title: Comparison of clinical associations of patients with vasculopathic and idiopathic downbeat nystagmus.
abstract: OBJECTIVE
  To perform a pilot study comparing age and vascular risk factors of patients with vasculopathic and idiopathic downbeat nystagmus (DBN).
  
  
  METHODS
  We reviewed the case records of 57 patients with DBN evaluated between 1987 and 1999, and classified each patient into three groups: vasculopathic, idiopathic, and other known causes. We then compared age and five weighted established stroke risk factors in patients with vasculopathic and idiopathic DBN.
  
  
  RESULTS
  Of ten idiopathic cases, there were seven women and three men, ranging in age from 31 to 90 years (median, 79 years). Of the nine vasculopathic cases, there were seven women and two men, ranging in age from 50 to 86 years (median, 80 years). Using the Mann-Whitney U test, there was no significant difference between the two groups in terms of age (p = 0.84) or vascular risk-factor profile (p = 0.24).
  
  
  CONCLUSIONS
  The lack of significant difference between the two groups for age and vascular risk factors supports the hypothesis that some idiopathic cases of DBN may be caused by strategically located and radiographically occult cerebral infarctions.
authors.affiliation: Department of Medical Education, Marshfield Clinic, Wisconsin 54449, USA.
authors.forename: J L
authors.initials: JL
authors.lastname: Olson
authors.forename: D M
authors.initials: DM
authors.lastname: Jacobson
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002544:Cerebral Infarction / Q000150:complications*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009759:Nystagmus, Pathologic / Q000209:etiology*; D010865:Pilot Projects; D012307:Risk Factors; D020521:Stroke / Q000150:complications*