1
|
Fujihira H, Yamagishi S, Furukawa S, Kashino M. Auditory brainstem response to paired clicks as a candidate marker of cochlear synaptopathy in humans. Clin Neurophysiol 2024; 165:44-54. [PMID: 38959535 DOI: 10.1016/j.clinph.2024.06.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2024] [Revised: 06/02/2024] [Accepted: 06/08/2024] [Indexed: 07/05/2024]
Abstract
OBJECTIVE This study aimed to evaluate whether auditory brainstem response (ABR) using a paired-click stimulation paradigm could serve as a tool for detecting cochlear synaptopathy (CS). METHODS The ABRs to single-clicks and paired-clicks with various inter-click intervals (ICIs) and scores for word intelligibility in degraded listening conditions were obtained from 57 adults with normal hearing. The wave I peak amplitude and root mean square values for the post-wave I response within a range delayed from the wave I peak (referred to as the RMSpost-w1) were calculated for the single- and second-click responses. RESULTS The wave I peak amplitudes did not correlate with age except for the second-click responses at an ICI of 7 ms, and the word intelligibility scores. However, we found that the RMSpost-w1 values for the second-click responses significantly decreased with increasing age. Moreover, the RMSpost-w1 values for the second-click responses at an ICI of 5 ms correlated significantly with the scores for word intelligibility in degraded listening conditions. CONCLUSIONS The magnitude of the post-wave I response for the second-click response could serve as a tool for detecting CS in humans. SIGNIFICANCE Our findings shed new light on the analytical methods of ABR for quantifying CS.
Collapse
Affiliation(s)
- Haruna Fujihira
- NTT Communication Science Laboratories, Atsugi, Kanagawa, Japan; Department of Informatics, Faculty of Information Science and Electrical Engineering, Kyushu University, Fukuoka, Japan.
| | | | - Shigeto Furukawa
- NTT Communication Science Laboratories, Atsugi, Kanagawa, Japan; Graduate School of Public Health, Shizuoka Graduate University of Public Health, Shizuoka, Japan; Speech-Language-Hearing Center, Shizuoka General Hospital, Shizuoka, Japan
| | - Makio Kashino
- NTT Communication Science Laboratories, Atsugi, Kanagawa, Japan
| |
Collapse
|
2
|
Devolder P, Keppler H, Keshishzadeh S, Taghon B, Dhooge I, Verhulst S. The role of hidden hearing loss in tinnitus: Insights from early markers of peripheral hearing damage. Hear Res 2024; 450:109050. [PMID: 38852534 DOI: 10.1016/j.heares.2024.109050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2024] [Revised: 05/24/2024] [Accepted: 05/28/2024] [Indexed: 06/11/2024]
Abstract
Since the presence of tinnitus is not always associated with audiometric hearing loss, it has been hypothesized that hidden hearing loss may act as a potential trigger for increased central gain along the neural pathway leading to tinnitus perception. In recent years, the study of hidden hearing loss has improved with the discovery of cochlear synaptopathy and several objective diagnostic markers. This study investigated three potential markers of peripheral hidden hearing loss in subjects with tinnitus: extended high-frequency audiometric thresholds, the auditory brainstem response, and the envelope following response. In addition, speech intelligibility was measured as a functional outcome measurement of hidden hearing loss. To account for age-related hidden hearing loss, participants were grouped according to age, presence of tinnitus, and audiometric thresholds. Group comparisons were conducted to differentiate between age- and tinnitus-related effects of hidden hearing loss. All three markers revealed age-related differences, whereas no differences were observed between the tinnitus and non-tinnitus groups. However, the older tinnitus group showed improved performance on low-pass filtered speech in noise tests compared to the older non-tinnitus group. These low-pass speech in noise scores were significantly correlated with tinnitus distress, as indicated using questionnaires, and could be related to the presence of hyperacusis. Based on our observations, cochlear synaptopathy does not appear to be the underlying cause of tinnitus. The improvement in low-pass speech-in-noise could be explained by enhanced temporal fine structure encoding or hyperacusis. Therefore, we recommend that future tinnitus research takes into account age-related factors, explores low-frequency encoding, and thoroughly assesses hyperacusis.
Collapse
Affiliation(s)
- Pauline Devolder
- Hearing Technology @ WAVES, Department of Information Technology, Ghent University, Zwijnaarde, Belgium; Department of Rehabilitation Sciences, Ghent University, Ghent, Belgium.
| | - Hannah Keppler
- Department of Rehabilitation Sciences, Ghent University, Ghent, Belgium; Department of Ear, Nose and Throat, Ghent University Hospital, Ghent, Belgium
| | - Sarineh Keshishzadeh
- Hearing Technology @ WAVES, Department of Information Technology, Ghent University, Zwijnaarde, Belgium
| | - Baziel Taghon
- Hearing Technology @ WAVES, Department of Information Technology, Ghent University, Zwijnaarde, Belgium
| | - Ingeborg Dhooge
- Department of Ear, Nose and Throat, Ghent University Hospital, Ghent, Belgium; Department of Head and Skin, Ghent University, Ghent, Belgium
| | - Sarah Verhulst
- Hearing Technology @ WAVES, Department of Information Technology, Ghent University, Zwijnaarde, Belgium
| |
Collapse
|
3
|
van den Berg MM, Wong AB, Houtak G, Williamson RS, Borst JGG. Sodium salicylate improves detection of amplitude-modulated sound in mice. iScience 2024; 27:109691. [PMID: 38736549 PMCID: PMC11088340 DOI: 10.1016/j.isci.2024.109691] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Revised: 01/14/2024] [Accepted: 04/05/2024] [Indexed: 05/14/2024] Open
Abstract
Salicylate is commonly used to induce tinnitus in animals, but its underlying mechanism of action is still debated. We therefore tested its effects on the firing properties of neurons in the mouse inferior colliculus (IC). Salicylate induced a large decrease in the spontaneous activity and an increase of ∼20 dB SPL in the minimum threshold of single units. In response to sinusoidally modulated noise (SAM noise) single units showed both an increase in phase locking and improved rate coding. Mice also became better at detecting amplitude modulations, and a simple threshold model based on the IC population response could reproduce this improvement. The responses to dynamic random chords (DRCs) suggested that the improved AM encoding was due to a linearization of the cochlear output, resulting in larger contrasts during SAM noise. These effects of salicylate are not consistent with the presence of tinnitus, but should be taken into account when studying hyperacusis.
Collapse
Affiliation(s)
- Maurits M. van den Berg
- Department of Neuroscience, Erasmus MC, University Medical Center Rotterdam, NL-3015 GD Rotterdam, the Netherlands
| | - Aaron B. Wong
- Department of Neuroscience, Erasmus MC, University Medical Center Rotterdam, NL-3015 GD Rotterdam, the Netherlands
| | - Ghais Houtak
- Department of Neuroscience, Erasmus MC, University Medical Center Rotterdam, NL-3015 GD Rotterdam, the Netherlands
| | - Ross S. Williamson
- Pittsburgh Hearing Research Center, Department of Otolaryngology, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - J. Gerard G. Borst
- Department of Neuroscience, Erasmus MC, University Medical Center Rotterdam, NL-3015 GD Rotterdam, the Netherlands
| |
Collapse
|
4
|
Bovee S, Klump GM, Köppl C, Pyott SJ. The Stria Vascularis: Renewed Attention on a Key Player in Age-Related Hearing Loss. Int J Mol Sci 2024; 25:5391. [PMID: 38791427 PMCID: PMC11121695 DOI: 10.3390/ijms25105391] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2024] [Revised: 05/08/2024] [Accepted: 05/10/2024] [Indexed: 05/26/2024] Open
Abstract
Age-related hearing loss (HL), or presbycusis, is a complex and heterogeneous condition, affecting a significant portion of older adults and involving various interacting mechanisms. Metabolic presbycusis, a type of age-related HL, is characterized by the dysfunction of the stria vascularis, which is crucial for maintaining the endocochlear potential necessary for hearing. Although attention on metabolic presbycusis has waned in recent years, research continues to identify strial pathology as a key factor in age-related HL. This narrative review integrates past and recent research, bridging findings from animal models and human studies, to examine the contributions of the stria vascularis to age-related HL. It provides a brief overview of the structure and function of the stria vascularis and then examines mechanisms contributing to age-related strial dysfunction, including altered ion transport, changes in pigmentation, inflammatory responses, and vascular atrophy. Importantly, this review outlines the contribution of metabolic mechanisms to age-related HL, highlighting areas for future research. It emphasizes the complex interdependence of metabolic and sensorineural mechanisms in the pathology of age-related HL and highlights the importance of animal models in understanding the underlying mechanisms. The comprehensive and mechanistic investigation of all factors contributing to age-related HL, including cochlear metabolic dysfunction, remains crucial to identifying the underlying mechanisms and developing personalized, protective, and restorative treatments.
Collapse
Affiliation(s)
- Sonny Bovee
- Department of Neuroscience, School of Medicine and Health Science, Carl von Ossietzky Universität Oldenburg, 26129 Oldenburg, Germany; (S.B.); (G.M.K.); (C.K.)
| | - Georg M. Klump
- Department of Neuroscience, School of Medicine and Health Science, Carl von Ossietzky Universität Oldenburg, 26129 Oldenburg, Germany; (S.B.); (G.M.K.); (C.K.)
- Cluster of Excellence “Hearing4all”, Carl von Ossietzky Universität Oldenburg, 26129 Oldenburg, Germany
- Research Centre Neurosensory Science, Carl von Ossietzky Universität Oldenburg, 26129 Oldenburg, Germany
| | - Christine Köppl
- Department of Neuroscience, School of Medicine and Health Science, Carl von Ossietzky Universität Oldenburg, 26129 Oldenburg, Germany; (S.B.); (G.M.K.); (C.K.)
- Cluster of Excellence “Hearing4all”, Carl von Ossietzky Universität Oldenburg, 26129 Oldenburg, Germany
- Research Centre Neurosensory Science, Carl von Ossietzky Universität Oldenburg, 26129 Oldenburg, Germany
| | - Sonja J. Pyott
- Department of Otorhinolaryngology/Head and Neck Surgery, University Medical Center Groningen, University of Groningen, P.O. Box 30.001, 9700 RB Groningen, The Netherlands
- The Research School of Behavioural and Cognitive Neurosciences, University of Groningen, P.O. Box 30.001, 9700 RB Groningen, The Netherlands
| |
Collapse
|
5
|
Schirmer J, Wolpert S, Dapper K, Rühle M, Wertz J, Wouters M, Eldh T, Bader K, Singer W, Gaudrain E, Başkent D, Verhulst S, Braun C, Rüttiger L, Munk MHJ, Dalhoff E, Knipper M. Neural Adaptation at Stimulus Onset and Speed of Neural Processing as Critical Contributors to Speech Comprehension Independent of Hearing Threshold or Age. J Clin Med 2024; 13:2725. [PMID: 38731254 PMCID: PMC11084258 DOI: 10.3390/jcm13092725] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2024] [Revised: 04/24/2024] [Accepted: 04/26/2024] [Indexed: 05/13/2024] Open
Abstract
Background: It is assumed that speech comprehension deficits in background noise are caused by age-related or acquired hearing loss. Methods: We examined young, middle-aged, and older individuals with and without hearing threshold loss using pure-tone (PT) audiometry, short-pulsed distortion-product otoacoustic emissions (pDPOAEs), auditory brainstem responses (ABRs), auditory steady-state responses (ASSRs), speech comprehension (OLSA), and syllable discrimination in quiet and noise. Results: A noticeable decline of hearing sensitivity in extended high-frequency regions and its influence on low-frequency-induced ABRs was striking. When testing for differences in OLSA thresholds normalized for PT thresholds (PTTs), marked differences in speech comprehension ability exist not only in noise, but also in quiet, and they exist throughout the whole age range investigated. Listeners with poor speech comprehension in quiet exhibited a relatively lower pDPOAE and, thus, cochlear amplifier performance independent of PTT, smaller and delayed ABRs, and lower performance in vowel-phoneme discrimination below phase-locking limits (/o/-/u/). When OLSA was tested in noise, listeners with poor speech comprehension independent of PTT had larger pDPOAEs and, thus, cochlear amplifier performance, larger ASSR amplitudes, and higher uncomfortable loudness levels, all linked with lower performance of vowel-phoneme discrimination above the phase-locking limit (/i/-/y/). Conslusions: This study indicates that listening in noise in humans has a sizable disadvantage in envelope coding when basilar-membrane compression is compromised. Clearly, and in contrast to previous assumptions, both good and poor speech comprehension can exist independently of differences in PTTs and age, a phenomenon that urgently requires improved techniques to diagnose sound processing at stimulus onset in the clinical routine.
Collapse
Affiliation(s)
- Jakob Schirmer
- Department of Otolaryngology, Head and Neck Surgery, University of Tübingen, Elfriede-Aulhorn-Str. 5, 72076 Tübingen, Germany; (J.S.); (S.W.); (K.D.); (M.R.); (J.W.); (T.E.); (K.B.); (W.S.); (L.R.)
| | - Stephan Wolpert
- Department of Otolaryngology, Head and Neck Surgery, University of Tübingen, Elfriede-Aulhorn-Str. 5, 72076 Tübingen, Germany; (J.S.); (S.W.); (K.D.); (M.R.); (J.W.); (T.E.); (K.B.); (W.S.); (L.R.)
| | - Konrad Dapper
- Department of Otolaryngology, Head and Neck Surgery, University of Tübingen, Elfriede-Aulhorn-Str. 5, 72076 Tübingen, Germany; (J.S.); (S.W.); (K.D.); (M.R.); (J.W.); (T.E.); (K.B.); (W.S.); (L.R.)
- Department of Biology, Technical University Darmstadt, 64287 Darmstadt, Germany
| | - Moritz Rühle
- Department of Otolaryngology, Head and Neck Surgery, University of Tübingen, Elfriede-Aulhorn-Str. 5, 72076 Tübingen, Germany; (J.S.); (S.W.); (K.D.); (M.R.); (J.W.); (T.E.); (K.B.); (W.S.); (L.R.)
| | - Jakob Wertz
- Department of Otolaryngology, Head and Neck Surgery, University of Tübingen, Elfriede-Aulhorn-Str. 5, 72076 Tübingen, Germany; (J.S.); (S.W.); (K.D.); (M.R.); (J.W.); (T.E.); (K.B.); (W.S.); (L.R.)
| | - Marjoleen Wouters
- Department of Information Technology, Ghent University, Technologiepark 126, 9052 Zwijnaarde, Belgium; (M.W.); (S.V.)
| | - Therese Eldh
- Department of Otolaryngology, Head and Neck Surgery, University of Tübingen, Elfriede-Aulhorn-Str. 5, 72076 Tübingen, Germany; (J.S.); (S.W.); (K.D.); (M.R.); (J.W.); (T.E.); (K.B.); (W.S.); (L.R.)
| | - Katharina Bader
- Department of Otolaryngology, Head and Neck Surgery, University of Tübingen, Elfriede-Aulhorn-Str. 5, 72076 Tübingen, Germany; (J.S.); (S.W.); (K.D.); (M.R.); (J.W.); (T.E.); (K.B.); (W.S.); (L.R.)
| | - Wibke Singer
- Department of Otolaryngology, Head and Neck Surgery, University of Tübingen, Elfriede-Aulhorn-Str. 5, 72076 Tübingen, Germany; (J.S.); (S.W.); (K.D.); (M.R.); (J.W.); (T.E.); (K.B.); (W.S.); (L.R.)
| | - Etienne Gaudrain
- Lyon Neuroscience Research Center, Centre National de la Recherche Scientifique UMR5292, Inserm U1028, Université Lyon 1, Centre Hospitalier Le Vinatier-Bâtiment 462–Neurocampus, 95 Boulevard Pinel, 69675 Bron CEDEX, France;
- Department of Otorhinolaryngology, University Medical Center Groningen (UMCG), Hanzeplein 1, BB21, 9700 RB Groningen, The Netherlands;
| | - Deniz Başkent
- Department of Otorhinolaryngology, University Medical Center Groningen (UMCG), Hanzeplein 1, BB21, 9700 RB Groningen, The Netherlands;
| | - Sarah Verhulst
- Department of Information Technology, Ghent University, Technologiepark 126, 9052 Zwijnaarde, Belgium; (M.W.); (S.V.)
| | - Christoph Braun
- Magnetoencephalography-Centre and Hertie Institute for Clinical Brain Research, University of Tübingen, Otfried-Müller-Straße 27, 72076 Tübingen, Germany;
- Center for Mind and Brain Research, University of Trento, Palazzo Fedrigotti-corso Bettini 31, 38068 Rovereto, Italy
| | - Lukas Rüttiger
- Department of Otolaryngology, Head and Neck Surgery, University of Tübingen, Elfriede-Aulhorn-Str. 5, 72076 Tübingen, Germany; (J.S.); (S.W.); (K.D.); (M.R.); (J.W.); (T.E.); (K.B.); (W.S.); (L.R.)
| | - Matthias H. J. Munk
- Department of Biology, Technical University Darmstadt, 64287 Darmstadt, Germany
- Department of Psychiatry & Psychotherapy, University of Tübingen, Calwerstraße 14, 72076 Tübingen, Germany
| | - Ernst Dalhoff
- Department of Otolaryngology, Head and Neck Surgery, University of Tübingen, Elfriede-Aulhorn-Str. 5, 72076 Tübingen, Germany; (J.S.); (S.W.); (K.D.); (M.R.); (J.W.); (T.E.); (K.B.); (W.S.); (L.R.)
| | - Marlies Knipper
- Department of Otolaryngology, Head and Neck Surgery, University of Tübingen, Elfriede-Aulhorn-Str. 5, 72076 Tübingen, Germany; (J.S.); (S.W.); (K.D.); (M.R.); (J.W.); (T.E.); (K.B.); (W.S.); (L.R.)
| |
Collapse
|
6
|
Schmidt FH, Dörmann A, Ehrt K, Grossmann W, Mlynski R, Zhang L. The curvature quantification of wave I in auditory brainstem responses detects cochlear synaptopathy in human beings. Eur Arch Otorhinolaryngol 2024:10.1007/s00405-024-08699-6. [PMID: 38703194 DOI: 10.1007/s00405-024-08699-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Accepted: 04/18/2024] [Indexed: 05/06/2024]
Abstract
PURPOSE Patients with age-related hearing loss complain often about reduced speech perception in adverse listening environment. Studies on animals have suggested that cochlear synaptopathy may be one of the primary mechanisms responsible for this phenomenon. A decreased wave I amplitude in supra-threshold auditory brainstem response (ABR) can diagnose this pathology non-invasively. However, the interpretation of the wave I amplitude in humans remains controversial. Recent studies in mice have established a robust and reliable mathematic algorithm, i.e., curve curvature quantification, for detecting cochlear synaptopathy. This study aimed to determine whether the curve curvature has sufficient test-retest reliability to detect cochlear synaptopathy in aging humans. METHODS Healthy participants were recruited into this prospective study. All subjects underwent an audiogram examination with standard and extended high frequencies ranging from 0.125 to 16 kHz and an ABR with a stimulus of 80 dB nHL click. The peak amplitude, peak latency, curvature at the peak, and the area under the curve of wave I were calculated and analyzed. RESULTS A total of 80 individuals with normal hearing, aged 18 to 61 years, participated in this study, with a mean age of 26.4 years. Pearson correlation analysis showed a significant negative correlation between curvature and age, as well as between curvature and extended high frequency (EHF) threshold (10-16 kHz). Additionally, the same correlation was observed between age and area as well as age and EHF threshold. The model comparison demonstrated that the curvature at the peak of wave I is the best metric to correlate with EHF threshold. CONCLUSION The curvature at the peak of wave I is the most sensitive metric for detecting cochlear synaptopathy in humans and may be applied in routine diagnostics to detect early degenerations of the auditory nerve.
