title: Onset time of benign paroxysmal positional vertigo.
abstract: CONCLUSIONS
  Benign paroxysmal positional vertigo (BPPV) is strongly related to sleep. This study proposes a micro-otoconia accumulation theory in which the pathological debris is an aggregate of micro-otoconia over a long time period, and which begins to slide by its own weight during sleep.
  
  
  OBJECTIVE
  To examine the onset time of idiopathic BPPV and to investigate its etiology.
  
  
  METHODS
  Patients (n = 351) were classified as posterior canalolithiasis (PC), horizontal canalolithiasis (HC), and horizontal heavy cupula (HHC) according to nystagmus findings. This study examined the medical records, and categorized the onset times into the following four groups; (1) during sleep, (2) at the time of rising, (3) morning, and (4) afternoon.
  
  
  RESULTS
  PC (n = 135): In 33 patients, vertigo occurred during sleep, in 69 patients at rising, in 10 patients in the morning, and in 23 patients in the afternoon. HC (n = 87): In 38 patients, vertigo occurred during sleep, in 30 patients at rising, in eight patients in the morning, and in 11 patients in the afternoon. HHC (n = 129): In 27 patients, vertigo occurred during sleep, in 59 patients at rising, in 15 patients in the morning, and in 28 patients in the afternoon.
authors: a Department of Otolaryngology , Ichijo Ear, Nose and Throat Clinic , Hirosaki , Japan.
authors: Hiroaki
authors: H
authors: Ichijo
mesh_terms: D065635:Benign Paroxysmal Positional Vertigo / Q000209:etiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012890:Sleep; D013997:Time Factors
keywords: Canalolithiasis; heavy cupula; otoconia accumulation theory; positional nystagmus; semicircular canal; sleep