Special Somatic Sensory Afferent Systems Overview

2021 ◽  
pp. 34-40
Author(s):  
Scott D. Eggers ◽  
Eduardo E. Benarroch
Keyword(s):  
Tympanic Membrane ◽  
Middle Ear ◽  
Cranial Nerve ◽  
Visual Information ◽  
Ossicular Chain ◽  
Structural Components ◽  
Impedance Mismatch ◽  
Visual Systems ◽  
Afferent Information ◽  
Cranial Nerve Viii

The special somatic sensory afferent systems include the auditory, vestibular, and visual systems. Auditory and vestibular afferent information is received by cranial nerve VIII, which projects to central pathways. Cranial nerve II carries afferent visual information to central pathways. This chapter reviews the receptors and structural components of these special somatic sensory afferent systems. The ossicular chain (malleus, incus, and stapes) within the air-filled middle ear serves as a transformer that bridges the impedance mismatch between sound vibrations in air on the large tympanic membrane and the resulting vibrations onto the small stapedial footplate.

Ossicular Chain Reconstruction in a Developing Country

2018 ◽  
Vol 127 (5) ◽  
pp. 306-311 ◽  
Author(s):  
Es-Hak Bedri ◽  
Miriam Redleaf
Keyword(s):  
Tympanic Membrane ◽  
Developing Country ◽  
Middle Ear ◽  
Granulation Tissue ◽  
Ossicular Chain ◽  
Single Stage ◽  
Limited Resources ◽  
Closure Rate ◽  
Average Improvement ◽  
Ossicular Chain Reconstruction

Objectives: In Ethiopia, 2-stage operations with middle ear prostheses are economically unfavorable. We hypothesized that single-stage autologous ossiculoplasty results in acceptable tympanic membrane (TM) and hearing improvements in a setting of limited resources. Methods: One hundred eighty-eight patients (197 ears) who underwent 1-stage autologous ossiculoplasty for ossicular dysfunction are presented. All but 14 of these ears also had perforations of the TM. Conditions of the middle ear were granulation tissue, ossicular disruption only, tympanosclerosis, and cholesteatoma. Reconstructions of the ossicular chain were performed with autologous ossicles only. Results: The closure rate of TM perforations was 95%. Preoperative air bone gaps were 27 to 60 dB (mean [SD] = 44 [7] dB); postoperative air bone gaps were 0 to 50 dB (average [SD] = 23 [10] dB), for an average improvement of 21 dB across all reconstruction types ( P < .001). The largest favorable changes in air bone gaps were with incus and malleus columellas from the footplate to the TM (33 and 23 dB, respectively) ( P < .001). No patient had worsening of sensorineural hearing levels or extrusion of the reconstructed ossicles. Conclusion: Autologous ossiculoplasty performed well in this setting. Acceptable TM closure rates and improvement of air bone gaps were seen in 1-stage operations without the use of prostheses.

scholarly journals Study on the Prosthesis Structural Design and Vibration Characteristics Based on the Conduction Effect of Human Middle Ear

2020 ◽  
Vol 2020 ◽  
pp. 1-7
Author(s):  
Wu Ren ◽  
Huijuan Yan ◽  
Yi Yu ◽  
Jinghong Ren ◽  
Jinlong Chang ◽  
...  
Keyword(s):  
Frequency Response ◽  
Inner Ear ◽  
Tympanic Membrane ◽  
Middle Ear ◽  
Transmission Function ◽  
Ossicular Chain ◽  
Sound Signal ◽  
Sound Perception ◽  
Response Characteristics ◽  
Middle Ear Prosthesis

As a bridge from the sound signal in the air to the sound perception of the inner ear auditory receptor, the tympanic membrane and ossicular chain of the middle ear transform the sound signal in the outer ear through two gas-solid and solid-liquid conversions. In addition, through the lever principle formed by three auditory ossicle structure, the sound was concentrated and amplified to the inner ear. However, the sound transmission function of the middle ear will be decreased by disease, genetic, or trauma. Hence, using middle ear prosthesis to replace the damaged ossicles can restore the conduction function. The function realization of middle ear prosthesis depends on the vibration response of the prosthesis from the tympanic membrane to the stapes plate on the human auditory perception frequency, which is affected by the way the prosthesis combined with the tympanic membrane, the material, and the geometric shape. In this study, reasonable prosthetic structures had been designed for different types of ossicular chain injuries, and the frequency response characteristics were analyzed by the finite element method then. Moreover, in order to achieve better vibration frequency response, a ball structure was designed in the prosthesis to simulate its amplification function. The results showed that the middle ear prostheses constructed by different injury types can effectively transfer vibration energy. In particular, the first- and second-order resonant frequencies and response amplitudes are close to each other when ball structure models of different materials are added. Instead, the resonance frequency of the third stage formed by aluminum alloy ball materials is larger than that of the other two, which showed good response features.