Collapse
Affiliation(s)
- Florian Herrmann Schmidt
- Department of Otorhinolaryngology, Head and Neck Surgery, Otto Körner, Rostock University Medical Center, Doberaner Strasse 137-139, 18057, Rostock, Germany
| | - Alexander Dörmann
- Department of Otorhinolaryngology, Head and Neck Surgery, Otto Körner, Rostock University Medical Center, Doberaner Strasse 137-139, 18057, Rostock, Germany
| | - Karsten Ehrt
- Department of Otorhinolaryngology, Head and Neck Surgery, Otto Körner, Rostock University Medical Center, Doberaner Strasse 137-139, 18057, Rostock, Germany
| | - Wilma Grossmann
- Department of Otorhinolaryngology, Head and Neck Surgery, Otto Körner, Rostock University Medical Center, Doberaner Strasse 137-139, 18057, Rostock, Germany
| | - Robert Mlynski
- Department of Otorhinolaryngology, Head and Neck Surgery, Otto Körner, Rostock University Medical Center, Doberaner Strasse 137-139, 18057, Rostock, Germany
| | - Lichun Zhang
- Department of Otorhinolaryngology, Head and Neck Surgery, Otto Körner, Rostock University Medical Center, Doberaner Strasse 137-139, 18057, Rostock, Germany.
| |
Collapse
|
7
|
Temboury-Gutierrez M, Märcher-Rørsted J, Bille M, Yde J, Encina-Llamas G, Hjortkjær J, Dau T. Electrocochleographic frequency-following responses as a potential marker of age-related cochlear neural degeneration. Hear Res 2024; 446:109005. [PMID: 38598943 DOI: 10.1016/j.heares.2024.109005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2023] [Revised: 03/19/2024] [Accepted: 04/01/2024] [Indexed: 04/12/2024]
Abstract
Auditory nerve (AN) fibers that innervate inner hair cells in the cochlea degenerate with advancing age. It has been proposed that age-related reductions in brainstem frequency-following responses (FFR) to the carrier of low-frequency, high-intensity pure tones may partially reflect this neural loss in the cochlea (Märcher-Rørsted et al., 2022). If the loss of AN fibers is the primary factor contributing to age-related changes in the brainstem FFR, then the FFR could serve as an indicator of cochlear neural degeneration. In this study, we employed electrocochleography (ECochG) to investigate the effects of age on frequency-following neurophonic potentials, i.e., neural responses phase-locked to the carrier frequency of the tone stimulus. We compared these findings to the brainstem-generated FFRs obtained simultaneously using the same stimulation. We conducted recordings in young and older individuals with normal hearing. Responses to pure tones (250 ms, 516 and 1086 Hz, 85 dB SPL) and clicks were recorded using both ECochG at the tympanic membrane and traditional scalp electroencephalographic (EEG) recordings of the FFR. Distortion product otoacoustic emissions (DPOAE) were also collected. In the ECochG recordings, sustained AN neurophonic (ANN) responses to tonal stimulation, as well as the click-evoked compound action potential (CAP) of the AN, were significantly reduced in the older listeners compared to young controls, despite normal audiometric thresholds. In the EEG recordings, brainstem FFRs to the same tone stimulation were also diminished in the older participants. Unlike the reduced AN CAP response, the transient-evoked wave-V remained unaffected. These findings could indicate that a decreased number of AN fibers contributes to the response in the older participants. The results suggest that the scalp-recorded FFR, as opposed to the clinical standard wave-V of the auditory brainstem response, may serve as a more reliable indicator of age-related cochlear neural degeneration.
Collapse
Affiliation(s)
- Miguel Temboury-Gutierrez
- Hearing Systems Section, Department of Health Technology, Technical University of Denmark, Ørsteds Plads, Building 352, DK-2800 Kgs. Lyngby, Denmark.
| | - Jonatan Märcher-Rørsted
- Hearing Systems Section, Department of Health Technology, Technical University of Denmark, Ørsteds Plads, Building 352, DK-2800 Kgs. Lyngby, Denmark
| | - Michael Bille
- Copenhagen Hearing and Balance Center, Ear, Nose and Throat (ENT) and Audiology Clinic, Rigshospitalet, Copenhagen University Hospital, Denmark, Inge Lehmanns Vej 8, DK-2100 København Ø, Denmark
| | - Jesper Yde
- Copenhagen Hearing and Balance Center, Ear, Nose and Throat (ENT) and Audiology Clinic, Rigshospitalet, Copenhagen University Hospital, Denmark, Inge Lehmanns Vej 8, DK-2100 København Ø, Denmark
| | - Gerard Encina-Llamas
- Hearing Systems Section, Department of Health Technology, Technical University of Denmark, Ørsteds Plads, Building 352, DK-2800 Kgs. Lyngby, Denmark; Copenhagen Hearing and Balance Center, Ear, Nose and Throat (ENT) and Audiology Clinic, Rigshospitalet, Copenhagen University Hospital, Denmark, Inge Lehmanns Vej 8, DK-2100 København Ø, Denmark; Faculty of Medicine. University of Vic - Central University of Catalonia (UVic-UCC), Vic, 08500, Catalonia - Spain
| | - Jens Hjortkjær
- Hearing Systems Section, Department of Health Technology, Technical University of Denmark, Ørsteds Plads, Building 352, DK-2800 Kgs. Lyngby, Denmark; Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Hvidovre, Kettegård Allé 30, DK-2650 Hvidovre, Denmark
| | - Torsten Dau
- Hearing Systems Section, Department of Health Technology, Technical University of Denmark, Ørsteds Plads, Building 352, DK-2800 Kgs. Lyngby, Denmark
| |
Collapse
|
8
|
Castaño-González K, Köppl C, Pyott SJ. The crucial role of diverse animal models to investigate cochlear aging and hearing loss. Hear Res 2024; 445:108989. [PMID: 38518394 DOI: 10.1016/j.heares.2024.108989] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/26/2023] [Revised: 02/18/2024] [Accepted: 03/04/2024] [Indexed: 03/24/2024]
Abstract
Age-related hearing loss affects a large and growing segment of the population, with profound impacts on quality of life. Age-related pathology of the cochlea-the mammalian hearing organ-underlies age-related hearing loss. Because investigating age-related changes in the cochlea in humans is challenging and often impossible, animal models are indispensable to investigate these mechanisms as well as the complex consequences of age-related hearing loss on the brain and behavior. In this review, we advocate for a comparative and interdisciplinary approach while also addressing the challenges of comparing age-related hearing loss across species with varying lifespans. We describe the experimental advantages and limitations as well as areas for future research in well-established models of age-related hearing loss, including mice, rats, gerbils, chinchillas, and birds. We also indicate the need to expand characterization of age-related hearing loss in other established animal models, especially guinea pigs, cats, and non-human primates, in which auditory function is well characterized but age-related cochlear pathology is understudied. Finally, we highlight the potential of emerging animal models for advancing our understanding of age-related hearing loss, including deer mice, with their notably extended lifespans and preserved hearing, naked mole rats, with their exceptional longevity and extensive vocal communications, as well as zebrafish, which offer genetic tractability and suitability for drug screening. Ultimately, a comparative and interdisciplinary approach in auditory research, combining insights from various animal models with human studies, is key to robust and reliable research outcomes that better advance our understanding and treatment of age-related hearing loss.
Collapse
Affiliation(s)
- Karen Castaño-González
- Department of Otorhinolaryngology, Head & Neck Surgery, University Medical Center Groningen; The Research School of Behavioural and Cognitive Neurosciences, University of Groningen, Groningen, The Netherlands
| | - Christine Köppl
- Cluster of Excellence "Hearing4All", Department of Neuroscience, School of Medicine and Health Sciences, Carl von Ossietzky Universität; Research Center Neurosensory Science, Carl von Ossietzky Universität, Oldenburg, Germany
| | - Sonja J Pyott
- Department of Otorhinolaryngology, Head & Neck Surgery, University Medical Center Groningen; The Research School of Behavioural and Cognitive Neurosciences, University of Groningen, Groningen, The Netherlands.
| |
Collapse
|
9
|
Temboury-Gutierrez M, Encina-Llamas G, Dau T. Predicting early auditory evoked potentials using a computational model of auditory-nerve processing. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2024; 155:1799-1812. [PMID: 38445986 DOI: 10.1121/10.0025136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Accepted: 02/16/2024] [Indexed: 03/07/2024]
Abstract
Non-invasive electrophysiological measures, such as auditory evoked potentials (AEPs), play a crucial role in diagnosing auditory pathology. However, the relationship between AEP morphology and cochlear degeneration remains complex and not well understood. Dau [J. Acoust. Soc. Am. 113, 936-950 (2003)] proposed a computational framework for modeling AEPs that utilized a nonlinear auditory-nerve (AN) model followed by a linear unitary response function. While the model captured some important features of the measured AEPs, it also exhibited several discrepancies in response patterns compared to the actual measurements. In this study, an enhanced AEP modeling framework is presented, incorporating an improved AN model, and the conclusions from the original study were reevaluated. Simulation results with transient and sustained stimuli demonstrated accurate auditory brainstem responses (ABRs) and frequency-following responses (FFRs) as a function of stimulation level, although wave-V latencies remained too short, similar to the original study. When compared to physiological responses in animals, the revised model framework showed a more accurate balance between the contributions of auditory-nerve fibers (ANFs) at on- and off-frequency regions to the predicted FFRs. These findings emphasize the importance of cochlear processing in brainstem potentials. This framework may provide a valuable tool for assessing human AN models and simulating AEPs for various subtypes of peripheral pathologies, offering opportunities for research and clinical applications.
Collapse
Affiliation(s)
- Miguel Temboury-Gutierrez
- Hearing Systems Section, Department of Health Technology, Technical University of Denmark, Kongens Lyngby, DK-2800, Denmark
| | - Gerard Encina-Llamas
- Copenhagen Hearing and Balance Center, Ear, Nose and Throat (ENT) and Audiology Clinic, Rigshospitalet, Copenhagen University Hospital, Copenhagen, DK-2100, Denmark
- Faculty of Medicine, University of Vic-Central University of Catalonia (UVic-UCC), Vic, 08500, Catalonia, Spain
| | - Torsten Dau
- Hearing Systems Section, Department of Health Technology, Technical University of Denmark, Kongens Lyngby, DK-2800, Denmark
- Copenhagen Hearing and Balance Center, Ear, Nose and Throat (ENT) and Audiology Clinic, Rigshospitalet, Copenhagen University Hospital, Copenhagen, DK-2100, Denmark
| |
Collapse
|
10
|
Liu J, Stohl J, Overath T. Hidden hearing loss: Fifteen years at a glance. Hear Res 2024; 443:108967. [PMID: 38335624 DOI: 10.1016/j.heares.2024.108967] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 01/15/2024] [Accepted: 01/29/2024] [Indexed: 02/12/2024]
Abstract
Hearing loss affects approximately 18% of the population worldwide. Hearing difficulties in noisy environments without accompanying audiometric threshold shifts likely affect an even larger percentage of the global population. One of the potential causes of hidden hearing loss is cochlear synaptopathy, the loss of synapses between inner hair cells (IHC) and auditory nerve fibers (ANF). These synapses are the most vulnerable structures in the cochlea to noise exposure or aging. The loss of synapses causes auditory deafferentation, i.e., the loss of auditory afferent information, whose downstream effect is the loss of information that is sent to higher-order auditory processing stages. Understanding the physiological and perceptual effects of this early auditory deafferentation might inform interventions to prevent later, more severe hearing loss. In the past decade, a large body of work has been devoted to better understand hidden hearing loss, including the causes of hidden hearing loss, their corresponding impact on the auditory pathway, and the use of auditory physiological measures for clinical diagnosis of auditory deafferentation. This review synthesizes the findings from studies in humans and animals to answer some of the key questions in the field, and it points to gaps in knowledge that warrant more investigation. Specifically, recent studies suggest that some electrophysiological measures have the potential to function as indicators of hidden hearing loss in humans, but more research is needed for these measures to be included as part of a clinical test battery.
Collapse
Affiliation(s)
- Jiayue Liu
- Department of Psychology and Neuroscience, Duke University, Durham, USA.
| | - Joshua Stohl
- North American Research Laboratory, MED-EL Corporation, Durham, USA
| | - Tobias Overath
- Department of Psychology and Neuroscience, Duke University, Durham, USA
| |
Collapse
|
11
|
Kreeger LJ, Honnuraiah S, Maeker S, Shea S, Fishell G, Goodrich LV. An Anatomical and Physiological Basis for Coincidence Detection Across Time Scales in the Auditory System. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.29.582808. [PMID: 38464181 PMCID: PMC10925315 DOI: 10.1101/2024.02.29.582808] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/12/2024]
Abstract
Coincidence detection is a common neural computation that identifies co-occurring stimuli by integration of inputs. In the auditory system, octopus cells act as coincidence detectors for complex sounds that include both synchronous and sequenced combinations of frequencies. Octopus cells must detect coincidence on both the millisecond and submillisecond time scale, unlike the average neuron, which integrates inputs over time on the order of tens of milliseconds. Here, we show that octopus cell computations in the cell body are shaped by inhibition in the dendrites, which adjusts the strength and timing of incoming signals to achieve submillisecond acuity. This mechanism is crucial for the fundamental process of integrating the synchronized frequencies of natural auditory signals over time.
Collapse
Affiliation(s)
- Lauren J Kreeger
- Harvard Medical School, Department of Neurobiology, Boston, MA 02115, USA
| | - Suraj Honnuraiah
- Harvard Medical School, Department of Neurobiology, Boston, MA 02115, USA
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Sydney Maeker
- Harvard Medical School, Department of Neurobiology, Boston, MA 02115, USA
| | - Siobhan Shea
- Harvard Medical School, Department of Neurobiology, Boston, MA 02115, USA
| | - Gord Fishell
- Harvard Medical School, Department of Neurobiology, Boston, MA 02115, USA
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Lisa V Goodrich
- Harvard Medical School, Department of Neurobiology, Boston, MA 02115, USA
| |
Collapse
|
12
|
Bovee S, Klump GM, Pyott SJ, Sielaff C, Köppl C. Cochlear Ribbon Synapses in Aged Gerbils. Int J Mol Sci 2024; 25:2738. [PMID: 38473985 DOI: 10.3390/ijms25052738] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2023] [Revised: 02/15/2024] [Accepted: 02/21/2024] [Indexed: 03/14/2024] Open
Abstract
In mammalian hearing, type-I afferent auditory nerve fibers comprise the basis of the afferent auditory pathway. They are connected to inner hair cells of the cochlea via specialized ribbon synapses. Auditory nerve fibers of different physiological types differ subtly in their synaptic location and morphology. Low-spontaneous-rate auditory nerve fibers typically connect on the modiolar side of the inner hair cell, while high-spontaneous-rate fibers are typically found on the pillar side. In aging and noise-damaged ears, this fine-tuned balance between auditory nerve fiber populations can be disrupted and the functional consequences are currently unclear. Here, using immunofluorescent labeling of presynaptic ribbons and postsynaptic glutamate receptor patches, we investigated changes in synaptic morphology at three different tonotopic locations along the cochlea of aging gerbils compared to those of young adults. Quiet-aged gerbils showed about 20% loss of afferent ribbon synapses. While the loss was random at apical, low-frequency cochlear locations, at the basal, high-frequency location it almost exclusively affected the modiolar-located synapses. The subtle differences in volumes of pre- and postsynaptic elements located on the inner hair cell's modiolar versus pillar side were unaffected by age. This is consistent with known physiology and suggests a predominant, age-related loss in the low-spontaneous-rate auditory nerve population in the cochlear base, but not the apex.
