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Arán-Tapia I, Soto-Varela A, Pérez-Muñuzuri V, Santos-Pérez S, Arán I, Muñuzuri AP. Numerical simulations to determine the stimulation of the crista ampullaris during the Head Impulse Test. Comput Biol Med 2023; 163:107225. [PMID: 37437361 DOI: 10.1016/j.compbiomed.2023.107225] [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: 04/11/2023] [Revised: 06/13/2023] [Accepted: 06/30/2023] [Indexed: 07/14/2023]
Abstract
The Head Impulse Test, the most widely accept test to assess the vestibular function, comprises rotations of the head based on idealized orientations of the semicircular canals, instead of their individual arrangement specific for each patient. In this study, we show how computational modelling can help personalize the diagnosis of vestibular diseases. Based on a micro-computed tomography reconstruction of the human membranous labyrinth and their simulation using Computational Fluid Dynamics and Fluid-Solid Interaction techniques, we evaluated the stimulus experienced by the six cristae ampullaris under different rotational conditions mimicking the Head Impulse Test. The results show that the maximum stimulation of the crista ampullaris occurs for directions of rotation that are more aligned with the orientation of the cupulae (average deviation from alignment of 4.7°, 9.8°, and 19.4° for the horizontal, posterior, and superior maxima, respectively) than with the planes of the semicircular canals (average deviation from alignment of 32.4°, 70.5°, and 67.8° for the horizontal, posterior, and superior maxima, respectively). A plausible explanation is that when rotations are applied with respect to the center of the head, the inertial forces acting directly over the cupula become dominant over the endolymphatic fluid forces generated in the semicircular canals. Our results indicate that it is necessary to consider cupulae orientation to ensure optimal conditions for testing the vestibular function.
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Affiliation(s)
- Ismael Arán-Tapia
- Group of Non-Linear Physics, Campus Sur, University of Santiago de Compostela, Spain; Galician Center for Mathematical Research and Technology (CITMAga), Santiago de Compostela, Spain; CRETUS Institute, Santiago de Compostela, Spain.
| | - Andrés Soto-Varela
- Division of Neurotology, Department of Otorhinolaryngology, Complexo Hospitalario Universitario, Santiago de Compostela, Spain; Department of Surgery and Medical-Surgical Specialities, Universidade de Santiago de Compostela, Santiago de Compostela, Spain; Health Research Institute of Santiago (IDIS), Santiago de Compostela, Spain
| | - Vicente Pérez-Muñuzuri
- Group of Non-Linear Physics, Campus Sur, University of Santiago de Compostela, Spain; CRETUS Institute, Santiago de Compostela, Spain
| | - Sofía Santos-Pérez
- Division of Neurotology, Department of Otorhinolaryngology, Complexo Hospitalario Universitario, Santiago de Compostela, Spain; Department of Surgery and Medical-Surgical Specialities, Universidade de Santiago de Compostela, Santiago de Compostela, Spain
| | - Ismael Arán
- Otoneurology Unit of the Complexo Hospitalario Universitario de Pontevedra, Spain
| | - Alberto P Muñuzuri
- Group of Non-Linear Physics, Campus Sur, University of Santiago de Compostela, Spain; Galician Center for Mathematical Research and Technology (CITMAga), Santiago de Compostela, Spain.
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Curthoys IS, Smith CM, Burgess AM, Dlugaiczyk J. A Review of Neural Data and Modelling to Explain How a Semicircular Canal Dehiscence (SCD) Causes Enhanced VEMPs, Skull Vibration Induced Nystagmus (SVIN), and the Tullio Phenomenon. Audiol Res 2023; 13:418-430. [PMID: 37366683 DOI: 10.3390/audiolres13030037] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2023] [Revised: 05/24/2023] [Accepted: 05/30/2023] [Indexed: 06/28/2023] Open
Abstract
Angular acceleration stimulation of a semicircular canal causes an increased firing rate in primary canal afferent neurons that result in nystagmus in healthy adult animals. However, increased firing rate in canal afferent neurons can also be caused by sound or vibration in patients after a semicircular canal dehiscence, and so these unusual stimuli will also cause nystagmus. The recent data and model by Iversen and Rabbitt show that sound or vibration may increase firing rate either by neural activation locked to the individual cycles of the stimulus or by slow changes in firing rate due to fluid pumping ("acoustic streaming"), which causes cupula deflection. Both mechanisms will act to increase the primary afferent firing rate and so trigger nystagmus. The primary afferent data in guinea pigs indicate that in some situations, these two mechanisms may oppose each other. This review has shown how these three clinical phenomena-skull vibration-induced nystagmus, enhanced vestibular evoked myogenic potentials, and the Tullio phenomenon-have a common tie: they are caused by the new response of semicircular canal afferent neurons to sound and vibration after a semicircular canal dehiscence.
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Affiliation(s)
- Ian S Curthoys
- Vestibular Research Laboratory, School of Psychology, University of Sydney, Sydney, NSW 2006, Australia
| | - Christopher M Smith
- Center for Anatomy and Functional Morphology, Icahn School of Medicine at Mount Sinai, Annenberg Building, Room 12-90, 1468 Madison Ave., New York, NY 10029, USA
| | - Ann M Burgess
- Vestibular Research Laboratory, School of Psychology, University of Sydney, Sydney, NSW 2006, Australia
| | - Julia Dlugaiczyk
- Department of Otorhinolaryngology, Head and Neck Surgery & Interdisciplinary Center of Vertigo, Balance and Ocular Motor Disorders, University Hospital Zurich (USZ), University of Zurich (UZH), CH-8091 Zürich, Switzerland
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3
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Castle N, Liang J, Smith M, Petersen B, Matson C, Eldridge T, Zhang K, Lee CH, Liu Y, Dai C. Finite Element Modeling of Residual Hearing after Cochlear Implant Surgery in Chinchillas. Bioengineering (Basel) 2023; 10:bioengineering10050539. [PMID: 37237608 DOI: 10.3390/bioengineering10050539] [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: 03/28/2023] [Revised: 04/20/2023] [Accepted: 04/24/2023] [Indexed: 05/28/2023] Open
Abstract
Cochlear implant (CI) surgery is one of the most utilized treatments for severe hearing loss. However, the effects of a successful scala tympani insertion on the mechanics of hearing are not yet fully understood. This paper presents a finite element (FE) model of the chinchilla inner ear for studying the interrelationship between the mechanical function and the insertion angle of a CI electrode. This FE model includes a three-chambered cochlea and full vestibular system, accomplished using µ-MRI and µ-CT scanning technologies. This model's first application found minimal loss of residual hearing due to insertion angle after CI surgery, and this indicates that it is a reliable and helpful tool for future applications in CI design, surgical planning, and stimuli setup.
