title: [Pathophysiology and diagnosis of congenital periodic alternating nystagmus].
abstract: OBJECTIVE
  Not many cases of congenital periodic alternating nystagmus have been reported in Japan. We investigated the pathophysiology and diagnosis of congenital periodic alternating nystagmus noting the age when this disease began, which had not been reported previously.
  
  
  METHODS
  Ninety-one patients with congenital nystagmus who were seen in our department in Teikyo University School of Medicine between July 1994 and January 2002 were studied.
  
  
  RESULTS
  Eighteen patients(19.8%) among the 91 congenital nystagmus patients were diagnosed with congenital periodic alternating nystagmus. A manifestation of the periodic face turning was seen between the age of three and nine. Visual acuity over 0.6 with correction was obtained in all patients. Almost all the patients had an asymmetric cycle of null point shifting and the face turning was seen at one side for a long time.
  
  
  CONCLUSIONS
  When we see congenital nystagmus patients whose face turning alters periodically with fairly good vision over the age of three, we must check out the direction of jerk nystagmus changes at the same gazing point using electronystagmography or video cassette recording to detect the possibility of congenital periodic alternating nystagmus.
authors.affiliation: Department of Ophthalmology, Seibo Internatinal Catholic Hospital, 2-5-1 Naka-Ochiai, Shinjyuku-ku, Tokyo 161-8521, Japan.
authors.forename: Takao
authors.initials: T
authors.lastname: Hayashi
authors.forename: Fumiyo
authors.initials: F
authors.lastname: Hasegawa
authors.forename: Chie
authors.initials: C
authors.lastname: Usui
authors.forename: Nobue
authors.initials: N
authors.lastname: Kubota
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D020417:Nystagmus, Congenital / Q000175:diagnosis* / Q000503:physiopathology*