Collapse
Affiliation(s)
- Sonny Bovee
- Department of Neuroscience, School of Medicine and Health Science, Carl von Ossietzky Universität Oldenburg, 26129 Oldenburg, Germany
| | - Georg M Klump
- Department of Neuroscience, School of Medicine and Health Science, Carl von Ossietzky Universität Oldenburg, 26129 Oldenburg, Germany
- Cluster of Excellence "Hearing4all", Carl von Ossietzky Universität Oldenburg, 26129 Oldenburg, Germany
- Research Centre Neurosensory Science, Carl von Ossietzky Universität Oldenburg, 26129 Oldenburg, Germany
| | - Sonja J Pyott
- Department of Otorhinolaryngology/Head and Neck Surgery, University Medical Center Groningen, University of Groningen, P.O. Box 30.001, 9700 RB Groningen, The Netherlands
| | - Charlotte Sielaff
- Department of Neuroscience, School of Medicine and Health Science, Carl von Ossietzky Universität Oldenburg, 26129 Oldenburg, Germany
- Fraunhofer Institute for Toxicology and Experimental Medicine (ITEM), 30625 Hannover, Germany
| | - Christine Köppl
- Department of Neuroscience, School of Medicine and Health Science, Carl von Ossietzky Universität Oldenburg, 26129 Oldenburg, Germany
- Cluster of Excellence "Hearing4all", Carl von Ossietzky Universität Oldenburg, 26129 Oldenburg, Germany
- Research Centre Neurosensory Science, Carl von Ossietzky Universität Oldenburg, 26129 Oldenburg, Germany
| |
Collapse
|
13
|
Xie R, Wang M, Zhang C. Mechanisms of age-related hearing loss at the auditory nerve central synapses and postsynaptic neurons in the cochlear nucleus. Hear Res 2024; 442:108935. [PMID: 38113793 PMCID: PMC10842789 DOI: 10.1016/j.heares.2023.108935] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Revised: 12/04/2023] [Accepted: 12/08/2023] [Indexed: 12/21/2023]
Abstract
Sound information is transduced from mechanical vibration to electrical signals in the cochlea, conveyed to and further processed in the brain to form auditory perception. During the process, spiral ganglion neurons (SGNs) are the key cells that connect the peripheral and central auditory systems by receiving information from hair cells in the cochlea and transmitting it to neurons of the cochlear nucleus (CN). Decades of research in the cochlea greatly improved our understanding of SGN function under normal and pathological conditions, especially about the roles of different subtypes of SGNs and their peripheral synapses. However, it remains less clear how SGN central terminals or auditory nerve (AN) synapses connect to CN neurons, and ultimately how peripheral pathology links to structural alterations and functional deficits in the central auditory nervous system. This review discusses recent progress about the morphological and physiological properties of different subtypes of AN synapses and associated postsynaptic CN neurons, their changes during aging, and the potential mechanisms underlying age-related hearing loss.
Collapse
Affiliation(s)
- Ruili Xie
- Department of Otolaryngology, The Ohio State University, 420 W 12th Ave, Columbus OH 43210, USA; Department of Neuroscience, The Ohio State University, 420W 12th Ave, Columbus, OH 43210, USA.
| | - Meijian Wang
- Department of Otolaryngology, The Ohio State University, 420 W 12th Ave, Columbus OH 43210, USA
| | - Chuangeng Zhang
- Department of Otolaryngology, The Ohio State University, 420 W 12th Ave, Columbus OH 43210, USA
| |
Collapse
|
14
|
Marchetta P, Dapper K, Hess M, Calis D, Singer W, Wertz J, Fink S, Hage SR, Alam M, Schwabe K, Lukowski R, Bourien J, Puel JL, Jacob MH, Munk MHJ, Land R, Rüttiger L, Knipper M. Dysfunction of specific auditory fibers impacts cortical oscillations, driving an autism phenotype despite near-normal hearing. FASEB J 2024; 38:e23411. [PMID: 38243766 DOI: 10.1096/fj.202301995r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 12/04/2023] [Accepted: 12/22/2023] [Indexed: 01/21/2024]
Abstract
Autism spectrum disorder is discussed in the context of altered neural oscillations and imbalanced cortical excitation-inhibition of cortical origin. We studied here whether developmental changes in peripheral auditory processing, while preserving basic hearing function, lead to altered cortical oscillations. Local field potentials (LFPs) were recorded from auditory, visual, and prefrontal cortices and the hippocampus of BdnfPax2 KO mice. These mice develop an autism-like behavioral phenotype through deletion of BDNF in Pax2+ interneuron precursors, affecting lower brainstem functions, but not frontal brain regions directly. Evoked LFP responses to behaviorally relevant auditory stimuli were weaker in the auditory cortex of BdnfPax2 KOs, connected to maturation deficits of high-spontaneous rate auditory nerve fibers. This was correlated with enhanced spontaneous and induced LFP power, excitation-inhibition imbalance, and dendritic spine immaturity, mirroring autistic phenotypes. Thus, impairments in peripheral high-spontaneous rate fibers alter spike synchrony and subsequently cortical processing relevant for normal communication and behavior.
Collapse
Affiliation(s)
- Philine Marchetta
- Molecular Physiology of Hearing, Department of Otolaryngology, Head and Neck Surgery, Tübingen Hearing Research Centre, University of Tübingen, Tübingen, Germany
| | - Konrad Dapper
- Molecular Physiology of Hearing, Department of Otolaryngology, Head and Neck Surgery, Tübingen Hearing Research Centre, University of Tübingen, Tübingen, Germany
| | - Morgan Hess
- Molecular Physiology of Hearing, Department of Otolaryngology, Head and Neck Surgery, Tübingen Hearing Research Centre, University of Tübingen, Tübingen, Germany
| | - Dila Calis
- Molecular Physiology of Hearing, Department of Otolaryngology, Head and Neck Surgery, Tübingen Hearing Research Centre, University of Tübingen, Tübingen, Germany
| | - Wibke Singer
- Molecular Physiology of Hearing, Department of Otolaryngology, Head and Neck Surgery, Tübingen Hearing Research Centre, University of Tübingen, Tübingen, Germany
| | - Jakob Wertz
- Molecular Physiology of Hearing, Department of Otolaryngology, Head and Neck Surgery, Tübingen Hearing Research Centre, University of Tübingen, Tübingen, Germany
| | - Stefan Fink
- Molecular Physiology of Hearing, Department of Otolaryngology, Head and Neck Surgery, Tübingen Hearing Research Centre, University of Tübingen, Tübingen, Germany
| | - Steffen R Hage
- Werner Reichardt Centre for Integrative Neuroscience, University of Tübingen, Tübingen, Germany
| | - Mesbah Alam
- Experimental Neurosurgery, Department of Neurosurgery, Hannover Medical School, Hannover, Germany
| | - Kerstin Schwabe
- Experimental Neurosurgery, Department of Neurosurgery, Hannover Medical School, Hannover, Germany
| | - Robert Lukowski
- Institute of Pharmacy, Pharmacology, Toxicology and Clinical Pharmacy, University of Tübingen, Tübingen, Germany
| | - Jerome Bourien
- Institute for Neurosciences Montpellier, Institut National de la Santé et de la Recherche Médical, University of Montpellier, Montpellier, France
| | - Jean-Luc Puel
- Institute for Neurosciences Montpellier, Institut National de la Santé et de la Recherche Médical, University of Montpellier, Montpellier, France
| | - Michele H Jacob
- Department of Neuroscience, Tufts University School of Medicine, Sackler School of Biomedical Sciences, Boston, Massachusetts, USA
| | - Matthias H J Munk
- Department of Psychiatry & Psychotherapy, University of Tübingen, Tübingen, Germany
- Department of Biology, Technical University Darmstadt, Darmstadt, Germany
| | - Rüdiger Land
- Department of Experimental Otology, Institute of Audioneurotechnology, Hannover Medical School, Hannover, Germany
| | - Lukas Rüttiger
- Molecular Physiology of Hearing, Department of Otolaryngology, Head and Neck Surgery, Tübingen Hearing Research Centre, University of Tübingen, Tübingen, Germany
| | - Marlies Knipper
- Molecular Physiology of Hearing, Department of Otolaryngology, Head and Neck Surgery, Tübingen Hearing Research Centre, University of Tübingen, Tübingen, Germany
| |
Collapse
|
15
|
Saidia AR, François F, Casas F, Mechaly I, Venteo S, Veechi JT, Ruel J, Puel JL, Wang J. Oxidative Stress Plays an Important Role in Glutamatergic Excitotoxicity-Induced Cochlear Synaptopathy: Implication for Therapeutic Molecules Screening. Antioxidants (Basel) 2024; 13:149. [PMID: 38397748 PMCID: PMC10886292 DOI: 10.3390/antiox13020149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Revised: 01/12/2024] [Accepted: 01/20/2024] [Indexed: 02/25/2024] Open
Abstract
The disruption of the synaptic connection between the sensory inner hair cells (IHCs) and the auditory nerve fiber terminals of the type I spiral ganglion neurons (SGN) has been observed early in several auditory pathologies (e.g., noise-induced or ototoxic drug-induced or age-related hearing loss). It has been suggested that glutamate excitotoxicity may be an inciting element in the degenerative cascade observed in these pathological cochlear conditions. Moreover, oxidative damage induced by free hydroxyl radicals and nitric oxide may dramatically enhance cochlear damage induced by glutamate excitotoxicity. To investigate the underlying molecular mechanisms involved in cochlear excitotoxicity, we examined the molecular basis responsible for kainic acid (KA, a full agonist of AMPA/KA-preferring glutamate receptors)-induced IHC synapse loss and degeneration of the terminals of the type I spiral ganglion afferent neurons using a cochlear explant culture from P3 mouse pups. Our results demonstrated that disruption of the synaptic connection between IHCs and SGNs induced increased levels of oxidative stress, as well as altered both mitochondrial function and neurotrophin signaling pathways. Additionally, the application of exogenous antioxidants and neurotrophins (NT3, BDNF, and small molecule TrkB agonists) clearly increases synaptogenesis. These results suggest that understanding the molecular pathways involved in cochlear excitotoxicity is of crucial importance for the future clinical trials of drug interventions for auditory synaptopathies.
Collapse
Affiliation(s)
- Anissa Rym Saidia
- Institute for Neurosciences of Montpellier (INM), INSERM U1298, University Montpellier, 34295 Montpellier, France; (F.F.); (I.M.); (S.V.); (J.T.V.); (J.-L.P.)
| | - Florence François
- Institute for Neurosciences of Montpellier (INM), INSERM U1298, University Montpellier, 34295 Montpellier, France; (F.F.); (I.M.); (S.V.); (J.T.V.); (J.-L.P.)
| | - François Casas
- INRA, UMR 866 Dynamique Musculaire et Métabolisme, 34060 Montpellier, France;
| | - Ilana Mechaly
- Institute for Neurosciences of Montpellier (INM), INSERM U1298, University Montpellier, 34295 Montpellier, France; (F.F.); (I.M.); (S.V.); (J.T.V.); (J.-L.P.)
| | - Stéphanie Venteo
- Institute for Neurosciences of Montpellier (INM), INSERM U1298, University Montpellier, 34295 Montpellier, France; (F.F.); (I.M.); (S.V.); (J.T.V.); (J.-L.P.)
| | - Joseph T. Veechi
- Institute for Neurosciences of Montpellier (INM), INSERM U1298, University Montpellier, 34295 Montpellier, France; (F.F.); (I.M.); (S.V.); (J.T.V.); (J.-L.P.)
| | - Jérôme Ruel
- Centre de Recherche en CardioVasculaire et Nutrition, Aix-Marseille Université-INSERM, 1263-INRAE 1260, 13385 Marseille, France;
| | - Jean-Luc Puel
- Institute for Neurosciences of Montpellier (INM), INSERM U1298, University Montpellier, 34295 Montpellier, France; (F.F.); (I.M.); (S.V.); (J.T.V.); (J.-L.P.)
| | - Jing Wang
- Institute for Neurosciences of Montpellier (INM), INSERM U1298, University Montpellier, 34295 Montpellier, France; (F.F.); (I.M.); (S.V.); (J.T.V.); (J.-L.P.)
| |
Collapse
|
16
|
Wertz J, Rüttiger L, Bender B, Klose U, Stark RS, Dapper K, Saemisch J, Braun C, Singer W, Dalhoff E, Bader K, Wolpert SM, Knipper M, Munk MHJ. Differential cortical activation patterns: pioneering sub-classification of tinnitus with and without hyperacusis by combining audiometry, gamma oscillations, and hemodynamics. Front Neurosci 2024; 17:1232446. [PMID: 38239827 PMCID: PMC10794389 DOI: 10.3389/fnins.2023.1232446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Accepted: 10/16/2023] [Indexed: 01/22/2024] Open
Abstract
The ongoing controversies about the neural basis of tinnitus, whether linked with central neural gain or not, may hamper efforts to develop therapies. We asked to what extent measurable audiometric characteristics of tinnitus without (T) or with co-occurrence of hyperacusis (TH) are distinguishable on the level of cortical responses. To accomplish this, electroencephalography (EEG) and concurrent functional near-infrared spectroscopy (fNIRS) were measured while patients performed an attentionally demanding auditory discrimination task using stimuli within the individual tinnitus frequency (fTin) and a reference frequency (fRef). Resting-state-fMRI-based functional connectivity (rs-fMRI-bfc) in ascending auditory nuclei (AAN), the primary auditory cortex (AC-I), and four other regions relevant for directing attention or regulating distress in temporal, parietal, and prefrontal cortex was compiled and compared to EEG and concurrent fNIRS activity in the same brain areas. We observed no group differences in pure-tone audiometry (PTA) between 10 and 16 kHz. However, the PTA threshold around the tinnitus pitch was positively correlated with the self-rated tinnitus loudness and also correlated with distress in T-groups, while TH experienced their tinnitus loudness at minimal loudness levels already with maximal suffering scores. The T-group exhibited prolonged auditory brain stem (ABR) wave I latency and reduced ABR wave V amplitudes (indicating reduced neural synchrony in the brainstem), which were associated with lower rs-fMRI-bfc between AAN and the AC-I, as observed in previous studies. In T-subjects, these features were linked with elevated spontaneous and reduced evoked gamma oscillations and with reduced deoxygenated hemoglobin (deoxy-Hb) concentrations in response to stimulation with lower frequencies in temporal cortex (Brodmann area (BA) 41, 42, 22), implying less synchronous auditory responses during active auditory discrimination of reference frequencies. In contrast, in the TH-group gamma oscillations and hemodynamic responses in temporoparietal regions were reversed during active discrimination of tinnitus frequencies. Our findings suggest that T and TH differ in auditory discrimination and memory-dependent directed attention during active discrimination at either tinnitus or reference frequencies, offering a test paradigm that may allow for more precise sub-classification of tinnitus and future improved treatment approaches.
Collapse
Affiliation(s)
- Jakob Wertz
- Department of Otolaryngology, Head and Neck Surgery, Tübingen Hearing Research Centre, University of Tübingen, Tübingen, Germany
| | - Lukas Rüttiger
- Department of Otolaryngology, Head and Neck Surgery, Tübingen Hearing Research Centre, University of Tübingen, Tübingen, Germany
| | - Benjamin Bender
- Department of Diagnostic and Interventional Neuroradiology, University of Tübingen, Tübingen, Germany
| | - Uwe Klose
- Department of Diagnostic and Interventional Neuroradiology, University of Tübingen, Tübingen, Germany
| | - Robert S. Stark
- Department of Psychiatry and Psychotherapy, University of Tübingen, Tübingen, Germany
| | - Konrad Dapper
- Department of Otolaryngology, Head and Neck Surgery, Tübingen Hearing Research Centre, University of Tübingen, Tübingen, Germany
- Department of Biology, Technical University Darmstadt, Darmstadt, Germany
| | - Jörg Saemisch
- Department of Otolaryngology, Head and Neck Surgery, Tübingen Hearing Research Centre, University of Tübingen, Tübingen, Germany
| | | | - Wibke Singer
- Department of Otolaryngology, Head and Neck Surgery, Tübingen Hearing Research Centre, University of Tübingen, Tübingen, Germany
| | - Ernst Dalhoff
- Section of Physiological Acoustics and Communication, Department of Otolaryngology, Head and Neck Surgery, University of Tübingen, Tübingen, Germany
| | - Katharina Bader
- Section of Physiological Acoustics and Communication, Department of Otolaryngology, Head and Neck Surgery, University of Tübingen, Tübingen, Germany
| | - Stephan M. Wolpert
- Department of Otolaryngology, Head and Neck Surgery, Tübingen Hearing Research Centre, University of Tübingen, Tübingen, Germany
| | - Marlies Knipper
- Department of Otolaryngology, Head and Neck Surgery, Tübingen Hearing Research Centre, University of Tübingen, Tübingen, Germany
| | - Matthias H. J. Munk
- Department of Psychiatry and Psychotherapy, University of Tübingen, Tübingen, Germany
- Department of Biology, Technical University Darmstadt, Darmstadt, Germany
| |
Collapse
|
17
|
Vasilkov V, Caswell-Midwinter B, Zhao Y, de Gruttola V, Jung DH, Liberman MC, Maison SF. Evidence of cochlear neural degeneration in normal-hearing subjects with tinnitus. Sci Rep 2023; 13:19870. [PMID: 38036538 PMCID: PMC10689483 DOI: 10.1038/s41598-023-46741-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Accepted: 11/04/2023] [Indexed: 12/02/2023] Open
Abstract
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.
