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Anatomy and Physiology of Balance
Published in R James A England, Eamon Shamil, Rajeev Mathew, Manohar Bance, Pavol Surda, Jemy Jose, Omar Hilmi, Adam J Donne, Scott-Brown's Essential Otorhinolaryngology, 2022
Nishchay Mehta, Andrew Forge, Jonathan Gale
The hair bundles, which are bathed in endolymph, are covered by acellular membrane structures. In the maculae, the otolithic membrane is covered with otoconia, which are white crystalline particles composed predominantly of calcium carbonate. In semicircular canals, the hair cells of cristae protrude into a barrel-shaped gelatinous cap (termed the cupula) that lacks otoconia.
Vestibular Respiratory Regulation
Published in Alan D. Miller, Armand L. Bianchi, Beverly P. Bishop, Neural Control of the Respiratory Muscles, 2019
The stereocilia of otolith organ hair cells are embedded in a gelatinous membrane filled with calcium carbonate crystals; this otolithic membrane has a much higher specific gravity than the surrounding fluid, and shifts in position when the head is tilted or subjected to linear acceleration. Otolith organ hair cells have many different orientations, which allow the otolith organs to detect linear accelerations and head tilts in many different planes. The central nervous system can thus decipher the position of the head in space by analyzing the pattern of otolith organ afferent discharges.
Computational simulation of the vestibular system using a meshless particle method
Published in J. Belinha, R.M. Natal Jorge, J.C. Reis Campos, Mário A.P. Vaz, João Manuel, R.S. Tavares, Biodental Engineering V, 2019
C.F. Santos, Marco Parente, J. Belinha, R.M. Natal Jorge, Fernanda Gentil
The structure of the canal comprise a membranous labyrinth embraced by a bony labyrinth with the same shape. The membranous labyrinth is full of fluid called endolymph, which promotes the human movement. Moreover, a fluid called perilymph take place between both labyrinths (Davis, Xue, Peterson, & Grant, 2007). The complex and detailed structure of the vestibular system is not completed without mentioning the cupula and the macula of the ear. These structures are the ones with the sensory hair cells, responsible for sending signals to the brain, signalling the physical movement. The sensory cells exhibit a constant discharge of neurotransmitters that are modified by the direction of cupula deflection (Wolfe, 2012). Regarding the macula placed in the saccule and the utricle, which are the adjacent structures of the semi-circular canals, it is a membranous structure composed by a gel layer that contains calcium carbonate crystals called otoconia. The mass of the otolithic membrane allows the macula to be sensitive to gravity and linear acceleration.
Vestibular evoked myogenic potentials: what are they for? An opinion; a hypothesis
Published in Acta Oto-Laryngologica, 2020
The stapedius muscle contracts when there is internal body noise and this changes the vibratory response, which the saccule receives, and makes it different to when there is an external stimulus. The activity of the stapedius muscle is probably much more subtle and complex than is presently recognized by the relatively crude test methods we have, but muscle activity is unlikely to be subtle enough to respond substantially differently to various frequencies of sound. Response is elicited via vestibular efferent activity to neurological endings in the saccule. This changes the stiffness of the otolithic membrane via a kinociliary tonic effect on the otoliths. This is orchestrated via the stereocilia and striated organelle complex [12] and alters the response to vibration from internal sounds, so that these changed external sounds arriving at the macula of the saccule alert the individual to the fact that the stimulus is an external one. The cochlea is specifically sensitized for evaluation of incoming external sound via this macula saccular change rapidly, and also by the antidromic response via the nerve of Oort from the macula of the saccule to the cochlea.
Analysis of related factors of recurrence in horizontal semicircular canal benign paroxysmal positional vertigo: a pilot study
Published in Acta Oto-Laryngologica, 2020
Ling Ding, Tao Lin, Xuanchen Zhou, Jie Han, Anting Xu
Since RD is regarded as a common condition in patients with BPPV, more and more authors focus on its pathogenesis after maneuver. From the genesis of vestibular function, the theory to explain RD after repositioning maneuvers is a disorder of the otolith, which causes persistent utricular dysfunction by freely floating of otolith debris, and that can be verified by oVEMP [14]. It has been speculated that otoconial mass after the maneuvers re-attached to otolithic membrane leads to an altered stimulation between vestibular receptors and central vestibular neurons [15]. SVV was also used to determine otolithic dysfunction and it's thought to be the original of brief dizziness after CRP [6].
Evaluation of bone mineral density and 25-(OH) vitamin D levels in middle-aged and elderly women with recurrent benign paroxysmal positional vertigo
Published in Acta Oto-Laryngologica, 2020
Zhibin Wang, Guanghui Yao, Xiangming Tao, Jincui Zhang, Ting Zhang, Ziming Wu
Benign paroxysmal positional vertigo (BPPV), commonly known as ‘otolithiasis’, is the most common disorder observed in vertigo clinics [1]. Its pathogenesis is based on the detachment of vestibular otoliths in the otolithic membrane and their accumulation in the semi-circular canal. Their movement in the semi-circular canal changes with body position due to the effects of gravity, which stimulates vestibular firing and results in attacks of vertigo [2]. The disease can be secondary to trauma, surgery, and inner ear disease. The cause of BPPV is unknown in 60% to 90% of patients seeking clinical treatment; these cases are diagnosed as idiopathic BPPV [3].