title: Experimental study on the aetiology of benign paroxysmal positional vertigo due to canalolithiasis: comparison between normal and vestibular dysfunction models.
abstract: OBJECTIVE
  Using American bullfrog models under normal conditions and under vestibular dysfunction, we investigated whether mechanical vibration applied to the ear could induce otoconial dislodgement.
  
  
  METHODS
  Vibration was applied to the labyrinth of the bullfrog using a surgical drill. The time required for the otoconia to dislodge from the utricular macula was measured. Vestibular dysfunction models were created and the dislodgement time was compared with the normal models. The morphology of the utricular macula was also investigated.
  
  
  RESULTS
  In the normal models, the average time for otoconial dislodgement to occur was 7 min and 36 s; in the vestibular dysfunction models, it was 2 min and 11 s. Pathological investigation revealed that the sensory hairs of the utricle were reduced in number and that the sensory cells became atrophic in the vestibular dysfunction models.
  
  
  CONCLUSIONS
  The otoconia of the utricle were dislodged into the semicircular canal after applying vibration. The time to dislodgement was significantly shorter in the vestibular dysfunction models than in the normal models; the utricular macula sustained significant morphological damage.
authors.affiliation: Department of Otolaryngology, Tokyo Medical University, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Otsuka
authors.affiliation: Department of Otolaryngology, Tokyo Medical University, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Negishi
authors.affiliation: Department of Otolaryngology, Tokyo Medical University, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Suzuki
authors.affiliation: Department of Otolaryngology, Tokyo Medical University, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Inagaki
authors.affiliation: Department of Otolaryngology, Tokyo Medical University, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Yatomi
authors.affiliation: Department of Otolaryngology, Tokyo Medical University, Japan.
authors.forename: U
authors.initials: U
authors.lastname: Konomi
authors.affiliation: Department of Otolaryngology, Tokyo Medical University, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Kondo
authors.affiliation: Department of Otolaryngology, Tokyo Medical University, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Ogawa
mesh_terms: D000818:Animals; D065635:Benign Paroxysmal Positional Vertigo; D004195:Disease Models, Animal; D007758:Ear, Inner / Q000473:pathology; D006199:Hair Cells, Auditory, Inner / Q000473:pathology*; D010037:Otolithic Membrane / Q000503:physiopathology*; D011892:Rana catesbeiana; D012444:Saccule and Utricle / Q000473:pathology*; D014717:Vertigo / Q000473:pathology / Q000503:physiopathology*; D014732:Vibration / Q000009:adverse effects*