title: Uncrossed Asymmetry in Pattern Visual Evoked Potentials: A Reappraisal.
abstract: OBJECTIVE
  To demonstrate the utility of an uncrossed asymmetry in full-field pattern reversal visual evoked potentials (FF-PVEPs) will accurately predict a retrochiasmal lesion confirmed by MRI.
  
  
  METHODS
  During an 8-year period, 754 patients had FF-PVEPs performed and analyzed without knowledge of their clinical histories and imaging studies. Interhemispheric amplitude ratios were calculated between N75-P100 and P100-N145 and deemed significant if both demonstrated greater than 50% amplitude asymmetry no matter which eye was stimulated (uncrossed symmetry).
  
  
  RESULTS
  We identified 11 patients of 754 patients evaluated for 8 years (1.5%) whose FF-PVEP fulfilled our amplitude criteria. Ten of 11 had retrochiasmal lesions confirmed with MRI for a calculated positive predictive value of 91%.
  
  
  CONCLUSIONS
  These data provide initial support for the hypothesis that specified amplitude criteria in FF-PVEPs can provide evidence for a retrochiasmal lesion. An abnormal interhemispheric amplitude ratio in FF-PVEPs is underrecognized as a diagnostic criterion for retrochiasmal lesion prediction.
authors.affiliation: Neurological Testing Center, Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, U.S.A.
authors.forename: Eric J
authors.initials: EJ
authors.lastname: Ericson
authors.forename: Jonathan
authors.initials: J
authors.lastname: Lubin
authors.forename: Michael M
authors.initials: MM
authors.lastname: Minieka
authors.forename: Takashi
authors.initials: T
authors.lastname: Nishida
mesh_terms: D000328:Adult; D004569:Electroencephalography; D005074:Evoked Potentials, Visual / Q000502:physiology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009460:Neurologic Examination; D009897:Optic Chiasm / Q000002:abnormalities* / Q000000981:diagnostic imaging / Q000503:physiopathology*; D012189:Retrospective Studies; D014795:Visual Pathways / Q000503:physiopathology