51
|
Grinn SK, Wiseman KB, Baker JA, Le Prell CG. Hidden Hearing Loss? No Effect of Common Recreational Noise Exposure on Cochlear Nerve Response Amplitude in Humans. Front Neurosci 2017; 11:465. [PMID: 28919848 PMCID: PMC5585187 DOI: 10.3389/fnins.2017.00465] [Citation(s) in RCA: 97] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2017] [Accepted: 08/07/2017] [Indexed: 11/22/2022] Open
Abstract
This study tested hypothesized relationships between noise exposure and auditory deficits. Both retrospective assessment of potential associations between noise exposure history and performance on an audiologic test battery and prospective assessment of potential changes in performance after new recreational noise exposure were completed. Methods: 32 participants (13M, 19F) with normal hearing (25-dB HL or better, 0.25–8 kHz) were asked to participate in 3 pre- and post-exposure sessions including: otoscopy, tympanometry, distortion product otoacoustic emissions (DPOAEs) (f2 frequencies 1–8 kHz), pure-tone audiometry (0.25–8 kHz), Words-in-Noise (WIN) test, and electrocochleography (eCochG) measurements at 70, 80, and 90-dB nHL (click and 2–4 kHz tone-bursts). The first session was used to collect baseline data, the second session was collected the day after a loud recreational event, and the third session was collected 1-week later. Of the 32 participants, 26 completed all 3 sessions. Results: The retrospective analysis did not reveal statistically significant relationships between noise exposure history and any auditory deficits. The day after new exposure, there was a statistically significant correlation between noise “dose” and WIN performance overall, and within the 4-dB signal-to-babble ratio. In contrast, there were no statistically significant correlations between noise dose and changes in threshold, DPOAE amplitude, or AP amplitude the day after new noise exposure. Additional analyses revealed a statistically significant relationship between TTS and DPOAE amplitude at 6 kHz, with temporarily decreased DPOAE amplitude observed with increasing TTS. Conclusions: There was no evidence of auditory deficits as a function of previous noise exposure history, and no permanent changes in audiometric, electrophysiologic, or functional measures after new recreational noise exposure. There were very few participants with TTS the day after exposure - a test time selected to be consistent with previous animal studies. The largest observed TTS was approximately 20-dB. The observed pattern of small TTS suggests little risk of synaptopathy from common recreational noise exposure, and that we should not expect to observe changes in evoked potentials for this reason. No such changes were observed in this study. These data do not support suggestions that common, recreational noise exposure is likely to result in “hidden hearing loss”.
Collapse
Affiliation(s)
- Sarah K Grinn
- School of Behavioral and Brain Sciences, University of Texas at DallasDallas, TX, United States.,College of Public Health and Health Professions, University of FloridaGainesville, FL, United States
| | - Kathryn B Wiseman
- School of Behavioral and Brain Sciences, University of Texas at DallasDallas, TX, United States
| | - Jason A Baker
- School of Behavioral and Brain Sciences, University of Texas at DallasDallas, TX, United States
| | - Colleen G Le Prell
- School of Behavioral and Brain Sciences, University of Texas at DallasDallas, TX, United States
| |
Collapse
|
52
|
Sagers JE, Landegger LD, Worthington S, Nadol JB, Stankovic KM. Human Cochlear Histopathology Reflects Clinical Signatures of Primary Neural Degeneration. Sci Rep 2017; 7:4884. [PMID: 28687782 PMCID: PMC5501826 DOI: 10.1038/s41598-017-04899-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Accepted: 05/22/2017] [Indexed: 01/22/2023] Open
Abstract
Auditory neuropathy is a significant and understudied cause of human hearing loss, diagnosed in patients who demonstrate abnormal function of the cochlear nerve despite typical function of sensory cells. Because the human inner ear cannot be visualized during life, histopathological analysis of autopsy specimens is critical to understanding the cellular mechanisms underlying this pathology. Here we present statistical models of severe primary neuronal degeneration and its relationship to pure tone audiometric thresholds and word recognition scores in comparison to age-matched control patients, spanning every decade of life. Analysis of 30 ears from 23 patients shows that severe neuronal loss correlates with elevated audiometric thresholds and poor word recognition. For each ten percent increase in total neuronal loss, average thresholds across patients at each audiometric test frequency increase by 6.0 dB hearing level (HL). As neuronal loss increases, threshold elevation proceeds more rapidly in low audiometric test frequencies than in high frequencies. Pure tone average closely agrees with word recognition scores in the case of severe neural pathology. Histopathologic study of the human inner ear continues to emphasize the need for non- or minimally invasive clinical tools capable of establishing cellular-level diagnoses.
