Why Do Benign Paroxysmal Positional Vertigo Episodes Recover Spontaneously?

Abstract

It is well known that most episodes of benign paroxysmal positional vertigo (BPPV), even in untreated, recover spontaneously in 2 to 6 weeks. In the present study, we put forward the hypothesis that this is mainly due to the fact that endolymph, owing to its low calcium content (20μM) is able to dissolve otoconia. To support this, the fate of frog saccular otoconia immersed in normal endolymph (Ca²⁺ content 20μM) and in Ca²⁺-rich endolymphatic fluids (up to 500μM) was studied by observing the crystals at regular intervals for 3 weeks. The results demonstrated that normal endolymph can dissolve otoconia very rapidly (in about 20 hours). When the endolymphatic Ca²⁺ content was increased (50 to 200μM) otoconia dissolution time was slowed down (about 100 to 130 hours, respectively) and completely stopped when the endolymphatic Ca²⁺ content was of 500μM. The present results therefore suggest that the major process involved in the spontaneous recovery of BPPV episodes is the capability of the endolymph to dissolve dislodged otoconia.