title: Immediate and Short-Term Therapeutic Results Between Direction-Changing Positional Nystagmus with Short- and Long-Duration Groups.
abstract: OBJECTIVE
  Clinicians sometimes treat patients with relatively long-duration geotropic direction-changing positional nystagmus (DCPN), without latency. Recently, the concept of a "light cupula" in the lateral canal that reveals persistent geotropic DCPN has been introduced. In the present study, we investigated the immediate and short-term therapeutic findings in long-duration DCPN.
  
  
  METHODS
  The authors prospectively compared the therapeutic efficacy of a canalith-repositioning procedure (CRP) in short- and long-duration geotropic DCPN.
  
  
  RESULTS
  In patients with long-duration DCPN, the authors found no immediate therapeutic effect, and the number of patients showing short-term effects (on the next day) was very low compared with the comparable figure among those with short-duration DCPN. In addition, no cases exhibited canal conversion after the CRP.
  
  
  CONCLUSIONS
  Our results suggest that CRP is not useful in patients with long-duration geotropic DCPN, and the pathogenesis of long-duration geotropic DCPN may not originate from free-floating debris but from deflection of the cupula.
authors.affiliation: 1Department of Otorhinolaryngology-Head and Neck Surgery, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Korea; and 2Department of Otorhinolaryngology-Head and Neck Surgery, Dongtan Sacred Heart Hospital, Hallym University College of Medicine, Hwaseong, Korea.
authors.forename: Jae Ho
authors.initials: JH
authors.lastname: Ban
authors.forename: Min-Beom
authors.initials: MB
authors.lastname: Kim
authors.forename: Seok Min
authors.initials: SM
authors.lastname: Hong
mesh_terms: D000328:Adult; D000368:Aged; D065635:Benign Paroxysmal Positional Vertigo / Q000503:physiopathology / Q000628:therapy*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009759:Nystagmus, Pathologic / Q000503:physiopathology / Q000628:therapy*; D009760:Nystagmus, Physiologic; D056888:Patient Positioning / Q000379:methods*; D011187:Posture; D011446:Prospective Studies; D012665:Semicircular Canals; D013997:Time Factors; D055815:Young Adult