title: Vertical canal function in normal subjects and patients with benign paroxysmal positional vertigo.
abstract: OBJECTIVE
  To assess the dynamics of the vertical semicircular canal (VSCC)-ocular reflex in normal subjects and then to compare their gain in VSCC-ocular reflex with that of patients with benign paroxysmal positional vertigo (BPPV).
  
  
  METHODS
  Subjects were sinusoidally rotated around the earth-vertical axis with their head tilted 60 degrees backward and turned 45 degrees to the right or left side from the sagittal plane at frequencies of 0.1, 0.3, 0.5, 0.7 and 1.0 Hz with a maximum angular velocity of 50 degrees/s. Head rotation to the right side on the right anterior semicircular canal (SCC)-left posterior SCC plane or to the left side on the left anterior SCC-right posterior SCC plane stimulated the pair of VSCCs. Eye movements were recorded on a video imaging system with an infrared charge-coupled device camera, using our new technique for analyzing the rotation vector of eye movements in three dimensions.
  
  
  RESULTS
  The mean gains in left posterior SCC-ocular reflex in normal subjects ranged from 0.44 at 0.1 Hz to 0.79 at 1.0 Hz, while the mean gains in right anterior SCC-ocular reflex ranged from 0.45 at 0.1 Hz to 0.73 at 1.0 Hz. The mean gains in right posterior SCC-ocular reflex in normal subjects ranged from 0.53 at 0.1 Hz to 0.89 at 1.0 Hz, while the mean gains in left anterior SCC-ocular reflex ranged from 0.53 at 0.1 Hz to 0.88 at 1.0 Hz. Thus, the gains in VSCC-ocular reflex did not differ among the four VSCCs in normal subjects. Similarly, vestibulo-ocular reflex (VOR) gains of the four VSCCs in patients with right- or left-sided BPPV were almost the same at all frequencies compared to those of normal subjects.
  
  
  CONCLUSIONS
  In patients with BPPV, gains in VOR in the four VSCCs were not changed in comparison with those of normal subjects. It is suggested that the mass of free-floating otoconial debris associated with canalolithiasis was too small compared to that of the endolymph to change the canal dynamics.
authors.affiliation: Department of Otolaryngology, University of Tokushima School of Medicine, Tokushima, Japan. seky@clin.med.tokushima-u.ac.jp
authors.forename: Kazunori
authors.initials: K
authors.lastname: Sekine
authors.forename: Takao
authors.initials: T
authors.lastname: Imai
authors.forename: Masahiro
authors.initials: M
authors.lastname: Morita
authors.forename: Koji
authors.initials: K
authors.lastname: Nakamae
authors.forename: Katsuyoshi
authors.initials: K
authors.lastname: Miura
authors.forename: Hiromu
authors.initials: H
authors.lastname: Fujioka
authors.forename: Takeshi
authors.initials: T
authors.lastname: Kubo
authors.forename: Koichi
authors.initials: K
authors.lastname: Tamura
authors.forename: Noriaki
authors.initials: N
authors.lastname: Takeda
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002150:Caloric Tests / Q000379:methods; D003952:Diagnostic Imaging / Q000379:methods; D005133:Eye Movements; D005260:Female; D006801:Humans; D020347:Lithiasis / Q000150:complications; D008297:Male; D008875:Middle Aged; D009760:Nystagmus, Physiologic / Q000502:physiology; D012399:Rotation; D012665:Semicircular Canals / Q000502:physiology*; D014717:Vertigo / Q000503:physiopathology*