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Affiliation(s)
- Nicholas Castle
- Department of Aerospace and Mechanical Engineering, University of Oklahoma, Norman, OK 73019, USA
| | - Junfeng Liang
- Department of Aerospace and Mechanical Engineering, University of Oklahoma, Norman, OK 73019, USA
| | - Matthew Smith
- Department of Aerospace and Mechanical Engineering, University of Oklahoma, Norman, OK 73019, USA
| | - Brett Petersen
- Department of Aerospace and Mechanical Engineering, University of Oklahoma, Norman, OK 73019, USA
| | - Cayman Matson
- Department of Aerospace and Mechanical Engineering, University of Oklahoma, Norman, OK 73019, USA
| | - Tara Eldridge
- Department of Aerospace and Mechanical Engineering, University of Oklahoma, Norman, OK 73019, USA
| | - Ke Zhang
- Department of Aerospace and Mechanical Engineering, University of Oklahoma, Norman, OK 73019, USA
| | - Chung-Hao Lee
- Department of Aerospace and Mechanical Engineering, University of Oklahoma, Norman, OK 73019, USA
| | - Yingtao Liu
- Department of Aerospace and Mechanical Engineering, University of Oklahoma, Norman, OK 73019, USA
| | - Chenkai Dai
- Department of Aerospace and Mechanical Engineering, University of Oklahoma, Norman, OK 73019, USA
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Pastras CJ, Gholami N, Jennings S, Zhu H, Zhou W, Brown DJ, Curthoys IS, Rabbitt RD. A mathematical model for mechanical activation and compound action potential generation by the utricle in response to sound and vibration. Front Neurol 2023; 14:1109506. [PMID: 37051057 PMCID: PMC10083375 DOI: 10.3389/fneur.2023.1109506] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2022] [Accepted: 03/01/2023] [Indexed: 03/28/2023] Open
Abstract
IntroductionCalyx bearing vestibular afferent neurons innervating type I hair cells in the striolar region of the utricle are exquisitely sensitive to auditory-frequency air conducted sound (ACS) and bone conducted vibration (BCV). Here, we present experimental data and a mathematical model of utricular mechanics and vestibular compound action potential generation (vCAP) in response to clinically relevant levels of ACS and BCV. Vibration of the otoconial layer relative to the sensory epithelium was simulated using a Newtonian two-degree-of-freedom spring-mass-damper system, action potential timing was simulated using an empirical model, and vCAPs were simulated by convolving responses of the population of sensitive neurons with an empirical extracellular voltage kernel. The model was validated by comparison to macular vibration and vCAPs recorded in the guinea pig, in vivo.ResultsTransient stimuli evoked short-latency vCAPs that scaled in magnitude and timing with hair bundle mechanical shear rate for both ACS and BCV. For pulse BCV stimuli with durations <0.8 ms, the vCAP magnitude increased in proportion to temporal bone acceleration, but for pulse durations >0.9 ms the magnitude increased in proportion to temporal bone jerk. Once validated using ACS and BCV data, the model was applied to predict blast-induced hair bundle shear, with results predicting acute mechanical damage to bundles immediately upon exposure.DiscussionResults demonstrate the switch from linear acceleration to linear jerk as the adequate stimulus arises entirely from mechanical factors controlling the dynamics of sensory hair bundle deflection. The model describes the switch in terms of the mechanical natural frequencies of vibration, which vary between species based on morphology and mechanical factors.
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Affiliation(s)
- Christopher J. Pastras
- Faculty of Science and Engineering, School of Engineering, Macquarie University, Sydney, NSW, Australia
| | - Nastaran Gholami
- Biomedical Engineering, University of Utah, Salt Lake City, UT, United States
| | - Skyler Jennings
- Communication Sciences and Neuroscience Program, University of Utah, Salt Lake City, UT, United States
| | - Hong Zhu
- University of Mississippi Medical Center, Jackson, MS, United States
| | - Wu Zhou
- University of Mississippi Medical Center, Jackson, MS, United States
| | - Daniel J. Brown
- School of Pharmacy and Biomedical Sciences, Curtin University, Bentley, WA, Australia
| | - Ian S. Curthoys
- Vestibular Research Laboratory, School of Psychology, The University of Sydney, Sydney, NSW, Australia
| | - Richard D. Rabbitt
- Biomedical Engineering, University of Utah, Salt Lake City, UT, United States
- Otolaryngology and Neuroscience Program, University of Utah, Salt Lake City, UT, United States
- *Correspondence: Richard D. Rabbitt,
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Kalmanson O, Foster CA. Cupulolithiasis: A Critical Reappraisal. OTO Open 2023; 7:e38. [PMID: 36998555 PMCID: PMC10046726 DOI: 10.1002/oto2.38] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2022] [Revised: 01/04/2023] [Accepted: 01/21/2023] [Indexed: 03/06/2023] Open
Abstract
Objective To review the history and pathophysiologic theories for cupulolithiasis and canalith jam in benign paroxysmal positional vertigo. Data Sources PubMed, Google Scholar. Review Methods Three PubMed and Google Scholar searches were performed, keywords: "cupulolithiasis," "apogeotropic [and] benign," and "canalith jam," resulting in 187 unique full-text articles in English or with English translation. Figures-Labyrinthine photographs were obtained of fresh utricles, ampullae, and cupulae of a 37-day-old mouse. Conclusions Freely moving otoconial masses explain most cases (>98%) of benign paroxysmal positional vertigo. Evidence that otoconia adhere strongly or persistently to the cupula is lacking. Apogeotropic nystagmus in the horizontal canal form is often attributed to cupulolithiasis; however, periampullary canalithiasis explains self-limited nystagmus, and reversible canalith jam explains prolonged apogeotropic nystagmus. Treatment-resistant cases can be explained by entrapment of particles in the canals or ampullae, but persistent adherence to the cupula remains theoretical. Implications for Practice Apogeotropic nystagmus is usually due to freely moving particles and should not be used in studies of horizontal canal benign paroxysmal positional vertigo as the sole method to define entrapment or cupulolithiasis. Caloric testing and imaging may help differentiate jam from cupulolithiasis. Treatment for apogeotropic benign paroxysmal positional vertigo should include maneuvers that rotate the head through 270° to fully clear the canal of mobile particles, using mastoid vibration or head shaking if entrapment is suspected. Canal plugging can be used for treatment failures.
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Affiliation(s)
- Olivia Kalmanson
- Department of Otolaryngology University of Colorado Anschutz SOM Boulder Colorado USA
| | - Carol A. Foster
- Department of Otolaryngology University of Colorado Anschutz SOM Boulder Colorado USA
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Goyens J, Baeckens S, Smith ESJ, Pozzi J, Mason MJ. Parallel evolution of semicircular canal form and sensitivity in subterranean mammals. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2022; 208:627-640. [PMID: 36251041 DOI: 10.1007/s00359-022-01578-7] [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: 02/18/2022] [Revised: 09/19/2022] [Accepted: 09/21/2022] [Indexed: 12/14/2022]
Abstract
The vertebrate vestibular system is crucial for balance and navigation, and the evolution of its form and function in relation to species' lifestyle and mode of locomotion has been the focus of considerable recent study. Most research, however, has concentrated on aboveground mammals, with much less published on subterranean fauna. Here, we explored variation in anatomy and sensitivity of the semicircular canals among 91 mammal species, including both subterranean and non-subterranean representatives. Quantitative phylogenetically informed analyses showed significant widening of the canals relative to radius of curvature in subterranean species. A relative canal width above 0.166 indicates with 95% certainty that a species is subterranean. Fluid-structure interaction modelling predicted that canal widening leads to a substantial increase in canal sensitivity; a reasonably good estimation of the absolute sensitivity is possible based on the absolute internal canal width alone. In addition, phylogenetic comparative modelling and functional landscape exploration revealed repeated independent evolution of increased relative canal width and anterior canal sensitivity associated with the transition to a subterranean lifestyle, providing evidence of parallel adaptation. Our results suggest that living in dark, subterranean tunnels requires good balance and/or navigation skills which may be facilitated by more sensitive semicircular canals.
