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Lee C, Hartsock JJ, Salt AN, Lichtenhan JT. A Guinea Pig Model Suggests That Objective Assessment of Acoustic Hearing Preservation in Human Ears With Cochlear Implants Is Confounded by Shifts in the Spatial Origin of Acoustically Evoked Potential Measurements Along the Cochlear Length. Ear Hear 2024; 45:666-678. [PMID: 38178312 DOI: 10.1097/aud.0000000000001457] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2024]
Abstract
OBJECTIVES Our recent empirical findings have shown that the auditory nerve compound action potential (CAP) evoked by a low-level tone burst originates from a narrow cochlear region tuned to the tone burst frequency. At moderate to high sound levels, the origins shift to the most sensitive audiometric regions rather than the extended high-frequency regions of the cochlear base. This means that measurements evoked from extended high-frequency sound stimuli can shift toward the apex with increasing level. Here we translate this study to understand the spatial origin of acoustically evoked responses from ears that receive cochlear implants, an emerging area of research and clinical practice that is not completely understood. An essential step is to first understand the influence of the cochlear implant in otherwise naive ears. Our objective was to understand how function of the high-frequency cochlear base, which can be excited by the intense low-frequency sounds that are frequently used for objective intra- and postoperative monitoring, can be influenced by the presence of the cochlear implant. DESIGN We acoustically evoked responses and made measurements with an electrode placed near the guinea pig round window. The cochlear implant was not utilized for either electrical stimulation or recording purposes. With the cochlear implant in situ, CAPs were acoustically evoked from 2 to 16 kHz tone bursts of various levels while utilizing the slow perfusion of a kainic acid solution from the cochlear apex to the cochlear aqueduct in the base, which sequentially reduced neural responses from finely spaced cochlear frequency regions. This cochlear perfusion technique reveals the spatial origin of evoked potential measurements and provides insight on what influence the presence of an implant has on acoustical hearing. RESULTS Threshold measurements at 3 to 11 kHz were elevated by implantation. In an individual ear, thresholds were elevated and lowered as cochlear implant was respectively inserted and removed, indicative of "conductive hearing loss" induced by the implant. The maximum threshold elevation occurred at most sensitive region of the naive guinea pig ear (33.66 dB at 8 kHz), making 11 kHz the most sensitive region to acoustic sounds for guinea pig ears with cochlear implants. Conversely, the acute implantation did not affect the low-frequency, 500 Hz thresholds and suprathreshold function, as shown by the auditory nerve overlapped waveform. As the sound pressure level of the tone bursts increased, mean data show that the spatial origin of CAPs along the cochlear length shifted toward the most sensitive cochlear region of implanted ears, not the extended high-frequency cochlear regions. However, data from individual ears showed that after implantation, measurements from moderate to high sound pressure levels originate in places that are unique to each ear. CONCLUSIONS Alterations to function of the cochlear base from the in situ cochlear implant may influence objective measurements of implanted ears that are frequently made with intense low-frequency sound stimuli. Our results from guinea pigs advance the interpretation of measurements used to understand how and when residual acoustic hearing is lost in human ears receiving a cochlear implant.