scholarly journals Factors that have an influence on bone conduction thresholds changes after otosurgery in the patients operated on due to the perforation of the tympanic membrane with the preserved ossicular chain

2017 ◽  
Vol 71 (4) ◽  
pp. 26-33
Author(s):  
Maciej Wiatr ◽  
Agnieszka Wiatr ◽  
Sebastian Kocoń ◽  
Jacek Składzień
Keyword(s):  
Tympanic Membrane ◽  
Middle Ear ◽  
Negative Impact ◽  
Positive Impact ◽  
Round Window ◽  
Bone Conduction ◽  
Ossicular Chain ◽  
Middle Ear Surgery ◽  
Ear Surgery ◽  
Study Objective

Introduction: The aim of the middle ear surgery is to eliminate abnormalities from the mucous, ensure the due airing of the postoperative cavity and reconstruct the sound-conducting system in the middle ear. Numerous reports can be found in literature on the changes to bone conduction as a consequence of middle ear surgery. Study objective: The aim of the work is to define the factors that affect bone conduction in the patients operated on due to the perforation of the tympanic membrane with the preserved and normal mobile ossicular chain. Material and method: A prospective analysis of patients operated on due to diseases of the middle ear in 2009–2012 was carried out. The cases of patients operated on for the first time due to chronic otitis media were taken into consideration. The analysis encompassed the patients who had undergone myringoplasty. The patients were divided into several groups taking into account the abnormalities of the mucous observed during otosurgery. Results: A significant improvement of bone conduction was observed in the patients with dry perforation, without other lesions in the middle ear. The appropriate pharmacological treatment before otosurgery in patients with permanent discharge from the ear resulted in significant bone conduction improvement. The elimination of granulation lesions turned out to be a positive factor for the future improvement of the function of the inner ear. Conclusions: The lack of abnormalities on the mucous of the middle ear (e.g. granulation,) and discharge has a positive impact on improvement of bone conduction after myringoplasty. Adhesions in the tympanic cavity, especially in the niche of the round window, have a negative impact on improvement of bone conduction in patients after myringoplasty.

2D Modeling of the Human Ear Using the Equivalent Mechanical Impedance

2020 ◽  
Author(s):  
Chahbi Aziz ◽  
Assif Safaa ◽  
Faiz Adil ◽  
Hajjaji Abdelowahed.
Keyword(s):  
Tympanic Membrane ◽  
Middle Ear ◽  
Sound Pressure ◽  
Mechanical Impedance ◽  
Ossicular Chain ◽  
Body Parts ◽  
Frequency Range ◽  
Ear Canal ◽  
Finite Elements Analysis ◽  
Human Tympanic Membrane

Several mass–spring–damper models have been developed to study the response of the human body parts. In such models, the lumped elements represent the mass of different body parts, and stiffness and damping properties of various tissues. The aim of this research is to develop a 2D axisymmetric model to simulate the motion of the human tympanic membrane. In this contribution we develop our model using a Comsol Multiphysics software to construct a 2D axisymmetric objects, the acoustic structure interaction between the ear canal (field of propagation of the acoustic wave) and the structure of ear (skin, cartilage, bone, tympanic membrane) was solved using finite elements analysis (FEA). A number of studies have investigated the motion of the human tympanic membrane attached to the ossicular chain and the middle ear cavity. While, in our model the tympanic annular is assumed to be fixed and the loading of what comes behind the tympanic membrane as the ossicular chain, middle ear cavity and cochlea were replaced by the equivalent mechanical impedance of a spring mass damper system. The obtained results demonstrate that the maximum displacements of the umbo are obtained at the frequency range of [0.9 - 2.6] kHz, the sound pressure gain had the shape of peak with a maximum at [2 – 3] kHz frequency range. The umbo displacement depends on the damping coefficient d, and the sound pressure at the tympanic membrane was enhanced compared to that at the ear canal entrance.