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Affiliation(s)
- Jana Goyens
- Laboratory of Functional Morphology, University of Antwerp, Antwerp, Belgium.
| | - Simon Baeckens
- Laboratory of Functional Morphology, University of Antwerp, Antwerp, Belgium.,Evolution and Optics of Nanostructures Lab, Department of Biology, Ghent University, Ghent, Belgium
| | | | - Jasmine Pozzi
- Laboratory of Functional Morphology, University of Antwerp, Antwerp, Belgium
| | - Matthew J Mason
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK
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Helminski JO. Case report: Atypical patterns of nystagmus suggest posterior canal cupulolithiasis and short-arm canalithiasis. Front Neurol 2022; 13:982191. [PMID: 36299265 PMCID: PMC9588913 DOI: 10.3389/fneur.2022.982191] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Accepted: 07/26/2022] [Indexed: 12/03/2022] Open
Abstract
Background Atypical posterior canal (PC) positional nystagmus may be due to the changes in cupular response dynamics from cupulolithiasis (cu), canalithiasis of the short arm (ca-sa), or a partial/complete obstruction—jam. Factors that change the dynamics are the position of the head in the pitch plane, individual variability in the location of the PC attachment to the utricle and the position of the cupula within the ampulla, and the location of debris within the short arm and on the cupula. The clinical presentation of PC-BPPV-cu is DBN with torsion towards the contralateral side in the DH positions and SHHP or no nystagmus in the ipsilateral DH position and no nystagmus upon return to sitting from each position. The clinical presentation of PC-BPPV-ca-sa is no nystagmus in the DH position and upbeat nystagmus (UBN) with torsion lateralized to the involved side upon return to sitting from each position. Case description A 68-year-old woman, diagnosed with BPPV, presented with DBN associated with vertigo in both DH positions and without nystagmus or symptoms on sitting up. In the straight head hanging position (SHHP), the findings of a transient burst of UBN with left torsion associated with vertigo suggested ipsicanal conversion from the left PC-BPPV-cu to canalithiasis. Treatment included a modified canalith repositioning procedure (CRP), which resulted in complete resolution. BPPV recurred 17 days later. Clinical presentation of BPPV included no nystagmus/symptoms in both the contralateral DH position and SHHP, DBN in the ipsilateral DH position without symptoms, and UBN with left torsion associated with severe truncal retropulsion and nausea on sitting up from provoking position. The findings suggested the left PC-BPPV-cu-sa and PC-BPPV-ca-sa. Treatment included neck extension, a modified CRP, and demi-Semont before complete resolution. Conclusion An understanding of the biomechanics of the vestibular system is necessary to differentially diagnose atypical PC-BPPV. DH test (DHT) findings suggest that PC-BPPV-cu presents with DBN or no nystagmus in one or two DH positions and sometimes SHHP and without nystagmus or no reversal/reversal of nystagmus on sitting up. The findings suggest PC-BPPV-ca-sa has no nystagmus in DH positions or DBN in the ipsilateral DH position and UBN with torsion lateralized to the involved side on sitting up.
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The human vestibulo-ocular reflex and compensatory saccades in schwannoma patients before and after vestibular nerve section. Clin Neurophysiol 2022; 138:197-213. [DOI: 10.1016/j.clinph.2022.02.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 01/25/2022] [Accepted: 02/13/2022] [Indexed: 11/19/2022]
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Liang J, Ke Z, Welch PV, Gan RZ, Dai C. A comprehensive finite element model for studying Cochlear-Vestibular interaction. Comput Methods Biomech Biomed Engin 2021; 25:204-214. [PMID: 34641759 DOI: 10.1080/10255842.2021.1946522] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
We present a 3-D finite element (FE) model of the chinchilla's inner ear consisting of the entire cochlea structure and the vestibular system. The reaction of the basilar membrane to the head rotation and the reaction of ampulla to the stapes movement were investigated. These results demonstrate the existence of hearing-vestibular system interaction. They provide an explanation to the clinical finding on the coexistence between hearing loss and equilibration dysfunction. It is a preliminary, yet critical step toward the development of a comprehensive FE model of an entire ear for mechano-acoustic analysis.
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Affiliation(s)
- Junfeng Liang
- Aerospace & Mechanical Engineering, University of Oklahoma, Norman, OK, USA
| | - Zhang Ke
- Aerospace & Mechanical Engineering, University of Oklahoma, Norman, OK, USA
| | - Paige V Welch
- Aerospace & Mechanical Engineering, University of Oklahoma, Norman, OK, USA
| | - Rong Z Gan
- Aerospace & Mechanical Engineering, University of Oklahoma, Norman, OK, USA
| | - Chenkai Dai
- Aerospace & Mechanical Engineering, University of Oklahoma, Norman, OK, USA
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Wu X, Yu S, Shen S, Liu W. Quantitative analysis of the biomechanical response of semicircular canals and nystagmus under different head positions. Hear Res 2021; 407:108282. [PMID: 34130038 DOI: 10.1016/j.heares.2021.108282] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 05/20/2021] [Accepted: 05/26/2021] [Indexed: 01/11/2023]
Abstract
The semicircular canals (SCCs) in the vestibular system can sense angular motion of the head, which performs a crucial role in maintaining the human's sense of balance. The different spatial orientations of the head affect the response of human SCCs to rotational movement. In this study, we combined the numerical model of bilateral human SCCs with vestibulo-ocular reflex experiments, and quantitatively investigated the responses of SCCs to constant angular acceleration when the head was in different left-leaning positions, including the head tilted 0°, 15°, 30°, 45°, 60°, 70°, 80°, and 90° to the left. The results showed that the vertical nystagmus slow-phase velocity (SPV) and the corresponding maximal cupula shear strain at the crista surface rose with an increase in the left-leaning angle of the head, reached a maximum at the position of the head tilted approximately 70° to the left, and then decreased gradually. Both the horizontal nystagmus SPV and the corresponding maximal cupula shear strain at the crista surface were the largest under the position of the head tilted 0° to the left, and decreased gradually as the left-leaning angle of the head increased. The numerical results of cupula shear strain at the crista surface in bilateral SCCs can quantitatively explain the combined effects of each SCC's excitation or inhibition on volunteers' nystagmus SPV under different head positions. In addition, a fluid-structure interaction investigation revealed that different left-leaning head positions changed the endolymphatic pressure gradient distribution in SCCs, which determined the transcupular pressure, cupula shear strain at the crista surface, and nystagmus SPV.
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Affiliation(s)
- Xiang Wu
- School of Information and Communication Engineering, Dalian University of Technology, Dalian 116024, China
| | - Shen Yu
- State Key Laboratory of Structural Analysis for Industrial Equipment, Dalian University of Technology, Dalian 116024, China
| | - Shuang Shen
- School of Rehabilitation Medicine, Binzhou Medical University, Yantai 264003, China
| | - Wenlong Liu
- School of Information and Communication Engineering, Dalian University of Technology, Dalian 116024, China.