Collapse
Affiliation(s)
- Viacheslav Vasilkov
- Eaton-Peabody Laboratories, Massachusetts Eye and Ear, 243 Charles Street, Boston, MA, 02114, USA
- Department of Otolaryngology, Harvard Medical School, Boston, MA, 02114, USA
| | - Benjamin Caswell-Midwinter
- Eaton-Peabody Laboratories, Massachusetts Eye and Ear, 243 Charles Street, Boston, MA, 02114, USA
- Department of Otolaryngology, Harvard Medical School, Boston, MA, 02114, USA
| | - Yan Zhao
- Eaton-Peabody Laboratories, Massachusetts Eye and Ear, 243 Charles Street, Boston, MA, 02114, USA
| | - Victor de Gruttola
- Department of Biostatistics, Harvard T.H. Chan School of Public Health, Boston, MA, 02114, USA
| | - David H Jung
- Eaton-Peabody Laboratories, Massachusetts Eye and Ear, 243 Charles Street, Boston, MA, 02114, USA
- Department of Otolaryngology, Harvard Medical School, Boston, MA, 02114, USA
| | - M Charles Liberman
- Eaton-Peabody Laboratories, Massachusetts Eye and Ear, 243 Charles Street, Boston, MA, 02114, USA
- Department of Otolaryngology, Harvard Medical School, Boston, MA, 02114, USA
| | - Stéphane F Maison
- Eaton-Peabody Laboratories, Massachusetts Eye and Ear, 243 Charles Street, Boston, MA, 02114, USA.
- Department of Otolaryngology, Harvard Medical School, Boston, MA, 02114, USA.
| |
Collapse
|
18
|
Wang Y, Abrams KS, Youngman M, Henry KS. Histological Correlates of Auditory Nerve Injury from Kainic Acid in the Budgerigar (Melopsittacus undulatus). J Assoc Res Otolaryngol 2023; 24:473-485. [PMID: 37798548 PMCID: PMC10695905 DOI: 10.1007/s10162-023-00910-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Accepted: 09/11/2023] [Indexed: 10/07/2023] Open
Abstract
PURPOSE Loss of auditory nerve afferent synapses with cochlear hair cells, called cochlear synaptopathy, is a common pathology in humans caused by aging and noise overexposure. The perceptual consequences of synaptopathy in isolation from other cochlear pathologies are still unclear. Animal models provide an effective approach to resolve uncertainty regarding the physiological and perceptual consequences of auditory nerve loss, because neural lesions can be induced and readily quantified. The budgerigar, a parakeet species, has recently emerged as an animal model for synaptopathy studies based on its capacity for vocal learning and ability to behaviorally discriminate simple and complex sounds with acuity similar to humans. Kainic acid infusions in the budgerigar produce a profound reduction of compound auditory nerve responses, including wave I of the auditory brainstem response, without impacting physiological hair cell measures. These results suggest selective auditory nerve damage. However, histological correlates of neural injury from kainic acid are still lacking. METHODS We quantified the histological effects caused by intracochlear infusion of kainic acid (1 mM; 2.5 µL), and evaluated correlations between the histological and physiological assessments of auditory nerve status. RESULTS Kainic acid infusion in budgerigars produced pronounced loss of neural auditory nerve soma (60% on average) in the cochlear ganglion, and of peripheral axons, at time points 2 or more months following injury. The hair cell epithelium was unaffected by kainic acid. Neural loss was significantly correlated with reduction of compound auditory nerve responses and auditory brainstem response wave I. CONCLUSION Compound auditory nerve responses and wave I provide a useful index of cochlear synaptopathy in this animal model.
Collapse
Affiliation(s)
- Yingxuan Wang
- Department of Biomedical Engineering, University of Rochester, Rochester, NY 14642, USA
| | - Kristina S Abrams
- Department of Neuroscience, University of Rochester, Rochester, NY 14642, USA
| | - Margaret Youngman
- Department of Otolaryngology, University of Rochester, Rochester, NY 14642, USA
| | - Kenneth S Henry
- Department of Biomedical Engineering, University of Rochester, Rochester, NY 14642, USA.
- Department of Neuroscience, University of Rochester, Rochester, NY 14642, USA.
- Department of Otolaryngology, University of Rochester, Rochester, NY 14642, USA.
| |
Collapse
|
19
|
Heeringa AN, Teske F, Ashida G, Köppl C. Cochlear aging disrupts the correlation between spontaneous rate- and sound-level coding in auditory nerve fibers. J Neurophysiol 2023; 130:736-750. [PMID: 37584075 DOI: 10.1152/jn.00090.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 07/12/2023] [Accepted: 08/10/2023] [Indexed: 08/17/2023] Open
Abstract
The spiking activity of auditory nerve fibers (ANFs) transmits information about the acoustic environment from the cochlea to the central auditory system. Increasing age leads to degeneration of cochlear tissues, including the sensory hair cells and stria vascularis. Here, we aim to identify the functional effects of such age-related cochlear pathologies of ANFs. Rate-level functions (RLFs) were recorded from single-unit ANFs of young adult (n = 52, 3-12 months) and quiet-aged (n = 24, >36 months) Mongolian gerbils of either sex. RLFs were used to determine sensitivity and spontaneous rates (SRs) and were classified into flat-saturating, sloping-saturating, and straight categories, as previously established. A physiologically based cochlear model, adapted for the gerbil, was used to simulate the effects of cochlear degeneration on ANF physiology. In ANFs tuned to low frequencies (<3.5 kHz), SR was lower in those of aged gerbils, while an age-related loss of low-SR fibers was evident in ANFs tuned to high frequencies. These changes in SR distribution did not affect the typical SR versus sensitivity correlation. The distribution of RLF types among low-SR fibers, however, shifted toward that of high-SR fibers, specifically showing more fast-saturating and fewer sloping-saturating RLFs. A modeled striatal degeneration, which affects the combined inner hair cell and synaptic output, reduced SR but left RLF type unchanged. An additional reduced basilar membrane gain, which decreased sensitivity, explained the changed RLF types. Overall, the data indicated age-related changes in the characteristics of single ANFs that blurred the established relationships between SR and RLF types.NEW & NOTEWORTHY Auditory nerve fibers, which connect the cochlea to the central auditory system, change their encoding of sound level in aged gerbils. In addition to a general shift to higher levels, indicative of decreased sensitivity, level coding was also differentially affected in fibers with low- and high-spontaneous rates. Loss of low-spontaneous rate fibers, combined with a general decrease of spontaneous rate, further blurs the categorization of auditory nerve fiber types in the aged gerbil.
Collapse
Affiliation(s)
- Amarins N Heeringa
- Cluster of Excellence "Hearing4all," Department of Neuroscience, School of Medicine and Health Science, Carl von Ossietzky University Oldenburg, Oldenburg, Germany
- Research Centre Neurosensory Science, Department of Neuroscience, School of Medicine and Health Science, Carl von Ossietzky University Oldenburg, Oldenburg, Germany
| | - Fiona Teske
- Research Centre Neurosensory Science, Department of Neuroscience, School of Medicine and Health Science, Carl von Ossietzky University Oldenburg, Oldenburg, Germany
| | - Go Ashida
- Cluster of Excellence "Hearing4all," Department of Neuroscience, School of Medicine and Health Science, Carl von Ossietzky University Oldenburg, Oldenburg, Germany
- Research Centre Neurosensory Science, Department of Neuroscience, School of Medicine and Health Science, Carl von Ossietzky University Oldenburg, Oldenburg, Germany
| | - Christine Köppl
- Cluster of Excellence "Hearing4all," Department of Neuroscience, School of Medicine and Health Science, Carl von Ossietzky University Oldenburg, Oldenburg, Germany
- Research Centre Neurosensory Science, Department of Neuroscience, School of Medicine and Health Science, Carl von Ossietzky University Oldenburg, Oldenburg, Germany
| |
Collapse
|
20
|
Haggerty RA, Hutson KA, Riggs WJ, Brown KD, Pillsbury HC, Adunka OF, Buchman CA, Fitzpatrick DC. Assessment of cochlear synaptopathy by electrocochleography to low frequencies in a preclinical model and human subjects. Front Neurol 2023; 14:1104574. [PMID: 37483448 PMCID: PMC10361575 DOI: 10.3389/fneur.2023.1104574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Accepted: 06/19/2023] [Indexed: 07/25/2023] Open
Abstract
Cochlear synaptopathy is the loss of synapses between the inner hair cells and the auditory nerve despite survival of sensory hair cells. The findings of extensive cochlear synaptopathy in animals after moderate noise exposures challenged the long-held view that hair cells are the cochlear elements most sensitive to insults that lead to hearing loss. However, cochlear synaptopathy has been difficult to identify in humans. We applied novel algorithms to determine hair cell and neural contributions to electrocochleographic (ECochG) recordings from the round window of animal and human subjects. Gerbils with normal hearing provided training and test sets for a deep learning algorithm to detect the presence of neural responses to low frequency sounds, and an analytic model was used to quantify the proportion of neural and hair cell contributions to the ECochG response. The capacity to detect cochlear synaptopathy was validated in normal hearing and noise-exposed animals by using neurotoxins to reduce or eliminate the neural contributions. When the analytical methods were applied to human surgical subjects with access to the round window, the neural contribution resembled the partial cochlear synaptopathy present after neurotoxin application in animals. This result demonstrates the presence of viable hair cells not connected to auditory nerve fibers in human subjects with substantial hearing loss and indicates that efforts to regenerate nerve fibers may find a ready cochlear substrate for innervation and resumption of function.
Collapse
Affiliation(s)
- Raymond A. Haggerty
- Department of Otolaryngology, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Kendall A. Hutson
- Department of Otolaryngology, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - William J. Riggs
- Department of Otolaryngology, The Ohio State University, Columbus, OH, United States
| | - Kevin D. Brown
- Department of Otolaryngology, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
- University of North Carolina School of Medicine, Chapel Hill, NC, United States
| | - Harold C. Pillsbury
- Department of Otolaryngology, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
- University of North Carolina School of Medicine, Chapel Hill, NC, United States
| | - Oliver F. Adunka
- Department of Otolaryngology, The Ohio State University, Columbus, OH, United States
| | - Craig A. Buchman
- Department of Otolaryngology, Washington University in St. Louis, St. Louis, MO, United States
| | - Douglas C. Fitzpatrick
- Department of Otolaryngology, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| |
Collapse
|
21
|
Alamri Y, Jennings SG. Computational modeling of the human compound action potential. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2023; 153:2376. [PMID: 37092943 PMCID: PMC10119875 DOI: 10.1121/10.0017863] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Revised: 03/21/2023] [Accepted: 04/04/2023] [Indexed: 05/03/2023]
Abstract
The auditory nerve (AN) compound action potential (CAP) is an important tool for assessing auditory disorders and monitoring the health of the auditory periphery during surgical procedures. The CAP has been mathematically conceptualized as the convolution of a unit response (UR) waveform with the firing rate of a population of AN fibers. Here, an approach for predicting experimentally recorded CAPs in humans is proposed, which involves the use of human-based computational models to simulate AN activity. CAPs elicited by clicks, chirps, and amplitude-modulated carriers were simulated and compared with empirically recorded CAPs from human subjects. In addition, narrowband CAPs derived from noise-masked clicks and tone bursts were simulated. Many morphological, temporal, and spectral aspects of human CAPs were captured by the simulations for all stimuli tested. These findings support the use of model simulations of the human CAP to refine existing human-based models of the auditory periphery, aid in the design and analysis of auditory experiments, and predict the effects of hearing loss, synaptopathy, and other auditory disorders on the human CAP.
Collapse
Affiliation(s)
- Yousef Alamri
- Department of Biomedical Engineering, The University of Utah, 390 South, 1530 East, BEHS 1201, Salt Lake City, Utah 84112, USA
| | - Skyler G Jennings
- Department of Communication Sciences and Disorders, The University of Utah, 390 South, 1530 East, BEHS 1201, Salt Lake City, Utah 84112, USA
| |
Collapse
|
22
|
Shrestha BR, Wu L, Goodrich LV. Runx1 controls auditory sensory neuron diversity in mice. Dev Cell 2023; 58:306-319.e5. [PMID: 36800995 PMCID: PMC10202259 DOI: 10.1016/j.devcel.2023.01.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Revised: 08/28/2022] [Accepted: 01/26/2023] [Indexed: 02/18/2023]
Abstract
Sound stimulus is encoded in mice by three molecularly and physiologically diverse subtypes of sensory neurons, called Ia, Ib, and Ic spiral ganglion neurons (SGNs). Here, we show that the transcription factor Runx1 controls SGN subtype composition in the murine cochlea. Runx1 is enriched in Ib/Ic precursors by late embryogenesis. Upon the loss of Runx1 from embryonic SGNs, more SGNs take on Ia rather than Ib or Ic identities. This conversion was more complete for genes linked to neuronal function than to connectivity. Accordingly, synapses in the Ib/Ic location acquired Ia properties. Suprathreshold SGN responses to sound were enhanced in Runx1CKO mice, confirming the expansion of neurons with Ia-like functional properties. Runx1 deletion after birth also redirected Ib/Ic SGNs toward Ia identity, indicating that SGN identities are plastic postnatally. Altogether, these findings show that diverse neuronal identities essential for normal auditory stimulus coding arise hierarchically and remain malleable during postnatal development.
Collapse
Affiliation(s)
- Brikha R Shrestha
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA; Eaton-Peabody Laboratories, Massachusetts Eye and Ear, Boston, MA 02114, USA; Department of Otolaryngology, Harvard Medical School, Boston, MA 02114, USA.
| | - Lorna Wu
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Lisa V Goodrich
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA.
| |
Collapse
|
23
|
Feeney MP, Schairer KS, Putterman DB. Wideband Acoustic Reflex Measurement. Semin Hear 2023; 44:84-92. [PMID: 36925659 PMCID: PMC10014201 DOI: 10.1055/s-0043-1763296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/17/2023] Open
Abstract
Acoustic reflex thresholds (ART) obtained using pure-tone probe stimuli as part of a traditional immittance test battery can be used to evaluate site of lesion and provide a cross-check with behavioral results. ARTs obtained as part of a wideband acoustic immittance (WAI) test battery using a click as the probe stimulus can be used in the same way with the added benefit that they may provide lower ARTs than those obtained using a pure-tone probe. Another benefit of the WAI ART test is that it can be completed without requiring a hermetic seal or pressurizing the ear canal. A new adaptive method of obtaining ARTs using WAI techniques may cut test time in half, thus making this an attractive option for future clinical use. More advanced uses of WAI ART tests include the measurement of AR growth functions. These may be used to investigate the possible effects of synaptopathy related to high levels of noise exposure and possible auditory deficits related to ototoxicity.
Collapse
Affiliation(s)
- M Patrick Feeney
- VA Portland Health Care System, National Center for Rehabilitative Auditory Research, Portland, Oregon.,Department of Otolaryngology, Head and Neck Surgery, Oregon Health & Science University, Portland, Oregon
| | - Kim S Schairer
- Hearing and Balance Research Program, James H. Quillen VA Medical Center, Mountain Home, Tennessee.,Department of Audiology & Speech Language Pathology, East Tennessee State University, Johnson City, Tennessee
| | - Daniel B Putterman
- VA Portland Health Care System, National Center for Rehabilitative Auditory Research, Portland, Oregon.,Department of Otolaryngology, Head and Neck Surgery, Oregon Health & Science University, Portland, Oregon
| |
Collapse
|
24
|
Shehabi AM, Prendergast G, Guest H, Plack CJ. Binaural temporal coding and the middle ear muscle reflex in audiometrically normal young adults. Hear Res 2023; 427:108663. [PMID: 36502543 DOI: 10.1016/j.heares.2022.108663] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Revised: 11/11/2022] [Accepted: 11/29/2022] [Indexed: 12/07/2022]
Abstract
Noise exposure may damage the synapses that connect inner hair cells with auditory nerve fibers, before outer hair cells are lost. In humans, this cochlear synaptopathy (CS) is thought to decrease the fidelity of peripheral auditory temporal coding. In the current study, the primary hypothesis was that higher middle ear muscle reflex (MEMR) thresholds, as a proxy measure of CS, would be associated with smaller values of the binaural intelligibility level difference (BILD). The BILD, which is a measure of binaural temporal coding, is defined here as the difference in thresholds between the diotic and the antiphasic versions of the digits in noise (DIN) test. This DIN BILD may control for factors unrelated to binaural temporal coding such as linguistic, central auditory, and cognitive factors. Fifty-six audiometrically normal adults (34 females) aged 18 - 30 were tested. The test battery included standard pure tone audiometry, tympanometry, MEMR using a 2 kHz elicitor and 226 Hz and 1 kHz probes, the Noise Exposure Structured Interview, forward digit span test, extended high frequency (EHF) audiometry, and diotic and antiphasic DIN tests. The study protocol was pre-registered prior to data collection. MEMR thresholds did not predict the DIN BILD. Secondary analyses showed no association between MEMR thresholds and the individual diotic and antiphasic DIN thresholds. Greater lifetime noise exposure was non-significantly associated with higher MEMR thresholds, larger DIN BILD values, and lower (better) antiphasic DIN thresholds, but not with diotic DIN thresholds, nor with EHF thresholds. EHF thresholds were associated with neither MEMR thresholds nor any of the DIN outcomes, including the DIN BILD. Results provide no evidence that young, audiometrically normal people incur CS with impacts on binaural temporal processing.