Collapse
Affiliation(s)
- Jessica E Sagers
- Eaton-Peabody Laboratories, Department of Otolaryngology, Massachusetts Eye and Ear, Boston, MA, 02114, United States.,Program in Speech and Hearing Bioscience and Technology, Harvard Medical School, Boston, MA, 02114, United States
| | - Lukas D Landegger
- Eaton-Peabody Laboratories, Department of Otolaryngology, Massachusetts Eye and Ear, Boston, MA, 02114, United States.,Department of Otolaryngology, Vienna General Hospital, Medical University of Vienna, Vienna, 1090, Austria.,Department of Otolaryngology, Harvard Medical School, Boston, MA, 02114, United States
| | - Steven Worthington
- Harvard Institute for Quantitative Social Science, Harvard University, Cambridge, MA, 02138, USA
| | - Joseph B Nadol
- Eaton-Peabody Laboratories, Department of Otolaryngology, Massachusetts Eye and Ear, Boston, MA, 02114, United States.,Department of Otolaryngology, Harvard Medical School, Boston, MA, 02114, United States
| | - Konstantina M Stankovic
- Eaton-Peabody Laboratories, Department of Otolaryngology, Massachusetts Eye and Ear, Boston, MA, 02114, United States. .,Program in Speech and Hearing Bioscience and Technology, Harvard Medical School, Boston, MA, 02114, United States. .,Department of Otolaryngology, Harvard Medical School, Boston, MA, 02114, United States.
| |
Collapse
|
53
|
Du X, West MB, Cai Q, Cheng W, Ewert DL, Li W, Floyd RA, Kopke RD. Antioxidants reduce neurodegeneration and accumulation of pathologic Tau proteins in the auditory system after blast exposure. Free Radic Biol Med 2017; 108:627-643. [PMID: 28438658 DOI: 10.1016/j.freeradbiomed.2017.04.343] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Revised: 04/17/2017] [Accepted: 04/21/2017] [Indexed: 12/31/2022]
Abstract
Cochlear neurodegeneration commonly accompanies hair cell loss resulting from aging, ototoxicity, or exposures to intense noise or blast overpressures. However, the precise pathophysiological mechanisms that drive this degenerative response have not been fully elucidated. Our laboratory previously demonstrated that non-transgenic rats exposed to blast overpressures exhibited marked somatic accumulation of neurotoxic variants of the microtubule-associated protein, Tau, in the hippocampus. In the present study, we extended these analyses to examine neurodegeneration and pathologic Tau accumulation in the auditory system in response to blast exposure and evaluated the potential therapeutic efficacy of antioxidants on short-circuiting this pathological process. Blast injury induced ribbon synapse loss and retrograde neurodegeneration in the cochlea in untreated animals. An accompanying perikaryal accumulation of neurofilament light chain and pathologic Tau oligomers were observed in neurons from both the peripheral and central auditory system, spanning from the spiral ganglion to the auditory cortex. Due to its coincident accumulation pattern and well-documented neurotoxicity, our results suggest that the accumulation of pathologic Tau oligomers may actively contribute to blast-induced cochlear neurodegeneration. Therapeutic intervention with a combinatorial regimen of 2,4-disulfonyl α-phenyl tertiary butyl nitrone (HPN-07) and N-acetylcysteine (NAC) significantly reduced both pathologic Tau accumulation and indications of ongoing neurodegeneration in the cochlea and the auditory cortex. These results demonstrate that a combination of HPN-07 and NAC administrated shortly after a blast exposure can serve as a potential therapeutic strategy for preserving auditory function among military personnel or civilians with blast-induced traumatic brain injuries.