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Straka H, Paulin MG, Hoffman LF. Translations of Steinhausen's Publications Provide Insight Into Their Contributions to Peripheral Vestibular Neuroscience. Front Neurol 2021; 12:676723. [PMID: 34149604 PMCID: PMC8212934 DOI: 10.3389/fneur.2021.676723] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Accepted: 04/08/2021] [Indexed: 12/25/2022] Open
Abstract
The quantitative relationship between angular head movement and semicircular canal function is most often referenced to the well-known torsion-pendulum model that predicts cupular displacement from input head acceleration. The foundation of this model can be traced back to Steinhausen's series of papers between 1927 and 1933 whereby he endeavored to document observations of cupular displacements that would directly infer movement of the endolymph resulting from angular rotation. He also was the first to establish the direct relationship between cupular displacement and compensatory eye movements. While the chronology of these findings, with their successes and pitfalls, are documented in Steinhausen's work, it reflects a fascinating journey that has been inaccessible to the non-German speaking community. Therefore, the present compilation of translations, with accompanying introduction and discussion, was undertaken to allow a larger component of the vestibular scientific community to gain insight into peripheral labyrinthine mechanics provided by this historical account.
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Affiliation(s)
- Hans Straka
- Department Biology II, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Michael G Paulin
- Department of Zoology, University of Otago, Dunedin, New Zealand
| | - Larry F Hoffman
- Department of Head & Neck Surgery and the Brain Research Institute, David Geffen School of Medicine at University of California at Los Angeles, Los Angeles, CA, United States
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12
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Yu S, Wang J, Shen S, Tang Y, Sun X, Liu Y. Study of the biomechanical mechanisms of benign paroxysmal positional vertigo. J Vestib Res 2021; 31:163-172. [PMID: 33459677 DOI: 10.3233/ves-201547] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract. From a biomechanical point of view, the process of Benign paroxysmal positional vertigo (BPPV) includes 2 fluid¯solid coupling effects: the interaction between particles and endolymph and the interaction between endolymph and cupula. The interaction between the canaliths and the wall would affect the coupling effects. This study aimed to investigate the entire process of cupula motion caused by canaliths motion and the influence of canalith particles composition. A biomechanical numerical model was established to simulate the canalith falling process and study the influence of canalith diameter, number, and initial falling position on cupula movement. Simultaneously, the relationship between cupula displacement and the nystagmus signal was analyzed in BPPV patients. The results revealed that the particle velocity was proportional to the particle diameter. The pressure difference between the two sides of the cupula was directly proportional to the canalith diameter and number. The degree of vertigo was positively related to the slow angular velocity of the nystagmus and, therefore, reflected canalith number and diameter. The BPPV latent period and vertigo duration were inversely related to particle diameter. Thus, the number of particles, particle radius, and initial falling position affected cupula movement, which was reflected in the nystagmus.
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Affiliation(s)
- Shen Yu
- State Key Laboratory of Structural Analysis for Industrial Equipment, Dalian University of Technology, Dalian, China
| | - Jizhe Wang
- Otorhinolaryngology Department, The Second Hospital of Dalian Medical University, Dalian, China
| | - Shuang Shen
- Hearing and Speech Rehabilitation Institute, College of Special Education, Binzhou Medical University, Yantai, China
| | - Yuanyuan Tang
- Otorhinolaryngology Department, The Second Hospital of Dalian Medical University, Dalian, China
| | - Xiuzhen Sun
- Otorhinolaryngology Department, The Second Hospital of Dalian Medical University, Dalian, China
| | - Yingxi Liu
- State Key Laboratory of Structural Analysis for Industrial Equipment, Dalian University of Technology, Dalian, China
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13
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Exploring the biomechanical responses of human cupula by numerical analysis of temperature experiments. Sci Rep 2021; 11:8208. [PMID: 33859270 PMCID: PMC8050243 DOI: 10.1038/s41598-021-87730-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2021] [Accepted: 03/30/2021] [Indexed: 11/09/2022] Open
Abstract
The vestibular receptor of cupula acts an important role in maintaining body balance. However, the cupula buried in the semicircular canals (SCCs) will be destroyed if it is detached from the relevant environment. The mechanical properties of human cupula still remain ambiguous. In this paper, we explored the cupula responses changing with temperature by experiments and numerical simulation of SCCs model. We obtained 3 volunteers’ nystagmus induced by constant angular acceleration when the temperature of volunteers’ SCCs was 36 °C and 37 °C respectively. The slow-phase velocity of 3 volunteers decreased by approximately 3°/s when the temperature of SCCs reduced by 1 °C, which corresponded to the reduction of cupula deformation by 0.3–0.8 μm in the numerical model. Furthermore, we investigated the effects of the variation of endolymphatic properties induced by temperature reduction on cupula deformation through numerical simulation. We found that the decrease of cupula deformation was not caused by the change of endolymphatic properties, but probably by the increase of cupula’s elastic modulus. With the temperature reducing by 1 °C, the cupula’s elastic modulus may increase by 6–20%, suggesting that the stiffness of cupula is enhanced. This exploration of temperature characteristic of human cupula promotes the research of alleviating vestibular diseases.
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Honjo M, Honda K, Tsutsumi T. Unusual Vestibulo-Ocular Reflex Responses in Patients With Peripheral Vestibular Disorders Detected by the Caloric Step Stimulus Test. Front Neurol 2020; 11:597562. [PMID: 33329351 PMCID: PMC7734291 DOI: 10.3389/fneur.2020.597562] [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: 08/21/2020] [Accepted: 11/09/2020] [Indexed: 11/13/2022] Open
Abstract
The caloric step stimulus test consists of the changes in head position from the sitting to supine positions and continuous caloric irrigation. This test can provide a single labyrinth with a stimulus similar to constant head acceleration in rotational testing and, therefore, can evaluate vestibulo-ocular reflex (VOR) dynamics more precisely than can conventional methods. To assess the clinical utility of the test in the assessment of the VOR dynamics of diseases, we performed the test in patients with peripheral vestibular disorders, including sudden idiopathic hearing loss, vestibular neuritis, Meniere disease, vestibular Meniere disease, or chronic unilateral idiopathic vestibulopathy and normal controls. Slow-phase eye velocity (SPV) was measured with videonystagmography. We fitted the time course of SPV across 2 min to a mathematical model containing two exponential components and time constants: the caloric step VOR time constant (T1) and caloric step VOR adaptation time constant (T2). All responses of normal controls (n = 15 ears) were fit to the model. Several responses of the 101 ears of the patients differed from the time courses predicted by the model. We divided the data of 116 ears into four patterns based on SPV, T1, and T2. The thresholds for the classification were determined according to the lower limits of the capability of curve fitting for SPV and the upper limits of normal controls for T1 and T2. Seventy-eight ears followed pattern A (normal T1 and T2): the SPV trajectory formed a rapid rise with subsequent decay. Nineteen followed pattern B (normal T1 and prolonged T2): the SPV trajectory formed a rapid rise without decay. Six followed pattern C (prolonged T1 and T2): the SPV trajectory formed a slow rise. Thirteen ears followed pattern D: a low VOR response. There were no significant differences in time constants between the affected and healthy ears in patients with each disease. However, prolonged T1 and T2 were significantly more frequent in the affected ears than the healthy ears. In conclusion, the caloric step stimulus test can be potentially useful in detecting unusual VOR responses and thus reflect some pathological changes in the vestibular system.