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Affiliation(s)
- Choongheon Lee
- Department of Otolaryngology, University of Rochester, Rochester, New York, USA
| | - Jared J Hartsock
- Department of Cochlear Surgery, Turner Scientific, Inc., Jacksonville, Illinois, USA
| | - Alec N Salt
- Department of Pharmacokinetics, Turner Scientific, Inc., Jacksonville, Illinois, USA
| | - Jeffery T Lichtenhan
- Department of Otolaryngology, University of South Florida Morsani School of Medicine, Tampa, Florida, USA
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Almohammad HA, Chertoff ME, Ferraro JA, Diaz FJ. Auditory nerve phase-locked response recorded from normal hearing adults using electrocochleography. Int J Audiol 2023; 62:172-181. [PMID: 35130459 DOI: 10.1080/14992027.2021.2024283] [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: 02/03/2023]
Abstract
OBJECTIVE The auditory nerve overlapped waveform response (ANOW), a new measure that can be recorded non-invasively from humans, holds promise for providing more accurate assessment of low frequency hearing thresholds than currently used objective measures. This research aims to investigate the robustness and the nature of the ANOW response in humans. DESIGN Repeated within-session recordings of the ANOW response using low-frequency Tone Bursts (TBs) were obtained at multiple stimulus levels. ANOW's absolute amplitude and phase locking value (PLV) measures were analysed to obtain normative data and to test the reliability of the ANOW response. STUDY SAMPLE Thirteen normal hearing adults within the age range of 25 to 40 years. RESULTS ANOW response was obtained to both 250 Hz and 500 Hz TBs and was traced down to 30-40 dB nHL. ANOW response showed significantly higher amplitude and stronger phase locking using 250 Hz TB compared to 500 Hz TB. High degree of test retest reliability of the ANOW response was found using 250 Hz TB at presentation levels higher than 40 dB nHL. CONCLUSIONS ANOW response is recordable noninvasively using low-frequency TBs and shows higher robustness as the stimulus frequency decreases.
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Affiliation(s)
- Hana A Almohammad
- Department of Rehabilitation Sciences, Faculty of Applied Medical Sciences, Jordan University of Science and Technology, Irbid, Jordan
| | - Mark E Chertoff
- Department of Hearing and Speech, University of Kansas Medical Center, Kansas City, KS, USA
| | - John A Ferraro
- Department of Biostatistics and Data Science, University of Kansas Medical Center, Kansas City, KS, USA
| | - Francisco J Diaz
- Department of Hearing and Speech, University of Kansas Medical Center, Kansas City, KS, USA
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Zhou F, Wang Z, Huang Y, Chen X. Application of inner ear MRI after intravenous gadolinium injection in SSNHL. Acta Otolaryngol 2023; 143:1-5. [PMID: 36650911 DOI: 10.1080/00016489.2022.2164612] [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: 01/19/2023]
Abstract
BACKGROUND With the development of inner ear gadolinium imaging technology, its clinical application is more and more frequent. OBJECTIVES To explore the application value of inner ear MRI after intravenous gadolinium injection in sudden sensorineural hearing loss. MATERIAL AND METHODS The clinical data of 28 patients who were preliminarily diagnosed with sudden sensorineural hearing loss and the results of intravenous gadolinium MRI examination were analyzed to find the relationship between them. RESULTS Of the 28 patients (30 ears) with idiopathic sudden sensorineural hearing loss, 20 (71.4%) showed normal MRI. MRI abnormalities related to hearing loss were found in 8 cases (28.6%), of which 5 cases (17.9%) showed hydrops in the inner ear membrane labyrinth, 2 cases (7.1%) showed mastoiditis on the affected side, and 1 case (3.6%) showed vestibular schwannoma. CONCLUSIONS AND SIGNIFICANCE Inner ear MRI after intravenous gadolinium injection can be used as an index to detect the cause of sudden deafness, one of the factors to guide clinical treatment, and an important means to further explore the relationship between hydrops of membranous labyrinth and SSNHL.