Collapse
Affiliation(s)
| | | | | | | | | | - Wei Li
- Hough Ear Institute, Oklahoma City, OK, USA
| | - Robert A Floyd
- Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - Richard D Kopke
- Hough Ear Institute, Oklahoma City, OK, USA; Oklahoma Medical Research Foundation, Oklahoma City, OK, USA; Departments of Physiology and Otolaryngology, University of Oklahoma Health Sciences Center, Oklahoma City 73014, USA.
| |
Collapse
|
54
|
Landegger LD, Dilwali S, Stankovic KM. Neonatal Murine Cochlear Explant Technique as an In Vitro Screening Tool in Hearing Research. J Vis Exp 2017. [PMID: 28654047 DOI: 10.3791/55704] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
While there have been remarkable advances in hearing research over the past few decades, there is still no cure for Sensorineural Hearing Loss (SNHL), a condition that typically involves damage to or loss of the delicate mechanosensory structures of the inner ear. Sophisticated in vitro and ex vivo assays have emerged in recent years, enabling the screening of an increasing number of potentially therapeutic compounds while minimizing resources and accelerating efforts to develop cures for SNHL. Though homogenous cultures of certain cell types continue to play an important role in current research, many scientists now rely on more complex organotypic cultures of murine inner ears, also known as cochlear explants. The preservation of organized cellular structures within the inner ear facilitates the in situ evaluation of various components of the cochlear infrastructure, including inner and outer hair cells, spiral ganglion neurons, neurites, and supporting cells. Here we present the preparation, culture, treatment, and immunostaining of neonatal murine cochlear explants. The careful preparation of these explants facilitates the identification of mechanisms that contribute to SNHL and constitutes a valuable tool for the hearing research community.
Collapse
Affiliation(s)
- Lukas D Landegger
- Eaton Peabody Laboratories, Department of Otolaryngology, Massachusetts Eye and Ear; Department of Otolaryngology, Harvard Medical School; Department of Otolaryngology, Vienna General Hospital, Medical University of Vienna
| | - Sonam Dilwali
- Eaton Peabody Laboratories, Department of Otolaryngology, Massachusetts Eye and Ear; Harvard Program in Speech and Hearing Bioscience and Technology
| | - Konstantina M Stankovic
- Eaton Peabody Laboratories, Department of Otolaryngology, Massachusetts Eye and Ear; Department of Otolaryngology, Harvard Medical School; Harvard Program in Speech and Hearing Bioscience and Technology;
| |
Collapse
|
55
|
Noise-induced cochlear synaptopathy: Past findings and future studies. Hear Res 2017; 349:148-154. [DOI: 10.1016/j.heares.2016.12.008] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Revised: 11/08/2016] [Accepted: 12/08/2016] [Indexed: 01/12/2023]
|
56
|
Hickox AE, Larsen E, Heinz MG, Shinobu L, Whitton JP. Translational issues in cochlear synaptopathy. Hear Res 2017; 349:164-171. [PMID: 28069376 DOI: 10.1016/j.heares.2016.12.010] [Citation(s) in RCA: 107] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Revised: 12/15/2016] [Accepted: 12/16/2016] [Indexed: 10/20/2022]
Abstract
Understanding the biology of the previously underappreciated sensitivity of cochlear synapses to noise insult, and its clinical consequences, is becoming a mission for a growing number of auditory researchers. In addition, several research groups have become interested in developing therapeutic approaches that can reverse synaptopathy and restore hearing function. One of the major challenges to realizing the potential of synaptopathy rodent models is that current clinical audiometric approaches cannot yet reveal the presence of this subtle cochlear pathology in humans. This has catalyzed efforts, both from basic and clinical perspectives, to investigate novel means for diagnosing synaptopathy and to determine the main functional consequences for auditory perception and hearing abilities. Such means, and a strong concordance between findings in pre-clinical animal models and clinical studies in humans, are important for developing and realizing therapeutics. This paper frames the key outstanding translational questions that need to be addressed to realize this ambitious goal.