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Affiliation(s)
- Motomu Honjo
- Department of Otolaryngology, Tsuchiura Kyodo General Hospital, Ibaraki, Japan.,Department of Otolaryngology, Tokyo Medical and Dental University, Tokyo, Japan
| | - Keiji Honda
- Department of Otolaryngology, Tsuchiura Kyodo General Hospital, Ibaraki, Japan.,Department of Otolaryngology, Tokyo Medical and Dental University, Tokyo, Japan
| | - Takeshi Tsutsumi
- Department of Otolaryngology, Tokyo Medical and Dental University, Tokyo, Japan
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Smith CM, Laitman JT. Alterations to vestibular morphology in highly bred domestic dogs may affect balance. Anat Rec (Hoboken) 2020; 304:116-126. [PMID: 32478937 DOI: 10.1002/ar.24423] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 03/11/2020] [Accepted: 03/24/2020] [Indexed: 12/23/2022]
Abstract
The modern domestic dog (Canis lupus familiaris) provides an excellent model to examine the effects of cranial modification. Extreme variation in skull length among dog breeds due to high levels of selective breeding is known to be linked to disorders of the head and neck. Such alteration may also influence sensory organs including those of the vestibular system (VS), one of the most fundamental sense organs, essential in maintaining balance. Studies in mammals have shown that orientation of ipsilateral semicircular canals (SCCs) of the VS at right angles (orthogonality) is related to angular acceleration sensitivity. Due to their considerable variation in craniofacial form while exhibiting similar locomotion, domestic dogs provide an excellent natural experiment to examine if cranial alteration influences VS functional morphology. Our methods examine how change in cranial base length across dog breeds relates to SCC orthogonality using linear modeling and analyses of variance. The sample studied (29 bony labyrinths of 17 dog breeds) was obtained from a previous study on canid inner ear metrics. Results support the hypothesis that orthogonality between the anterior and posterior SCC + ampulla significantly correlates with cranial base length. This suggests a close relationship between the orientations of SCCs with their ampullae and cranial structure among dog breeds. Specifically, highly derived breeds, such as the brachycephalic pug, have anterior and posterior SCCs and ampullae that deviate the most from orthogonality. Therefore, such highly bred domestic dogs may also have altered vestibular function due to compressed cranial form.
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Affiliation(s)
- Christopher M Smith
- The Graduate Center, City University of New York, New York, New York, USA.,Center for Anatomy and Functional Morphology, Icahn School of Medicine at Mount Sinai, New York, New York, USA.,New York Consortium in Evolutionary Primatology, New York, New York, USA
| | - Jeffrey T Laitman
- The Graduate Center, City University of New York, New York, New York, USA.,Center for Anatomy and Functional Morphology, Icahn School of Medicine at Mount Sinai, New York, New York, USA.,New York Consortium in Evolutionary Primatology, New York, New York, USA.,Department of Otolaryngology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
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Wu X, Yu S, Liu W, Shen S. Numerical modeling and verification by nystagmus slow-phase velocity of the function of semicircular canals. Biomech Model Mechanobiol 2020; 19:2343-2356. [DOI: 10.1007/s10237-020-01343-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2019] [Accepted: 05/12/2020] [Indexed: 01/09/2023]
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Goyens J, Aerts P. Why the semicircular canals are not stimulated by linear accelerations. BIOINSPIRATION & BIOMIMETICS 2019; 14:056004. [PMID: 31239423 DOI: 10.1088/1748-3190/ab2cbf] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Head accelerations are sensed by the vestibular system in the inner ear. Linear accelerations stimulate the otolith organs, while the semicircular canals (SCC) sense angular accelerations. Fluid-structure interaction (FSI) models of the cupula sensor (simulated with finite element method (FEM)) and the endolymph fluid (simulated with computational fluid dynamics (CFD)) in the semicircular canal offer the possibility to investigate why the SCC are not stimulated by linear accelerations. Two hypotheses exist in the literature. The first hypothesis focusses on the density of the cupula sensor in the SCC, while the second is based on the continuous loop of fluid in the semicircular canal. However, neither increasing the cupula density, nor disrupting the continuous fluid circulation substantially increase the cupula deformation under linear head acceleration, thereby rejecting both existing hypotheses. We propose an alternative hypothesis, based on the circular geometry of the semicircular canal. During angular head acceleration, the cupula intersects the body of endolymph and 'pushes' it forward because the cupula seals the semicircular canal like a diaphragm. This results in cupula deflection and neural stimulation. During linear head acceleration, on the other hand, a large part of the canal wall also 'pushes' the endolymph forward, which leads to hardly any cupula deflection.
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Affiliation(s)
- J Goyens
- Laboratory of Functional Morphology, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Belgium. Author to whom any correspondence should be addressed
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Asymmetric cupula displacement due to endolymph vortex in the human semicircular canal. Biomech Model Mechanobiol 2019; 18:1577-1590. [DOI: 10.1007/s10237-019-01160-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Accepted: 04/26/2019] [Indexed: 10/26/2022]
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Rabbitt RD. Semicircular canal biomechanics in health and disease. J Neurophysiol 2019; 121:732-755. [PMID: 30565972 PMCID: PMC6520623 DOI: 10.1152/jn.00708.2018] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Revised: 12/11/2018] [Accepted: 12/11/2018] [Indexed: 12/12/2022] Open
Abstract
The semicircular canals are responsible for sensing angular head motion in three-dimensional space and for providing neural inputs to the central nervous system (CNS) essential for agile mobility, stable vision, and autonomic control of the cardiovascular and other gravity-sensitive systems. Sensation relies on fluid mechanics within the labyrinth to selectively convert angular head acceleration into sensory hair bundle displacements in each of three inner ear sensory organs. Canal afferent neurons encode the direction and time course of head movements over a broad range of movement frequencies and amplitudes. Disorders altering canal mechanics result in pathological inputs to the CNS, often leading to debilitating symptoms. Vestibular disorders and conditions with mechanical substrates include benign paroxysmal positional nystagmus, direction-changing positional nystagmus, alcohol positional nystagmus, caloric nystagmus, Tullio phenomena, and others. Here, the mechanics of angular motion transduction and how it contributes to neural encoding by the semicircular canals is reviewed in both health and disease.
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Affiliation(s)
- R. D. Rabbitt
- Department of Biomedical Engineering, University of Utah, Salt Lake City, Utah
- Otolaryngology-Head Neck Surgery, University of Utah, Salt Lake City, Utah
- Neuroscience Program, University of Utah, Salt Lake City, Utah
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Iversen MM, Rabbitt RD. Wave Mechanics of the Vestibular Semicircular Canals. Biophys J 2017; 113:1133-1149. [PMID: 28877495 DOI: 10.1016/j.bpj.2017.08.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2017] [Revised: 07/14/2017] [Accepted: 08/02/2017] [Indexed: 01/08/2023] Open
Abstract
The semicircular canals are biomechanical sensors responsible for detecting and encoding angular motion of the head in 3D space. Canal afferent neurons provide essential inputs to neural circuits responsible for representation of self-position/orientation in space, and to compensatory circuits including the vestibulo-ocular and vestibulo-collic reflex arcs. In this work we derive, to our knowledge, a new 1D mathematical model quantifying canal biomechanics based on the morphology, dynamics of the inner ear fluids, and membranous labyrinth deformability. The model takes the form of a dispersive wave equation and predicts canal responses to angular motion, sound, and mechanical stimulation. Numerical simulations were carried out for the morphology of the human lateral canal using known physical properties of the endolymph and perilymph in three diverse conditions: surgical plugging, rotation, and mechanical indentation. The model reproduces frequency-dependent attenuation and phase shift in cases of canal plugging. During rotation, duct deformability extends the frequency bandwidth and enhances the high frequency gain. Mechanical indentation of the membranous duct at high frequencies evokes traveling waves that move away from the location of indentation and at low frequencies compels endolymph displacement along the canal. These results demonstrate the importance of the conformal perilymph-filled bony labyrinth to pressure changes and to high frequency sound and vibration.
