Numerical modeling of the cupular displacement and motion of otoconia particles in a semicircular canal

Abstract

Balance is achieved and maintained by a balance system called a labyrinth that is composed of three semicircular canals and the otolith organs that sense linear gravity and acceleration. Within each semicircular canal, there is a gelatinous structure called the cupula, which is deformed under the influence of the surrounding endolymph. One of the balance disorders is benign paroxysmal positional vertigo, and one of the pathological conditions that have been identified as possible causes of this syndrome is canalithiasis-disturbance of the endolymph flow and cupular displacement caused by the free-moving otoconia particles within the lumen of the canal. Analysis of phenomena occurring within the semicircular canal can help to explain some balance-related disorders and the response of the vestibular system to external perturbations under various pathological conditions. Numerical simulations allow a study of the influence of a wide range of factors, without the need to perform experiments and clinical examinations. In case of canalithiasis, an accurate explanation and tracking of the motion of otoconia particles in vivo is obviously nearly impossible. In this study, a numerical model was developed to predict the motion of otoconia particles within the semicircular canal and the effect of the endolymph flow and particles on the deformation of the cupula.

Asymmetric cupula displacement due to endolymph vortex in the human semicircular canal

“…All ampullas end in the utricle (U), which houses a macula (turquoise, M) 1 3 particular, the effect of the endolymph vortex in the utricle which was first described by Boselli et al (2013). While the existing 3D FSI models in the literature have a very simplified, toroidal geometry (Djukic and Filipovic 2017;Santos et al 2017b), we constructed a realistic geometry of the human lateral semicircular canal and utricle, based on the anatomical literature. A further novel aspect of the current study is the analysis of the relative magnitude of the terms in the Navier-Stokes (NS) equations.…”

“…It is generally thought that the endolymph fluid lags behind due to its inertia when the head accelerates angularly. This causes flow of the (slower) fluid, relative to the (faster) membranous wall (Kandel et al 1991;Muller and Verhagen 2002;Rabbitt et al 2004Rabbitt et al , 2009Angelaki and Cullen 2008;Latash 2008;Ekdale 2016;Grohé et al 2016;Djukic and Filipovic 2017). The relative endolymph flow deflects sensory hairs, resulting in a neural signal to the brain.…”

“…These models were mainly developed to gain a better understanding of vestibular pathologies and clinical practices (e.g. Kassemi et al 2005;Boselli et al 2014;Grieser et al 2016;Djukic and Filipovic 2017). For example, the computational model by Boselli et al (2014) of the fluid-particle dynamics of a semicircular canal with benign paroxysmal positional vertigo (BPPV) showed the particle displacement within the canal after a provocative head manoeuvre.…”

“…This is an unnatural situation, however, because in reality, the cupula fills the entire cross section of the endolymph such that endolymph flow is blocked (McLaren and Hillman 1979;Yamauchi et al 2002;Rabbitt et al 2004Rabbitt et al , 2009. Recently, some authors have resolved this issue by combining 3D fluid simulations of the endolymph with a 3D finite element model of the cupula in a single model (Djukic and Filipovic 2017;Santos et al 2017a). Kassemi et al (2005) and Wu et al (2011) previously did the same in 2D.…”

Development of an Ultra-Sensitive and Flexible Piezoresistive Flow Sensor Using Vertical Graphene Nanosheets

“…S1. Many numerical investigations [26][27][28] have been conducted to analyze the hair cell deformation over oscillatory movements; however, few studies on the vestibular system have been experimentally undertaken. Most of the experiments during the last two decades used accelerometers and gyroscopes [29][30][31] for detecting linear motion and rotational motion, respectively.…”