Effects of long-term non-traumatic noise exposure on the adult central auditory system. Hearing problems without hearing loss

Noise exposure leads to an immediate hearing loss and is followed by a long-lasting permanent threshold shift, accompanied by changes of cellular properties within the central auditory pathway. Electrophysiological recordings have demonstrated an upregulation of spontaneous neuronal activity. It is still discussed if the observed effects are related to changes of peripheral input or evoked within the central auditory system. The present study should describe the intrinsic temporal patterns of single-unit activity upon noise-induced hearing loss of the dorsal and ventral cochlear nucleus (DCN and VCN) and the inferior colliculus (IC) in adult mouse brain slices. Recordings showed a slight, but significant, elevation in spontaneous firing rates in DCN and VCN immediately after noise trauma, whereas no differences were found in IC. One week postexposure, neuronal responses remained unchanged compared to controls. At 14 days after noise trauma, intrinsic long-term hyperactivity in brain slices of the DCN and the IC was detected for the first time. Therefore, increase in spontaneous activity seems to develop within the period of two weeks, but not before day 7. The results give insight into the complex temporal neurophysiological alterations after noise trauma, leading to a better understanding of central mechanisms in noise-induced hearing loss.

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Amino acid concentrations in the hamster central auditory system and long-term effects of intense tone exposure

Journal of Neuroscience Research ◽

10.1002/jnr.23095 ◽

2012 ◽

Vol 90 (11) ◽

pp. 2214-2224 ◽

Cited By ~ 17

Author(s):

Donald A. Godfrey ◽

James A. Kaltenbach ◽

Kejian Chen ◽

Omer Ilyas ◽

Xiaochen Liu ◽

...

Keyword(s):

Amino Acid ◽

Auditory System ◽

Central Auditory System ◽

Long Term Effects ◽

Amino Acid Concentrations

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Evoked Potentials Reveal Noise Exposure–Related Central Auditory Changes Despite Normal Audiograms

American Journal of Audiology ◽

10.1044/2019_aja-19-00060 ◽

2020 ◽

Vol 29 (2) ◽

pp. 152-164 ◽

Cited By ~ 3

Author(s):

Naomi F. Bramhall ◽

Christopher E. Niemczak ◽

Sean D. Kampel ◽

Curtis J. Billings ◽

Garnett P. McMillan

Keyword(s):

Auditory System ◽

Noise Exposure ◽

Otoacoustic Emission ◽

Auditory Brainstem ◽

Auditory Nerve Fiber ◽

Central Auditory System ◽

Distortion Product Otoacoustic Emission ◽

Distortion Product ◽

Brainstem Response ◽

Latency Response

Purpose Complaints of auditory perceptual deficits, such as tinnitus and difficulty understanding speech in background noise, among individuals with clinically normal audiograms present a perplexing problem for audiologists. One potential explanation for these “hidden” auditory deficits is loss of the synaptic connections between the inner hair cells and their afferent auditory nerve fiber targets, a condition that has been termed cochlear synaptopathy . In animal models, cochlear synaptopathy can occur due to aging or exposure to noise or ototoxic drugs and is associated with reduced auditory brainstem response (ABR) wave I amplitudes. Decreased ABR wave I amplitudes have been demonstrated among young military Veterans and non-Veterans with a history of firearm use, suggesting that humans may also experience noise-induced synaptopathy. However, the downstream consequences of synaptopathy are unclear. Method To investigate how noise-induced reductions in wave I amplitude impact the central auditory system, the ABR, the middle latency response (MLR), and the late latency response (LLR) were measured in 65 young Veterans and non-Veterans with normal audiograms. Results In response to a click stimulus, the MLR was weaker for Veterans compared to non-Veterans, but the LLR was not reduced. In addition, low ABR wave I amplitudes were associated with a reduced MLR, but with an increased LLR. Notably, Veterans reporting tinnitus showed the largest mean LLRs. Conclusions These findings indicate that decreased peripheral auditory input leads to compensatory gain in the central auditory system, even among individuals with normal audiograms, and may impact auditory perception. This pattern of reduced MLR, but not LLR, was observed among Veterans even after statistical adjustment for sex and distortion product otoacoustic emission differences, suggesting that synaptic loss plays a role in the observed central gain. Supplemental Material https://doi.org/10.23641/asha.11977854