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Affiliation(s)
- Marta M Iversen
- Department of Bioengineering, University of Utah, Salt Lake City, Utah.
| | - Richard D Rabbitt
- Department of Bioengineering, University of Utah, Salt Lake City, Utah; Department of Otolaryngology, University of Utah, Salt Lake City, Utah; Marine Biological Laboratory, Woods Hole, Massachusetts
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BODIPY-Conjugated Xyloside Primes Fluorescent Glycosaminoglycans in the Inner Ear of Opsanus tau. J Assoc Res Otolaryngol 2016; 17:525-540. [PMID: 27619213 DOI: 10.1007/s10162-016-0585-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2016] [Accepted: 08/23/2016] [Indexed: 12/22/2022] Open
Abstract
We report on a new xyloside conjugated to BODIPY, BX and its utility to prime fluorescent glycosaminoglycans (BX-GAGs) within the inner ear in vivo. When BX is administered directly into the endolymphatic space of the oyster toadfish (Opsanus tau) inner ear, fluorescent BX-GAGs are primed and become visible in the sensory epithelia of the semicircular canals, utricle, and saccule. Confocal and 2-photon microscopy of vestibular organs fixed 4 h following BX treatment, reveal BX-GAGs constituting glycocalyces that envelop hair cell kinocilium, nerve fibers, and capillaries. In the presence of GAG-specific enzymes, the BX-GAG signals are diminished, suggesting that chondroitin sulfates are the primary GAGs primed by BX. Results are consistent with similar click-xylosides in CHO cell lines, where the xyloside enters the Golgi and preferentially initiates chondroitin sulfate B production. Introduction of BX produces a temporary block of hair cell mechanoelectrical transduction (MET) currents in the crista, reduction in background discharge rate of afferent neurons, and a reduction in sensitivity to physiological stimulation. A six-degree-of-freedom pharmacokinetic mathematical model has been applied to interpret the time course and spatial distribution of BX and BX-GAGs. Results demonstrate a new optical approach to study GAG biology in the inner ear, for tracking synthesis and localization in real time.
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Shen S, Sun X, Yu S, Liu Y, Su Y, Zhao W, Liu W. Numerical simulation of the role of the utriculo-endolymphatic valve in the rotation-sensing capabilities of semicircular canals. J Biomech 2016; 49:1532-1539. [DOI: 10.1016/j.jbiomech.2016.03.028] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2015] [Revised: 03/01/2016] [Accepted: 03/17/2016] [Indexed: 10/22/2022]
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Jareonsettasin P, Otero-Millan J, Ward BK, Roberts DC, Schubert MC, Zee DS. Multiple Time Courses of Vestibular Set-Point Adaptation Revealed by Sustained Magnetic Field Stimulation of the Labyrinth. Curr Biol 2016; 26:1359-66. [PMID: 27185559 DOI: 10.1016/j.cub.2016.03.066] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Revised: 03/24/2016] [Accepted: 03/30/2016] [Indexed: 11/28/2022]
Abstract
A major focus in neurobiology is how the brain adapts its motor behavior to changes in its internal and external environments [1, 2]. Much is known about adaptively optimizing the amplitude and direction of eye and limb movements, for example, but little is known about another essential form of learning, "set-point" adaptation. Set-point adaptation balances tonic activity so that reciprocally acting, agonist and antagonist muscles have a stable platform from which to launch accurate movements. Here, we use the vestibulo-ocular reflex-a simple behavior that stabilizes the position of the eye while the head is moving-to investigate how tonic activity is adapted toward a new set point to prevent eye drift when the head is still [3, 4]. Set-point adaptation was elicited with magneto-hydrodynamic vestibular stimulation (MVS) by placing normal humans in a 7T MRI for 90 min. MVS is ideal for prolonged labyrinthine activation because it mimics constant head acceleration and induces a sustained nystagmus similar to natural vestibular lesions [5, 6]. The MVS-induced nystagmus diminished slowly but incompletely over multiple timescales. We propose a new adaptation hypothesis, using a cascade of imperfect mathematical integrators, that reproduces the response to MVS (and more natural chair rotations), including the gradual decrease in nystagmus as the set point changes over progressively longer time courses. MVS set-point adaptation is a biological model with applications to basic neurophysiological research into all types of movements [7], functional brain imaging [8], and treatment of vestibular and higher-level attentional disorders by introducing new biases to counteract pathological ones [9].
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Affiliation(s)
- Prem Jareonsettasin
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB2 1TA, UK
| | - Jorge Otero-Millan
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Bryan K Ward
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Dale C Roberts
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA; Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Michael C Schubert
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA; Department of Physical Medicine and Rehabilitation, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - David S Zee
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA; Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA; Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA; Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA.
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Abstract
The inner ear of mammals consists of the cochlea, which is involved with the sense of hearing, and the vestibule and three semicircular canals, which are involved with the sense of balance. Although different regions of the inner ear contribute to different functions, the bony chambers and membranous ducts are morphologically continuous. The gross anatomy of the cochlea that has been related to auditory physiologies includes overall size of the structure, including volume and total spiral length, development of internal cochlear structures, including the primary and secondary bony laminae, morphology of the spiral nerve ganglion, and the nature of cochlear coiling, including total number of turns completed by the cochlear canal and the relative diameters of the basal and apical turns. The overall sizes, shapes, and orientations of the semicircular canals are related to sensitivity to head rotations and possibly locomotor behaviors. Intraspecific variation, primarily in the shape and orientation of the semicircular canals, may provide additional clues to help us better understand form and function of the inner ear.
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Affiliation(s)
- Eric G. Ekdale
- Department of BiologySan Diego State UniversitySan DiegoCAUSA
- Department of PaleontologySan Diego Natural History MuseumSan DiegoCAUSA
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25
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Tomanovic T, Büki B. The diagnostic framework of peripheral positional vertigo and dizziness (PPVD): a new concept based on the observation of alcohol-induced posterior canal light cupula. ACTA OTO-LARYNGOLOGICA CASE REPORTS 2016. [DOI: 10.1080/23772484.2016.1209640] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
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Vortical flow in the utricle and the ampulla: a computational study on the fluid dynamics of the vestibular system. Biomech Model Mechanobiol 2012; 12:335-48. [DOI: 10.1007/s10237-012-0402-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2011] [Accepted: 04/28/2012] [Indexed: 10/28/2022]
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Suarez H, Alonso R, Arocena M, Suarez A, Geisinger D. Clinical characteristics of positional vertigo after mild head trauma. Acta Otolaryngol 2011; 131:377-81. [PMID: 21189053 DOI: 10.3109/00016489.2010.534113] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
CONCLUSION This study showed that a population with benign paroxysmal positional vertigo related to mild head trauma (BPPVAT) was younger and more frequently presented with bilateral canalithiasis than another population with idiopathic etiology (IBPPV). In both groups, females presented a higher risk of BPPV. OBJECTIVE To compare the clinical features of a population with BPPVAT and another with IBBPV. METHODS We carried out statistical analysis of a population of 51 subjects with BPPVAT and another of 325 subjects with IBPPV, comparing age, gender, recurrence of symptoms, associated chronic dizziness (CD), and clinical presentation. Kolmogorov Smirnov test, Student's t test, Mann-Whitney test, 95% binomial confidence interval for proportions, chi-squared, and Fisher's test were used as statistical tools. A significance level of p < 0.05 was considered in all cases. RESULTS The population affected with BPPVAT was younger and bilateral canalithiasis was also more frequent. No differences were found in gender distribution, semicircular canals involved in the symptoms, recurrence after repositioning maneuvers, or associated CD.