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Affiliation(s)
- Feng Zhou
- Department of Otolaryngology-Head and Neck Surgery, The Affiliated People's Hospital of Fujian University of Traditional Chinese Medicine, Fujian, China
| | - Zilin Wang
- First Clinical Medical College, Fujian University of Traditional Chinese Medicine, Fujian, China
| | - Yichao Huang
- First Clinical Medical College, Fujian University of Traditional Chinese Medicine, Fujian, China
| | - Xi Chen
- Department of Otolaryngology-Head and Neck Surgery, The Affiliated People's Hospital of Fujian University of Traditional Chinese Medicine, Fujian, China
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Paik CB, Pei M, Oghalai JS. Review of blast noise and the auditory system. Hear Res 2022; 425:108459. [PMID: 35181171 PMCID: PMC9357863 DOI: 10.1016/j.heares.2022.108459] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Revised: 02/03/2022] [Accepted: 02/07/2022] [Indexed: 11/22/2022]
Abstract
The auditory system is particularly vulnerable to blast injury due to the ear's role as a highly sensitive pressure transducer. Over the past several decades, studies have used a variety of animal models and experimental procedures to recreate blast-induced acoustic trauma. Given the developing nature of this field and our incomplete understanding of molecular mechanisms underlying blast-related auditory disturbances, an updated discussion about these studies is warranted. Here, we comprehensively review well-established blast-related auditory pathology including tympanic membrane perforation and hair cell loss. In addition, we discuss important mechanistic studies that aim to bridge gaps in our current understanding of the molecular and microstructural events underlying blast-induced cochlear, auditory nerve, brainstem, and central auditory system damage. Key findings from the recent literature include the association between endolymphatic hydrops and cochlear synaptic loss, blast-induced neuroinflammatory markers in the peripheral and central auditory system, and therapeutic approaches targeting biochemical markers of blast injury. We conclude that blast is an extreme form of noise exposure. Blast waves produce cochlear damage that appears similar to, but more extreme than, the standard noise exposure protocols used in auditory research. However, experimental variations in studies of blast-induced acoustic trauma make it challenging to compare and interpret data across studies.
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Affiliation(s)
- Connie B Paik
- Caruso Department of Otolaryngology-Head and Neck Surgery, Keck School of Medicine of the University of Southern California, Los Angeles, CA USA
| | - Michelle Pei
- Caruso Department of Otolaryngology-Head and Neck Surgery, Keck School of Medicine of the University of Southern California, Los Angeles, CA USA
| | - John S Oghalai
- Caruso Department of Otolaryngology-Head and Neck Surgery, Keck School of Medicine of the University of Southern California, Los Angeles, CA USA.
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Wang SQ, Li CL, Xu JQ, Chen LL, Xie YZ, Dai PD, Ren LJ, Yao WJ, Zhang TY. The Effect of Endolymphatic Hydrops and Mannitol Dehydration Treatment on Guinea Pigs. Front Cell Neurosci 2022; 16:836093. [PMID: 35480960 PMCID: PMC9035551 DOI: 10.3389/fncel.2022.836093] [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: 12/15/2021] [Accepted: 02/24/2022] [Indexed: 01/14/2023] Open
Abstract
Background Endolymphatic hydrops (EH) is considered as the pathological correlate of Menière’s disease (MD) and cause of hearing loss. The mechanism of EH, remaining unrevealed, poses challenges for formalized clinical trials. Objective This study aims to investigate the development of hearing loss, as well as the effect of dehydration treatment on EH animal models. Methods In this study, different severity EH animal models were created. The laser Doppler vibrometer (LDV) and auditory brainstem responses (ABR) were used to study the effects of EH and the dehydration effects of mannitol. The LDV was used to measure the vibration of the round window membrane (RWM) reflecting the changes in inner ear impedance. ABR was used to evaluate the hearing changes. Furthermore, tissue section and scanning electron microscopy (SEM) observations were used to analyze the anatomical change to the cochlea and outer hair cells. Results The RWM vibrations decreased with the severity of EH, indicating an increase in the cochlear impedance. The dehydration therapy lowered the impedance to restore acoustic transduction in EH 10- and 20-day animal models. Simultaneously, the ABR thresholds increased in EH models and were restored after dehydration. Moreover, a difference in the hearing was found between ABR and LDV results in severe EH animal models, and the dehydration therapy was less effective, indicating a sensorineural hearing loss (SNHL). Conclusion Endolymphatic hydrops causes hearing loss by increasing the cochlear impedance in all tested groups, and mannitol dehydration is an effective therapy to restore hearing. However, SNHL occurs for the EH 30-day animal models, limiting the effectiveness of dehydration. Our results suggest the use of dehydrating agents in the early stage of EH.