Collapse
Affiliation(s)
- Ann E Hickox
- Decibel Therapeutics, 215 First St, Cambridge, MA, 02142, USA.
| | - Erik Larsen
- Decibel Therapeutics, 215 First St, Cambridge, MA, 02142, USA.
| | - Michael G Heinz
- Speech, Language, and Hearing Sciences and Biomedical Engineering, Purdue University, 715 Clinic Drive, West Lafayette, IN, 47907, USA.
| | - Leslie Shinobu
- Decibel Therapeutics, 215 First St, Cambridge, MA, 02142, USA.
| | | |
Collapse
|
57
|
Grose JH, Buss E, Hall JW. Loud Music Exposure and Cochlear Synaptopathy in Young Adults: Isolated Auditory Brainstem Response Effects but No Perceptual Consequences. Trends Hear 2017; 21:2331216517737417. [PMID: 29105620 PMCID: PMC5676494 DOI: 10.1177/2331216517737417] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Accepted: 09/21/2017] [Indexed: 01/20/2023] Open
Abstract
The purpose of this study was to test the hypothesis that listeners with frequent exposure to loud music exhibit deficits in suprathreshold auditory performance consistent with cochlear synaptopathy. Young adults with normal audiograms were recruited who either did ( n = 31) or did not ( n = 30) have a history of frequent attendance at loud music venues where the typical sound levels could be expected to result in temporary threshold shifts. A test battery was administered that comprised three sets of procedures: (a) electrophysiological tests including distortion product otoacoustic emissions, auditory brainstem responses, envelope following responses, and the acoustic change complex evoked by an interaural phase inversion; (b) psychoacoustic tests including temporal modulation detection, spectral modulation detection, and sensitivity to interaural phase; and (c) speech tests including filtered phoneme recognition and speech-in-noise recognition. The results demonstrated that a history of loud music exposure can lead to a profile of peripheral auditory function that is consistent with an interpretation of cochlear synaptopathy in humans, namely, modestly abnormal auditory brainstem response Wave I/Wave V ratios in the presence of normal distortion product otoacoustic emissions and normal audiometric thresholds. However, there were no other electrophysiological, psychophysical, or speech perception effects. The absence of any behavioral effects in suprathreshold sound processing indicated that, even if cochlear synaptopathy is a valid pathophysiological condition in humans, its perceptual sequelae are either too diffuse or too inconsequential to permit a simple differential diagnosis of hidden hearing loss.
Collapse
Affiliation(s)
- John H. Grose
- Department of Otolaryngology—Head and Neck Surgery, University of North Carolina at Chapel Hill, NC, USA
| | - Emily Buss
- Department of Otolaryngology—Head and Neck Surgery, University of North Carolina at Chapel Hill, NC, USA
| | - Joseph W. Hall
- Department of Otolaryngology—Head and Neck Surgery, University of North Carolina at Chapel Hill, NC, USA
| |
Collapse
|
58
|
Abstract
OBJECTIVE Hearing loss is the most common sensory deficit and congenital anomaly, yet the decision-making processes involved in disclosing hearing loss have been little studied. To address this issue, we have explored the phrases that adults with hearing loss use to disclose their hearing loss. DESIGN Since self-disclosure research has not focused on hearing loss-specific issues, we created a 15-question survey about verbally disclosing hearing loss. English speaking adults (>18 years old) with hearing loss of any etiology were recruited from otology clinics in a major referral hospital. Three hundred and thirty-seven participants completed the survey instrument. Participants' phrase(s) used to tell people they have hearing loss were compared across objective characteristics (age; sex; type, degree, and laterality of hearing loss; word recognition scores) and self-reported characteristics (degree of hearing loss; age of onset and years lived with hearing loss; use of technology; hearing handicap score). RESULTS Participants' responses revealed three strategies to address hearing loss: Multipurpose disclosure (phrases that disclose hearing loss and provide information to facilitate communication), Basic disclosure (phrases that disclose hearing loss through the term, a label, or details about the condition), or nondisclosure (phrases that do not disclose hearing loss). Variables were compared between patients who used and who did not use each disclosure strategy using χ or Wilcoxon rank sum tests. Multipurpose disclosers were mostly female (p = 0.002); had experienced reactions of help, support, and accommodation after disclosing (p = 0.008); and had experienced reactions of being overly helpful after disclosing (p=0.039). Basic disclosers were predominantly male (p = 0.004); reported feeling somewhat more comfortable disclosing their hearing loss over time (p = 0.009); had not experienced reactions of being treated unfairly or discriminated against (p = 0.021); and were diagnosed with mixed hearing loss (p = 0.004). Nondisclosers tended not to disclose in a group setting (p = 0.002) and were diagnosed with bilateral hearing loss (p = 0.005). In addition, all of the variables were examined to build logistic regression models to predict the use of each disclosure strategy. CONCLUSIONS Our results reveal three simple strategies for verbally addressing hearing loss that can be used in a variety of contexts. We recommend educating people with hearing loss about these strategies-this could improve the experience of disclosing hearing loss, and could educate society at large about how to interact with those who have a hearing loss.
