Pathology of benign paroxysmal positional vertigo revisited.

The pathophysiology of benign paroxysmal positional vertigo (BPPV) is not completely understood. Although the concept of degenerated otoconia transforming the posterior canal (PC) crista into a gravity-sensitive sense organ has gained popular support, several temporal bone (TB) series have revealed similar deposits in normal TBs, suggesting they are a normal change in the aging labyrinth. Furthermore, some TBs from patients with BPPV do not contain particles in the posterior canal. Five TBs from patients with BPPV were studied quantitatively and qualitatively. A small PC cupular deposit was found in 1 TB, while none was seen in the other 4 TBs. The major pathological changes were 1) a 50% loss of ganglion cells in the superior vestibular division of all 5 TBs and 2) a 50% loss of neurons in the inferior division of 3 TBs, and a 30% loss in 2 TBs that contained abnormal saccular ganglion cells. These observations support a concept in the pathophysiology of BPPV that includes loss of the inhibitory effect of otolith organs on canal sense organs.