Functional Model of Benign Paroxysmal Positional Vertigo Using an Isolated Frog Semicircular Canal

Abstract

Bull frogs posterior semicircular canals (psc) were used to simulate the condition of benign paroxysmal positional vertigo (BPPV). The psc was isolated in frog Ringer's solution, and the saccular otoconia were used as a responsible material to stimulate the cupula. When the otoconia were placed on the cupular surface to mimic the condition of cupulolithiasis, the psc ampullary nerve action potentials instantaneously changed according to the direction of the gravity produced by otoconia. When the otoconia were dropped into the canal to mimic the condition of moving otoconia in the canal, the action potentials changed together with the otoconial flow after a latent period. Both cupulolithiasis and moving otoconia are possibly valid mechanisms of BPPV, since they effectively stimulate the cupula. However, moving otoconia with a latent period would better explain clinical features of BPPV.

A mathematical model for top-shelf vertigo: the role of sedimenting otoconia in BPPV

“…The experimental results (Suzuki et al, 1996) contrast with the predictions of the present theory, the theory of House and Honrubia, and clinical observations (House & Honrubia, 2003;Semont et al, 1998) in one significant aspect: a latent period was measured for a clump of otoconia started in the duct, which Suzuki et al attributed to a re-orientation of the clump itself. It should also be noted that in these experiments, otoconia typically travelled in 'clumps' and slid along side walls.…”

“…Experimental investigations of BPPV models have used the vestibular systems of frogs. Otoconia were inserted into the open end of an isolated posterior semicircular canal (PSC) (Suzuki et al, 1996), or dislodged from the utricle and driven into the PSC of an intact labyrinth (Otsuka et al, 2003). Neural activity was measured following a change in PSC orientation, with free-floating otoconia ('canalithiasis') and attached otoconia ('cupulolithiasis').…”

Efficacy of Treatments for Posterior Canal Benign Paroxysmal Positional Vertigo

“…Anatomic work 3,7,8 and surgeons' observations 9 have suggested that it is caused by displacement of otoconial matter into the lumen or onto the cupula of the posterior semicircular canal (i.e., canalithiasis and cupulolithiasis, respectively). Recent work in a frog model 10 supported both theories.…”

Human Experience with Canalith Repositioning Maneuvers

“…In vestibular lithiasis , dense particles (mostly otoconial debris from the utricle) enter the SCs and alter their biomechanics, often by a distortion of function. Although it has not been feasible to directly observe the action of these dense particles while causing distortion of function within the SCs of humans, animal studies11 have been illuminating. There are also pathologic2 and surgical correlations 12.…”