Hearing ResearchPub Date : 2024-10-16DOI: 10.1016/j.heares.2024.109131
Priyanka Mohan, Saku T. Sinkkonen, Ville Sivonen
{"title":"The association of intraoperative electric field and neural excitation patterns of the cochlear implant with patient-related factors of age, gender, cochlear diameter, and postoperative speech measures","authors":"Priyanka Mohan, Saku T. Sinkkonen, Ville Sivonen","doi":"10.1016/j.heares.2024.109131","DOIUrl":"10.1016/j.heares.2024.109131","url":null,"abstract":"<div><h3>Purpose</h3><div>To assess the relationships between the electric field (EF) and neural excitation patterns in cochlear implants (CIs) and explore their associations with the cochlear diameter, patient age and gender, and postoperative speech recognition.</div></div><div><h3>Method</h3><div>The intraoperative transimpedance matrix (TIM) and spread of excitation (SOE) measures were computed to obtain their 50 % widths corresponding to six electrode contacts of a lateral-wall electrode array. The measures were then analyzed for intercorrelations, associations with the cochlear diameter, as well as age and gender-related differences. The relationships between the computed intraoperative measures and postimplant speech recognition were also studied.</div></div><div><h3>Results</h3><div>The TIM and SOE 50 % widths present moderate correlations and exhibit differences between adults and children. The TIM 50 % widths show additional associations with the cochlear diameter and partly vary with the implantee's gender. Speech recognition was found to have a significant relationship with the exponential spread coefficients (ESCs) obtained for individual electrode contacts.</div></div><div><h3>Conclusion</h3><div>Although interrelated, the EF and neural excitation measures of the CI are associated with different variables. The ESC, derived from computations of the TIM<sub>,</sub> is the only measure linked to postoperative speech recognition.</div></div>","PeriodicalId":12881,"journal":{"name":"Hearing Research","volume":"453 ","pages":"Article 109131"},"PeriodicalIF":2.5,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142499172","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Hearing ResearchPub Date : 2024-10-16DOI: 10.1016/j.heares.2024.109129
Min Zhu , Qin Gong
{"title":"Alterations in brain activity and functional connectivity originating residual inhibition of tinnitus induced by tailor-made notched music training","authors":"Min Zhu , Qin Gong","doi":"10.1016/j.heares.2024.109129","DOIUrl":"10.1016/j.heares.2024.109129","url":null,"abstract":"<div><div>Tinnitus arises from the intricate interplay of multiple, parallel but overlapping networks, involving neuroplastic changes in both auditory and non-auditory activity. Tailor-made notched music training (TMNMT) has emerged as a promising therapeutic approach for tinnitus. Residual inhibition (RI) represents one of the rare interventions capable of temporarily alleviating tinnitus, offering a valuable tool that can be applied to tinnitus research to explore underlying tinnitus mechanisms. To our knowledge, this study is the first to investigate the neural mechanisms underlying the RI effect of TMNMT through analysis of neural source activity and functional connectivity of EEG. Forty-four participants with tinnitus were divided into TMNMT group (twenty-two participants; ECnm, NMnm, RInm represented that EEG recordings with eyes closed stimuli-pre, stimuli-ing, stimuli-post by TMNMT music, respectively) and Placebo control group (twenty-two participants; ECpb, PBpb, RIpb represented that EEG recordings with eyes closed stimuli-pre, stimuli-ing, stimuli-post by Placebo music, respectively) in a single-blind manner. Source localization analysis revealed that RI effect of TMNMT significantly increased in current density at the delta band in the insula, subgenual anterior cingulate cortex (sgACC), parahippocampus (PHC), and secondary auditory cortex (AⅡ), and significantly increased in current density at the theta band in the sgACC, and significantly decreased in current density at the alpha band in the precuneus, PHC, primary (AI) and secondary (AII) auditory cortex. Meanwhile, RI effect of Placebo significantly decreased in current density at the alpha band in the PHC. Functional connectivity analysis demonstrated that RI effect of TMNMT significantly increased in phase coherence between the left AⅡ and the right sgACC; and between the left PHC and the left retrosplenial cortex (RSC) at the theta band. It significantly decreased in phase coherence between the left PHC and the right precuneus, the right posterior cingulate cortex (PCC), the right AⅡ; between the right PHC and the right PCC; and between the right PCC and the right AⅡ at the alpha band. RI effect of Placebo significantly increased in phase coherence between the left insula and the right precuneus, the