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Affiliation(s)
- Hamlet Suarez
- Laboratory of Otoneurology, British Hospital, Montevideo, Uruguay
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Virtual labyrinth model of vestibular afferent excitation via implanted electrodes: validation and application to design of a multichannel vestibular prosthesis. Exp Brain Res 2011; 210:623-40. [PMID: 21380738 DOI: 10.1007/s00221-011-2599-x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2010] [Accepted: 02/07/2011] [Indexed: 10/18/2022]
Abstract
To facilitate design of a multichannel vestibular prosthesis that can restore sensation to individuals with bilateral loss of vestibular hair cell function, we created a virtual labyrinth model. Model geometry was generated through 3-dimensional (3D) reconstruction of microMRI and microCT scans of normal chinchillas (Chinchilla lanigera) acquired with 30-48 μm and 12 μm voxels, respectively. Virtual electrodes were positioned based on anatomic landmarks, and the extracellular potential field during a current pulse was computed using finite element methods. Potential fields then served as inputs to stochastic, nonlinear dynamic models for each of 2,415 vestibular afferent axons with spiking dynamics based on a modified Smith and Goldberg model incorporating parameters that varied with fiber location in the neuroepithelium. Action potential propagation was implemented by a well validated model of myelinated fibers. We tested the model by comparing predicted and actual 3D angular vestibulo-ocular reflex (aVOR) axes of eye rotation elicited by prosthetic stimuli. Actual responses were measured using 3D video-oculography. The model was individualized for each animal by placing virtual electrodes based on microCT localization of real electrodes. 3D eye rotation axes were predicted from the relative proportion of model axons excited within each of the three ampullary nerves. Multiple features observed empirically were observed as emergent properties of the model, including effects of active and return electrode position, stimulus amplitude and pulse waveform shape on target fiber recruitment and stimulation selectivity. The modeling procedure is partially automated and can be readily adapted to other species, including humans.
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Yakushin SB, Dai M, Raphan T, Suzuki JI, Arai Y, Cohen B. Spatial orientation of the angular vestibulo-ocular reflex (aVOR) after semicircular canal plugging and canal nerve section. Exp Brain Res 2011; 210:583-94. [PMID: 21340443 DOI: 10.1007/s00221-011-2586-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2010] [Accepted: 01/28/2011] [Indexed: 10/18/2022]
Abstract
We investigated spatial responses of the aVOR to small and large accelerations in six canal-plugged and lateral canal nerve-sectioned monkeys. The aim was to determine whether there was spatial adaptation after partial and complete loss of all inputs in a canal plane. Impulses of torques generated head thrusts of ≈ 3,000°/s². Smaller accelerations of ≈ 300°/s² initiated the steps of velocity (60°/s). Animals were rotated about a spatial vertical axis while upright (0°) or statically tilted fore-aft up to ± 90°. Temporal aVOR yaw and roll gains were computed at every head orientation and were fit with a sinusoid to obtain the spatial gains and phases. Spatial gains peaked at ≈ 0° for yaw and ≈ 90° for roll in normal animals. After bilateral lateral canal nerve section, the spatial yaw and roll gains peaked when animals were tilted back ≈ 50°, to bring the intact vertical canals in the plane of rotation. Yaw and roll gains were identical in the lateral canal nerve-sectioned monkeys tested with both low- and high-acceleration stimuli. The responses were close to normal for high-acceleration thrusts in canal-plugged animals, but were significantly reduced when these animals were given step stimuli. Thus, high accelerations adequately activated the plugged canals, whereas yaw and roll spatial aVOR gains were produced only by the intact vertical canals after total loss of lateral canal input. We conclude that there is no spatial adaptation of the aVOR even after complete loss of specific semicircular canal input.
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Affiliation(s)
- Sergei B Yakushin
- Department of Neurology, Mount Sinai School of Medicine, New York, NY 10029, USA.
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Rajguru SM, Richter CP, Matic AI, Holstein GR, Highstein SM, Dittami GM, Rabbitt RD. Infrared photostimulation of the crista ampullaris. J Physiol 2011; 589:1283-94. [PMID: 21242259 DOI: 10.1113/jphysiol.2010.198333] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
The present results show that the semicircular canal crista ampullaris of the toadfish, Opsanus tau, is sensitive to infrared radiation (IR) applied in vivo. IR pulse trains (∼1862 nm, ∼200 μs pulse⁻¹) delivered to the sensory epithelium by an optical fibre evoked profound changes in phasic and tonic discharge rates of postsynaptic afferent neurons. Phasic afferent responses to pulsed IR occurred with a latency of <8 ms while tonic responses developed with a time constant (τ) of 7 ms to 10 s following the onset or cessation of the radiation. Afferents responded to direct optical radiation of the sensory epithelium but did not respond to thermal stimuli that generated nearly equivalent temperature increases of the whole organ. A subset of afferent neurons fired an action potential in response to each IR pulse delivered to the sensory epithelium, at phase-locked rates up to 96 pulses per second. The latency between IR pulses and afferent nerve action potentials was much greater than synaptic delay and spike generation, demonstrating the presence of a signalling delay interposed between the IR pulse and the action potential. The same IR stimulus applied to afferent nerve axons failed to evoke responses of similar magnitude and failed to phase-lock afferent nerve action potentials. The present data support the hypothesis that pulsed IR activates sensory hair cells, thus leading to modulation of synaptic transmission and afferent nerve discharge reported here.
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Affiliation(s)
- Suhrud M Rajguru
- Department of Otolaryngology, Northwestern University, Chicago, IL 60611, USA.
