title: Electrophysiological evidence for heterogeneity of lesions in optic neuritis.
abstract: OBJECTIVE
  To examine the natural history of multifocal visual evoked potentials (mfVEPs) within 12 months of the first episode of optic neuritis (ON) in patients with possible multiple sclerosis (MS).
  
  
  METHODS
  Twenty-seven patients with a first episode of ON, no previous demyelinating events, and MRI lesions consistent with demyelination were examined with mfVEP. Changes in amplitude and latency of mfVEP were analyzed at 1, 3, 6, and 12 months after an acute attack.
  
  
  RESULTS
  Five of 27 patients had persistent loss of amplitude after 12 months of follow-up. This loss was most marked centrally. Amplitude recovered in the remaining 22 patients at 1 month, but delayed latency, which was also most marked centrally, persisted. Of these, two distinct subgroups were identified: six patients with no improvement in latency and 16 patients with significant latency recovery over the 12 months of follow-up, suggesting remyelination. Conversion to MS was highest in the group with severe amplitude loss, followed by the group with no latency recovery. The conversion rate was lowest in the group of patients with latency improvement.
  
  
  CONCLUSIONS
  Distinct patterns of disease evolution were identified using mfVEP in patients with first episode of optic neuritis and at high risk for MS, supporting the concept of heterogeneity of early lesions in MS.
authors: Department of Ophthalmology, Save Sight Institute, University of Sydney, Sydney, Australia.
authors: Alexander
authors: A
authors: Klistorner
authors: Stuart
authors: S
authors: Graham
authors: Clare
authors: C
authors: Fraser
authors: Raymond
authors: R
authors: Garrick
authors: Tan
authors: T
authors: Nguyen
authors: Michael
authors: M
authors: Paine
authors: Justin
authors: J
authors: O'Day
authors: John
authors: J
authors: Grigg
authors: Hemamalini
authors: H
authors: Arvind
authors: Frank A
authors: FA
authors: Billson
mesh_terms: D000208:Acute Disease; D000293:Adolescent; D000328:Adult; D005074:Evoked Potentials, Visual / Q000502:physiology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000503:physiopathology; D009902:Optic Neuritis / Q000175:diagnosis / Q000503:physiopathology*; D011446:Prospective Studies; D011930:Reaction Time