left PHC, the right PHC, the left AⅠ, the left AⅡ; between the left sgACC and the right PHC; between the left AⅡ and the right PHC, the left PCC at the delta band. It was found that the current density of sgACC was significantly positively correlated with the tinnitus evaluation indicators (Loudness, VAS, THI, TFI) at the alpha band in TMNMT group. These findings indicated that TMNMT, a novel music therapy for tinnitus, revealed a robust RI effect, and RI effect of TMNMT was not only involved in the activity of auditory networks (AⅠ, AⅡ), but also extended to non-auditory networks, particularly higher-level auditory association cortices, such as the sgACC, PHC and PCC. The current","PeriodicalId":12881,"journal":{"name":"Hearing Research","volume":"457 ","pages":"Article 109129"},"PeriodicalIF":2.5,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143100494","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Hearing ResearchPub Date : 2024-10-05DOI: 10.1016/j.heares.2024.109127
Simon Kersten , Henning Taschke , Michael Vorländer
{"title":"Influence of the cochlear partition’s flexibility on the macro mechanisms in the inner ear","authors":"Simon Kersten , Henning Taschke , Michael Vorländer","doi":"10.1016/j.heares.2024.109127","DOIUrl":"10.1016/j.heares.2024.109127","url":null,"abstract":"<div><div>Recent studies have highlighted the anatomy of the cochlear partition (CP), revealing insights into the flexible nature of the osseous spiral lamina (OSL) and the existence of a flexible cochlear partition bridge (CPB) between the OSL and the basilar membrane (BM). However, most existing inner ear models treat the OSL as a rigid structure and ignore the CPB, neglecting their potential impact on intracochlear sound pressure and motion of the BM. In this paper, we investigate the effect of the CP’s flexibility by including the OSL and CPB as either rigid or flexible structures in a numerical anatomical model of the human inner ear. Our findings demonstrate that the flexibility of the OSL and the presence of the CPB significantly affect cochlear macro mechanisms, including differential intracochlear sound pressure, resistive behavior in cochlear impedances, CP stiffness, and BM velocity. These results emphasize the importance of considering the flexibility of the entire CP to enhance our understanding of cochlear function and to accurately interpret experimental data on inner ear mechanics.</div></div>","PeriodicalId":12881,"journal":{"name":"Hearing Research","volume":"453 ","pages":"Article 109127"},"PeriodicalIF":2.5,"publicationDate":"2024-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142499169","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Hearing ResearchPub Date : 2024-10-04DOI: 10.1016/j.heares.2024.109125
Merle Sehlmeyer , Mit B. Bhavsar , Stefan Zimmermann , Hannes Maier
{"title":"A simple electrical circuit model for impedance spectroscopy with cochlear implant electrodes","authors":"Merle Sehlmeyer , Mit B. Bhavsar , Stefan Zimmermann , Hannes Maier","doi":"10.1016/j.heares.2024.109125","DOIUrl":"10.1016/j.heares.2024.109125","url":null,"abstract":"<div><div>Although cochlear implants are an established method of restoring hearing, they can have limitations such as increasing current spread and decreasing frequency resolution due to tissue growth around the electrode array. Impedance measurements in cochlear implants have become a versatile tool for intra- and post-operative diagnosis of cochlear implant state. However, most clinical devices use current pulse stimulation already available in the implants and analyze the voltage response in the time-domain and spread along the cochlea. To use the full potential of impedance spectroscopy in differentiating cell types, measurement over an extended frequency range is required. This study presents a simple electrical equivalent circuit for impedance spectroscopy with cochlear implants in a 2-pole configuration. The electrical equivalent circuit describes the electrical properties of the cochlear implant electrode and its electrochemical behavior at the electrode-electrolyte interface by comparing two non-linear bilayer models, Cole-Cole and Schwan-Faraday. The model is validated for four cochlear implant electrodes from four different manufacturers (MED-EL FlexSoft, AB HiFocus SlimJ, Oticon EVO, Cochlear Nucleus CI622) characterized by impedance spectroscopy between 5 Hz and 13 MHz. In the future, this electrical equivalent circuit may help to extract parameters for differentiating cell types around the cochlear implant electrode from an impedance spectroscopic measurement.</div></div>","PeriodicalId":12881,"journal":{"name":"Hearing Research","volume":"453 ","pages":"Article 109125"},"PeriodicalIF":2.5,"publicationDate":"2024-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142424747","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Hearing ResearchPub Date : 2024-10-04DOI: 10.1016/j.heares.2024.109122