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Affiliation(s)
- Shu-Qi Wang
- Department of Facial Plastic Reconstruction Surgery, Eye and ENT Hospital of Fudan University, Shanghai, China
- ENT Institute, Eye and ENT Hospital of Fudan University, Shanghai, China
| | - Chen-Long Li
- Department of Facial Plastic Reconstruction Surgery, Eye and ENT Hospital of Fudan University, Shanghai, China
- ENT Institute, Eye and ENT Hospital of Fudan University, Shanghai, China
- Hearing Medicine Key Laboratory, National Health Commission of China, Shanghai, China
| | - Jing-Qi Xu
- Department of Facial Plastic Reconstruction Surgery, Eye and ENT Hospital of Fudan University, Shanghai, China
- ENT Institute, Eye and ENT Hospital of Fudan University, Shanghai, China
| | - Li-Li Chen
- Department of Facial Plastic Reconstruction Surgery, Eye and ENT Hospital of Fudan University, Shanghai, China
- ENT Institute, Eye and ENT Hospital of Fudan University, Shanghai, China
- Hearing Medicine Key Laboratory, National Health Commission of China, Shanghai, China
| | - You-Zhou Xie
- Department of Facial Plastic Reconstruction Surgery, Eye and ENT Hospital of Fudan University, Shanghai, China
- ENT Institute, Eye and ENT Hospital of Fudan University, Shanghai, China
- Hearing Medicine Key Laboratory, National Health Commission of China, Shanghai, China
| | - Pei-Dong Dai
- Department of Facial Plastic Reconstruction Surgery, Eye and ENT Hospital of Fudan University, Shanghai, China
- ENT Institute, Eye and ENT Hospital of Fudan University, Shanghai, China
| | - Liu-Jie Ren
- Department of Facial Plastic Reconstruction Surgery, Eye and ENT Hospital of Fudan University, Shanghai, China
- ENT Institute, Eye and ENT Hospital of Fudan University, Shanghai, China
- Hearing Medicine Key Laboratory, National Health Commission of China, Shanghai, China
- *Correspondence: Liu-Jie Ren,
| | - Wen-Juan Yao
- School of Mechanics and Engineering Science, Shanghai University, Shanghai, China
- Shanghai Institute of Applied Mathematics and Mechanics, Shanghai, China
- Wen-Juan Yao,
| | - Tian-Yu Zhang
- Department of Facial Plastic Reconstruction Surgery, Eye and ENT Hospital of Fudan University, Shanghai, China
- ENT Institute, Eye and ENT Hospital of Fudan University, Shanghai, China
- Hearing Medicine Key Laboratory, National Health Commission of China, Shanghai, China
- Tian-Yu Zhang,
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Badash I, Quiñones PM, Oghalai KJ, Wang J, Lui CG, Macias-Escriva F, Applegate BE, Oghalai JS. Endolymphatic Hydrops is a Marker of Synaptopathy Following Traumatic Noise Exposure. Front Cell Dev Biol 2021; 9:747870. [PMID: 34805158 PMCID: PMC8602199 DOI: 10.3389/fcell.2021.747870] [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: 07/27/2021] [Accepted: 10/20/2021] [Indexed: 12/28/2022] Open
Abstract
After acoustic trauma, there can be loss of synaptic connections between inner hair cells and auditory neurons in the cochlea, which may lead to hearing abnormalities including speech-in-noise difficulties, tinnitus, and hyperacusis. We have previously studied mice with blast-induced cochlear synaptopathy and found that they also developed a build-up of endolymph, termed endolymphatic hydrops. In this study, we used optical coherence tomography to measure endolymph volume in live CBA/CaJ mice exposed to various noise intensities. We quantified the number of synaptic ribbons and postsynaptic densities under the inner hair cells 1 week after noise exposure to determine if they correlated with acute changes in endolymph volume measured in the hours after the noise exposure. After 2 h of noise at an intensity of 95 dB SPL or below, both endolymph volume and synaptic counts remained normal. After exposure to 2 h of 100 dB SPL noise, mice developed endolymphatic hydrops and had reduced synaptic counts in the basal and middle regions of the cochlea. Furthermore, round-window application of hypertonic saline reduced the degree of endolymphatic hydrops that developed after 100 dB SPL noise exposure and partially prevented the reduction in synaptic counts in the cochlear base. Taken together, these results indicate that endolymphatic hydrops correlates with noise-induced cochlear synaptopathy, suggesting that these two pathologic findings have a common mechanistic basis.
