title: Office-based differential diagnosis of transient and persistent geotropic positional nystagmus in patients with horizontal canal type of benign paroxysmal positional vertigo.
abstract: CONCLUSIONS
  A 30 s observation of geotropic positional nystagmus is sufficient to distinguish persistent geotropic positional nystagmus (PGPN) from transient geotropic positional nystagmus (TGPN) in patients with horizontal canal type of benign paroxysmal positional vertigo (H-BPPV) in ENT office.
  
  
  OBJECTIVE
  As a canalith repositioning procedure effectively treats H-BPPV with TGPN, but not PGPN, the differentiation between patients with PGPN and with TGPN is essential. The purpose of this study is to determine the observation period enough to distinguish TGPN from PGPN.
  
  
  METHODS
  This study first analyzed positional nystagmus images recorded with an infrared CCD camera three-dimensionally in 47 patients with H-BPPV. PGPN is distinguished from TGPN in patients with H-BPPV precisely by means of time constant calculated form analysis of positional nystagmus. Ten-second and 30-s movies were made of positional nystagmus of the all 47 patients. Ten independent otolaryngologists were then asked to distinguish TGPN from PGPN after a 10 s or 30 s observation of the geotropic positional nystagmus images in 47 patients with H-BPPV.
  
  
  RESULTS
  The sensitivity and specificity to distinguish TGPN from PGPN was 100% and 97% after 30 s observation, but 100% and 40% after 10 s observation, respectively.
authors.affiliation: a Department of Otorhinolaryngology - Head and Neck Surgery , Osaka University Graduate School of Medicine , Osaka , Japan.
authors.forename: Suzuyo
authors.initials: S
authors.lastname: Okazaki
authors.affiliation: a Department of Otorhinolaryngology - Head and Neck Surgery , Osaka University Graduate School of Medicine , Osaka , Japan.
authors.forename: Takao
authors.initials: T
authors.lastname: Imai
authors.affiliation: b Department of Otolaryngology , Suita Municipal Hospital , Osaka , Japan.
authors.forename: Kayoko
authors.initials: K
authors.lastname: Higashi-Shingai
authors.affiliation: c Department of Otorhinolaryngology - Head and Neck Surgery , Tokushima University Graduate School of Medicine , Tokushima , Japan.
authors.forename: Kazunori
authors.initials: K
authors.lastname: Matsuda
authors.affiliation: c Department of Otorhinolaryngology - Head and Neck Surgery , Tokushima University Graduate School of Medicine , Tokushima , Japan.
authors.forename: Noriaki
authors.initials: N
authors.lastname: Takeda
authors.affiliation: d Department of Otolaryngology - Head and Neck Surgery , Nara Medical University , Nara , Japan.
authors.forename: Tadashi
authors.initials: T
authors.lastname: Kitahara
authors.affiliation: e Department of Otorhinolaryngology - Head and Neck Surgery , Osaka General Medical Center , Osaka , Japan.
authors.forename: Atsuhiko
authors.initials: A
authors.lastname: Uno
authors.affiliation: f Department of Otolaryngology - Head and Neck Surgery , Niigata University Graduate School of Medical and Dental Sciences , Niigata , Japan.
authors.forename: Arata
authors.initials: A
authors.lastname: Horii
authors.affiliation: a Department of Otorhinolaryngology - Head and Neck Surgery , Osaka University Graduate School of Medicine , Osaka , Japan.
authors.forename: Yumi
authors.initials: Y
authors.lastname: Ohta
authors.affiliation: g Department of Otorhinolaryngology , National Hospital Organization Osaka National Hospital , Osaka , Japan.
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Morihana
authors.affiliation: b Department of Otolaryngology , Suita Municipal Hospital , Osaka , Japan.
authors.forename: Chisako
authors.initials: C
authors.lastname: Masumura
authors.affiliation: h Department Otorhinolaryngology - Head and Neck Surgery , Osaka Rosai Hospital , Osaka , Japan.
authors.forename: Suetaka
authors.initials: S
authors.lastname: Nishiike
authors.affiliation: a Department of Otorhinolaryngology - Head and Neck Surgery , Osaka University Graduate School of Medicine , Osaka , Japan.
authors.forename: Hidenori
authors.initials: H
authors.lastname: Inohara
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D065635:Benign Paroxysmal Positional Vertigo / Q000145:classification / Q000175:diagnosis*; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009760:Nystagmus, Physiologic
keywords: Geotropic positional nystagmus; benign paroxysmal positional vertigo; three-dimensional; time constant