Tori Kok , Rosemary Varley , Chris Clark , Madeleine Verriotis , Kiran Seunarine , Giriraj Singh Shekhawat
{"title":"Resting-state networks in chronic tinnitus: Increased connectivity between thalamus and visual areas","authors":"Tori Kok , Rosemary Varley , Chris Clark , Madeleine Verriotis , Kiran Seunarine , Giriraj Singh Shekhawat","doi":"10.1016/j.heares.2024.109122","DOIUrl":"10.1016/j.heares.2024.109122","url":null,"abstract":"<div><div>Tinnitus is thought to be associated with aberrant spontaneous activity in the central nervous system. Previous resting-state fMRI findings support this hypothesis and have shown a variety of alterations in neural activity in people with tinnitus compared to people without tinnitus. However, there is little replication of findings. Therefore, the current study aimed to extend on previous findings by investigating eight common resting-state networks (i.e. auditory, default mode, sensorimotor, visual, salience, dorsal attention, frontoparietal and language networks) using a control group (<em>n</em> = 36) and a group of tinnitus patients (<em>n</em> = 46) matched for age, sex and years of education. Hearing profiles matched up to 2 kHz and had a small but significant difference between groups in the high frequency range. Functional connectivity (FC) with dorsolateral prefrontal cortex (DLPFC) was also investigated separately for the first time, as this region is proposed to be core to tinnitus distress symptoms and most often used as a stimulation target in transcranial direct current stimulation (tDCS) research. The results showed that tinnitus patients had increased FC between bilateral thalamus and right visual association cortex compared to control participants. No differences were found with DLPFC, or with any of the resting-state networks (RSN), contrary to previous studies which have reported alterations in several RSNs.</div></div>","PeriodicalId":12881,"journal":{"name":"Hearing Research","volume":"453 ","pages":"Article 109122"},"PeriodicalIF":2.5,"publicationDate":"2024-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142499171","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Hearing ResearchPub Date : 2024-10-03DOI: 10.1016/j.heares.2024.109123
Jiaqiu Vince Sun , Zeyu Jing , James Rankin , John Rinzel
{"title":"Perceptual tri-stability, measured and fitted as emergent from a model for bistable alternations","authors":"Jiaqiu Vince Sun , Zeyu Jing , James Rankin , John Rinzel","doi":"10.1016/j.heares.2024.109123","DOIUrl":"10.1016/j.heares.2024.109123","url":null,"abstract":"<div><div>The human auditory system in attempting to decipher ambiguous sounds appears to resort to perceptual exploration as evidenced by multi-stable perceptual alternations. This phenomenon has been widely investigated via the auditory streaming paradigm, employing ABA_ triplet sequences with much research focused on perceptual bi-stability with the alternate percepts as either a single integrated stream or as two simultaneous distinct streams. We extend this inquiry with experiments and modeling to include tri-stable perception. Here, the segregated percepts may involve a foreground/background distinction. We collected empirical data from participants engaged in a tri-stable auditory task, utilizing this dataset to refine a neural mechanistic model that had successfully reproduced multiple features of auditory bi-stability. Remarkably, the model successfully emulated basic statistical characteristics of tri-stability without substantial modification. This model also allows us to demonstrate a parsimonious approach to account for individual variability by adjusting the parameter of either the noise level or the neural adaptation strength.</div></div>","PeriodicalId":12881,"journal":{"name":"Hearing Research","volume":"453 ","pages":"Article 109123"},"PeriodicalIF":2.5,"publicationDate":"2024-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142499170","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Hearing ResearchPub Date : 2024-10-02DOI: 10.1016/j.heares.2024.109128
Tianyi Ni , Ziyu Shen , Xiuling Lu , Hekai Shi , Hongbo Xie , Siyi Yang , Wenjie Zhuang , Yuehong Liu , Zhao Han