Collapse
Affiliation(s)
- Adnan M Shehabi
- Manchester Centre for Audiology and Deafness, University of Manchester, UK; Department of Audiology and Speech Therapy, Birzeit University, Palestine.
| | | | - Hannah Guest
- Manchester Centre for Audiology and Deafness, University of Manchester, UK
| | - Christopher J Plack
- Manchester Centre for Audiology and Deafness, University of Manchester, UK; Department of Psychology, Lancaster University, UK
| |
Collapse
|
25
|
Stoll TJ, Maddox RK. Enhanced Place Specificity of the Parallel Auditory Brainstem Response: A Modeling Study. Trends Hear 2023; 27:23312165231205719. [PMID: 37807857 PMCID: PMC10563492 DOI: 10.1177/23312165231205719] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 09/13/2023] [Accepted: 09/19/2023] [Indexed: 10/10/2023] Open
Abstract
While each place on the cochlea is most sensitive to a specific frequency, it will generally respond to a sufficiently high-level stimulus over a wide range of frequencies. This spread of excitation can introduce errors in clinical threshold estimation during a diagnostic auditory brainstem response (ABR) exam. Off-frequency cochlear excitation can be mitigated through the addition of masking noise to the test stimuli, but introducing a masker increases the already long test times of the typical ABR exam. Our lab has recently developed the parallel ABR (pABR) paradigm to speed up test times by utilizing randomized stimulus timing to estimate the thresholds for multiple frequencies simultaneously. There is reason to believe parallel presentation of multiple frequencies provides masking effects and improves place specificity while decreasing test times. Here, we use two computational models of the auditory periphery to characterize the predicted effect of parallel presentation on place specificity in the auditory nerve. We additionally examine the effect of stimulus rate and level. Both models show the pABR is at least as place specific as standard methods, with an improvement in place specificity for parallel presentation (vs. serial) at high levels, especially at high stimulus rates. When simulating hearing impairment in one of the models, place specificity was also improved near threshold. Rather than a tradeoff, this improved place specificity would represent a secondary benefit to the pABR's faster test times.
Collapse
Affiliation(s)
- Thomas J. Stoll
- Department of Biomedical Engineering, University of Rochester, Rochester, NY, USA
- Del Monte Institute for Neuroscience, University of Rochester, Rochester, NY, USA
| | - Ross K. Maddox
- Department of Biomedical Engineering, University of Rochester, Rochester, NY, USA
- Del Monte Institute for Neuroscience, University of Rochester, Rochester, NY, USA
- Department of Neuroscience, University of Rochester, Rochester, NY, USA
| |
Collapse
|
26
|
Chen J, Jennings SG. Temporal Envelope Coding of the Human Auditory Nerve Inferred from Electrocochleography: Comparison with Envelope Following Responses. J Assoc Res Otolaryngol 2022; 23:803-814. [PMID: 35948693 PMCID: PMC9789235 DOI: 10.1007/s10162-022-00865-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Accepted: 07/12/2022] [Indexed: 01/06/2023] Open
Abstract
Neural coding of the slow amplitude fluctuations of sound (i.e., temporal envelope) is thought to be essential for speech understanding; however, such coding by the human auditory nerve is poorly understood. Here, neural coding of the temporal envelope by the human auditory nerve is inferred from measurements of the compound action potential in response to an amplitude modulated carrier (CAPENV) for modulation frequencies ranging from 20 to 1000 Hz. The envelope following response (EFR) was measured simultaneously with CAPENV from active electrodes placed on the high forehead and tympanic membrane, respectively. Results support the hypothesis that phase locking to higher modulation frequencies (> 80 Hz) will be stronger for CAPENV, compared to EFR, consistent with the upper-frequency limits of phase locking for auditory nerve fibers compared to auditory brainstem/cortex neurons. Future work is needed to determine the extent to which (1) CAPENV is a useful tool for studying how temporal processing of the auditory nerve is affected by aging, hearing loss, and noise-induced cochlear synaptopathy and (2) CAPENV reveals the relationship between auditory nerve temporal processing and perception of the temporal envelope.
Collapse
Affiliation(s)
- Jessica Chen
- Department of Communication Sciences and Disorders, The University of Utah, 390 South BEHS 1201, Salt Lake City, UT, USA
| | - Skyler G Jennings
- Department of Communication Sciences and Disorders, The University of Utah, 390 South BEHS 1201, Salt Lake City, UT, USA.
| |
Collapse
|
27
|
Cross-species experiments reveal widespread cochlear neural damage in normal hearing. Commun Biol 2022; 5:733. [PMID: 35869142 PMCID: PMC9307777 DOI: 10.1038/s42003-022-03691-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Accepted: 07/08/2022] [Indexed: 11/24/2022] Open
Abstract
Animal models suggest that cochlear afferent nerve endings may be more vulnerable than sensory hair cells to damage from acoustic overexposure and aging. Because neural degeneration without hair-cell loss cannot be detected in standard clinical audiometry, whether such damage occurs in humans is hotly debated. Here, we address this debate through co-ordinated experiments in at-risk humans and a wild-type chinchilla model. Cochlear neuropathy leads to large and sustained reductions of the wideband middle-ear muscle reflex in chinchillas. Analogously, human wideband reflex measures revealed distinct damage patterns in middle age, and in young individuals with histories of high acoustic exposure. Analysis of an independent large public dataset and additional measurements using clinical equipment corroborated the patterns revealed by our targeted cross-species experiments. Taken together, our results suggest that cochlear neural damage is widespread even in populations with clinically normal hearing. Cross-species experiments on chinchillas and at-risk humans suggest cochlear synaptopathy from noise exposure and aging are widespread even among individuals with clinically normal hearing status.
Collapse
|
28
|
Kipping D, Nogueira W. A Computational Model of a Single Auditory Nerve Fiber for Electric-Acoustic Stimulation. J Assoc Res Otolaryngol 2022; 23:835-858. [PMID: 36333573 PMCID: PMC9789289 DOI: 10.1007/s10162-022-00870-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Accepted: 08/21/2022] [Indexed: 11/06/2022] Open
Abstract
Cochlear implant (CI) recipients with preserved acoustic low-frequency hearing in the implanted ear are a growing group among traditional CI users who benefit from hybrid electric-acoustic stimulation (EAS). However, combined ipsilateral electric and acoustic stimulation also introduces interactions between the two modalities that can affect the performance of EAS users. A computational model of a single auditory nerve fiber that is excited by EAS was developed to study the interaction between electric and acoustic stimulation. Two existing models of sole electric or acoustic stimulation were coupled to simulate responses to combined EAS. Different methods of combining both models were implemented. In the coupled model variant, the refractoriness of the simulated fiber leads to suppressive interaction between electrically evoked and acoustically evoked spikes as well as spontaneous activity. The second model variant is an uncoupled EAS model without electric-acoustic interaction. By comparing predictions between the coupled and the noninteracting EAS model, it was possible to infer electric-acoustic interaction at the level of the auditory nerve. The EAS model was used to simulate fiber populations with realistic inter-unit variability, where each unit was represented by the single-fiber model. Predicted thresholds and dynamic ranges, spike rates, latencies, jitter, and vector strengths were compared to empirical data. The presented EAS model provides a framework for future studies of peripheral electric-acoustic interaction.
Collapse
Affiliation(s)
- Daniel Kipping
- Department of Otolaryngology, Hannover Medical School (MHH), Hannover, Germany
- Cluster of Excellence Hearing4all, Hannover, Germany
| | - Waldo Nogueira
- Department of Otolaryngology, Hannover Medical School (MHH), Hannover, Germany
- Cluster of Excellence Hearing4all, Hannover, Germany
| |
Collapse
|
29
|
Pinsonnault-Skvarenina A, Soucy W, Noël J, Doucet F, Lévesque É, Fuente A, Leroux T. Supra-threshold deficits in normal hearing military recruits exposed to impulse noise. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2022; 152:2419. [PMID: 36319241 DOI: 10.1121/10.0014829] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Accepted: 09/23/2022] [Indexed: 06/16/2023]
Abstract
The aim of this study was to determine the effect of impulse noise exposure on various proxy measures of cochlear synaptopathy in young military recruits. A total of 27 military recruits with exposure to firearm and artillery noise and 13 non exposed participants were recruited. All presented with normal hearing thresholds and the presence of distortion product otoacoustic emissions (DPOAEs). The Noise Exposure Structured Interview (NESI) was used to quantify noise exposure. Speech perception in noise (SPiN), equivalent rectangular bandwidth (ERB) of auditory filters, auditory brainstem response wave I amplitude, wave I amplitude growth function, wave I/V amplitude ratio, wave V latency, wave V latency shift with ipsilateral noise, and the summating potential/action potential ratio of the electrocochleography were measured. In military participants, SPiN was worse, ERB at 4 kHz was larger, wave I amplitude at 75 dBnHL was reduced, and wave V latency was delayed. However, no significant correlations were observed between NESI and auditory measures, once multiplicity of tests was controlled for. These results suggest that military recruits may exhibit supra-threshold deficits, despite presenting with normal hearing thresholds and presence of DPOAEs. Future studies should include a measure of auditory filters in their test battery.
Collapse
Affiliation(s)
| | - William Soucy
- École d'orthophonie et d'audiologie, Faculté de médecine, Université de Montréal, Montréal, Québec, H3C 3J7, Canada
| | - Jonathan Noël
- École d'orthophonie et d'audiologie, Faculté de médecine, Université de Montréal, Montréal, Québec, H3C 3J7, Canada
| | - Félicia Doucet
- École d'orthophonie et d'audiologie, Faculté de médecine, Université de Montréal, Montréal, Québec, H3C 3J7, Canada
| | - Élise Lévesque
- École d'orthophonie et d'audiologie, Faculté de médecine, Université de Montréal, Montréal, Québec, H3C 3J7, Canada
| | - Adrian Fuente
- École d'orthophonie et d'audiologie, Faculté de médecine, Université de Montréal, Montréal, Québec, H3C 3J7, Canada
| | - Tony Leroux
- École d'orthophonie et d'audiologie, Faculté de médecine, Université de Montréal, Montréal, Québec, H3C 3J7, Canada
| |
Collapse
|
30
|
Valderrama JT, de la Torre A, McAlpine D. The hunt for hidden hearing loss in humans: From preclinical studies to effective interventions. Front Neurosci 2022; 16:1000304. [PMID: 36188462 PMCID: PMC9519997 DOI: 10.3389/fnins.2022.1000304] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Accepted: 08/29/2022] [Indexed: 11/30/2022] Open
Abstract
Many individuals experience hearing problems that are hidden under a normal audiogram. This not only impacts on individual sufferers, but also on clinicians who can offer little in the way of support. Animal studies using invasive methodologies have developed solid evidence for a range of pathologies underlying this hidden hearing loss (HHL), including cochlear synaptopathy, auditory nerve demyelination, elevated central gain, and neural mal-adaptation. Despite progress in pre-clinical models, evidence supporting the existence of HHL in humans remains inconclusive, and clinicians lack any non-invasive biomarkers sensitive to HHL, as well as a standardized protocol to manage hearing problems in the absence of elevated hearing thresholds. Here, we review animal models of HHL as well as the ongoing research for tools with which to diagnose and manage hearing difficulties associated with HHL. We also discuss new research opportunities facilitated by recent methodological tools that may overcome a series of barriers that have hampered meaningful progress in diagnosing and treating of HHL.
Collapse
Affiliation(s)
- Joaquin T. Valderrama
- National Acoustic Laboratories, Sydney, NSW, Australia
- Department of Linguistics, Macquarie University Hearing, Macquarie University, Sydney, NSW, Australia
- *Correspondence: Joaquin T. Valderrama, ;
| | - Angel de la Torre
- Department of Signal Theory, Telematics and Communications, University of Granada, Granada, Spain
- Research Centre for Information and Communications Technologies (CITIC-UGR), University of Granada, Granada, Spain
| | - David McAlpine
- Department of Linguistics, Macquarie University Hearing, Macquarie University, Sydney, NSW, Australia
| |
Collapse
|
31
|
Pinsonnault-Skvarenina A, Moïn-Darbari K, Zhao W, Zhang M, Qiu W, Fuente A. No effect of occupational noise exposure on auditory brainstem response and speech perception in noise. Front Neurosci 2022; 16:915211. [PMID: 35937884 PMCID: PMC9354017 DOI: 10.3389/fnins.2022.915211] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Accepted: 07/05/2022] [Indexed: 11/13/2022] Open
Abstract
The primary aim of this study was to investigate whether auditory brainstem response (ABR) and speech perception in noise (SPiN) were associated with occupational noise exposure in normal hearing young factory workers. Forty young adults occupationally exposed to noise and 40 non-exposed young adults (control group) from Zhejiang province in China were selected. All participants presented with normal hearing thresholds and distortion product otoacoustic emissions. Participants were evaluated with the Mandarin Bamford-Kowal-Bench (BKB) test and ABR. The latter was obtained for click stimulus at 50, 60, 70, 80, and 90 dBnHL. Peak-to-trough amplitudes and latencies for waves I and V were obtained. The ABR wave I amplitude, the wave I/V amplitude ratio, the slope of the wave I amplitude growth as a function of stimulus intensity (AMP-ISlope), and the wave V latency shift with ipsilateral noise (LAT-VSlope) were used as ABR outcomes. Finally, equivalent continuous average sound pressure level normalized to 8 h (LAeq.8h) and cumulative noise exposure (CNE) were obtained for noise-exposed participants. No significant differences between groups were found for any ABR outcomes. Noise-exposed participants exhibited worse BKB scores than control group participants. A multivariate regression model showed that 23.3% of the variance in BKB scores was explained by group category (exposed vs. non-exposed) and hearing thresholds. However, since none of the ABR outcomes exploring cochlear synaptopathy were associated with noise exposure, we cannot conclude that cochlear synaptopathy was the contributing factor for the differences between groups for BKB scores. Factors that go beyond sensory processing may explain such results, especially given socio-economic differences between the noise-exposed and control groups. We conclude that in this sample of participants, occupational noise exposure was not associated with signs of cochlear synaptopathy as measured by ABR and BKB.
Collapse
Affiliation(s)
- Alexis Pinsonnault-Skvarenina
- École d’Orthophonie et d’Audiologie, Faculté de Médecine, Université de Montréal, Montréal, QC, Canada
- Centre de Recherche Interdisciplinaire en Réadaptation du Montréal Métropolitain – CIUSSS du Centre-Sud-de-l’Île-de-Montréal, Montréal, QC, Canada
- Centre for Interdisciplinary Research in Music Media and Technology, McGill University, Montréal, QC, Canada
| | - Karina Moïn-Darbari
- École d’Orthophonie et d’Audiologie, Faculté de Médecine, Université de Montréal, Montréal, QC, Canada
- Centre de Recherche de l’Institut Universitaire de Gériatrie de Montréal – CIUSSS du Centre-Sud-de-l’ÎIe-de-Montréal, Montréal, QC, Canada
| | - Wulan Zhao
- Zhejiang Chinese Medical University, Hangzhou, China
| | - Meibian Zhang
- National Institute of Occupational Health and Poison Control, Beijing, China
| | - Wei Qiu
- Auditory Research Laboratory, State University of New York at Plattsburgh, Plattsburgh, NY, United States
| | - Adrian Fuente
- École d’Orthophonie et d’Audiologie, Faculté de Médecine, Université de Montréal, Montréal, QC, Canada
- Centre de Recherche de l’Institut Universitaire de Gériatrie de Montréal – CIUSSS du Centre-Sud-de-l’ÎIe-de-Montréal, Montréal, QC, Canada
- *Correspondence: Adrian Fuente,
| |
Collapse
|
32
|
Shehabi AM, Prendergast G, Plack CJ. The Relative and Combined Effects of Noise Exposure and Aging on Auditory Peripheral Neural Deafferentation: A Narrative Review. Front Aging Neurosci 2022; 14:877588. [PMID: 35813954 PMCID: PMC9260498 DOI: 10.3389/fnagi.2022.877588] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Accepted: 05/30/2022] [Indexed: 11/13/2022] Open
Abstract
Animal studies have shown that noise exposure and aging cause a reduction in the number of synapses between low and medium spontaneous rate auditory nerve fibers and inner hair cells before outer hair cell deterioration. This noise-induced and age-related cochlear synaptopathy (CS) is hypothesized to compromise speech recognition at moderate-to-high suprathreshold levels in humans. This paper evaluates the evidence on the relative and combined effects of noise exposure and aging on CS, in both animals and humans, using histopathological and proxy measures. In animal studies, noise exposure seems to result in a higher proportion of CS (up to 70% synapse loss) compared to aging (up to 48% synapse loss). Following noise exposure, older animals, depending on their species, seem to either exhibit significant or little further synapse loss compared to their younger counterparts. In humans, temporal bone studies suggest a possible age- and noise-related auditory nerve fiber loss. Based on the animal data obtained from different species, we predict that noise exposure may accelerate age-related CS to at least some extent in humans. In animals, noise-induced and age-related CS in separation have been consistently associated with a decreased amplitude of wave 1 of the auditory brainstem response, reduced middle ear muscle reflex strength, and degraded temporal processing as demonstrated by lower amplitudes of the envelope following response. In humans, the individual effects of noise exposure and aging do not seem to translate clearly into deficits in electrophysiological, middle ear muscle reflex, and behavioral measures of CS. Moreover, the evidence on the combined effects of noise exposure and aging on peripheral neural deafferentation in humans using electrophysiological and behavioral measures is even more sparse and inconclusive. Further research is necessary to establish the individual and combined effects of CS in humans using temporal bone, objective, and behavioral measures.