Collapse
|
59
|
Lobarinas E, Spankovich C, Le Prell CG. Evidence of "hidden hearing loss" following noise exposures that produce robust TTS and ABR wave-I amplitude reductions. Hear Res 2016; 349:155-163. [PMID: 28003148 DOI: 10.1016/j.heares.2016.12.009] [Citation(s) in RCA: 83] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Revised: 11/21/2016] [Accepted: 12/12/2016] [Indexed: 11/30/2022]
Abstract
In animals, noise exposures that produce robust temporary threshold shifts (TTS) can produce immediate damage to afferent synapses and long-term degeneration of low spontaneous rate auditory nerve fibers. This synaptopathic damage has been shown to correlate with reduced auditory brainstem response (ABR) wave-I amplitudes at suprathreshold levels. The perceptual consequences of this "synaptopathy" remain unknown but have been suggested to include compromised hearing performance in competing background noise. Here, we used a modified startle inhibition paradigm to evaluate whether noise exposures that produce robust TTS and ABR wave-I reduction but not permanent threshold shift (PTS) reduced hearing-in-noise performance. Animals exposed to 109 dB SPL octave band noise showed TTS >30 dB 24-h post noise and modest but persistent ABR wave-I reduction 2 weeks post noise despite full recovery of ABR thresholds. Hearing-in-noise performance was negatively affected by the noise exposure. However, the effect was observed only at the poorest signal to noise ratio and was frequency specific. Although TTS >30 dB 24-h post noise was a predictor of functional deficits, there was no relationship between the degree of ABR wave-I reduction and degree of functional impairment.
Collapse
Affiliation(s)
- Edward Lobarinas
- The University of Texas at Dallas, School of Behavioral and Brain Sciences, USA.
| | - Christopher Spankovich
- University of Mississippi Medical Center, Department of Otolaryngology and Communicative Sciences, USA
| | - Colleen G Le Prell
- The University of Texas at Dallas, School of Behavioral and Brain Sciences, USA
| |
Collapse
|
60
|
Ohlemiller KK, Jones SM, Johnson KR. Application of Mouse Models to Research in Hearing and Balance. J Assoc Res Otolaryngol 2016; 17:493-523. [PMID: 27752925 PMCID: PMC5112220 DOI: 10.1007/s10162-016-0589-1] [Citation(s) in RCA: 79] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Accepted: 09/15/2016] [Indexed: 01/10/2023] Open
Abstract
Laboratory mice (Mus musculus) have become the major model species for inner ear research. The major uses of mice include gene discovery, characterization, and confirmation. Every application of mice is founded on assumptions about what mice represent and how the information gained may be generalized. A host of successes support the continued use of mice to understand hearing and balance. Depending on the research question, however, some mouse models and research designs will be more appropriate than others. Here, we recount some of the history and successes of the use of mice in hearing and vestibular studies and offer guidelines to those considering how to apply mouse models.
