title: Predictive properties of the video head impulse test: measures of caloric symmetry and self-report dizziness handicap.
abstract: OBJECTIVE
  The purpose of this investigation was to determine whether a predictable relationship existed between self-reported dizziness handicap and video Head Impulse Test (vHIT) results in a large sample of patients reporting to a dizziness clinic. Secondary objectives included describing the characteristics of the vHIT ipsilesional and contralesional vestibulo-ocular reflex slow-phase velocity in patients with varying levels of canal paresis. Finally, the authors calculated the sensitivity and specificity of the vHIT for detecting horizontal semicircular canal impairment using the caloric test as the "gold standard."
  
  
  METHODS
  Participants were 115 adults presenting to a tertiary medical care center with symptoms of dizziness. Participants were administered a measure of self-report dizziness handicap (i.e., Dizziness Handicap Inventory) and underwent caloric testing and vHIT at the same appointment.
  
  
  RESULTS
  Results showed that (1) there were no significant group differences (i.e., vHIT normal versus vHIT abnormal) in the Dizziness Handicap Inventory total score, (2) both ipsilesional and contralateral velocity gain decreased with increases in caloric paresis, and (3) a caloric asymmetry of 39.5% was determined to be the cutoff that maximized discrimination of vHIT outcome.
  
  
  CONCLUSIONS
  The level of self-reported dizziness handicap is not predicted by the outcome of the vHIT, which is consistent with the majority of published reports describing the poor relationship between quantitative tests of vestibular function and dizziness handicap. Further, the study findings have demonstrated that vHIT and caloric data are not redundant, and each test provides unique information regarding the functional integrity of the horizontal semicircular canal at different points on the frequency spectrum. The vHIT does offer some advantages over caloric testing, but at the expense of sensitivity. The vHIT can be completed in less time, is not noxious to the patient, and requires very little laboratory space. However, the study data show that a caloric asymmetry of 39.5% is required to optimize discrimination between an abnormal and normal vHIT. It is the authors' contention that the vHIT is a complementary test to the balance function examination and should viewed as such rather than as a replacement for caloric testing.
authors.affiliation: 1Division of Vestibular Sciences, Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, Nashville, Tennessee, USA; and 2Department of Otolaryngology-Head and Neck Surgery, Vanderbilt University Medical Center, Nashville, Tennessee, USA.
authors.forename: Devin L
authors.initials: DL
authors.lastname: McCaslin
authors.forename: Gary P
authors.initials: GP
authors.lastname: Jacobson
authors.forename: Marc L
authors.initials: ML
authors.lastname: Bennett
authors.forename: Jill M
authors.initials: JM
authors.lastname: Gruenwald
authors.forename: Andrea P
authors.initials: AP
authors.lastname: Green
mesh_terms: D000328:Adult; D002150:Caloric Tests; D004244:Dizziness; D005260:Female; D064087:Head Impulse Test; D006801:Humans; D008297:Male; D008875:Middle Aged; D012027:Reflex, Vestibulo-Ocular; D057566:Self Report; D012665:Semicircular Canals / Q000503:physiopathology*; D012680:Sensitivity and Specificity; D014717:Vertigo / Q000175:diagnosis* / Q000503:physiopathology; D015837:Vestibular Diseases / Q000175:diagnosis / Q000503:physiopathology; D014741:Video Recording