Noise-Induced Structural Damage to the Cochlea

Hu, Bohua

doi:10.1007/978-1-4419-9523-0_5

Cited by 20 publications

(8 citation statements)

References 104 publications

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“…Thus, taken together, the data appear to suggest the agents that reduce TTS are likely to reduce PTS, but, failure to reduce TTS does not preclude the possibility that an agent will reduce PTS. These findings are consistent with existing data on the histopathological correlates of TTS and PTS (Wang et al, 2002; for recent review, see Hu, 2011) as well as the molecular response to TTS and PTS-inducing sounds (Yamashita et al, 2008). We stress the need for additional confirmatory data in PTS trials in order to extrapolate from protection against TTS to protection against PTS.…”

Section: Introductionsupporting

confidence: 91%

Digital Music Exposure Reliably Induces Temporary Threshold Shift in Normal-Hearing Human Subjects

et al. 2012

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Objectives One of the challenges for evaluating new otoprotective agents for potential benefit in human populations is availability of an established clinical paradigm with real world relevance. These studies were explicitly designed to develop a real-world digital music exposure that reliably induces temporary threshold shift (TTS) in normal hearing human subjects. Design Thirty-three subjects participated in studies that measured effects of digital music player use on hearing. Subjects selected either rock or pop music, which was then presented at 93–95 (n=10), 98–100 (n=11), or 100–102 (n=12) dBA in-ear exposure level for a period of four hours. Audiograms and distortion product otoacoustic emissions (DPOAEs) were measured prior to and after music exposure. Post-music tests were initiated 15 min, 1 hr 15 min, 2 hr 15 min, and 3 hr 15 min after the exposure ended. Additional tests were conducted the following day and one week later. Results Changes in thresholds after the lowest level exposure were difficult to distinguish from test-retest variability; however, TTS was reliably detected after higher levels of sound exposure. Changes in audiometric thresholds had a “notch” configuration, with the largest changes observed at 4 kHz (mean=6.3±3.9dB; range=0–13 dB). Recovery was largely complete within the first 4 hours post-exposure, and all subjects showed complete recovery of both thresholds and DPOAE measures when tested 1-week post-exposure. Conclusions These data provide insight into the variability of TTS induced by music player use in a healthy, normal-hearing, young adult population, with music playlist, level, and duration carefully controlled. These data confirm the likelihood of temporary changes in auditory function following digital music player use. Such data are essential for the development of a human clinical trial protocol that provides a highly powered design for evaluating novel therapeutics in human clinical trials. Care must be taken to fully inform potential subjects in future TTS studies, including protective agent evaluations, that some noise exposures have resulted in neural degeneration in animal models, even when both audiometric thresholds and DPOAE levels returned to pre-exposure values.

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Section: Introductionsupporting

confidence: 91%

Digital Music Exposure Reliably Induces Temporary Threshold Shift in Normal-Hearing Human Subjects

et al. 2012

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“…Exposure to loud sound has the potential to damage cells in the inner ear. It has long been known that the outer hair cells (OHCs) are particularly vulnerable to noise injury (Wang, Hirose, and Liberman 2002; for review, see Hu 2012), as well as other diverse insults such as occupational chemical exposure (for review, see Morata and Johnson 2012) and ototoxic drugs including aminoglycoside antibiotics and chemotherapeutics (for review, see Campbell and Le Prell 2018). More recently, it has become clear that the synapses connecting the inner hair cells (IHCs) to the auditory nerve dendrites are also vulnerable to loss as a consequence of noise (for review, see Kujawa and Liberman 2015), aminoglycoside antibiotics (Hinojosa and Lerner, 1987) and aging (Sergeyenko et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

Effects of noise exposure on auditory brainstem response and speech-in-noise tasks: a review of the literature

Prell

2018

International Journal of Audiology

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Objective: Short-term noise exposure that induces transient changes in thresholds has induced permanent cochlear synaptopathy in multiple species. Here, the literature was reviewed to gain translational insight into the relationships between noise exposure, ABR metrics, speech-in-noise performance and TTS in humans. Design: PubMed-based literature search, retrieval and review of full-text articles. Study Sample: Peerreviewed literature identified using PubMed search. Results: Permanent occupational noise-induced hearing loss (NIHL) is frequently accompanied by abnormal ABR amplitude and latency. In the absence of NIHL, there are mixed results for relationships between noise exposure and ABR metrics. Interpretation of speech-in-noise deficits is difficult as both cochlear synaptopathy and outer hair cell (OHC) loss can drive deficits. Reductions in Wave I amplitude during TTS may reflect temporary OHC pathology rather than cochlear synaptopathy. Use of diverse protocols across studies reduces the ability to compare outcomes across studies. Conclusions: Longitudinal ABR and speech-in-noise data collected using consistent protocols are needed. Although speech-in-noise testing may not reflect cochlear synaptopathy, speech-in-noise testing should be completed as part of a comprehensive test battery to provide the objective measurement of patient difficulty.

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“…Noise exposure causes structural damage to the cochlear sensory epithelium, particularly to its sensory cells. While the functional and pathological impacts of acoustic trauma have been thoroughly documented (Saunders et al, 1985; Raphael and Altschuler, 1991; Raphael et al, 1993; Henderson et al, 2006; Bohne et al, 2007; Hu, 2012), the molecular mechanisms responsible for these functional and structural changes remain elusive.…”

Section: Introductionmentioning

confidence: 99%

Metalloproteinases and Their Associated Genes Contribute to the Functional Integrity and Noise-Induced Damage in the Cochlear Sensory Epithelium

Cai

et al. 2012

J. Neurosci.

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Matrix metalloproteinases (MMPs) and their related gene products regulate essential cellular functions. An imbalance in MMPs has been implicated in various neurological disorders, including traumatic injuries. Here, we report a role for MMPs and their related gene products in the modulation of cochlear responses to acoustic trauma in rats. The normal cochlea was shown to be enriched in MMP enzymatic activity, and this activity was reduced in a time-dependent fashion after traumatic noise injury. The analysis of gene expression by RNA-seq and qRT-PCR revealed the differential expression of MMPs and their related genes between functionally specialized regions of the sensory epithelium. The expression of these genes was dynamically regulated between the acute and chronic phases of noise-induced hearing loss. Moreover, noise-induced expression changes in two endogenous MMP inhibitors, Timp1 and Timp2, in sensory cells were dependent upon the stage of nuclear condensation, suggesting a specific role for MMP activity in sensory cell apoptosis. A short-term application of doxycycline, a broad-spectrum inhibitor of MMPs, prior to noise exposure reduced noise-induced hearing loss and sensory cell death. By contrast, a 7-day treatment compromised hearing sensitivity and potentiated noise-induced hearing loss. This detrimental effect of the long-term inhibition of MMPs on noise-induced hearing loss was further confirmed using targeted Mmp7 knockout mice. Together, these observations suggest that MMPs and their related genes participate in the regulation of cochlear responses to acoustic overstimulation and that the modulation of MMP activity can serve as a novel therapeutic target for the reduction of noise-induced cochlear damage.

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Noise-Induced Structural Damage to the Cochlea

Cited by 20 publications

References 104 publications

Digital Music Exposure Reliably Induces Temporary Threshold Shift in Normal-Hearing Human Subjects

Digital Music Exposure Reliably Induces Temporary Threshold Shift in Normal-Hearing Human Subjects

Effects of noise exposure on auditory brainstem response and speech-in-noise tasks: a review of the literature

Metalloproteinases and Their Associated Genes Contribute to the Functional Integrity and Noise-Induced Damage in the Cochlear Sensory Epithelium

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