Middle ear mechanics in normal, diseased and reconstructed ears

1998 ◽  
Vol 112 (8) ◽  
pp. 715-731 ◽  
Author(s):  
Saumil N. Merchant ◽  
Michael E. Ravicz ◽  
Susan E. Voss ◽  
William T. Peake ◽  
John J. Rosowski
Keyword(s):  
Structure Function ◽  
Tympanic Membrane ◽  
Middle Ear ◽  
Ossicular Chain ◽  
Acoustic Stimulation ◽  
Tympanic Membrane Perforation ◽  
Acoustic Coupling ◽  
Type Iv ◽  
Middle Ear Mechanics ◽  
Wide Range

AbstractA review of the structure-function relationships in normal, diseased and reconstructed middle ears is presented. Variables used to describe the system are sound pressure, volume velocity and acoustic impedance. We discuss the following(1) Sound can be transmitted from the ear canal to the cochlea via two mechanisms: the tympanoossicular system (ossicular coupling) and direct acoustic stimulation of the oval and round windows (acoustic coupling). In the normal ear, middle-ear pressure gain, which is the result of ossicular coupling, is frequency-dependent and smaller than generally believed. Acoustic coupling is negligibly small in normal ears, but can play a significant role in some diseased and reconstructed ears.(2) The severity of conductive hearing loss due to middle-ear disease or after tympanoplasty surgery can be predicted by the degree to which ossicular coupling, acoustic coupling, and stapes-cochlear input impedance are compromised. Such analyses are used to explain the air-bone gaps associated with lesions such as ossicular interruption, ossicular fixation and tympanic membrane perforation.(3) With type IV and V tympanoplasty, hearing is determined solely by acoustic coupling. A quantitative analysis of structure-function relationships can both explain the wide range of observed postoperative hearing results and suggest surgical guidelines in order to optimize the post-operative results.(4) In tympanoplasty types I, II and III, the hearing result depends on the efficacy of the reconstructed tympanic membrane, the efficacy of the reconstructed ossicular chain and adequacy of middle-ear aeration. Currently, our knowledge of the mechanics of these three factors is incomplete. The mechanics of mastoidectomy and stapedectomy are also discussed.

scholarly journals A comparative study of tragal cartilage and autologous incus for ossicular chain reconstruction in type IIB tympanoplasty at Dr. Hedgewar Hospital, Aurangabad

2019 ◽  
Vol 6 (1) ◽  
pp. 78
Author(s):  
Bharat G. Deshmukh ◽  
Deepak Bhisegaonkar ◽  
Akanksha Bakre
Keyword(s):  
Tympanic Membrane ◽  
Otitis Media ◽  
Middle Ear ◽  
Chronic Otitis Media ◽  
Ossicular Chain ◽  
Suppurative Otitis Media ◽  
High Incidence ◽  
Ossicular Chain Reconstruction ◽  
Small Bones ◽  
Set Up

<p class="abstract"><strong>Background:</strong> Tympanoplasty is the surgical operation performed for the reconstruction of the eardrum (tympanic membrane) and/or the small bones of the middle ear. Chronic otitis media is a very common condition of middle ear which not only has a high incidence in the world but also in our set up. So, in view of this, we decided to conduct a study on the surgical management of CSOM-tubotympanic type.</p><p class="abstract"><strong>Methods:</strong> We conducted this study at ENT department of Dr. Hedgewar Rugnalaya, Aurangabad to compare air bone gap closure by using tragal cartilage and autologous incus in type IIB tympanoplasty in patients with chronic suppurative otitis media, (tubotympanic). 66 patients with central perforation of tympanic membrane, necrosed incus and mobile stapes requiring type IIB tympanoplasty, were included as a part of the study.</p><p class="abstract"><strong>Results:</strong> We performed type IIB tympanoplasty with a routine post-aural incision in 66 patients. According to our observation, both incus and cartilage are good materials for ossiculoplasty, tragal cartilage being better.</p><p class="abstract"><strong>Conclusions:</strong> After conducting this study we concluded that incus and tragal cartilage both are excellent materials for ossiculoplasty.</p>

scholarly journals Evaluation of the Facial Recess and Cochlea on the Temporal Bone of Stillbirths regarding the Percutaneous Cochlear Implant

