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Ebrahimian A, Mohammadi H, Rosowski JJ, Cheng JT, Maftoon N. Inaccuracies of deterministic finite-element models of human middle ear revealed by stochastic modelling. Sci Rep 2023; 13:7329. [PMID: 37147426 PMCID: PMC10163043 DOI: 10.1038/s41598-023-34018-w] [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: 11/11/2022] [Accepted: 04/22/2023] [Indexed: 05/07/2023] Open
Abstract
For over 40 years, finite-element models of the mechanics of the middle ear have been mostly deterministic in nature. Deterministic models do not take into account the effects of inter-individual variabilities on middle-ear parameters. We present a stochastic finite-element model of the human middle ear that uses variability in the model parameters to investigate the uncertainty in the model outputs (umbo, stapes, and tympanic-membrane displacements). We demonstrate: (1) uncertainties in the model parameters can be magnified by more than three times in the umbo and stapes footplate responses at frequencies above 2 kHz; (2) middle-ear models are biased and they distort the output distributions; and (3) with increased frequency, the highly-uncertain regions spatially spread out on the tympanic membrane surface. Our results assert that we should be mindful when using deterministic finite-element middle-ear models for critical tasks such as novel device developments and diagnosis.
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Affiliation(s)
- Arash Ebrahimian
- Department of Systems Design Engineering, University of Waterloo, Waterloo, ON, Canada
- Centre for Bioengineering and Biotechnology, University of Waterloo, Waterloo, ON, Canada
| | - Hossein Mohammadi
- Department of Systems Design Engineering, University of Waterloo, Waterloo, ON, Canada
- Centre for Bioengineering and Biotechnology, University of Waterloo, Waterloo, ON, Canada
| | - John J Rosowski
- Eaton-Peabody Laboratories, Massachusetts Eye and Ear, Boston, MA, 02114, USA
- Department of Otolaryngology-Head and Neck Surgery, Harvard Medical School, Boston, MA, 02114, USA
| | - Jeffrey Tao Cheng
- Eaton-Peabody Laboratories, Massachusetts Eye and Ear, Boston, MA, 02114, USA
- Department of Otolaryngology-Head and Neck Surgery, Harvard Medical School, Boston, MA, 02114, USA
| | - Nima Maftoon
- Department of Systems Design Engineering, University of Waterloo, Waterloo, ON, Canada.
- Centre for Bioengineering and Biotechnology, University of Waterloo, Waterloo, ON, Canada.
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Liang J, Smith KD, Lu H, Seale TW, Gan RZ. Mechanical properties of the Papio anubis tympanic membrane: Change significantly from infancy to adulthood. Hear Res 2018; 370:143-154. [PMID: 30388572 DOI: 10.1016/j.heares.2018.10.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Revised: 10/05/2018] [Accepted: 10/14/2018] [Indexed: 11/16/2022]
Abstract
Mechanical properties of the tympanic membrane (TM) are important for studying the transfer function of the auditory system. However, nearly all reported human data are limited to adults because of the unavailability of temporal bones from children. In this study, we used the baboon (Papio anubis), a genetically close human relative, as a model to address the occurrence of age-dependent changes of the human TM. Forty-five baboon TMs were characterized in five age groups: <1 year, 1 to <2 years, 2 to <3 years, 3 to <5, and >5 years of age, comparable to human ages ranging from newborn to adult. The elastic properties of the baboon TMs were characterized by a micro-fringe projection technique. Volume displacement of the TM under quasi-static pressure was first determined from its micro-fringe pattern. Subsequently, these displacement values were used in a finite element model to derive mechanical properties. The Young's modulus of the baboon TM exhibited a modest decrease from 29.1 MPa to 26.0 MPa over the age groups. The average Young's modulus was ∼1.4 times higher than that of the adult human TM. This is the first time that age-related TM mechanical properties of high primate are reported. These new findings may help to explore the potential value of the baboon as a new primate model for future age-related hearing research on the normal and diseased ear.
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Affiliation(s)
- Junfeng Liang
- School of Aerospace and Mechanical Engineering, University of Oklahoma, Norman, OK, USA; Dept. of Mechanical Engineering, University of Texas at Dallas, Richardson, TX, USA
| | - Kyle D Smith
- School of Aerospace and Mechanical Engineering, University of Oklahoma, Norman, OK, USA
| | - Hongbing Lu
- Dept. of Mechanical Engineering, University of Texas at Dallas, Richardson, TX, USA
| | - Thomas W Seale
- Dept. of Pediatrics, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Rong Z Gan
- School of Aerospace and Mechanical Engineering, University of Oklahoma, Norman, OK, USA.