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Büki B, Simon L, Garab S, Lundberg YW, Jünger H, Straumann D. Sitting-up vertigo and trunk retropulsion in patients with benign positional vertigo but without positional nystagmus. J Neurol Neurosurg Psychiatry 2011; 82:98-104. [PMID: 20660923 PMCID: PMC4196320 DOI: 10.1136/jnnp.2009.199208] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
BACKGROUND Presently, the unambiguous diagnosis of benign paroxysmal positioning vertigo (BPPV) requires the detection of positioning or positional nystagmus provoked by Dix-Hallpike (for vertical semicircular canals) or supine roll (for horizontal semicircular canals) manoeuvres, which indicates canalo- or cupolithiasis of affected semicircular canals. There are patients, however, in whom--despite typical complaints of BPPV--no positional nystagmus can be documented; this is called 'subjective BPPV' (sBPPV). These patients usually complain of short vertigo spells during and after sitting up, sometimes with abnormal retropulsion of the trunk. AIM In this study, the authors aimed to ascertain whether these patients in fact demonstrate abnormal sitting-up trunk oscillations when measured by posturography. Of 200 unselected patients with vertigo or dizziness, 43% had sBPPV with vertigo spells while sitting up, and 20% classical BPPV. METHODS Posturographic recordings were performed in 20 patients with sBPPV and sitting-up vertigo. RESULTS AND DISCUSSION Seven of the 20 patients had trunk oscillations during the act of sitting up and for a short time immediately afterwards. Based on their findings, the authors propose a new type of BPPV, the so-called Type 2 BPPV (typical complaints of BPPV, no nystagmus in Dix-Hallpike positions but short vertigo spell while sitting up), which may be the result of chronic canalolithiasis within the short arm of a posterior canal. Furthermore, the authors suggest that Type 2 BPPV, which could be identical to sBPPV or constitute a major subgroup of it, occurs frequently among patients with vertigo. For therapy, the authors recommend repetitive sit-ups from the Dix-Hallpike positions to liberate the short arm of the posterior canal from canaloliths.
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Affiliation(s)
- Béla Büki
- Otorhinolaryngology Department, General Hospital of Krems, Austria.
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Obrist D, Hegemann S, Kronenberg D, Häuselmann O, Rösgen T. In vitro model of a semicircular canal: Design and validation of the model and its use for the study of canalithiasis. J Biomech 2010; 43:1208-14. [DOI: 10.1016/j.jbiomech.2009.11.027] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2009] [Revised: 11/05/2009] [Accepted: 11/20/2009] [Indexed: 11/27/2022]
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Abstract
Sensory hair cells are the essential mechanotransducers of the inner ear, responsible not only for the transduction of sound and motion stimuli but also, remarkably, for nanomechanical amplification of sensory stimuli. Here we show that semicircular canal hair cells generate a mechanical nonlinearity in vivo that increases sensitivity to angular motion by amplification at low stimulus strengths. Sensitivity at high stimulus strengths is linear and shows no evidence of amplification. Results suggest that the mechanical work done by hair cells contributes approximately 97 zJ/cell of amplification per stimulus cycle, improving sensitivity to angular velocity stimuli below approximately 5 degrees /s (0.3-Hz sinusoidal motion). We further show that mechanical amplification can be inhibited by the brain via activation of efferent synaptic contacts on hair cells. The experimental model was the oyster toadfish, Opsanus tau. Physiological manifestation of mechanical amplification and efferent control in a teleost vestibular organ suggests the active motor process in sensory hair cells is ancestral. The biophysical basis of the motor(s) remains hypothetical, but a key discriminating question may involve how changes in somatic electrical impedance evoked by efferent synaptic action alter function of the motor(s).
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Boyle R, Rabbitt RD, Highstein SM. Efferent control of hair cell and afferent responses in the semicircular canals. J Neurophysiol 2009; 102:1513-25. [PMID: 19571186 DOI: 10.1152/jn.91367.2008] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The sensations of sound and motion generated by the inner ear are controlled by the brain through extensive centripetal innervation originating within the brain stem. In the semicircular canals, brain stem efferent neurons make synaptic contacts with mechanosensory hair cells and with the dendrites of afferent neurons. Here, we examine the relative contributions of efferent action on hair cells and afferents. Experiments were performed in vivo in the oyster toadfish, Opsanus tau. The efferent system was activated via electrical pulses to the brain stem and sensory responses to motion stimuli were quantified by simultaneous voltage recording from afferents and intracellular current- and/or voltage-clamp recordings from hair cells. Results showed synaptic inputs to both afferents and hair cells leading to relatively long-latency intracellular signaling responses: excitatory in afferents and inhibitory in hair cells. Generally, the net effect of efferent action was an increase in afferent background discharge and a simultaneous decrease in gain to angular motion stimuli. Inhibition of hair cells was likely the result of a ligand-gated opening of a major basolateral conductance. The reversal potential of the efferent-evoked current was just below the hair cell resting potential, thus resulting in a small hyperpolarization. The onset latency averaged about 90 ms and latency to peak response was 150-400 ms. Hair cell inhibition often outlasted afferent excitation and, in some cases, latched hair cells in the "off" condition for >1 s following cessation of stimulus. These features endow the animal with a powerful means to adjust the sensitivity and dynamic range of motion sensation.
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Affiliation(s)
- Richard Boyle
- NASA Ames Research Center, BioVIS Center, M/S 239-11, Moffett Field, CA 94035, USA.
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Yamauchi A, Rabbitt RD, Boyle R, Highstein SM. Relationship between inner-ear fluid pressure and semicircular canal afferent nerve discharge. J Assoc Res Otolaryngol 2002; 3:26-44. [PMID: 12083722 PMCID: PMC3202362 DOI: 10.1007/s101620010088] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
Abstract
The present study was designed to determine (1) the transcupular fluid pressure (deltaP) generated across the semicircular canal cupula in response to sinusoidal head rotation, (2) the translabyrinthine dilational pressure (P0) generated across the membranous labyrinth in response to an increase in endolymph fluid volume (hydrops), (3) afferent nerve discharge patterns generated by these distinct pressure stimuli and, (4) threshold values of deltaP and P0 required to elicit afferent neural responses. The experimental model was the oyster toadfish, Opsanus tau. Micromechanical indentation of the horizontal canal (HC) duct and utricular vestibule was used to simulate sinusoidal head rotation and fluid volume injection. Single-unit neural spike trains and endolymph pressure within the ampulla, on both sides of the cupula, were recorded simultaneously. deltaP averaged 0.013 Pa per 1 degrees/s of sinusoidal angular head velocity and P0 averaged 0.2 Pa per 1 nL of endolymph volume injection. The most responsive afferents had a threshold sensitivity to deltaP of 10(-3) Pa and to P0 of 5 x 10(-2) Pa based on a discharge modulation criterion of 1 impulse/s per cycle for 2 Hz pressure stimuli. Neural sensitivity to AP was expected on the basis of transverse cupular and hair bundle deflections. Analysis of mechanics of the end organ, neuronal projections into the crista, and individual neural firing patterns indicates that P0 sensitivity resulted from pressure-induced distension of the ampulla that led to a nonuniform cupular deformation pattern and hair bundle deflections. This explanation is consistent with predictions of a finite element model of the end organ. Results have implications regarding the role of deltaP in angular motion transduction and the role of P0 under transient hydropic conditions.
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Affiliation(s)
- A. Yamauchi
- Department of Bioengineering, University of Utah, Salt Lake City, UT 84112, USA
| | - R. D. Rabbitt
- Department of Bioengineering, University of Utah, Salt Lake City, UT 84112, USA
- Marine Biological Laboratory, Woods Hole, MA, USA
| | - R. Boyle
- NASA Ames Center for Bioinformatics, Moffett Field, CA 94035, USA
- Marine Biological Laboratory, Woods Hole, MA, USA
| | - S. M. Highstein
- Department of Otolaryngology and Neurobiology, Washington University, St. Louis, MO, 62103, USA
- Marine Biological Laboratory, Woods Hole, MA, USA
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