title: Head position dependency of induced nystagmus to ice-water irrigation in peripheral vestibulopathy.
abstract: OBJECTIVE
  Evaluation of head-position dependency during the ice-water test is essential when the test is indicated. Because ice-water irrigation (IWI) in the prone position is frequently skipped in many laboratories, we investigated the importance of evaluating position dependency in an ice-water test.
  
  
  METHODS
  Twenty-five unilateral peripheral vestibulopathy patients showing no nystagmus during warm irrigation were included. IWI was performed in supine and prone positions, and maximum slow-phase velocity and direction of nystagmus were assessed by using video nystagmography.
  
  
  RESULTS
  Eleven cases showed head-position dependency and were interpreted as hypofunctional. Fourteen cases showed no dependency, suggesting the absence of end organ function. In the latter group, 6 patients showing definite nystagmus in supine position could have been misinterpreted as hypofunctional, had it not been for prone-position results.
  
  
  CONCLUSIONS
  Evaluation of head position dependency by using IWI is important in the determination of lateral semicircular canal function.
authors.affiliation: Department of Otolaryngology, Seoul National University College of Medicine, Korea.
authors.forename: Byung Yoon
authors.initials: BY
authors.lastname: Choi
authors.forename: Ja-Won
authors.initials: JW
authors.lastname: Koo
authors.forename: Seung Ha
authors.initials: SH
authors.lastname: Oh
authors.forename: Sun O
authors.initials: SO
authors.lastname: Chang
authors.forename: Chong-Sun
authors.initials: CS
authors.lastname: Kim
mesh_terms: D000328:Adult; D000368:Aged; D004584:Electronystagmography; D005133:Eye Movements / Q000502:physiology; D005260:Female; D006257:Head; D006801:Humans; D007053:Ice; D008297:Male; D008875:Middle Aged; D009760:Nystagmus, Physiologic; D011187:Posture; D007507:Therapeutic Irrigation; D015837:Vestibular Diseases / Q000209:etiology / Q000503:physiopathology*; D014743:Videotape Recording; D014867:Water
chemical_list: D007053:Ice; D014867:Water