impulse Noise ◽  
Noise Exposure ◽  
Service Members ◽  
Exposure Group ◽  
Validity And Reliability ◽  
Initial Validation ◽  
Lifetime Exposure ◽  
Hearing Difficulties

Purpose A need exists to investigate the short- and long-term impact of noise exposures during and following military service on auditory health. Currently available questionnaires are limited in their ability to meet this need because of (a) inability to evaluate noise exposures beyond a limited time frame, (b) lack of consensus on scoring, (c) inability to assess impulse exposures (e.g., firearm use), (d) lack of a single questionnaire that assesses both military and nonmilitary exposures, and (e) lack of validity and reliability data. To address these limitations, the Lifetime Exposure to Noise and Solvents Questionnaire (LENS-Q) was developed. The purpose of this report is to describe the development and initial validation of the LENS-Q as a measure of self-reported noise exposure. Method Six hundred ninety participants, consisting of current Service members and recently military-separated (within about 2.5 years) Veterans, completed the LENS-Q, additional study questionnaires, and comprehensive audiometric testing. Noise exposure scores were computed from LENS-Q responses using a simple scoring algorithm that distinguishes between different cumulative levels of exposure and allows for the inclusion of both continuous and impulse noise exposures. Results The LENS-Q demonstrates good construct validity as evidenced by measures of hearing loss, tinnitus, and subjective hearing difficulties all increasing with an increase in noise exposure scores. A logistic regression, adjusting for age and sex, revealed that participants in the highest exposure group were 2.4–3.9 times more likely to experience hearing loss, 2.7–2.8 times more likely to experience tinnitus, and 3.0–3.7 times more likely to report hearing difficulties compared with individuals in the lowest exposure group. Conclusions The LENS-Q captures noise exposure over an individual's lifetime and provides an alternative scoring metric capable of representing exposure to both continuous and impulse noise. Findings suggest that the LENS-Q is a valuable tool for capturing and measuring both military and nonmilitary noise exposure. Supplemental Material https://doi.org/10.23641/asha.14582937

Lateral Superior Olive

2019 ◽  
pp. 328-394 ◽  
Author(s):  
Eckhard Friauf ◽  
Elisa G. Krächan ◽  
Nicolas I.C. Müller
Keyword(s):  
Neural Plasticity ◽  
Auditory Processing ◽  
Sound Intensity ◽  
Inhibitory Synapses ◽  
Superior Olivary Complex ◽  
Central Auditory Processing ◽  
Spatial Cues ◽  
Lateral Superior Olive ◽  
Superior Olive ◽  
Interaural Level Differences

Auditory neurons in the mammalian brainstem are involved in several basic computation processes essential for survival; for example, sound localization. Differences in sound intensity between the two ears, so-called interaural level differences (ILDs), provide important spatial cues for localizing sound in the horizontal plane, particularly for animals with high-frequency hearing. The earliest center of ILD detection is the lateral superior olive (LSO), a prominent component of the superior olivary complex (SOC) in the medulla oblongata. LSO neurons receive input from both ears of excitatory and inhibitory nature and perform a subtraction-like process. The LSO has become a model system for studies addressing inhibitory synapses, map formation, and neural plasticity. This review aims to provide an overview of several facets of the LSO, focusing on its functional and anatomical organization, including development and plasticity. Understanding this important ILD detector is fundamental in multiple ways—among others, to analyze central auditory processing disorders and central presbyacusis.

scholarly journals Research and Discussion on the Relationships between Noise-Induced Hearing Loss and ATP2B2 Gene Polymorphism

2019 ◽  
Vol 2019 ◽  
pp. 1-8
Author(s):  
Suhao Zhang ◽  
Enmin Ding ◽  
Haoyang Yin ◽  
Hengdong Zhang ◽  
Baoli Zhu
Keyword(s):  
Hearing Loss ◽  
Gene Polymorphism ◽  
Noise Exposure ◽  
Venous Blood ◽  
Pure Tone Audiometry ◽  
Control Group ◽  
Case Group ◽  
Noise Induced Hearing Loss ◽  
Cochlear Hair Cells ◽  
Potential Biomarker

Long-term and continuous noise exposure can result in noise-induced hearing loss (NIHL), which is a worldwide problem resulting from the interaction of environmental and genetic factors. The ATP2B2 gene polymorphism can destroy cochlear hair cells and increase the risk of NIHL. A case-control study of 760 Chinese textile workers was conducted to investigate the relationship between ATP2B2 polymorphisms and NIHL susceptibility. Venous blood was collected and questionnaires were conducted by professional physicians. A case group and a control group which were typed by individuals’ pure-tone audiometry test results were set. Three polymorphism sites of ATP2B2 were genotyped by using the PCR technique. Analysis results revealed that the C allele of rs3209637 (95%CI=1.08–2.58, odds ratio OR=1.67, P=0.027) was a dangerous factor and could add to risks of NIHL in the Chinese employees. The data of stratified analysis revealed that individuals who are exposed to noise>95 dB with the rs3209637 C genotype have a higher susceptibility to NIHL (OR=1.34, 95%CI=1.07–1.68). Multifactor dimensionality reduction analysis revealed that the interaction between rs14154 and rs3209637 is linked to increased NIHL risk, and for the interaction among rs14154, smoking and drinking had the same function (OR=1.54 and 1.77, 95%CI=1.15–2.07, 1.33–2.37, and P=0.0037 and P<0.0001, respectively). Our results suggest that genetic polymorphism rs3209637 C within ATP2B2 is a risk factor for NIHL among Chinese employees and rs3209637 C could be a potential biomarker for NIHL patients.

scholarly journals Roles of Key Ion Channels and Transport Proteins in Age-Related Hearing Loss

2021 ◽  
Vol 22 (11) ◽  
pp. 6158
Author(s):  
Parveen Bazard ◽  
Robert D. Frisina ◽  
Alejandro A. Acosta ◽  
Sneha Dasgupta ◽  
Mark A. Bauer ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Ion Channels ◽  
Auditory System ◽  
Auditory Processing ◽  
Mechanical Energy ◽  
Transport Proteins ◽  
Oval Window ◽  
Cochlear Hair Cells ◽  
Age Related ◽  
Age Related Hearing Loss

The auditory system is a fascinating sensory organ that overall, converts sound signals to electrical signals of the nervous system. Initially, sound energy is converted to mechanical energy via amplification processes in the middle ear, followed by transduction of mechanical movements of the oval window into electrochemical signals in the cochlear hair cells, and finally, neural signals travel to the central auditory system, via the auditory division of the 8th cranial nerve. The majority of people above 60 years have some form of age-related hearing loss, also known as presbycusis. However, the biological mechanisms of presbycusis are complex and not yet fully delineated. In the present article, we highlight ion channels and transport proteins, which are integral for the proper functioning of the auditory system, facilitating the diffusion of various ions across auditory structures for signal transduction and processing. Like most other physiological systems, hearing abilities decline with age, hence, it is imperative to fully understand inner ear aging changes, so ion channel functions should be further investigated in the aging cochlea. In this review article, we discuss key various ion channels in the auditory system and how their functions change with age. Understanding the roles of ion channels in auditory processing could enhance the development of potential biotherapies for age-related hearing loss.

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