Collapse
Affiliation(s)
- Adnan M. Shehabi
- Manchester Centre for Audiology and Deafness, University of Manchester, Manchester, United Kingdom
- Department of Audiology and Speech Therapy, Birzeit University, Birzeit, Palestine
| | - Garreth Prendergast
- Manchester Centre for Audiology and Deafness, University of Manchester, Manchester, United Kingdom
| | - Christopher J. Plack
- Manchester Centre for Audiology and Deafness, University of Manchester, Manchester, United Kingdom
- Department of Psychology, Lancaster University, Lancaster, United Kingdom
| |
Collapse
|
33
|
Steenken F, Oetjen H, Beutelmann R, Carney LH, Koeppl C, Klump GM. Neural processing and perception of Schroeder-phase harmonic tone complexes in the gerbil: Relating single-unit neurophysiology to behavior. Eur J Neurosci 2022; 56:4060-4085. [PMID: 35724973 PMCID: PMC9632632 DOI: 10.1111/ejn.15744] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 05/22/2022] [Accepted: 05/25/2022] [Indexed: 11/30/2022]
Abstract
Schroeder-phase harmonic tone complexes have been used in physiological and psychophysical studies in several species to gain insight into cochlear function. Each pitch period of the Schroeder stimulus contains a linear frequency sweep; the duty cycle, sweep velocity, and direction are controlled by parameters of the phase spectrum. Here, responses to a range of Schroeder-phase harmonic tone complexes were studied both behaviorally and in neural recordings from the auditory nerve and inferior colliculus of Mongolian gerbils. Gerbils were able to discriminate Schroeder-phase harmonic tone complexes based on sweep direction, duty cycle, and/or velocity for fundamental frequencies up to 200 Hz. Temporal representation in neural responses based on the van Rossum spike-distance metric, with time constants of either 1 ms or related to the stimulus' period, was compared to average discharge rates. Neural responses and behavioral performance were both expressed in terms of sensitivity, d', to allow direct comparisons. Our results suggest that in the auditory nerve, stimulus fine structure is represented by spike timing while envelope is represented by rate. In the inferior colliculus, both temporal fine structure and envelope appear to be represented best by rate. However, correlations between neural d' values and behavioral sensitivity for sweep direction were strongest for both temporal metrics, for both auditory nerve and inferior colliculus. Furthermore, the high sensitivity observed in the inferior colliculus neural rate-based discrimination suggests that these neurons integrate across multiple inputs arising from the auditory periphery.
Collapse
Affiliation(s)
- Friederike Steenken
- Cluster of Excellence "Hearing4all" and Research Centre Neurosensory Science, Department of Neuroscience, School of Medicine and Health Science, Carl von Ossietzky University Oldenburg, Oldenburg, Germany
| | - Henning Oetjen
- Cluster of Excellence "Hearing4all" and Research Centre Neurosensory Science, Department of Neuroscience, School of Medicine and Health Science, Carl von Ossietzky University Oldenburg, Oldenburg, Germany
| | - Rainer Beutelmann
- Cluster of Excellence "Hearing4all" and Research Centre Neurosensory Science, Department of Neuroscience, School of Medicine and Health Science, Carl von Ossietzky University Oldenburg, Oldenburg, Germany
| | - Laurel H Carney
- Department of Biomedical Engineering, University of Rochester, Rochester, NY, USA.,Hanse-Wissenschaftskolleg, Delmenhorst, Germany
| | - Christine Koeppl
- Cluster of Excellence "Hearing4all" and Research Centre Neurosensory Science, Department of Neuroscience, School of Medicine and Health Science, Carl von Ossietzky University Oldenburg, Oldenburg, Germany
| | - Georg M Klump
- Cluster of Excellence "Hearing4all" and Research Centre Neurosensory Science, Department of Neuroscience, School of Medicine and Health Science, Carl von Ossietzky University Oldenburg, Oldenburg, Germany
| |
Collapse
|
34
|
Affortit C, Blanc F, Nasr J, Ceccato JC, Markossian S, Guyot R, Puel JL, Flamant F, Wang J. A disease-associated mutation in thyroid hormone receptor α1 causes hearing loss and sensory hair cell patterning defects in mice. Sci Signal 2022; 15:eabj4583. [PMID: 35700264 DOI: 10.1126/scisignal.abj4583] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Resistance to thyroid hormone due to mutations in THRA, which encodes the thyroid hormone receptor α (TRα1), shows variable clinical presentation. Mutations affecting TRβ1 and TRβ2 cause deafness in mice and have been associated with deafness in humans. To test whether TRα1 also affects hearing function, we used mice heterozygous for a frameshift mutation in Thra that is similar to human THRA mutations (ThraS1/+ mice) and reduces tissue sensitivity to thyroid hormone. Compared to wild-type littermates, ThraS1/+ mice showed moderate high-frequency sensorineural hearing loss as juveniles and increased age-related hearing loss. Ultrastructural examination revealed aberrant orientation of ~20% of sensory outer hair cells (OHCs), as well as increased numbers of mitochondria with fragmented morphology and autophagic vacuoles in both OHCs and auditory nerve fibers. Molecular dissection of the OHC lateral wall components revealed that the potassium ion channel Kcnq4 was aberrantly targeted to the cytoplasm of mutant OHCs. In addition, mutant cochleae showed increased oxidative stress, autophagy, and mitophagy associated with greater age-related cochlear cell damage, demonstrating that TRα1 is required for proper development of OHCs and for maintenance of OHC function. These findings suggest that patients with THRA mutations may present underdiagnosed, mild hearing loss and may be more susceptible to age-related hearing loss.
Collapse
Affiliation(s)
- Corentin Affortit
- Institute for Neurosciences of Montpellier (INM), University Montpellier, INSERM, Montpellier, France
| | - Fabian Blanc
- Institute for Neurosciences of Montpellier (INM), University Montpellier, INSERM, Montpellier, France.,Department of ENT and Head and Neck Surgery, University Hospital of Montpellier, Montpellier, France
| | - Jamal Nasr
- Institute for Neurosciences of Montpellier (INM), University Montpellier, INSERM, Montpellier, France
| | - Jean-Charles Ceccato
- Institute for Neurosciences of Montpellier (INM), University Montpellier, INSERM, Montpellier, France
| | - Suzy Markossian
- Institut de Génomique Fonctionnelle de Lyon (IGFL), INRAE USC1370, CNRS (UMR5242), ENS, Lyon, France
| | - Romain Guyot
- Institut de Génomique Fonctionnelle de Lyon (IGFL), INRAE USC1370, CNRS (UMR5242), ENS, Lyon, France
| | - Jean-Luc Puel
- Institute for Neurosciences of Montpellier (INM), University Montpellier, INSERM, Montpellier, France
| | - Frédéric Flamant
- Institut de Génomique Fonctionnelle de Lyon (IGFL), INRAE USC1370, CNRS (UMR5242), ENS, Lyon, France
| | - Jing Wang
- Institute for Neurosciences of Montpellier (INM), University Montpellier, INSERM, Montpellier, France.,Department of ENT and Head and Neck Surgery, University Hospital of Montpellier, Montpellier, France
| |
Collapse
|
35
|
Ripley S, Xia L, Zhang Z, Aiken SJ, Wang J. Animal-to-Human Translation Difficulties and Problems With Proposed Coding-in-Noise Deficits in Noise-Induced Synaptopathy and Hidden Hearing Loss. Front Neurosci 2022; 16:893542. [PMID: 35720689 PMCID: PMC9199355 DOI: 10.3389/fnins.2022.893542] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Accepted: 04/22/2022] [Indexed: 12/26/2022] Open
Abstract
Noise induced synaptopathy (NIS) and hidden hearing loss (NIHHL) have been hot topic in hearing research since a massive synaptic loss was identified in CBA mice after a brief noise exposure that did not cause permanent threshold shift (PTS) in 2009. Based upon the amount of synaptic loss and the bias of it to synapses with a group of auditory nerve fibers (ANFs) with low spontaneous rate (LSR), coding-in-noise deficit (CIND) has been speculated as the major difficult of hearing in subjects with NIS and NIHHL. This speculation is based upon the idea that the coding of sound at high level against background noise relies mainly on the LSR ANFs. However, the translation from animal data to humans for NIS remains to be justified due to the difference in noise exposure between laboratory animals and human subjects in real life, the lack of morphological data and reliable functional methods to quantify or estimate the loss of the afferent synapses by noise. Moreover, there is no clear, robust data revealing the CIND even in animals with the synaptic loss but no PTS. In humans, both positive and negative reports are available. The difficulty in verifying CINDs has led a re-examination of the hypothesis that CIND is the major deficit associated with NIS and NIHHL, and the theoretical basis of this idea on the role of LSR ANFs. This review summarized the current status of research in NIS and NIHHL, with focus on the translational difficulty from animal data to human clinicals, the technical difficulties in quantifying NIS in humans, and the problems with the SR theory on signal coding. Temporal fluctuation profile model was discussed as a potential alternative for signal coding at high sound level against background noise, in association with the mechanisms of efferent control on the cochlea gain.
Collapse
Affiliation(s)
- Sara Ripley
- School of Communication Sciences and Disorders, Dalhousie University, Halifax, NS, Canada
| | - Li Xia
- Department of Otolaryngology-Head and Neck Surgery, Mianyang Central Hospital, School of Medicine, University of Electronic Science and Technology of China, Mianyang, China
| | - Zhen Zhang
- Department of Otolaryngology-Head and Neck Surgery, Shanghai Jiao Tong University Affiliated Sixth People’s Hospital, Shanghai, China
- Otolaryngology Institute of Shanghai Jiao Tong University, Shanghai, China
| | - Steve J. Aiken
- School of Communication Sciences and Disorders, Dalhousie University, Halifax, NS, Canada
| | - Jian Wang
- School of Communication Sciences and Disorders, Dalhousie University, Halifax, NS, Canada
- Department of Otolaryngology-Head and Neck Surgery, Mianyang Central Hospital, School of Medicine, University of Electronic Science and Technology of China, Mianyang, China
| |
Collapse
|
36
|
Suthakar K, Liberman MC. Noise Masking in Cochlear Synaptopathy: Auditory Brainstem Response vs. Auditory Nerve Response in Mouse. J Neurophysiol 2022; 127:1574-1585. [PMID: 35583974 PMCID: PMC9169830 DOI: 10.1152/jn.00402.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Revised: 04/28/2022] [Accepted: 05/12/2022] [Indexed: 11/22/2022] Open
Abstract
After acoustic overexposure, many auditory-nerve fiber (ANF) synapses permanently retract from surviving cochlear hair cells. This synaptopathy is hard to diagnose, since it does not elevate audiometric thresholds until almost no synapses remain, nevertheless it may degrade discrimination of complex stimuli especially in noisy environments. Here, we study an assay based on masking the auditory brainstem responses (ABRs) to a moderate-level probe tone with continuous noise of varied sound levels, and we investigate the underlying ANF responses at the single-fiber level. Synaptopathy was induced by overexposure to octave-band noise, resulting in a permanent synaptic loss of ~50%, without permanent threshold elevation except at the highest frequencies. The normal progressive delay of ABR peaks with increasing masker level is diminished in synaptopathic ears; however, the single-fiber analysis suggests that this normal latency shift does not arise because contributing ANFs shift from low-threshold fibers (with high spontaneous rates) to high-threshold fibers (with low spontaneous rates). Rather, it may arise because of a shift in the cochlear region dominating the response. Surprisingly, the dynamic range of masking, i.e. the difference between the lowest masker level that attenuates the ABR to a fixed-level probe and the lowest masker level that eliminates the ABR, is enhanced in the synaptopathic ears. This ABR behavior mirrors the single-fiber data showing a paradoxical enhancement of onset-response synchrony and resistance to masking in responses of ANFs in the synaptopathic regions. An assay based on the dynamic range of masking could be useful in diagnosing synaptic damage in human populations.
Collapse
Affiliation(s)
- Kirupa Suthakar
- Eaton-Peabody Laboratories, Massachusetts Eye and Ear, Boston, MA, United States
- Department of Otolaryngology, Harvard Medical School, Boston, MA, United States
| | - M Charles Liberman
- Eaton-Peabody Laboratories, Massachusetts Eye and Ear, Boston, MA, United States
- Department of Otolaryngology, Harvard Medical School, Boston, MA, United States
| |
Collapse
|
37
|
Marchetta P, Eckert P, Lukowski R, Ruth P, Singer W, Rüttiger L, Knipper M. Loss of central mineralocorticoid or glucocorticoid receptors impacts auditory nerve processing in the cochlea. iScience 2022; 25:103981. [PMID: 35281733 PMCID: PMC8914323 DOI: 10.1016/j.isci.2022.103981] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 01/26/2022] [Accepted: 02/21/2022] [Indexed: 02/08/2023] Open
Abstract
The key auditory signature that may associate peripheral hearing with central auditory cognitive defects remains elusive. Suggesting the involvement of stress receptors, we here deleted the mineralocorticoid and glucocorticoid receptors (MR and GR) using a CaMKIIα-based tamoxifen-inducible CreERT2/loxP approach to generate mice with single or double deletion of central but not cochlear MR and GR. Hearing thresholds of MRGRCaMKIIαCreERT2 conditional knockouts (cKO) were unchanged, whereas auditory nerve fiber (ANF) responses were larger and faster and auditory steady state responses were improved. Subsequent analysis of single MR or GR cKO revealed discrete roles for both, central MR and GR on cochlear functions. Limbic MR deletion reduced inner hair cell (IHC) ribbon numbers and ANF responses. In contrast, GR deletion shortened the latency and improved the synchronization to amplitude-modulated tones without affecting IHC ribbon numbers. These findings imply that stress hormone-dependent functions of central MR/GR contribute to “precognitive” sound processing in the cochlea. Top-down MR/GR signaling differentially contributes to cochlear sound processing Limbic MR stimulates auditory nerve fiber discharge rates Central GR deteriorates auditory nerve fiber synchrony
Collapse
Affiliation(s)
- Philine Marchetta
- University of Tübingen, Department of Otolaryngology, Head and Neck Surgery, Tübingen Hearing Research Centre, Molecular Physiology of Hearing, Elfriede-Aulhorn-Straße 5, 72076 Tübingen, Germany
| | - Philipp Eckert
- University of Tübingen, Department of Otolaryngology, Head and Neck Surgery, Tübingen Hearing Research Centre, Molecular Physiology of Hearing, Elfriede-Aulhorn-Straße 5, 72076 Tübingen, Germany
| | - Robert Lukowski
- University of Tübingen, Institute of Pharmacy, Pharmacology, Toxicology and Clinical Pharmacy, 72076 Tübingen, Germany
| | - Peter Ruth
- University of Tübingen, Institute of Pharmacy, Pharmacology, Toxicology and Clinical Pharmacy, 72076 Tübingen, Germany
| | - Wibke Singer
- University of Tübingen, Department of Otolaryngology, Head and Neck Surgery, Tübingen Hearing Research Centre, Molecular Physiology of Hearing, Elfriede-Aulhorn-Straße 5, 72076 Tübingen, Germany
| | - Lukas Rüttiger
- University of Tübingen, Department of Otolaryngology, Head and Neck Surgery, Tübingen Hearing Research Centre, Molecular Physiology of Hearing, Elfriede-Aulhorn-Straße 5, 72076 Tübingen, Germany
| | - Marlies Knipper
- University of Tübingen, Department of Otolaryngology, Head and Neck Surgery, Tübingen Hearing Research Centre, Molecular Physiology of Hearing, Elfriede-Aulhorn-Straße 5, 72076 Tübingen, Germany
| |
Collapse
|
38
|
Bao J, Jegede SL, Hawks JW, Dade B, Guan Q, Middaugh S, Qiu Z, Levina A, Tsai TH. Detecting Cochlear Synaptopathy Through Curvature Quantification of the Auditory Brainstem Response. Front Cell Neurosci 2022; 16:851500. [PMID: 35356798 PMCID: PMC8959412 DOI: 10.3389/fncel.2022.851500] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Accepted: 02/14/2022] [Indexed: 11/13/2022] Open
Abstract
The sound-evoked electrical compound potential known as auditory brainstem response (ABR) represents the firing of a heterogenous population of auditory neurons in response to sound stimuli, and is often used for clinical diagnosis based on wave amplitude and latency. However, recent ABR applications to detect human cochlear synaptopathy have led to inconsistent results, mainly due to the high variability of ABR wave-1 amplitude. Here, rather than focusing on the amplitude of ABR wave 1, we evaluated the use of ABR wave curvature to detect cochlear synaptic loss. We first compared four curvature quantification methods using simulated ABR waves, and identified that the cubic spline method using five data points produced the most accurate quantification. We next evaluated this quantification method with ABR data from an established mouse model with cochlear synaptopathy. The data clearly demonstrated that curvature measurement is more sensitive and consistent in identifying cochlear synaptic loss in mice compared to the amplitude and latency measurements. We further tested this curvature method in a different mouse model presenting with otitis media. The change in curvature profile due to middle ear infection in otitis media is different from the profile of mice with cochlear synaptopathy. Thus, our study suggests that curvature quantification can be used to address the current ABR variability issue, and may lead to additional applications in the clinic diagnosis of hearing disorders.