Collapse
Affiliation(s)
- Kevin K Ohlemiller
- Department of Otolaryngology, Central Institute for the Deaf, Fay and Carl Simons Center for Hearing and Deafness, Washington University School of Medicine, 660 S. Euclid, Saint Louis, MO, 63110, USA.
| | - Sherri M Jones
- Department of Special Education and Communication Disorders, University of Nebraska-Lincoln, Lincoln, NE, 68583, USA
| | | |
Collapse
|
61
|
Dobie RA, Humes LE. Commentary on the regulatory implications of noise-induced cochlear neuropathy. Int J Audiol 2016; 56:74-78. [DOI: 10.1080/14992027.2016.1255359] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- Robert A. Dobie
- Department of Otolaryngology, Head and Neck Surgery, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA and
| | - Larry E. Humes
- Department of Speech and Hearing Sciences, Indiana University, Bloomington, IN, USA
| |
Collapse
|
62
|
|
63
|
Speech-in-Noise Tests and Supra-threshold Auditory Evoked Potentials as Metrics for Noise Damage and Clinical Trial Outcome Measures. Otol Neurotol 2016; 37:e295-302. [DOI: 10.1097/mao.0000000000001069] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
64
|
Le Prell CG, Fulbright A, Spankovich C, Griffiths SK, Lobarinas E, Campbell KCM, Antonelli PJ, Green GE, Guire K, Miller JM. Dietary supplement comprised of β-carotene, vitamin C, vitamin E, and magnesium: failure to prevent music-induced temporary threshold shift. AUDIOLOGY AND NEUROTOLOGY EXTRA 2016; 6:20-39. [PMID: 27990155 DOI: 10.1159/000446600] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
This study examined potential prevention of music-induced temporary threshold shift (TTS) in normal-hearing participants. A dietary supplement composed of β-carotene, vitamins C and E, and magnesium was assessed using a randomized, placebo-controlled, double-blind study design. Dosing began 3 days prior to the music exposure with the final dose consumed approximately 30-min pre-exposure. There were no group differences in post-exposure TTS or music-induced decreases in distortion product otoacoustic emission (DPOAE) amplitude. Transient tinnitus was more likely to be reported by the treatment group, but there were no group differences in perceived loudness or bothersomeness. All subjects were monitored until auditory function returned to pre-exposure levels. Taken together, this supplement had no effect on noise-induced changes in hearing. Recommendations for future clinical trials are discussed.
Collapse
Affiliation(s)
- C G Le Prell
- School of Behavioral and Brain Sciences, University of Texas at Dallas, Dallas, Tex
| | - A Fulbright
- Department of Speech, Language, and Hearing Sciences, University of Florida, Gainesville, Fla
| | - C Spankovich
- Department of Otolaryngology and Communicative Sciences, University of Mississippi Medical Center, Jackson, Miss
| | - S K Griffiths
- Department of Speech, Language, and Hearing Sciences, University of Florida, Gainesville, Fla
| | - E Lobarinas
- School of Behavioral and Brain Sciences, University of Texas at Dallas, Dallas, Tex
| | - K C M Campbell
- Department of Surgery, Southern Illinois University School of Medicine, Springfield, Ill
| | - P J Antonelli
- Department of Otolaryngology, University of Florida, Gainesville, Fla
| | - G E Green
- Department of Otolaryngology, University of Michigan, Ann Arbor, Mich
| | - K Guire
- Department of Biostatistics, University of Michigan, Ann Arbor, Mich
| | - J M Miller
- Department of Otolaryngology, University of Michigan, Ann Arbor, Mich
| |
Collapse
|
65
|
Paquette ST, Gilels F, White PM. Noise exposure modulates cochlear inner hair cell ribbon volumes, correlating with changes in auditory measures in the FVB/nJ mouse. Sci Rep 2016; 6:25056. [PMID: 27162161 PMCID: PMC4861931 DOI: 10.1038/srep25056] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Accepted: 04/08/2016] [Indexed: 12/25/2022] Open
Abstract
Cochlear neuropathy resulting from unsafe noise exposure is a life altering condition that affects many people. This hearing dysfunction follows a conserved mechanism where inner hair cell synapses are lost, termed cochlear synaptopathy. Here we investigate cochlear synaptopathy in the FVB/nJ mouse strain as a prelude for the investigation of candidate genetic mutations for noise damage susceptibility. We used measurements of auditory brainstem response (ABR) and distortion product otoacoustic emissions (DPOAE) to assess hearing recovery in FVB/nJ mice exposed to two different noise levels. We also utilized confocal fluorescence microscopy in mapped whole mount cochlear tissue, in conjunction with deconvolution and three-dimensional modeling, to analyze numbers, volumes and positions of paired synaptic components. We find evidence for significant synapse reorganization in response to both synaptopathic and sub-synaptopathic noise exposures in FVB/nJ. Specifically, we find that the modulation in volume of very small synaptic ribbons correlates with the presence of reduced ABR peak one amplitudes in both levels of noise exposures. These experiments define the use of FVB/nJ mice for further genetic investigations into the mechanisms of noise damage. They further suggest that in the cochlea, neuronal-inner hair cell connections may dynamically reshape as part of the noise response.