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Alper CM, Luntz M, Takahashi H, Ghadiali SN, Swarts JD, Teixeira MS, Csákányi Z, Yehudai N, Kania R, Poe DS. Panel 2: Anatomy (Eustachian Tube, Middle Ear, and Mastoid-Anatomy, Physiology, Pathophysiology, and Pathogenesis). Otolaryngol Head Neck Surg 2017; 156:S22-S40. [PMID: 28372527 DOI: 10.1177/0194599816647959] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Objective In this report, we review the recent literature (ie, past 4 years) to identify advances in our understanding of the middle ear-mastoid-eustachian tube system. We use this review to determine whether the short-term goals elaborated in the last report were achieved, and we propose updated goals to guide future otitis media research. Data Sources PubMed, Web of Science, Medline. Review Methods The panel topic was subdivided, and each contributor performed a literature search within the given time frame. The keywords searched included middle ear, eustachian tube, and mastoid for their intersection with anatomy, physiology, pathophysiology, and pathology. Preliminary reports from each panel member were consolidated and discussed when the panel met on June 11, 2015. At that meeting, the progress was evaluated and new short-term goals proposed. Conclusions Progress was made on 13 of the 20 short-term goals proposed in 2011. Significant advances were made in the characterization of middle ear gas exchange pathways, modeling eustachian tube function, and preliminary testing of treatments for eustachian tube dysfunction. Implications for Practice In the future, imaging technologies should be developed to noninvasively assess middle ear/eustachian tube structure and physiology with respect to their role in otitis media pathogenesis. The new data derived from these structure/function experiments should be integrated into computational models that can then be used to develop specific hypotheses concerning otitis media pathogenesis and persistence. Finally, rigorous studies on medical or surgical treatments for eustachian tube dysfunction should be undertaken.
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Affiliation(s)
- Cuneyt M Alper
- 1 Department of Pediatric Otolaryngology, Children's Hospital of Pittsburgh of University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA.,2 Department of Otolaryngology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA.,3 Clinical and Translational Science Institute, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Michal Luntz
- 4 Department of Otolaryngology Head and Neck Surgery, Bnai Zion Medical Center; Technion-The Ruth and Bruce Rappaport Faculty of Medicine, Haifa, Israel
| | - Haruo Takahashi
- 5 Department of Otolaryngology-Head and Neck Surgery, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
| | - Samir N Ghadiali
- 6 Department of Biomedical Engineering, Ohio University, Columbus, Ohio, USA.,7 Department of Internal Medicine, Division of Pulmonary, Allergy, Critical Care and Sleep Medicine, Ohio University, Columbus, Ohio, USA
| | - J Douglas Swarts
- 2 Department of Otolaryngology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Miriam S Teixeira
- 2 Department of Otolaryngology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Zsuzsanna Csákányi
- 8 Department of Pediatric Otorhinolaryngology, Heim Pal Children's Hospital, Budapest, Hungary
| | - Noam Yehudai
- 4 Department of Otolaryngology Head and Neck Surgery, Bnai Zion Medical Center; Technion-The Ruth and Bruce Rappaport Faculty of Medicine, Haifa, Israel
| | - Romain Kania
- 9 Department of Otorhinolaryngology-Head and Neck Surgery, Lariboisière Hospital, Diderot University, University Paris Sorbonne, Paris, France
| | - Dennis S Poe
- 10 Department of Otology and Laryngology, Harvard Medical School, Boston Children's Hospital, Boston, Massachusetts, USA.,11 Department of Otolaryngology and Communications Enhancement, Boston Children's Hospital, Boston, Massachusetts, USA
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Estimation of the Young's modulus of the human pars tensa using in-situ pressurization and inverse finite-element analysis. Hear Res 2017; 345:69-78. [DOI: 10.1016/j.heares.2017.01.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Revised: 01/03/2017] [Accepted: 01/05/2017] [Indexed: 11/19/2022]
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Xu D, Liu H, Zhou L, Cheng G, Yang J, Huang X, Liu X. The effect of actuator and its coupling conditions on eardrum-stimulated middle ear implants: A numerical analysis. Proc Inst Mech Eng H 2016. [DOI: 10.1177/0954411916675381] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Consisting of the actuator and coupling layer, a finite element model of the human middle ear was used to analyze the effect of the actuator and its coupling conditions on the performance of the eardrum-stimulated middle ear implants. This model which was based on the right ear of a healthy adult was built via microcomputed tomography imaging and the technique of reverse engineering. Based on this finite element model, the linear viscoelasticity of the human middle ear soft tissues and three-layer structure of the eardrum pars tensa which was orthotropic were considered. The validity of the model was verified by comparing the model calculated results with experimental data. After that, the influence of the three main design parameters of the actuator and two aspects of the coupling layer were investigated by the finite element model. The results show that (1) the manubrium tip is the optimal position for the actuator to stimulate; (2) the increased cross-section of the actuator would worsen its hearing compensation performance, especially in the low frequencies; (3) both the patients’ residual hearing and the actuator’s hearing compensation performance at high frequencies will be deteriorated with the increase in the actuator’s mass; and (4) a coupling layer with a small Young’s modulus and an area approximating 80% of the eardrum would reduce the stress of the eardrum effectively.
