Benign Paroxysmal Positional Vertigo (BPPV) is typically described by location and type. For example, the most common form of BPPV is posterior canal Canalithiasis. “Posterior” refers to the location (one can also have BPPV in the Horizontal or Anterior Canal), and Canalithiasis refers to the condition of the otoconia (Are they moving freely or stuck on the cupiula?)
In 1969, Dr. Harold Schuknecht first proposed the theory of Cupulolithiasis in which he suggested that BPPV was the result of otoconial debris attached to the cupula of the offending posterior semicircular canal. Epley (1992) offered an alternative theory of Canalithiasis, which more thoroughly explains the source of the typical signs and symptoms of BPPV.
The theory of Canalithiasis proposes that there are free-floating particles (otoconia) that have gravitated from the utricle and collect near the cupula of the posterior canal. When the head is moved into a position that causes the particles to move away from the cupula, the resulting hydrodynamic drag causes cupular deflection (and asymmetric stimulation) resulting in vertigo and nystagmus until the particles come to rest in the now gravitationally dependent section of the canal.
It is likely that both of these conditions exist and treatments have been proposed for both.