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Affiliation(s)
- Ido Badash
- Caruso Department of Otolaryngology-Head and Neck Surgery, Keck School of Medicine of the University of Southern California, Los Angeles, CA, United States
| | - Patricia M Quiñones
- Caruso Department of Otolaryngology-Head and Neck Surgery, Keck School of Medicine of the University of Southern California, Los Angeles, CA, United States
| | - Kevin J Oghalai
- Viterbi School of Engineering, University of Southern California, Los Angeles, CA, United States
| | - Juemei Wang
- Caruso Department of Otolaryngology-Head and Neck Surgery, Keck School of Medicine of the University of Southern California, Los Angeles, CA, United States
| | - Christopher G Lui
- Department of Otolaryngology-Head and Neck Surgery, Northwestern University Feinberg School of Medicine, Chicago, IL, United States
| | - Frank Macias-Escriva
- Caruso Department of Otolaryngology-Head and Neck Surgery, Keck School of Medicine of the University of Southern California, Los Angeles, CA, United States
| | - Brian E Applegate
- Caruso Department of Otolaryngology-Head and Neck Surgery, Keck School of Medicine of the University of Southern California, Los Angeles, CA, United States.,Viterbi School of Engineering, University of Southern California, Los Angeles, CA, United States
| | - John S Oghalai
- Caruso Department of Otolaryngology-Head and Neck Surgery, Keck School of Medicine of the University of Southern California, Los Angeles, CA, United States.,Viterbi School of Engineering, University of Southern California, Los Angeles, CA, United States
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Lefler SM, Duncan RK, Goodman SS, Guinan JJ, Lichtenhan JT. Measurements From Ears With Endolymphatic Hydrops and 2-Hydroxypropyl-Beta-Cyclodextrin Provide Evidence That Loudness Recruitment Can Have a Cochlear Origin. Front Surg 2021; 8:687490. [PMID: 34676239 PMCID: PMC8523923 DOI: 10.3389/fsurg.2021.687490] [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: 03/29/2021] [Accepted: 09/02/2021] [Indexed: 11/21/2022] Open
Abstract
Background: Loudness recruitment is commonly experienced by patients with putative endolymphatic hydrops. Loudness recruitment is abnormal loudness growth with high-level sounds being perceived as having normal loudness even though hearing thresholds are elevated. The traditional interpretation of recruitment is that cochlear amplification has been reduced. Since the cochlear amplifier acts primarily at low sound levels, an ear with elevated thresholds from reduced cochlear amplification can have normal processing at high sound levels. In humans, recruitment can be studied using perceptual loudness but in animals physiological measurements are used. Recruitment in animal auditory-nerve responses has never been unequivocally demonstrated because the animals used had damage to sensory and neural cells, not solely a reduction of cochlear amplification. Investigators have thus looked for, and found, evidence of recruitment in the auditory central nervous system (CNS). While studies on CNS recruitment are informative, they cannot rule out the traditional interpretation of recruitment originating in the cochlea. Design: We used techniques that could assess hearing function throughout entire frequency- and dynamic-range of hearing. Measurements were made from two animal models: guinea-pig ears with endolymphatic-sac-ablation surgery to produce endolymphatic hydrops, and naïve guinea-pig ears with cochlear perfusions of 13 mM 2-Hydroxypropyl-Beta-Cyclodextrin (HPBCD) in artificial perilymph. Endolymphatic sac ablation caused low-frequency loss. Animals treated with HPBCD had hearing loss at all frequencies. None of these animals had loss of hair cells or synapses on auditory nerve fibers. Results: In ears with endolymphatic hydrops and those perfused with HPBCD, auditory-nerve based measurements at low frequencies showed recruitment compared to controls. Recruitment was not found at high frequencies (> 4 kHz) where hearing thresholds were normal in ears with endolymphatic hydrops and elevated in ears treated with HPBCD. Conclusions: We found compelling evidence of recruitment in auditory-nerve data. Such clear evidence has never been shown before. Our findings suggest that, in patients suspected of having endolymphatic hydrops, loudness recruitment may be a good indication that the associated low-frequency hearing loss originates from a reduction of cochlear amplification, and that measurements of recruitment could be used in differential diagnosis and treatment monitoring of Ménière's disease.