{"title":"No causal relationship serum lipids on age-related hearing loss based on Mendelian randomized evidence","authors":"Tianyi Ni , Ziyu Shen , Xiuling Lu , Hekai Shi , Hongbo Xie , Siyi Yang , Wenjie Zhuang , Yuehong Liu , Zhao Han","doi":"10.1016/j.heares.2024.109128","DOIUrl":"10.1016/j.heares.2024.109128","url":null,"abstract":"<div><h3>Objectives</h3><div>Presbycusis, or age-related hearing loss (ARHL) has been a common disability disease among the elderly population. It is particularly essential to identify the underlying role of related risk factors for ARHL diagnosis and treatment. Observational studies have shown that cardiovascular disease may be a factor in ARHL. Serum lipids are a key risk factor for cardiovascular disease. Therefore, it may be a potentially influencing factor for elderly deafness. We conduct the study to analyze the causal relationship between serum lipids and European elderly deafness.</div></div><div><h3>Design</h3><div>Using genetic variation data related to serum lipids (total cholesterol levels [TCL], total triglycerides levels [TGL], and lipoprotein fractions, including apolipoprotein A1 levels [APOA1L], apolipoprotein B levels [APOBL], high-density lipoprotein cholesterol levels [HDL], and low-density lipoprotein cholesterol levels [LDL]) as instrumental variables, the outcome events were summarized from the genome-wide association study data of elderly deafness, and Mendelian randomization (MR) analysis was used in our analysis. The relationship between serum lipids levels and ARHL was analyzed using five methods, including inverse variance weighted, weighted mode, MR-Egger, weighted median, and simple mode. The study aims to use bidirectional MR analysis.</div></div><div><h3>Results</h3><div>Among all 5 methods, no significant causal effects were found between serum lipids (TCL OR = 0.936, <em>p</em> = .488; TGL OR = 0.955, <em>p</em> = 0.657; APOA1L OR = 0.864, <em>p</em> = .061; APOBL OR = 0.979, <em>p</em> = .786; HDL OR = 0.998, <em>p</em> = .979; LDL OR = 1.089, <em>p</em> = .281) and presbycusis.</div></div><div><h3>Conclusion</h3><div>The findings of MR causal inference analysis did not support the causal relationship between presbycusis and serum lipids, including cholesterol, triglycerides, and lipoprotein fractions (APOA1L, APOBL, HDL and LDL).</div></div>","PeriodicalId":12881,"journal":{"name":"Hearing Research","volume":"453 ","pages":"Article 109128"},"PeriodicalIF":2.5,"publicationDate":"2024-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142400040","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Hearing ResearchPub Date : 2024-10-01DOI: 10.1016/j.heares.2024.109126
Helen J Kennedy , Michael G Evans
{"title":"Conductance properties of the α9α10 nicotinic acetylcholine receptor of neonatal mouse inner and outer hair cells","authors":"Helen J Kennedy , Michael G Evans","doi":"10.1016/j.heares.2024.109126","DOIUrl":"10.1016/j.heares.2024.109126","url":null,"abstract":"<div><div>In the developing cochlea, just before the onset of hearing on postnatal day 12, the medial olivocochlear efferent axons in synaptic contact with the inner hair cells (IHCs) start withdrawing and new efferent synaptic connections are formed on the outer hair cells (OHCs), thereby progressing towards the adult pattern of medial olivocochlear efferent innervation. The synapses are inhibitory, calcium influx through the α9α10 nicotinic acetylcholine receptors (nAChRs) driving opening of calcium-dependent potassium channels. The nAChRs appear to function similarly in IHCs and OHCs, although with probable kinetic differences. Our aim was to assess their functional similarity in the neonatal mouse cochlea by making whole-cell recordings from both hair cell types between postnatal day 7 and 10 when nAChRs are expressed. ACh was applied to voltage-clamped hair cells by pressure-ejection from a pipette. The cells were dialysed with a Cs<sup>+</sup>-based solution designed to eliminate calcium-dependent potassium currents. There were differences in amplitude, voltage-sensitivity and reversal potential of the nAChR currents between IHCs and OHCs. There was also some indication that IHC nAChRs have slower activation and desensitization kinetics, although the relatively slow ACh application limited interpretation of this result. These differences, particularly concerning the reversal potential, might indicate the presence of different auxiliary protein subunits of the α9α10 receptor in neonatal IHCs and OHCs.</div></div>","PeriodicalId":12881,"journal":{"name":"Hearing Research","volume":"453 ","pages":"Article 109126"},"PeriodicalIF":2.5,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142389875","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Hearing ResearchPub Date : 2024-09-23DOI: 10.1016/j.heares.2024.109124
Lilian M. Mennink , Lina B.M. Albakri , Marlien W. Aalbers , Pim van Dijk , J.Marc C. van Dijk
