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

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

Goyens, J. (Universiteit Antwerpen)
Pourquie, M.J.B.M. (TU Delft Fluid Mechanics)
Poelma, C. (TU Delft Multi Phase Systems)
Westerweel, J. (TU Delft Fluid Mechanics)

2019

The vestibular system in the inner ear senses angular head manoeuvres by endolymph fluid which deforms a gelatinous sensory structure (the cupula). We constructed computer models that include both the endolymph flow (using CFD modelling), the cupula deformation (using FEM modelling), and the interaction between both (using fluid–structure interaction modelling). In the wide utricle, we observe an endolymph vortex. In the initial time steps, both the displacement of the cupula and its restorative forces are still small. As a result, the endolymph vortex causes the cupula to deform asymmetrically in an S-shape. The asymmetric deflection increases the cupula strain near the crista and, as a result, enhances the sensitivity of the vestibular system. Throughout the head manoeuvre, the maximal cupula strain is located at the centre of the crista. The hair cells at the crista centre supply irregularly spiking afferents, which are more sensitive than the afferents from the periphery. Hence, the location of the maximal strain at the crista may also increase the sensitivity of the semicircular canal, but this remains to be tested. The cupula overshoots its relaxed position in a simulation of the Dix-Hallpike head manoeuvre (3 s in total). A much faster head manoeuvre of 0.222 s showed to be too short to cause substantial cupula overshoot, because the cupula time scale of both models (estimated to be 3.3 s) is an order of magnitude larger than the duration of this manoeuvre.

Balance
Computational fluid dynamics
Finite element model
Fluid–structure interaction
Navier–Stokes equations
Time constant
Vestibular system

http://resolver.tudelft.nl/uuid:d9d6b851-6f17-4c94-91d3-90dadf97a8a1

https://doi.org/10.1007/s10237-019-01160-2

2019-11-08

1617-7959

Biomechanics and Modeling in Mechanobiology (online), 18 (6), 1577-1590

Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.

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journal article

© 2019 J. Goyens, M.J.B.M. Pourquie, C. Poelma, J. Westerweel