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Cranial Neuropathies I, V, and VII–XII
Published in Philip B. Gorelick, Fernando D. Testai, Graeme J. Hankey, Joanna M. Wardlaw, Hankey's Clinical Neurology, 2020
Sound waves are transmitted by the pump-like effect of the stapes in the oval window, which creates shock waves that are passed to the round window where the energy dissipates. The pressure wave is transmitted through the perilymph, and leads to vibration of the basilar membrane, depending on the frequency of the sound. When the basilar membrane oscillates, the tectorial membrane has a shearing effect across the hair cells, stimulating the cochlear nerve fibers.
The Twentieth Century
Published in Arturo Castiglioni, A History of Medicine, 2019
In otology more knowledge has been obtained of the functions of the oval window. Various “fenestration” operations for otosclerosis, based on the newer knowledge, have come into vogue, beginning with Maurice sourdille’s (b. 1885) three-stage operation opening a new window into a semicircular canal. In 1938 J. lempert (now of New York) elaborated a successful one-stage operation, which, in spite of its difficulties, has achieved some excellent results. Due to the brilliant work, chiefly by Americans, of such men as E. H. campbell, K. M. day, Walter hughson (1891–1944), and J. R. page, good results in suitable cases have been obtained in more than half the cases operated upon.
Anatomy
Published in Stanley A. Gelfand, Hearing, 2017
The major divisions of the ear are shown in Figure 2.2, and their relative positions within the head are given in Figure 2.3. The outer ear is made up of the pinna (auricle) and ear canal (external auditory meatus). The eardrum (tympanic membrane) separates the outer and middle ears, and is generally considered to be part of the latter. The middle ear also includes the tympanic (middle ear) cavity; the ossicular chain with its associated muscles, tendons, and ligaments; and the eustachian (auditory) tube. The inner ear begins at the oval window. It includes the sensory organs of hearing (the cochlea) and of balance (the semicircular canals, utricle, and saccule). While the balance system is certainly important, the concern here is hearing, and accordingly the balance apparatus is mentioned only insofar as it is directly associated with the auditory system.
Effect of ossicular chain deformity on reverse stimulation considering the overflow characteristics of third windows
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2022
Houguang Liu, Lin Xue, Jianhua Yang, Gang Cheng, Lei Zhou, Xinsheng Huang
The assumption that the fluid-filled cochlea is surrounded by bone with only two mobile windows, i.e., the oval window and the round window has been generally accepted under forward stimulation (Zhang and Gan 2013; Zhang et al. 2018). This assumption is supported by experimental studies (Kringlebotn 1995; Stenfelt et al. 2004), which found that the fluid volume displacement of the oval window and the round window are equal under forward stimulation. Whereas, the actual anatomy of the cochlea has other smaller-scale and longer sound pathways, mainly the vestibular aqueduct and cochlear aqueduct, which were named as third windows (Rosowski et al. 2018). By stimulating the round window with an actuator in human temporal bone experiment, Stieger et al. (2013) reported that there exists fluid flow through the third windows in the cochlea. Meanwhile, based on the measurement of intra-cochlear sound pressure and ossicular chain motion, Frear et al. (2018) also found that the third windows have volume velocities leakage during reverse stimulation. Moreover, our theoretical investigation found that the third windows have an important effect on the reverse stimulation at low frequencies (Xue et al. 2020). Therefore, incorporating the third windows is essential for investigating the influence of OCD during reverse stimulation.
A new phenomenon of cochlear otosclerosis: an acquired or congenital disease? – A clinical report of cochlear otosclerosis
Published in Acta Oto-Laryngologica, 2021
Simeng Lu, Xingmei Wei, Biao Chen, Jingyuan Chen, Lifang Zhang, Mengge Yang, Zhiming Sun, Ying Shi, Ying Kong, Sha Liu, Yongxin Li
Otosclerosis is an aberrant process of bone resorption in the labyrinthine capsule, followed by reparative deposition of new, immature sclerotic bone [1]. The most commonly affected location is around the oval window (fenestral otosclerosis), which results in conductive hearing loss due to the fixation of the stapes footplate. When otosclerosis involves the cochlear endosteum and only causes sensorineural hearing loss (SNHL) without stapes fixation, it is defined as cochlear otosclerosis [2]. The current concept of cochlear otosclerosis covers a wide range of pathologies. People with SNHL, including mixed hearing loss (MHL), are classified as having cochlear otosclerosis. Otosclerosis is responsible for 5–9% of cases of hearing loss and 18–22% of cases of conductive hearing loss [3]. The incidence of cochlear otosclerosis is approximately 0.3% in the general population [4]. The male-to-female ratio of patients with otosclerosis is 1:1.8 [5]. The diagnosis of cochlear otosclerosis mainly depends on temporal bone high-resolution computed tomography (HRCT). The sensitivity of HRCT to detect cochlear ossification is close to 80% [6]. HRCT of the temporal bones in patients with cochlear otosclerosis usually reveals extensive bone demineralization of the otic capsule, seen as the ‘double ring sign [1].’ CIs have been proven to be effective in treating patients with SNHL, including patients with cochlear otosclerosis [7].
Peristapedial bulb: an indicator of spontaneous CSF leak in cochlear candidates with Mondini dysplasia
Published in Acta Oto-Laryngologica, 2021
Xinbo Xu, Weiliang Chen, Xiao Han, Ruru Qiao, Xiaojie Ma, Yuanping Ding, Hanbing Zhang
When a CI candidate with bilateral Mondini anomaly has a history of meningitis, the optimal surgical strategy should allow both effective CSF leak control and unimpeded electrode array insertion. The vestibule is an interlinked bony space containing the saccule beneath the oval window and the initial portion of the cochlear duct beneath the round window. Therefore, vestibular obliteration may induce the fibrosis of the cochlear duct, which further impedes the electrode placement. As the infeasibility of electrode placement after vestibular packing, the two procedures should be conducted concurrently. Despite the active CSF leakage into the middle ear or the obvious labyrinthine defect in HRCT, many CSF fistulas are occult and inconspicuous, thus the bilateral vestibular obliteration better fit these patients, which means the bilateral CI should also be performed. Although Binaural implantation indeed provides the patient with a better auditory outcome, the cost and trauma may not be accepted by every patient. So, in clinical practice of some regions, this set of patients may be inclined to choose a single side-ear procedure to both resolves the potential intracranial infection and restores the hearing, so, correct diagnosis of the ear which leads to meningitis is a basis and key point of the surgery. Our study of the peristapedial bulb provides the otologists a new indicator to diagnose the correct candidate operating ear beside the traditional method.