title: A newly recognised cause of vertigo: horizontal canal variant of benign positional vertigo.
abstract: OBJECTIVE
  To describe the presentation, causes, treatment, and outcomes of patients presenting with the newly recognised horizontal canal variant of benign positional vertigo (BPV); and to emphasise the importance of performing a positional test on all patients being assessed for vertigo.
  
  
  METHODS
  The records on 400 patients presenting with BPV were analysed. Two detailed patient histories from 2004 are included.
  
  
  RESULTS
  Forty-nine patients (12%) had horizontal canal BPV. The median presentation age was 59 years. In 17 patients, it presented de novo during repositioning treatment for 'classical' posterior canal BPV. Repositioning is in the horizontal plane, with the direction depending on whether the mechanism is canalithiasis or cupulolithiasis.
  
  
  CONCLUSIONS
  Horizontal canal BPV explains nearly all variations on 'classical' (posterior canal) BPV. It accounts for at least 10% of BPV and has been frequently misdiagnosed. Repositioning is usually curative if the symptomatic ear is correctly identified.
authors.affiliation: Department of Otolaryngology-HNS, Christchurch Hospital, Christchurch, New Zealand. jhornibrook@paradise.net.nz
authors.forename: Jeremy
authors.initials: J
authors.lastname: Hornibrook
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004424:Ear Canal; D005260:Female; D006801:Humans; D020347:Lithiasis / Q000150:complications*; D008297:Male; D008875:Middle Aged; D009759:Nystagmus, Pathologic / Q000175:diagnosis / Q000209:etiology; D014717:Vertigo / Q000175:diagnosis* / Q000209:etiology* / Q000628:therapy; D014839:Vomiting / Q000209:etiology