2017 ◽  
Vol 22 (03) ◽  
pp. 260-265
Author(s):  
Gabriela Braga ◽  
Eloisa Gebrim ◽  
Ramya Balachandran ◽  
Jack Noble ◽  
Robert Labadie ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Facial Nerve ◽  
Cochlear Implant ◽  
Tympanic Membrane ◽  
Temporal Bone ◽  
Middle Ear ◽  
Ossicular Chain ◽  
Facial Recess ◽  
Ct Evaluation ◽  
Temporal Bone Anatomy

Introduction The literature shows that there are anatomical changes on the temporal bone anatomy during the first four years of life in children. Therefore, we decided to evaluate the temporal bone anatomy regarding the cochlear implant surgery in stillbirths between 32 and 40 weeks of gestational age using computed tomography to simulate the trajectory of the drill to the scala timpani avoiding vital structures. Objectives To measure the distances of the simulated trajectory to the facial recess, cochlea, ossicular chain and tympanic membrane, while performing the minimally invasive cochlear implant technique, using the Improvise imaging software (Vanderbilt University, Nashville, TN, US). Methods An experimental study with 9 stillbirth specimens, with gestational ages ranging between 32 and 40 weeks, undergoing tomographic evaluation with individualization and reconstruction of the labyrinth, facial nerve, ossicular chain, tympanic membrane and cochlea followed by drill path definition to the scala tympani. Improvise was used for the computed tomography (CT) evaluation and for the reconstruction of the structures and trajectory of the drill. Results Range of the distance of the trajectory to the facial nerve: 0.58 to 1.71 mm. to the ossicular chain: 0.38 to 1.49 mm; to the tympanic membrane: 0.85 to 1.96 mm; total range of the distance of the trajectory: 5.92 to 12.65 mm. Conclusion The measurements of the relationship between the drill and the anatomical structures of the middle ear and the simulation of the trajectory showed that the middle ear cavity at 32 weeks was big enough for surgical procedures such as cochlear implants. Although cochlear implantation at birth is not an indication yet, this study shows that the technique may be an option in the future.

TIME AVERAGE HOLOGRAPHY STUDY OF HUMAN TYMPANIC MEMBRANE WITH ALTERED MIDDLE EAR OSSICULAR CHAIN

2009 ◽  
Author(s):  
JEFFREY T. CHENG ◽  
MICHAEL E. RAVICZ ◽  
JOHN J. ROSOWSKI ◽  
NESIM HULLI ◽  
MARIA S. HERNANDEZ-MONTES ◽  
...  
Keyword(s):  
Tympanic Membrane ◽  
Middle Ear ◽  
Ossicular Chain ◽  
Time Average ◽  
Human Tympanic Membrane

A Sensitivity Study on a Hybrid FE/MB Human Middle Ear Model

2012 ◽  
Author(s):  
Gaia Volandri ◽  
Francesca Di Puccio ◽  
Paola Forte
Keyword(s):  
Finite Element ◽  
Tympanic Membrane ◽  
Middle Ear ◽  
Complex Geometry ◽  
Optimization Procedure ◽  
Ossicular Chain ◽  
Sensitivity Study ◽  
Rigid Bodies ◽  
Human Middle Ear ◽  
Multi Body

The human middle ear includes the tympanic membrane and the ossicular chain. The finite element method is capable of representing the complex geometry and the material orthotropy of the tympanic membrane. On the contrary, the ossicles can be considered as rigid bodies and a multi-body approach can be adopted. In the present study a multi-body model of the ossicular chain and other structures (joints, ligaments and muscle tendons) of the middle ear was developed and combined with a finite element model of the tympanic membrane through a feedback control strategy. An optimization procedure was used to calibrate unspecified or uncertain parameters with the aim of reproducing ascertained experimental literature data. The sensitivity of the calibrated models to both tympanic membrane and ossicular chain parameters was investigated. Material, geometrical and inertial parameters were considered, in particular those whose values were most widespread in the literature.

Sign in / Sign up

Export Citation Format

Share Document