Collapse
Affiliation(s)
- Stephen T Paquette
- Department of Neuroscience, University of Rochester School of Medicine and Dentistry, Box 603, 601 Elmwood Avenue, Rochester, NY, 14642, USA
| | - Felicia Gilels
- Department of Neuroscience, University of Rochester School of Medicine and Dentistry, Box 603, 601 Elmwood Avenue, Rochester, NY, 14642, USA
| | - Patricia M White
- Department of Neuroscience, University of Rochester School of Medicine and Dentistry, Box 603, 601 Elmwood Avenue, Rochester, NY, 14642, USA
| |
Collapse
|
66
|
Groth JB, Kao SY, Briët MC, Stankovic KM. Hepatocyte nuclear factor-4 alpha in noise-induced cochlear neuropathy. Dev Neurobiol 2016; 76:1374-1386. [PMID: 27112738 DOI: 10.1002/dneu.22399] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Revised: 03/14/2016] [Accepted: 04/22/2016] [Indexed: 01/12/2023]
Abstract
Noise-induced hearing loss (NIHL) is a problem of profound clinical significance and growing magnitude. Alarmingly, even moderate noise levels, previously assumed to cause only temporary shifts in auditory thresholds ("temporary" NIHL), are now known to cause cochlear synaptopathy and subsequent neuropathy. To uncover molecular mechanisms of this neuropathy, a network analysis of genes reported to have significantly altered expression after temporary threshold shift-inducing noise exposure was performed. The transcription factor Hepatocyte Nuclear Factor-4 alpha (HNF4α), which had not previously been studied in the context of cochlear response to noise, was identified as a hub of a top-ranking network. Hnf4α expression and localization using quantitative RT-PCR and in situ hybridization, respectively, were described in adolescent and adult mice exposed to neuropathic noise levels in adolescence. Isoforms α3 and α12 in the cochlea were also identified. At every age examined, Hnf4α mRNA expression in the cochlear apex was similar to expression in the base. Hnf4α expression was evident in select cochlear cells, including spiral ganglion neurons (SGNs) and hair cells, and was significantly upregulated from 6 to 70 weeks of age, especially in SGNs. This age-related Hnf4α upregulation was inhibited by neuropathic noise exposure in adolescence. Hnf4α silencing with shRNA transfection into auditory neuroblast cells (VOT-33) reduced cell viability, as measured with the MTT assay, suggesting that Hnf4α may be involved in SGN survival. Our results motivate future studies of HNF4α in cochlear pathophysiology, especially because HNF4α mutations and polymorphisms are associated with human diseases that may include hearing loss. © 2016 Wiley Periodicals, Inc. Develop Neurobiol 76: 1374-1386, 2016.
