title: Visual evoked potential latency, amplitude and habituation in migraine: a longitudinal study.
abstract: OBJECTIVE
  It has not been previously studied with a paired longitudinal design if visual excitability changes occur in the preattack period across the migraine cycle, or how excitability and habituation relate to migraine-attack severity, clinical photophobia and serotonin metabolism.
  
  
  METHODS
  Monocular 62' check reversals were applied in 33 adult migraine patients without aura (MwoA), 8 with aura (MA) and 31 controls. VEP was recorded in four blocks of 50 stimuli. P1 (P100) and N2 (N145) latency and N1P1 and P1N2 amplitude were measured. Serotonin was measured in plasma and platelets sampled before each session. Sessions were classified as preattack, attack, postattack or interictal.
  
  
  RESULTS
  Migraine patients had significantly higher P1N2 amplitude before the attack compared to a paired interictal recording (n=13, p=0.03), but habituation difference was not found. MA patients had significantly higher P1N2 and N1P1 amplitude than controls and MwoA. P1 latency correlated positively with headache history duration. During attack, a positive correlation between P1N2 amplitude habituation and serotonin emerged in MA patients.
  
  
  CONCLUSIONS
  Increased VEP P1N2 amplitude was observed within a few days before the attack. Visual cortex excitability seems to be generally increased in MA as compared to MwoA patients and controls.
  
  
  CONCLUSIONS
  Increased excitability of the visual cortex seems to be detectable in the preattack state, supporting the concept of a cyclic CNS dysfunction in migraine.
authors.affiliation: Department of Neuroscience, Norwegian University of Science and Technology, St. Olavs University Hospital, N-7006 Trondheim, Norway. trond.sand@ntnu.no
authors.forename: Trond
authors.initials: T
authors.lastname: Sand
authors.forename: Nikita
authors.initials: N
authors.lastname: Zhitniy
authors.forename: Linda R
authors.initials: LR
authors.lastname: White
authors.forename: Lars Jacob
authors.initials: LJ
authors.lastname: Stovner
mesh_terms: D000328:Adult; D001792:Blood Platelets / Q000737:chemistry / Q000378:metabolism; D004569:Electroencephalography; D005074:Evoked Potentials, Visual / Q000502:physiology*; D005260:Female; D006185:Habituation, Psychophysiologic / Q000502:physiology*; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008881:Migraine Disorders / Q000378:metabolism / Q000503:physiopathology*; D020795:Photophobia / Q000209:etiology; D011930:Reaction Time / Q000502:physiology*; D012701:Serotonin / Q000032:analysis
chemical_list: D012701:Serotonin