title: Clinical course of persistent geotropic direction-changing positional nystagmus with neutral position-Light cupula.
abstract: CONCLUSIONS
  A short clinical course and frequent recurrence are common features of persistent geotropic direction-changing positional nystagmus with neutral position (positional nystagmus of light cupula: PNLC) and cupulolithiasis of the lateral semicircular canal. It is suggested that PNLC is caused by light debris attached to the cupula of the lateral semicircular canal.
  
  
  OBJECTIVE
  PNLC is a sub-type of direction-changing positional nystagmus. It is thought to be caused by anti-gravitational deviation of the cupula of the lateral semicircular canal (light cupula); however, the exact mechanism is yet to be elucidated. To this end, the clinical features of PNLC were studied.
  
  
  METHODS
  Clinical charts of 27 patients (13 men and 14 women) with PNLC were reviewed.
  
  
  RESULTS
  The nystagmus had resolved within a week in 70% and within 30 days in 89% of the patients. The recurrence rate was 33%. The subjects did not have a history of alcohol intake, head trauma, or vestibular neuritis.
authors.affiliation: a Department of Otolaryngology , Kinki University Faculty of Medicine , Osakasayama, Osaka , Japan.
authors.forename: Toru
authors.initials: T
authors.lastname: Seo
authors.affiliation: a Department of Otolaryngology , Kinki University Faculty of Medicine , Osakasayama, Osaka , Japan.
authors.forename: Ko
authors.initials: K
authors.lastname: Shiraishi
authors.affiliation: a Department of Otolaryngology , Kinki University Faculty of Medicine , Osakasayama, Osaka , Japan.
authors.forename: Takaaki
authors.initials: T
authors.lastname: Kobayashi
authors.affiliation: a Department of Otolaryngology , Kinki University Faculty of Medicine , Osakasayama, Osaka , Japan.
authors.forename: Kitano
authors.initials: K
authors.lastname: Mutsukazu
authors.affiliation: a Department of Otolaryngology , Kinki University Faculty of Medicine , Osakasayama, Osaka , Japan.
authors.forename: Katsumi
authors.initials: K
authors.lastname: Doi
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009759:Nystagmus, Pathologic / Q000209:etiology* / Q000503:physiopathology*; D011187:Posture; D012008:Recurrence; D012307:Risk Factors; D012665:Semicircular Canals; D013997:Time Factors; D014724:Vestibular Function Tests
keywords: Ampulla; anti-gravitational deviation; lateral semicircular canal; light cupula