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Occupational Exposure to Noise and Age-related Hearing Loss in an Elderly Population of Southern Italy

The Open Public Health Journal ◽

10.2174/1874944502013010069 ◽

2020 ◽

Vol 13 (1) ◽

pp. 69-74 ◽

Cited By ~ 1

Author(s):

Luigi De Maria ◽

Antonio Caputi ◽

Rodolfo Sardone ◽

Enza Sabrina Silvana Cannone ◽

Francesca Mansi ◽

...

Keyword(s):

Hearing Loss ◽

Occupational Exposure ◽

Elderly Population ◽

Noise Exposure ◽

Exposed Population ◽

Age Related ◽

Age Dependent ◽

Occupationally Exposed ◽

Age Related Hearing Loss

Background: Age-Related Hearing Loss (ARHL) is a gradual and irreversible age-dependent decline in auditory function. There is still no consensus on the long-term functional effects of noise exposure on ARHL. Objective: This study aimed to compare the prevalence of ARHL in an elderly population occupationally exposed to noise in a non-exposed population. Methods: The population was divided into two groups: a group of 482 subjects professionally exposed to noise for over 10 years and a group of 1129 non-exposed subjects. Among the exposed subjects, a subgroup of 298 who worked for over 10 years in the glassware industry was selected. All the participants underwent a thorough otorhinolaryngological examination. Results: The presence of ARHL was found in 81% of exposed subjects and in 4% of non-exposed subjects. In the sub-group of glassware workers, the prevalence was 88%. The statistical analysis showed a significant association between previous occupational exposure to noise and ARHL (OR = 1.09; 95% CI = 1.067-1.124; p = 0.0012) and between exposure to the glassware industry and ARHL (OR = 1.89; 95% CI = 1.78-1.96; p = 0.006). Conclusion: Consistent with recent studies, we found a significantly higher prevalence of ARHL among workers exposed to noise; however, further studies are needed to support these findings.

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Effects of chemotherapy on the auditory system of children with cancer: a systematic literature review

Revista CEFAC ◽

10.1590/1982-0216/202022213919 ◽

2020 ◽

Vol 22 (2) ◽

Author(s):

Nila Berbardes Lopes ◽

Liliane Aparecida Fagundes Silva ◽

Alessandra Giannella Samelli ◽

Carla Gentile Matas

Keyword(s):

Hearing Loss ◽

Children And Adolescents ◽

Auditory System ◽

Otoacoustic Emissions ◽

Scientific Evidence ◽

Cochlear Function ◽

Children With Cancer ◽

Chemotherapy Drugs ◽

High Incidence

ABSTRACT Purpose: to identify and analyze the effects of chemotherapy on the auditory system of children and/or adolescents with cancer treated with cisplatin and carboplatin, assessed through standardized audiological procedures. Methods: studies in Brazilian Portuguese and in English were searched for, as available in the databases Science Direct, PubMed, LILACS, BIREME, Embase, SciELO, Web of Science and Cochrane. The descriptors were: Hearing Loss, Audiology, Child Cancer, Chemotherapy, and Child. Articles with levels 1 and 2 of scientific evidence, published in the last 20 years (1997 to 2017), were considered, of which the audiological results were analyzed, as well as the prevalence of hearing loss in children with cancer undergoing chemotherapy. Results: 3,625 articles were found, of which only 23 were selected for analysis in the present review. Studies have shown a high incidence of sensorineural hearing loss and decrease or even loss of otoacoustic emissions in children and adolescents with cancer, even after the first dose of chemotherapy drugs, with high frequencies being the most affected. Conclusion: there is evidence that both carboplatin and especially cisplatin from the first doses may impair the hearing of children and adolescents, mainly affecting the cochlear function, thus, the importance of long-term audiological monitoring.

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