Collapse
Affiliation(s)
- Jianxin Bao
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, OH, United States
- Department of Research and Development, Gateway Biotechnology Inc., Rootstown, OH, United States
- *Correspondence: Jianxin Bao,
| | - Segun Light Jegede
- Department of Mathematical Sciences, Kent State University, Kent, OH, United States
| | - John W. Hawks
- Department of Research and Development, Gateway Biotechnology Inc., Rootstown, OH, United States
| | - Bethany Dade
- Department of Research and Development, Gateway Biotechnology Inc., Rootstown, OH, United States
| | - Qiang Guan
- Department of Computer Science, Kent State University, Kent, OH, United States
| | - Samantha Middaugh
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, OH, United States
| | - Ziyu Qiu
- Department of Research and Development, Gateway Biotechnology Inc., Rootstown, OH, United States
| | - Anna Levina
- Department of Mathematical Sciences, Kent State University, Kent, OH, United States
| | - Tsung-Heng Tsai
- Department of Mathematical Sciences, Kent State University, Kent, OH, United States
| |
Collapse
|
39
|
Bramhall NF, Reavis KM, Feeney MP, Kampel SD. The Impacts of Noise Exposure on the Middle Ear Muscle Reflex in a Veteran Population. Am J Audiol 2022; 31:126-142. [PMID: 35050699 PMCID: PMC10831927 DOI: 10.1044/2021_aja-21-00133] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
PURPOSE Human studies of noise-induced cochlear synaptopathy using physiological indicators identified in animal models (auditory brainstem response [ABR] Wave I amplitude, envelope following response [EFR], and middle ear muscle reflex [MEMR]) have yielded mixed findings. Differences in the population studied may have contributed to the differing results. For example, due to differences in the intensity level of the noise exposure, noise-induced synaptopathy may be easier to detect in a military Veteran population than in populations with recreational noise exposure. We previously demonstrated a reduction in ABR Wave I amplitude and EFR magnitude for young Veterans with normal audiograms reporting high levels of noise exposure compared to non-Veteran controls. In this article, we expand on the previous analysis in the same population to determine if MEMR magnitude is similarly reduced. METHOD Contralateral MEMR growth functions were obtained in 92 young Veterans and non-Veterans with normal audiograms, and the relationship between noise exposure history and MEMR magnitude was assessed. Associations between MEMR magnitude and distortion product otoacoustic emission, EFR, and ABR measurements collected in the same sample were also evaluated. RESULTS The results of the statistical analysis, although not conventionally statistically significant, suggest a reduction in mean MEMR magnitude for Veterans reporting high noise exposure compared with non-Veteran controls. In addition, the MEMR appears relatively insensitive to subclinical outer hair cell dysfunction, as measured by distortion product otoacoustic emissions, and is not well correlated with ABR and EFR measurements. CONCLUSIONS When combined with our previous ABR and EFR findings in the same population, these results suggest that noise-induced synaptopathy occurs in humans. In addition, the findings indicate that the MEMR may be a good candidate for noninvasive diagnosis of cochlear synaptopathy/deafferentation and that the MEMR may reflect the integrity of different neural populations than the ABR and EFR. SUPPLEMENTAL MATERIAL https://doi.org/10.23641/asha.18665645.
Collapse
Affiliation(s)
- Naomi F Bramhall
- VA RR&D National Center for Rehabilitative Auditory Research, VA Portland Health Care System, OR
- Department of Otolaryngology - Head & Neck Surgery, Oregon Health & Science University, Portland
| | - Kelly M Reavis
- VA RR&D National Center for Rehabilitative Auditory Research, VA Portland Health Care System, OR
| | - M Patrick Feeney
- VA RR&D National Center for Rehabilitative Auditory Research, VA Portland Health Care System, OR
- Department of Otolaryngology - Head & Neck Surgery, Oregon Health & Science University, Portland
| | - Sean D Kampel
- VA RR&D National Center for Rehabilitative Auditory Research, VA Portland Health Care System, OR
| |
Collapse
|
40
|
Evidence for Loss of Activity in Low-Spontaneous-Rate Auditory Nerve Fibers of Older Adults. J Assoc Res Otolaryngol 2022; 23:273-284. [PMID: 35020090 PMCID: PMC8964899 DOI: 10.1007/s10162-021-00827-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Accepted: 11/29/2021] [Indexed: 10/19/2022] Open
Abstract
Auditory function declines with age, as evidenced by communication difficulties in challenging listening environments for older adults. Declining auditory function may arise, in part, from an age-related loss and/or inactivity of low-spontaneous-rate (SR) auditory nerve (AN) fibers, a subgroup of neurons important for suprathreshold processing. Compared to high-SR fibers, low-SR fibers take longer to recover from prior stimulation. Taking advantage of this difference, the forward-masked recovery function paradigm estimates the relative proportions of low- and high-SR fibers in the AN by quantifying the time needed for AN responses to recover from prior stimulation (ΔTrecovery). Due to the slower recovery of low-SR fibers, ANs that need more time to fully recover (longer ΔTrecovery) are estimated to have a larger proportion of low-SR fibers than ANs that need less time (shorter ΔTrecovery). To test the hypothesis that low-SR fiber activity is reduced in older humans, the current study assessed recovery functions in 32 older and 16 younger adults using the compound action potential. Results show that ΔTrecovery is shorter for older adults than for younger adults, consistent with a theorized age-related loss and/or inactivity of low-SR fibers. ΔTrecovery did not differ between individuals with and without a prior history of noise exposure as assessed by self-report. This study is the first to successfully assess forward-masked recovery functions in both younger and older adults and provides important insights into the structural and functional changes occurring in the AN with increasing age.
Collapse
|
41
|
Knipper M, Singer W, Schwabe K, Hagberg GE, Li Hegner Y, Rüttiger L, Braun C, Land R. Disturbed Balance of Inhibitory Signaling Links Hearing Loss and Cognition. Front Neural Circuits 2022; 15:785603. [PMID: 35069123 PMCID: PMC8770933 DOI: 10.3389/fncir.2021.785603] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Accepted: 12/08/2021] [Indexed: 12/19/2022] Open
Abstract
Neuronal hyperexcitability in the central auditory pathway linked to reduced inhibitory activity is associated with numerous forms of hearing loss, including noise damage, age-dependent hearing loss, and deafness, as well as tinnitus or auditory processing deficits in autism spectrum disorder (ASD). In most cases, the reduced central inhibitory activity and the accompanying hyperexcitability are interpreted as an active compensatory response to the absence of synaptic activity, linked to increased central neural gain control (increased output activity relative to reduced input). We here suggest that hyperexcitability also could be related to an immaturity or impairment of tonic inhibitory strength that typically develops in an activity-dependent process in the ascending auditory pathway with auditory experience. In these cases, high-SR auditory nerve fibers, which are critical for the shortest latencies and lowest sound thresholds, may have either not matured (possibly in congenital deafness or autism) or are dysfunctional (possibly after sudden, stressful auditory trauma or age-dependent hearing loss linked with cognitive decline). Fast auditory processing deficits can occur despite maintained basal hearing. In that case, tonic inhibitory strength is reduced in ascending auditory nuclei, and fast inhibitory parvalbumin positive interneuron (PV-IN) dendrites are diminished in auditory and frontal brain regions. This leads to deficits in central neural gain control linked to hippocampal LTP/LTD deficiencies, cognitive deficits, and unbalanced extra-hypothalamic stress control. Under these conditions, a diminished inhibitory strength may weaken local neuronal coupling to homeostatic vascular responses required for the metabolic support of auditory adjustment processes. We emphasize the need to distinguish these two states of excitatory/inhibitory imbalance in hearing disorders: (i) Under conditions of preserved fast auditory processing and sustained tonic inhibitory strength, an excitatory/inhibitory imbalance following auditory deprivation can maintain precise hearing through a memory linked, transient disinhibition that leads to enhanced spiking fidelity (central neural gain⇑) (ii) Under conditions of critically diminished fast auditory processing and reduced tonic inhibitory strength, hyperexcitability can be part of an increased synchronization over a broader frequency range, linked to reduced spiking reliability (central neural gain⇓). This latter stage mutually reinforces diminished metabolic support for auditory adjustment processes, increasing the risks for canonical dementia syndromes.
Collapse
Affiliation(s)
- Marlies Knipper
- Department of Otolaryngology, Head and Neck Surgery, Tübingen Hearing Research Center (THRC), Molecular Physiology of Hearing, University of Tübingen, Tübingen, Germany
- *Correspondence: Marlies Knipper,
| | - Wibke Singer
- Department of Otolaryngology, Head and Neck Surgery, Tübingen Hearing Research Center (THRC), Molecular Physiology of Hearing, University of Tübingen, Tübingen, Germany
| | - Kerstin Schwabe
- Experimental Neurosurgery, Department of Neurosurgery, Hannover Medical School, Hanover, Germany
| | - Gisela E. Hagberg
- Department of Biomedical Magnetic Resonance, University Hospital Tübingen (UKT), Tübingen, Germany
- High-Field Magnetic Resonance, Max Planck Institute for Biological Cybernetics, Tübingen, Germany
| | - Yiwen Li Hegner
- MEG Center, University of Tübingen, Tübingen, Germany
- Center of Neurology, Hertie-Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Lukas Rüttiger
- Department of Otolaryngology, Head and Neck Surgery, Tübingen Hearing Research Center (THRC), Molecular Physiology of Hearing, University of Tübingen, Tübingen, Germany
| | - Christoph Braun
- MEG Center, University of Tübingen, Tübingen, Germany
- Center of Neurology, Hertie-Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Rüdiger Land
- Department of Experimental Otology, Institute for Audioneurotechnology, Hannover Medical School, Hanover, Germany
| |
Collapse
|
42
|
Buran BN, McMillan GP, Keshishzadeh S, Verhulst S, Bramhall NF. Predicting synapse counts in living humans by combining computational models with auditory physiology. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2022; 151:561. [PMID: 35105019 PMCID: PMC8800592 DOI: 10.1121/10.0009238] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 12/09/2021] [Accepted: 12/13/2021] [Indexed: 05/28/2023]
Abstract
Aging, noise exposure, and ototoxic medications lead to cochlear synapse loss in animal models. As cochlear function is highly conserved across mammalian species, synaptopathy likely occurs in humans as well. Synaptopathy is predicted to result in perceptual deficits including tinnitus, hyperacusis, and difficulty understanding speech-in-noise. The lack of a method for diagnosing synaptopathy in living humans hinders studies designed to determine if noise-induced synaptopathy occurs in humans, identify the perceptual consequences of synaptopathy, or test potential drug treatments. Several physiological measures are sensitive to synaptopathy in animal models including auditory brainstem response (ABR) wave I amplitude. However, it is unclear how to translate these measures to synaptopathy diagnosis in humans. This work demonstrates how a human computational model of the auditory periphery, which can predict ABR waveforms and distortion product otoacoustic emissions (DPOAEs), can be used to predict synaptic loss in individual human participants based on their measured DPOAE levels and ABR wave I amplitudes. Lower predicted synapse numbers were associated with advancing age, higher noise exposure history, increased likelihood of tinnitus, and poorer speech-in-noise perception. These findings demonstrate the utility of this modeling approach in predicting synapse counts from physiological data in individual human subjects.
Collapse
Affiliation(s)
- Brad N Buran
- Oregon Hearing Research Center (OHRC), Department of Otolaryngology-Head & Neck Surgery, Oregon Health & Science University, Portland, Oregon, USA
| | - Garnett P McMillan
- Veterans Affairs (VA) Rehabilitation Research & Development Service (RR&D) National Center for Rehabilitative Auditory Research (NCRAR), VA Portland Health Care System, Portland, Oregon, USA
| | - Sarineh Keshishzadeh
- Hearing Technology @ WAVES, Department of Information Technology, Ghent University, Belgium
| | - Sarah Verhulst
- Hearing Technology @ WAVES, Department of Information Technology, Ghent University, Belgium
| | - Naomi F Bramhall
- Veterans Affairs (VA) Rehabilitation Research & Development Service (RR&D) National Center for Rehabilitative Auditory Research (NCRAR), VA Portland Health Care System, Portland, Oregon, USA
| |
Collapse
|
43
|
Carcagno S, Plack CJ. Relations between speech-reception, psychophysical temporal processing, and subcortical electrophysiological measures of auditory function in humans. Hear Res 2022; 417:108456. [PMID: 35149333 PMCID: PMC8935383 DOI: 10.1016/j.heares.2022.108456] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 01/05/2022] [Accepted: 01/27/2022] [Indexed: 11/04/2022]
|
44
|
Chen F, Zhao F, Mahafza N, Lu W. Detecting Noise-Induced Cochlear Synaptopathy by Auditory Brainstem Response in Tinnitus Patients With Normal Hearing Thresholds: A Meta-Analysis. Front Neurosci 2021; 15:778197. [PMID: 34987358 PMCID: PMC8721093 DOI: 10.3389/fnins.2021.778197] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Accepted: 11/15/2021] [Indexed: 01/10/2023] Open
Abstract
Noise-induced cochlear synaptopathy (CS) is defined as a permanent loss of synapses in the auditory nerve pathway following noise exposure. Several studies using auditory brainstem response (ABR) have indicated the presence of CS and increased central gain in tinnitus patients with normal hearing thresholds (TNHT), but the results were inconsistent. This meta-analysis aimed to review the evidence of CS and its pathological changes in the central auditory system in TNHT. Published studies using ABR to study TNHT were reviewed. PubMed, EMBASE, and Scopus databases were selected to search for relevant literature. Studies (489) were retrieved, and 11 were included for meta-analysis. The results supported significantly reduced wave I amplitude in TNHT, whereas the alternations in wave V amplitude were inconsistent among the studies. Consistently increased V/I ratio indicated noise-induced central gain enhancement. The results indicated the evidence of noise-induced cochlear synaptopathy in tinnitus patients with normal hearing. However, inconsistent changes in wave V amplitude may be explained by that the failure of central gain that triggers the pathological neural changes in the central auditory system and/or that increased central gain may be necessary to generate tinnitus but not to maintain tinnitus.
Collapse
Affiliation(s)
- Feifan Chen
- Centre for Speech and Language Therapy and Hearing Science, Cardiff School of Sport and Health Sciences, Cardiff Metropolitan University, Cardiff, United Kingdom
| | - Fei Zhao
- Centre for Speech and Language Therapy and Hearing Science, Cardiff School of Sport and Health Sciences, Cardiff Metropolitan University, Cardiff, United Kingdom
- Department of Hearing and Speech Science, Guangzhou Xinhua College, Guangzhou, China
| | - Nadeem Mahafza
- Centre for Speech and Language Therapy and Hearing Science, Cardiff School of Sport and Health Sciences, Cardiff Metropolitan University, Cardiff, United Kingdom
| | - Wei Lu
- Department of Otolaryngology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| |
Collapse
|
45
|
Bramhall NF. Use of the auditory brainstem response for assessment of cochlear synaptopathy in humans. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2021; 150:4440. [PMID: 34972291 PMCID: PMC10880747 DOI: 10.1121/10.0007484] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Accepted: 11/07/2021] [Indexed: 06/14/2023]
Abstract
Although clinical use of the auditory brainstem response (ABR) to detect retrocochlear disorders has been largely replaced by imaging in recent years, the discovery of cochlear synaptopathy has thrown this foundational measure of auditory function back into the spotlight. Whereas modern imaging now allows for the noninvasive detection of vestibular schwannomas, imaging technology is not currently capable of detecting cochlear synaptopathy, the loss of the synaptic connections between the inner hair cells and afferent auditory nerve fibers. However, animal models indicate that the amplitude of the first wave of the ABR, a far-field evoked potential generated by the synchronous firing of auditory nerve fibers, is highly correlated with synaptic integrity. This has led to many studies investigating the use of the ABR as a metric of synaptopathy in humans. However, these studies have yielded mixed results, leading to a lack of consensus about the utility of the ABR as an indicator of synaptopathy. This review summarizes the animal and human studies that have investigated the ABR as a measure of cochlear synaptic function, discusses factors that may have contributed to the mixed findings and the lessons learned, and provides recommendations for future use of this metric in the research and clinical settings.
