title: Benign intermittent upbeat nystagmus in infancy: a new clinical entity.
abstract: BACKGROUND
  Upbeat nystagmus in childhood is a rare phenomenon, which is classically associated with neurological or anterior visual pathway dysfunction.
  
  
  METHODS
  We report a series of five infants with an intermittent upbeat nystagmus, without any other ocular or neurological abnormality, having spontaneously resolved before the age of 14 months.
  
  
  RESULTS
  Nystagmus beating frequency was between 1.5 and 2.5 Hz for all patients, amplitude was remarkably large due to a baseline position in downgaze. The nystagmus mostly occurred in supine position and could be triggered by head rotations in the supine position. Age of onset was from the first weeks of life to two months; age of resolution was 5-14 months. All infants underwent complete clinical examination with ophthalmological, oto-neurological and neurological assessments and MRI-scan.
  
  
  CONCLUSIONS
  Clinical characteristics of the nystagmus suggest an involvement of the otolithic system, with a secondary recalibration of the vestibulo-ocular pathways; however, no obvious vestibular abnormality was found. The pathophysiology of this nystagmus therefore remains unclear.
authors.affiliation: AP-HP, Hôpital Universitaire Necker-Enfants Malades, Service d'ophtalmologie, Rue de Sèvres, 75015 Paris, France; COGNition and ACtion Group (COGNAC-G), UMR 8257: CNRS-IRBA-Université Paris Descartes, Sorbonne Paris Cité, France.
authors.forename: Matthieu P
authors.initials: MP
authors.lastname: Robert
authors.affiliation: AP-HP, Hôpital Universitaire Necker-Enfants Malades, Service d'ophtalmologie, Rue de Sèvres, 75015 Paris, France. Electronic address: sarahmichelawad@gmail.com.
authors.forename: Sarah
authors.initials: S
authors.lastname: Michel
authors.affiliation: Cabinet d'ophtalmologie, 17 Avenue de Luserna, 1203 Genève, Switzerland.
authors.forename: Elias
authors.initials: E
authors.lastname: Adjadj
authors.affiliation: AP-HP, Hôpital Universitaire Necker-Enfants Malades, Service d'imagerie Pédiatrique, Rue de Sèvres, 75015 Paris, France.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Boddaert
authors.affiliation: AP-HP, Hôpital Universitaire Necker-Enfants Malades, Service de Neurologie Pédiatrique, Rue de Sèvres, 75015 Paris, France.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Desguerre
authors.affiliation: COGNition and ACtion Group (COGNAC-G), UMR 8257: CNRS-IRBA-Université Paris Descartes, Sorbonne Paris Cité, France.
authors.forename: Pierre-Paul
authors.initials: PP
authors.lastname: Vidal
mesh_terms: D017668:Age of Onset; D005260:Female; D019416:Head Movements; D006320:Hearing Tests; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008279:Magnetic Resonance Imaging; D008297:Male; D009434:Neural Pathways / Q000503:physiopathology; D009460:Neurologic Examination; D009759:Nystagmus, Pathologic / Q000503:physiopathology*; D009760:Nystagmus, Physiologic; D012027:Reflex, Vestibulo-Ocular / Q000502:physiology; D012075:Remission, Spontaneous; D012399:Rotation; D016683:Supine Position; D014787:Vision Tests
keywords: Infant; Positional nystagmus; Tonic downgaze; Upbeat nystagmus