{"title":"Cross-sectional screening for inflammation in tinnitus with near-normal hearing","authors":"Lilian M. Mennink , Lina B.M. Albakri , Marlien W. Aalbers , Pim van Dijk , J.Marc C. van Dijk","doi":"10.1016/j.heares.2024.109124","DOIUrl":"10.1016/j.heares.2024.109124","url":null,"abstract":"<div><div>Tinnitus is the perception of sound without an external stimulus. Recently, inflammation has been implicated in the pathophysiology of tinnitus. In tinnitus animal models, cytokine levels are increased throughout the whole auditory pathway, and microglia and astrocytes are activated. However, only a few human studies on inflammation in tinnitus were conducted, which generally did not account for confounders such as hearing loss, anxiety and depression. The current study therefore aimed to evaluate the association between inflammation and tinnitus specifically in participants with (near-)normal hearing and without signs of anxiety or depression.</div><div>In this cross-sectional study, fifty tinnitus participants and fifty healthy controls completed a tinnitus questionnaire and underwent audiometric testing. Complete blood count measures were determined in blood plasma, as well as cytokine concentrations by using the enzyme-linked immunosorbent assay (ELISA) technique.</div><div>Platelet count and cytokine concentrations of IL-10 and IFN-γ were lower in participants with tinnitus compared to controls, and male sex, lower MCV, lower platelet count, and lower IL-10 and IFN-γ concentrations were significant predictors of tinnitus presence.</div><div>The current study shows that inflammatory parameters are altered in tinnitus patients after exclusion of important confounders such as hearing loss, anxiety, depression, and inflammatory diseases.</div></div>","PeriodicalId":12881,"journal":{"name":"Hearing Research","volume":"453 ","pages":"Article 109124"},"PeriodicalIF":2.5,"publicationDate":"2024-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142322649","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Hearing ResearchPub Date : 2024-09-20DOI: 10.1016/j.heares.2024.109121
Nathaniel T. Greene , Theodore F. Argo , James Easter , Tim Walilko , Daniel J. Tollin
{"title":"Frequency dependence and harmonic distortion of stapes displacement and intracochlear pressure in response to very high level sounds","authors":"Nathaniel T. Greene , Theodore F. Argo , James Easter , Tim Walilko , Daniel J. Tollin","doi":"10.1016/j.heares.2024.109121","DOIUrl":"10.1016/j.heares.2024.109121","url":null,"abstract":"<div><div>Previous reports have suggested that intracochlear pressures (P<sub>IC</sub>) measured at the base of the cochlea increase directly proportionally with stapes displacement (D<sub>Stap</sub>) in response to moderately high (<130 dB SPL) level sounds. Consistent with this assumption, we have reported that for low frequency sounds (<1 kHz), stapes displacement and intracochlear pressures increase linearly with sound pressure level (SPL) for moderately high levels (<130 dB SPL), but saturate at higher exposure levels (>130 dB SPL). However, the magnitudes of each response were found to be frequency dependent, thus the relationship between D<sub>Stap</sub> and P<sub>IC</sub> may vary at higher frequencies or higher levels.</div><div>In order to further examine this frequency and level dependence, measurements of D<sub>Stap</sub> and P<sub>IC</sub> were made in cadaveric human temporal bones prepared with a mastoidectomy and extended facial recess to expose the ossicular chain. P<sub>IC</sub> was measured in scala vestibuli (P<sub>SV</sub>) and scala tympani (P<sub>ST</sub>) simultaneously with SPL in the external auditory canal (P<sub>EAC</sub>) and laser Doppler vibrometry (LDV) measurements of stapes velocity (V<sub>Stap</sub>). Consistent with prior reports, D<sub>Stap</sub> and P<sub>SV</sub> increased proportionally with sound pressure level in the ear canal up to a frequency-dependent saturation point, above which both D<sub>Stap</sub> and P<sub>SV</sub> showed a distinct deviation from proportionality with P<sub>EAC</sub>, suggesting that their relationship may remain constant at these high frequencies. Likewise, while the asymptotic value, and SPL at which saturation occurred were frequency dependent in both D<sub>Stap</sub> and P<sub>SV,</sub> the reduction in gain with increasing SPL above this level was constant above this level at all frequencies, and the magnitude of responses at harmonics of the driving frequency increased with increasing level, consistent with harmonic distortion via peak clipping. Importantly, this nonlinear distortion shifts the energy arriving at the inner ear to higher frequencies than are present in incident stimulus, thus exposing the high frequency sensitive components of the auditory system to more noise than would be expected from measurement of that stimulus on its own. Overall, responses suggest that the cochlear representation of very high-level air conducted stimuli is limited by nonlinearities in the middle ear, and that this peak limiting leads to increased high frequency cochlear exposures than are present in the driving stimulus.</div></div>","PeriodicalId":12881,"journal":{"name":"Hearing Research","volume":"453 ","pages":"Article 109121"},"PeriodicalIF":2.5,"publicationDate":"2024-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142322650","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}