Collapse
Affiliation(s)
- Naomi F Bramhall
- Veterans Affairs (VA) Rehabilitation Research & Development Service (RR&D) National Center for Rehabilitative Auditory Research (NCRAR), VA Portland Health Care System Portland, Oregon 97239, USA
| |
Collapse
|
46
|
Suthakar K, Liberman MC. Auditory-nerve responses in mice with noise-induced cochlear synaptopathy. J Neurophysiol 2021; 126:2027-2038. [PMID: 34788179 DOI: 10.1152/jn.00342.2021] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Cochlear synaptopathy is the noise-induced or age-related loss of ribbon synapses between inner hair cells (IHCs) and auditory-nerve fibers (ANFs), first reported in CBA/CaJ mice. Recordings from single ANFs in anesthetized, noise-exposed guinea pigs suggested that neurons with low spontaneous rates (SRs) and high thresholds are more vulnerable than low-threshold, high-SR fibers. However, there is extensive postexposure regeneration of ANFs in guinea pigs but not in mice. Here, we exposed CBA/CaJ mice to octave-band noise and recorded sound-evoked and spontaneous activity from single ANFs at least 2 wk later. Confocal analysis of cochleae immunostained for pre- and postsynaptic markers confirmed the expected loss of 40%-50% of ANF synapses in the basal half of the cochlea; however, our data were not consistent with a selective loss of low-SR fibers. Rather they suggested a loss of both SR groups in synaptopathic regions. Single-fiber thresholds and frequency tuning recovered to pre-exposure levels; however, response to tone bursts showed increased peak and steady-state firing rates, as well as decreased jitter in first-spike latencies. This apparent gain-of-function increased the robustness of tone-burst responses in the presence of continuous masking noise. This study suggests that the nature of noise-induced synaptic damage varies between different species and that, in mouse, the noise-induced hyperexcitability seen in central auditory circuits is also observed at the level of the auditory nerve.NEW & NOTEWORTHY Noise-induced damage to synapses between inner hair cells and auditory-nerve fibers (ANFs) can occur without permanent hair cell damage, resulting in pathophysiology that "hides" behind normal thresholds. Prior single-fiber neurophysiology in guinea pig suggested that noise selectively targets high-threshold ANFs. Here, we show that the lingering pathophysiology differs in mouse, with both ANF groups affected and a paradoxical gain-of-function in surviving low-threshold fibers, including increased onset rate, decreased onset jitter, and reduced maskability.
Collapse
Affiliation(s)
- Kirupa Suthakar
- Eaton-Peabody Laboratories, Massachusetts Eye and Ear, Boston, Massachusetts.,Department of Otolaryngology Head and Neck Surgery, Harvard Medical School, Boston, Massachusetts
| | - M Charles Liberman
- Eaton-Peabody Laboratories, Massachusetts Eye and Ear, Boston, Massachusetts.,Department of Otolaryngology Head and Neck Surgery, Harvard Medical School, Boston, Massachusetts
| |
Collapse
|
47
|
Santarelli R, Scimemi P, La Morgia C, Cama E, del Castillo I, Carelli V. Electrocochleography in Auditory Neuropathy Related to Mutations in the OTOF or OPA1 Gene. Audiol Res 2021; 11:639-652. [PMID: 34940017 PMCID: PMC8698970 DOI: 10.3390/audiolres11040059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Revised: 11/18/2021] [Accepted: 11/19/2021] [Indexed: 11/16/2022] Open
Abstract
Auditory Neuropathy (AN) is characterized by disruption of temporal coding of acoustic signals in auditory nerve fibers resulting in alterations of auditory perceptions. Mutations in several genes have been associated to the most forms of AN. Underlying mechanisms include both pre-synaptic and post-synaptic damage involving inner hair cell (IHC) depolarization, neurotransmitter release, spike initiation in auditory nerve terminals, loss of auditory fibers and impaired conduction. In contrast, outer hair cell (OHC) activities (otoacoustic emissions [OAEs] and cochlear microphonic [CM]) are normal. Disordered synchrony of auditory nerve activity has been suggested as the basis of both the alterations of auditory brainstem responses (ABRs) and reduction of speech perception. We will review how electrocochleography (ECochG) recordings provide detailed information to help objectively define the sites of auditory neural dysfunction and their effect on receptor summating potential (SP) and neural compound action potential (CAP), the latter reflecting disorders of ribbon synapses and auditory nerve fibers.
Collapse
Affiliation(s)
- Rosamaria Santarelli
- Department of Neurosciences, University of Padova, Via Belzoni 160, 35121 Padova, Italy; (P.S.); (E.C.)
- Audiology Service, Santi Giovanni e Paolo Hospital, Campo Santi Giovanni e Paolo, Castello 6777, 30122 Venezia, Italy
- Correspondence:
| | - Pietro Scimemi
- Department of Neurosciences, University of Padova, Via Belzoni 160, 35121 Padova, Italy; (P.S.); (E.C.)
- Audiology Service, Santi Giovanni e Paolo Hospital, Campo Santi Giovanni e Paolo, Castello 6777, 30122 Venezia, Italy
| | - Chiara La Morgia
- Department of Biomedical and Neuromotor Sciences (DIBINEM), University of Bologna, Via Ugo Foscolo 7, 40123 Bologna, Italy; (C.L.M.); (V.C.)
- IRCCS Institute of Neurological Sciences of Bologna, Bellaria Hospital, Via Altura 3, 40139 Bologna, Italy
| | - Elona Cama
- Department of Neurosciences, University of Padova, Via Belzoni 160, 35121 Padova, Italy; (P.S.); (E.C.)
- Audiology Service, Santi Giovanni e Paolo Hospital, Campo Santi Giovanni e Paolo, Castello 6777, 30122 Venezia, Italy
| | - Ignacio del Castillo
- Servicio de Genética, Hospital Universitario Ramón y Cajal, IRYCIS, 28034 Madrid, Spain;
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), 28034 Madrid, Spain
| | - Valerio Carelli
- Department of Biomedical and Neuromotor Sciences (DIBINEM), University of Bologna, Via Ugo Foscolo 7, 40123 Bologna, Italy; (C.L.M.); (V.C.)
- IRCCS Institute of Neurological Sciences of Bologna, Bellaria Hospital, Via Altura 3, 40139 Bologna, Italy
| |
Collapse
|
48
|
Gratias P, Nasr J, Affortit C, Ceccato JC, François F, Casas F, Pujol R, Pucheu S, Puel JL, Wang J. Impulse Noise Induced Hidden Hearing Loss, Hair Cell Ciliary Changes and Oxidative Stress in Mice. Antioxidants (Basel) 2021; 10:antiox10121880. [PMID: 34942983 PMCID: PMC8698479 DOI: 10.3390/antiox10121880] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Revised: 11/19/2021] [Accepted: 11/22/2021] [Indexed: 12/14/2022] Open
Abstract
Recent studies demonstrated that reversible continuous noise exposure may induce a temporary threshold shift (TTS) with a permanent degeneration of auditory nerve fibers, although hair cells remain intact. To probe the impact of TTS-inducing impulse noise exposure on hearing, CBA/J Mice were exposed to noise impulses with peak pressures of 145 dB SPL. We found that 30 min after exposure, the noise caused a mean elevation of ABR thresholds of ~30 dB and a reduction in DPOAE amplitude. Four weeks later, ABR thresholds and DPOAE amplitude were back to normal in the higher frequency region (8–32 kHz). At lower frequencies, a small degree of PTS remained. Morphological evaluations revealed a disturbance of the stereociliary bundle of outer hair cells, mainly located in the apical regions. On the other hand, the reduced suprathreshold ABR amplitudes remained until 4 weeks later. A loss of synapse numbers was observed 24 h after exposure, with full recovery two weeks later. Transmission electron microscopy revealed morphological changes at the ribbon synapses by two weeks post exposure. In addition, increased levels of oxidative stress were observed immediately after exposure, and maintained for a further 2 weeks. These results clarify the pathology underlying impulse noise-induced sensory dysfunction, and suggest possible links between impulse-noise injury, cochlear cell morphology, metabolic changes, and hidden hearing loss.
Collapse
Affiliation(s)
- Paul Gratias
- Institute for Neurosciences of Montpellier (INM), University Montpellier, INSERM, 34091 Montpellier, France; (P.G.); (J.N.); (C.A.); (J.-C.C.); (F.F.); (R.P.); (J.-L.P.)
| | - Jamal Nasr
- Institute for Neurosciences of Montpellier (INM), University Montpellier, INSERM, 34091 Montpellier, France; (P.G.); (J.N.); (C.A.); (J.-C.C.); (F.F.); (R.P.); (J.-L.P.)
| | - Corentin Affortit
- Institute for Neurosciences of Montpellier (INM), University Montpellier, INSERM, 34091 Montpellier, France; (P.G.); (J.N.); (C.A.); (J.-C.C.); (F.F.); (R.P.); (J.-L.P.)
| | - Jean-Charles Ceccato
- Institute for Neurosciences of Montpellier (INM), University Montpellier, INSERM, 34091 Montpellier, France; (P.G.); (J.N.); (C.A.); (J.-C.C.); (F.F.); (R.P.); (J.-L.P.)
| | - Florence François
- Institute for Neurosciences of Montpellier (INM), University Montpellier, INSERM, 34091 Montpellier, France; (P.G.); (J.N.); (C.A.); (J.-C.C.); (F.F.); (R.P.); (J.-L.P.)
| | - François Casas
- Unité Dynamique Du Muscle et Métabolisme (DMEM), Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), University Montpellier, 34060 Montpellier, France;
| | - Rémy Pujol
- Institute for Neurosciences of Montpellier (INM), University Montpellier, INSERM, 34091 Montpellier, France; (P.G.); (J.N.); (C.A.); (J.-C.C.); (F.F.); (R.P.); (J.-L.P.)
| | - Sylvie Pucheu
- Cilcare, 371 Rue du Professeur J. Blayac, 34080 Montpellier, France;
| | - Jean-Luc Puel
- Institute for Neurosciences of Montpellier (INM), University Montpellier, INSERM, 34091 Montpellier, France; (P.G.); (J.N.); (C.A.); (J.-C.C.); (F.F.); (R.P.); (J.-L.P.)
| | - Jing Wang
- Institute for Neurosciences of Montpellier (INM), University Montpellier, INSERM, 34091 Montpellier, France; (P.G.); (J.N.); (C.A.); (J.-C.C.); (F.F.); (R.P.); (J.-L.P.)
- ENT Department, Hospital and University of Montpellier, 34091 Montpellier, France
- Correspondence: ; Tel.: +33-499-636-048; Fax: +33-499-636-020
| |
Collapse
|
49
|
Joshi Y, Petit CP, Miot S, Guillet M, Sendin G, Bourien J, Wang J, Pujol R, El Mestikawy S, Puel JL, Nouvian R. VGLUT3-p.A211V variant fuses stereocilia bundles and elongates synaptic ribbons. J Physiol 2021; 599:5397-5416. [PMID: 34783032 PMCID: PMC9299590 DOI: 10.1113/jp282181] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Accepted: 11/01/2021] [Indexed: 11/16/2022] Open
Abstract
Abstract DFNA25 is an autosomal‐dominant and progressive form of human deafness caused by mutations in the SLC17A8 gene, which encodes the vesicular glutamate transporter type 3 (VGLUT3). To resolve the mechanisms underlying DFNA25, we studied phenotypes of mice harbouring the p.A221V mutation in humans (corresponding to p.A224V in mice). Using auditory brainstem response and distortion product otoacoustic emissions, we showed progressive hearing loss with intact cochlear amplification in the VGLUT3A224V/A224V mouse. The summating potential was reduced, indicating the alteration of inner hair cell (IHC) receptor potential. Scanning electron microscopy examinations demonstrated the collapse of stereocilia bundles in IHCs, leaving those from outer hair cells unaffected. In addition, IHC ribbon synapses underwent structural and functional modifications at later stages. Using super‐resolution microscopy, we observed oversized synaptic ribbons and patch‐clamp membrane capacitance measurements showed an increase in the rate of the sustained releasable pool exocytosis. These results suggest that DFNA25 stems from a failure in the mechano‐transduction followed by a change in synaptic transfer. The VGLUT3A224V/A224V mouse model opens the way to a deeper understanding and to a potential treatment for DFNA25. Key points The vesicular glutamate transporter type 3 (VGLUT3) loads glutamate into the synaptic vesicles of auditory sensory cells, the inner hair cells (IHCs). The VGLUT3‐p.A211V variant is associated with human deafness DFNA25. Mutant mice carrying the VGLUT3‐p.A211V variant show progressive hearing loss. IHCs from mutant mice harbour distorted stereocilary bundles, which detect incoming sound stimulation, followed by oversized synaptic ribbons, which release glutamate onto the afferent nerve fibres. These results suggest that DFNA25 stems from the failure of auditory sensory cells to faithfully transduce acoustic cues into neural messages.
Collapse
Affiliation(s)
- Yuvraj Joshi
- INM, Univ Montpellier, INSERM, Montpellier, France
| | | | - Stéphanie Miot
- INM, Univ Montpellier, INSERM, Montpellier, France.,Sorbonne Universités, Université Pierre et Marie Curie UM 119, Neurosciences Paris Seine - Institut de Biologie Paris Seine (NPS - IBPS), Paris, France
| | | | | | | | - Jing Wang
- INM, Univ Montpellier, INSERM, Montpellier, France
| | - Rémy Pujol
- INM, Univ Montpellier, INSERM, Montpellier, France
| | - Salah El Mestikawy
- Sorbonne Universités, Université Pierre et Marie Curie UM 119, Neurosciences Paris Seine - Institut de Biologie Paris Seine (NPS - IBPS), Paris, France.,Department of Psychiatry, Douglas Mental Health University Institute, McGill University, Montreal, Quebec, Canada
| | | | - Régis Nouvian
- INM, Univ Montpellier, INSERM, Montpellier, France.,INM, Univ Montpellier, INSERM, CNRS, Montpellier, France
| |
Collapse
|
50
|
Salvi R, Radziwon K, Manohar S, Auerbach B, Ding D, Liu X, Lau C, Chen YC, Chen GD. Review: Neural Mechanisms of Tinnitus and Hyperacusis in Acute Drug-Induced Ototoxicity. Am J Audiol 2021; 30:901-915. [PMID: 33465315 DOI: 10.1044/2020_aja-20-00023] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Purpose Tinnitus and hyperacusis are debilitating conditions often associated with age-, noise-, and drug-induced hearing loss. Because of their subjective nature, the neural mechanisms that give rise to tinnitus and hyperacusis are poorly understood. Over the past few decades, considerable progress has been made in deciphering the biological bases for these disorders using animal models. Method Important advances in understanding the biological bases of tinnitus and hyperacusis have come from studies in which tinnitus and hyperacusis are consistently induced with a high dose of salicylate, the active ingredient in aspirin. Results Salicylate induced a transient hearing loss characterized by a reduction in otoacoustic emissions, a moderate cochlear threshold shift, and a large reduction in the neural output of the cochlea. As the weak cochlear neural signals were relayed up the auditory pathway, they were progressively amplified so that the suprathreshold neural responses in the auditory cortex were much larger than normal. Excessive central gain (neural amplification), presumably resulting from diminished inhibition, is believed to contribute to hyperacusis and tinnitus. Salicylate also increased corticosterone stress hormone levels. Functional imaging studies indicated that salicylate increased spontaneous activity and enhanced functional connectivity between structures in the central auditory pathway and regions of the brain associated with arousal (reticular formation), emotion (amygdala), memory/spatial navigation (hippocampus), motor planning (cerebellum), and motor control (caudate/putamen). Conclusion These results suggest that tinnitus and hyperacusis arise from aberrant neural signaling in a complex neural network that includes both auditory and nonauditory structures.
Collapse
Affiliation(s)
- Richard Salvi
- Center for Hearing & Deafness, Department of Communicative Disorders and Sciences, The State University of New York at Buffalo
| | - Kelly Radziwon
- Center for Hearing & Deafness, Department of Communicative Disorders and Sciences, The State University of New York at Buffalo
| | - Senthilvelan Manohar
- Center for Hearing & Deafness, Department of Communicative Disorders and Sciences, The State University of New York at Buffalo
| | - Ben Auerbach
- Center for Hearing & Deafness, Department of Communicative Disorders and Sciences, The State University of New York at Buffalo
| | - Dalian Ding
- Center for Hearing & Deafness, Department of Communicative Disorders and Sciences, The State University of New York at Buffalo
| | - Xiaopeng Liu
- Center for Hearing & Deafness, Department of Communicative Disorders and Sciences, The State University of New York at Buffalo
| | - Condon Lau
- Department of Physics, City University of Hong Kong
| | - Yu-Chen Chen
- Department of Radiology, Nanjing First Hospital, Nanjing Medical University, China
| | - Guang-Di Chen
- Center for Hearing & Deafness, Department of Communicative Disorders and Sciences, The State University of New York at Buffalo
| |
Collapse
|