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Affiliation(s)
- Dan Xu
- School of Mechatronic Engineering, China University of Mining and Technology, Xuzhou, P.R. China
| | - Houguang Liu
- School of Mechatronic Engineering, China University of Mining and Technology, Xuzhou, P.R. China
| | - Lei Zhou
- Department of Otorhinolaryngology-Head and Neck Surgery, Shanghai Zhongshan Hospital, Fudan University, Shanghai, P.R. China
| | - Gang Cheng
- School of Mechatronic Engineering, China University of Mining and Technology, Xuzhou, P.R. China
| | - Jianhua Yang
- School of Mechatronic Engineering, China University of Mining and Technology, Xuzhou, P.R. China
| | - Xinsheng Huang
- Department of Otorhinolaryngology-Head and Neck Surgery, Shanghai Zhongshan Hospital, Fudan University, Shanghai, P.R. China
| | - Xiaole Liu
- School of Mechatronic Engineering, China University of Mining and Technology, Xuzhou, P.R. China
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Liang J, Luo H, Yokell Z, Nakmali DU, Gan RZ, Lu H. Characterization of the nonlinear elastic behavior of chinchilla tympanic membrane using micro-fringe projection. Hear Res 2016; 339:1-11. [PMID: 27240479 DOI: 10.1016/j.heares.2016.05.012] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/25/2015] [Revised: 04/01/2016] [Accepted: 05/08/2016] [Indexed: 11/29/2022]
Abstract
The mechanical properties of an intact, full tympanic membrane (TM) inside the bulla of a fresh chinchilla were measured under quasi-static pressure from -1.0 kPa to 1.0 kPa applied on the TM lateral side. Images of the fringes projected onto the TM were acquired by a digital camera connected to a surgical microscope and analyzed using a phase-shift method to reconstruct the surface topography. The relationship between the applied pressure and the resulting volume displacement was determined and analyzed using a finite element model implementing a hyperelastic 2(nd)-order Ogden model. Through an inverse method, the best-fit model parameters for the TM were determined to allow the simulation results to agree with the experimental data. The nonlinear stress-strain relationship for the TM of a chinchilla was determined up to an equibiaxial tensile strain of 31% experienced by the TM in the experiments. The average Young's modulus of the chinchilla TM from ten bullas was determined as approximately 19 MPa.
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Affiliation(s)
- Junfeng Liang
- Department of Mechanical Engineering, The University of Texas at Dallas, Richardson, TX 75080, USA
| | - Huiyang Luo
- Department of Mechanical Engineering, The University of Texas at Dallas, Richardson, TX 75080, USA
| | - Zachary Yokell
- School of Aerospace and Mechanical Engineering, The University of Oklahoma, Norman, OK 73019, USA
| | - Don U Nakmali
- School of Aerospace and Mechanical Engineering, The University of Oklahoma, Norman, OK 73019, USA
| | - Rong Zhu Gan
- School of Aerospace and Mechanical Engineering, The University of Oklahoma, Norman, OK 73019, USA
| | - Hongbing Lu
- Department of Mechanical Engineering, The University of Texas at Dallas, Richardson, TX 75080, USA.
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Abstract
We present a finite-element model of the gerbil middle ear that, using a set of baseline parameters based primarily on a priori estimates from the literature, generates responses that are comparable with responses we measured in vivo using multi-point vibrometry and with those measured by other groups. We investigated the similarity of numerous features (umbo, pars-flaccida and pars-tensa displacement magnitudes, the resonance frequency and break-up frequency, etc.) in the experimental responses with corresponding ones in the model responses, as opposed to simply computing frequency-by-frequency differences between experimental and model responses. The umbo response of the model is within the range of variability seen in the experimental data in terms of the low-frequency (i.e., well below the middle-ear resonance) magnitude and phase, the main resonance frequency and magnitude, and the roll-off slope and irregularities in the response above the resonance frequency, but is somewhat high for frequencies above the resonance frequency. At low frequencies, the ossicular axis of rotation of the model appears to correspond to the anatomical axis but the behaviour is more complex at high frequencies (i.e., above the pars-tensa break-up). The behaviour of the pars tensa in the model is similar to what is observed experimentally in terms of magnitudes, phases, the break-up frequency of the spatial vibration pattern, and the bandwidths of the high-frequency response features. A sensitivity analysis showed that the parameters that have the strongest effects on the model results are the Young's modulus, thickness and density of the pars tensa; the Young's modulus of the stapedial annular ligament; and the Young's modulus and density of the malleus. Displacements of the tympanic membrane and manubrium and the low-frequency displacement of the stapes did not show large changes when the material properties of the incus, stapes, incudomallear joint, incudostapedial joint, and posterior incudal ligament were changed by ±10 % from their values in the baseline parameter set.
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