title: Head-shaking nystagmus predicts greater disability in unilateral peripheral vestibulopathy.
abstract: OBJECTIVE
  The objective of this study was to determine the association of the bedside test of head-shaking nystagmus (HSN) with patients' self-perceived dizziness handicap as well as this test's sensitivity and specificity in unilateral peripheral vestibular hypofunction.
  
  
  METHODS
  A retrospective case-control study was performed.
  
  
  METHODS
  The study was held at an academic, tertiary referral center.
  
  
  METHODS
  Fifty-three adult patients with unilateral peripheral hypofunction defined by the caloric test of the videonystagmography with documented bedside HSN and who had completed questionnaires of self-perceived dizziness handicap were included. The sensitivity and specificity of the bedside HSN in patients and 10 healthy controls in diagnosing unilateral vestibular hypofunction defined by videonystagmographic caloric testing and by abnormal gain and symmetry of the vestibular-ocular reflex by rotary chair testing were determined. Scores of the screening test of the Dizziness Handicap Index and Functional Level Scale questionnaires were taken.
  
  
  RESULTS
  When using the caloric irrigation test as the reference standard for unilateral vestibular hypofunction, the sensitivity, specificity, and positive predictive value of the bedside HSN were 31%, 96%, and 97%, respectively. When comparing with results of rotational chair testing (vestibular-ocular reflex gain and symmetry), the sensitivity of the HSN test increases to 71%. Patients with positive bedside HSN had higher scores (greater self-perceived dizziness handicap) of the Dizziness Handicap Index (P = .049) and higher (worse) scores of the Functional Level Scale (P = .0377) than those with negative bedside HSN (Wilcoxon rank test).
  
  
  CONCLUSIONS
  Greater perceived handicap was correlated with a positive bedside HSN in patients with unilateral peripheral vestibulopathy. The HSN has sufficient sensitivity to be used as screening test of uncompensated vestibulopathy in this series. However, a negative HSN alone does not rule out the diagnosis of peripheral vestibular dysfunction.
authors.affiliation: Department of Otolaryngology, University of Miami Ear Institute, University of Miami Miller School of Medicine, FL 33136, USA. sangeli@med.miami.edu
authors.forename: Simon I
authors.initials: SI
authors.lastname: Angeli
authors.forename: Sandra
authors.initials: S
authors.lastname: Velandia
authors.forename: Hillary
authors.initials: H
authors.lastname: Snapp
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002150:Caloric Tests; D016022:Case-Control Studies; D004185:Disability Evaluation; D004244:Dizziness / Q000175:diagnosis / Q000209:etiology; D005260:Female; D019416:Head Movements; D006801:Humans; D008297:Male; D008875:Middle Aged; D009759:Nystagmus, Pathologic / Q000150:complications / Q000175:diagnosis*; D011237:Predictive Value of Tests; D012016:Reference Values; D012189:Retrospective Studies; D012647:Self-Assessment; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D018709:Statistics, Nonparametric; D011795:Surveys and Questionnaires; D014717:Vertigo / Q000503:physiopathology*; D015837:Vestibular Diseases / Q000150:complications / Q000175:diagnosis*; D014724:Vestibular Function Tests; D055815:Young Adult