title: Visual cortex excitability and plasticity associated with remission from chronic to episodic migraine.
abstract: OBJECTIVE
  Previous magnetoencephalographic (MEG) studies showed different P100m (where 'm' denotes the magnetic counterpart of P100 in conventional visual evoked potentials) responses between episodic migraine (EM) and chronic migraine (CM) interictally. This study investigated the changes of visual P100m in CM patients who remitted to EM from CM after treatment.
  
  
  METHODS
  At baseline, 25 patients with CM were studied interictally. For each patient, 30 sequential blocks of 50 P100m responses were obtained by MEG. Sub-averaged amplitudes at blocks 2, 9, 16, 23 and 30 were further compared with that at block 1 to assess response habituation or potentiation (i.e. significant decrease or increase at either block vs block 1). The same study was repeated in those patients who remitted from CM to EM after topiramate treatment.
  
  
  RESULTS
  In total, 10 CM patients remitted to EM after treatment. In the follow-up study of these patients during the interictal stage, the P100m at block 1 decreased in amplitude from 53.6 ± 6.6 nAm before remission to 43.0 ± 5.1 nAm (p = 0.028), and the responses at subsequent blocks switched from habituation (amplitude block 30 < block 1 before remission, p = 0.011) to potentiation (block 2 > block 1, p = 0.028).
  
  
  CONCLUSIONS
  The pattern of P100m responses to consecutive stimulation changes with the transition from CM to EM. Visual cortex plasticity might be a potential biomarker reflecting clinical remission of CM.
authors.affiliation: Neurological Institute, Taipei Veterans General Hospital, Taipei, Taiwan, Republic of China.
authors.forename: Wei-Ta
authors.initials: WT
authors.lastname: Chen
authors.forename: Shuu-Jiun
authors.initials: SJ
authors.lastname: Wang
authors.forename: Jong-Ling
authors.initials: JL
authors.lastname: Fuh
authors.forename: Yu-Chieh
authors.initials: YC
authors.lastname: Ko
authors.forename: Yi-Chung
authors.initials: YC
authors.lastname: Lee
authors.forename: Matti S
authors.initials: MS
authors.lastname: Hämäläinen
authors.forename: Yung-Yang
authors.initials: YY
authors.lastname: Lin
mesh_terms: D000328:Adult; D000927:Anticonvulsants / Q000008:administration & dosage; D002908:Chronic Disease; D005074:Evoked Potentials, Visual / Q000187:drug effects / Q000502:physiology; D005260:Female; D005500:Follow-Up Studies; D005632:Fructose / Q000008:administration & dosage / Q000031:analogs & derivatives*; D006801:Humans; D015225:Magnetoencephalography; D008297:Male; D008881:Migraine Disorders / Q000188:drug therapy* / Q000503:physiopathology*; D009473:Neuronal Plasticity / Q000187:drug effects* / Q000502:physiology; D012074:Remission Induction; D000077236:Topiramate; D014793:Visual Cortex / Q000187:drug effects* / Q000502:physiology; D055815:Young Adult
chemical_list: D000927:Anticonvulsants; D000077236:Topiramate; D005632:Fructose