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Affiliation(s)
- Shannon M Lefler
- Department of Otolaryngology, Washington University School of Medicine in St. Louis, Saint Louis, MO, United States
| | - Robert K Duncan
- Department of Otolaryngology-Head and Neck Surgery, Kresge Hearing Research Institute, University of Michigan, Ann Arbor, MI, United States
| | - Shawn S Goodman
- Department of Communication Sciences and Disorders, University of Iowa, Iowa City, IA, United States
| | - John J Guinan
- Eaton-Peabody Laboratories, Massachusetts Eye and Ear, Boston, MA, United States.,Department of Otolaryngology, Harvard Medical School, Boston, MA, United States
| | - Jeffery T Lichtenhan
- Department of Otolaryngology, Washington University School of Medicine in St. Louis, Saint Louis, MO, United States
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Guinan JJ, Lefler SM, Buchman CA, Goodman SS, Lichtenhan JT. Altered mapping of sound frequency to cochlear place in ears with endolymphatic hydrops provide insight into the pitch anomaly of diplacusis. Sci Rep 2021; 11:10380. [PMID: 34001971 PMCID: PMC8128888 DOI: 10.1038/s41598-021-89902-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Accepted: 04/26/2021] [Indexed: 11/22/2022] Open
Abstract
A fundamental property of mammalian hearing is the conversion of sound pressure into a frequency-specific place of maximum vibration along the cochlear length, thereby creating a tonotopic map. The tonotopic map makes possible systematic frequency tuning across auditory-nerve fibers, which enables the brain to use pitch to separate sounds from different environmental sources and process the speech and music that connects us to people and the world. Sometimes a tone has a different pitch in the left and right ears, a perceptual anomaly known as diplacusis. Diplacusis has been attributed to a change in the cochlear frequency-place map, but the hypothesized abnormal cochlear map has never been demonstrated. Here we assess cochlear frequency-place maps in guinea-pig ears with experimentally-induced endolymphatic hydrops, a hallmark of Ménière’s disease. Our findings are consistent with the hypothesis that diplacusis is due to an altered cochlear map. Map changes can lead to altered pitch, but the size of the pitch change is also affected by neural synchrony. Our data show that the cochlear frequency-place map is not fixed but can be altered by endolymphatic hydrops. Map changes should be considered in assessing hearing pathologies and treatments.
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Affiliation(s)
- J J Guinan
- Eaton-Peabody Laboratories, Massachusetts Eye and Ear, Boston, MA, USA.,Department of Otolaryngology, Harvard Medical School, Boston, MA, USA
| | - S M Lefler
- Department of Otolaryngology, School of Medicine, Washington University St. Louis, Campus Box 8115, 660 South Euclid Avenue, Saint Louis, MO, 63110, USA
| | - C A Buchman
- Department of Otolaryngology, School of Medicine, Washington University St. Louis, Campus Box 8115, 660 South Euclid Avenue, Saint Louis, MO, 63110, USA
| | - S S Goodman
- Department of Communication Sciences and Disorders, University of Iowa, Iowa City, IA, USA
| | - J T Lichtenhan
- Department of Otolaryngology, School of Medicine, Washington University St. Louis, Campus Box 8115, 660 South Euclid Avenue, Saint Louis, MO, 63110, USA.
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