Collapse
Affiliation(s)
- Jane Bjerg Groth
- Eaton-Peabody Laboratories and Department of Otolaryngology, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts, 02114.,Department of Otology and Laryngology, Harvard Medical School, Boston, Massachusetts, 02115.,Department of Biomedical Sciences, University of Copenhagen, 2200, Copenhagen, Denmark
| | - Shyan-Yuan Kao
- Eaton-Peabody Laboratories and Department of Otolaryngology, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts, 02114
| | - Martijn C Briët
- Eaton-Peabody Laboratories and Department of Otolaryngology, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts, 02114.,Department of Otorhinolaryngology, Leiden University Medical Center, 2333 ZA, Leiden, The Netherlands
| | - Konstantina M Stankovic
- Eaton-Peabody Laboratories and Department of Otolaryngology, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts, 02114.,Department of Otology and Laryngology, Harvard Medical School, Boston, Massachusetts, 02115.,Program in Speech and Hearing Bioscience and Technology, Harvard Medical School, Boston, Massachusetts, 02115
| |
Collapse
|
67
|
Song Q, Shen P, Li X, Shi L, Liu L, Wang J, Yu Z, Stephen K, Aiken S, Yin S, Wang J. Coding deficits in hidden hearing loss induced by noise: the nature and impacts. Sci Rep 2016; 6:25200. [PMID: 27117978 PMCID: PMC4846864 DOI: 10.1038/srep25200] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Accepted: 04/13/2016] [Indexed: 12/18/2022] Open
Abstract
Hidden hearing refers to the functional deficits in hearing without deterioration in hearing sensitivity. This concept is proposed based upon recent finding of massive noise-induced damage on ribbon synapse between inner hair cells (IHCs) and spiral ganglion neurons (SGNs) in the cochlea without significant permanent threshold shifts (PTS). Presumably, such damage may cause coding deficits in auditory nerve fibers (ANFs). However, such deficits had not been detailed except that a selective loss of ANFs with low spontaneous rate (SR) was reported. In the present study, we investigated the dynamic changes of ribbon synapses and the coding function of ANF single units in one month after a brief noise exposure that caused a massive damage of ribbon synapses but no PTS. The synapse count and functional response measures indicates a large portion of the disrupted synapses were re-connected. This is consistent with the fact that the change of SR distribution due to the initial loss of low SR units is recovered quickly. However, ANF coding deficits were developed later with the re-establishment of the synapses. The deficits were found in both intensity and temporal processing, revealing the nature of synaptopathy in hidden hearing loss.
Collapse
Affiliation(s)
- Qiang Song
- Department of Otolaryngology, Affiliated Sixth People's Hospital, Shanghai Jiao Tong University, 600 Yishan Road, Shanghai 200233, China
| | - Pei Shen
- Department of Physiology, Medical College of Southeast University, 87 Dingjiaoqiao Road, Nanjing 210009, China
| | - Xiaowei Li
- Department of Physiology, Medical College of Southeast University, 87 Dingjiaoqiao Road, Nanjing 210009, China
| | - Lijuan Shi
- Department of Physiology, Medical College of Southeast University, 87 Dingjiaoqiao Road, Nanjing 210009, China
| | - Lijie Liu
- Department of Physiology, Medical College of Southeast University, 87 Dingjiaoqiao Road, Nanjing 210009, China
| | - Jiping Wang
- Department of Otolaryngology, Affiliated Sixth People's Hospital, Shanghai Jiao Tong University, 600 Yishan Road, Shanghai 200233, China
| | - Zhiping Yu
- School of Human Communication Disorders, Dalhousie University, 1256 Barrington St. Dalhousie University, Halifax, NS B3J1Y6, Canada
| | - Kegan Stephen
- School of Human Communication Disorders, Dalhousie University, 1256 Barrington St. Dalhousie University, Halifax, NS B3J1Y6, Canada
| | - Steve Aiken
- School of Human Communication Disorders, Dalhousie University, 1256 Barrington St. Dalhousie University, Halifax, NS B3J1Y6, Canada
| | - Shankai Yin
- Department of Otolaryngology, Affiliated Sixth People's Hospital, Shanghai Jiao Tong University, 600 Yishan Road, Shanghai 200233, China
| | - Jian Wang
- Department of Otolaryngology, Affiliated Sixth People's Hospital, Shanghai Jiao Tong University, 600 Yishan Road, Shanghai 200233, China.,School of Human Communication Disorders, Dalhousie University, 1256 Barrington St. Dalhousie University, Halifax, NS B3J1Y6, Canada
| |
Collapse
|