title: Binocular flash-induced nystagmus in humans.
abstract: OBJECTIVE
  The aim of this study was to demonstrate that binocular flash-induced nystagmus (B-FIN) can be evoked in humans.
  
  
  METHODS
  The study evaluated the presence of B-FIN by stimulation with a stroboscopic flash.
  
  
  METHODS
  The study was conducted with 12 healthy patients in the Otorhinolaryngology Department of the University of Genoa (Italy), between April 2008 and January 2009.
  
  
  METHODS
  Patients underwent binocular flashing light stimulation, in the dark, by stroboscopic flash presented through a photostimulator at frequencies of 4.7 and 7.69 cycles/second for 120 seconds, with their eyes covered by a homogeneous field hollow opal hemisphere. The photostimulator was placed in three different positions with respect to the anterior-posterior axis: 0 degrees, 45 degrees to the right, and 45 degrees to the left.
  
  
  METHODS
  Eye movements were recorded by electronystagmography (ENG). ENG recording started 30 seconds before the stimulation and stopped 60 seconds after the end of the luminance stimuli to test the presence of flash induced after nystagmus (FIAN).
  
  
  RESULTS
  B-FIN was clearly evoked from 10 of the 12 healthy adults, whereas FIAN was evoked from 4 of the 12 subjects. The best stimulation of B-FIN was obtained through an intermittent luminance stimulus presented at a frequency of 4.7 cycles/second and the photostimulator placed at 0 degrees to the optic axis.
  
  
  CONCLUSIONS
  Our investigation demonstrates that B-FIN can be evoked in humans and its possible value in the differential diagnosis between central and peripheral vertigo.
authors.affiliation: Otorhinolaryngology Department, University of Genoa, Genoa, Italy.
authors.forename: Angelo
authors.initials: A
authors.lastname: Salami
authors.forename: Massimo
authors.initials: M
authors.lastname: Dellepiane
authors.forename: Barbara
authors.initials: B
authors.lastname: Crippa
authors.forename: Luca
authors.initials: L
authors.lastname: Guastini
authors.forename: Renzo
authors.initials: R
authors.lastname: Mora
mesh_terms: D000328:Adult; D004584:Electronystagmography; D005133:Eye Movements; D005260:Female; D006801:Humans; D008297:Male; D009760:Nystagmus, Physiologic / Q000502:physiology*; D010775:Photic Stimulation