title: The occipital alpha rhythm related to the "migraine cycle" and headache burden: a blinded, controlled longitudinal study.
abstract: OBJECTIVE
  Neurophysiological studies have shown a fluctuating neural dysfunction in migraine. This pathophysiological feature has not previously been investigated by quantitative electroencephalography (QEEG). The alpha rhythm is especially interesting, because it is influenced by ischemia and neuronal dysfunction within the posterior circulation area.
  
  
  METHODS
  We investigated alpha peak frequency, variability, peak power and asymmetry in 41 migraineurs and 32 controls. Electroencephalography (EEG) was recorded on three random days and retrospectively classified as preattack, attack, postattack or interictal, based on the patient's headache diaries. We also searched for correlations between alpha rhythm parameters and disease duration, attack duration, attack frequency, pain intensity and photophobia.
  
  
  RESULTS
  Peak frequency reduction correlated with increasing disease- and attack duration. Frequency variability increased before the attack, while peak power increased during the attack. Alpha peak width, peak frequency and peak power were similar for migraineurs and controls in the interictal period.
  
  
  CONCLUSIONS
  The accumulated burden of migraine caused slight alterations in the physiology of the visual cortex. Small alpha rhythm changes were observed along the migraine cycle.
  
  
  CONCLUSIONS
  This is a longitudinal, controlled study. It is the first to report changes in alpha rhythm with increased migraine load, even when the QEEG is not influenced by recent or imminent attacks.
authors.affiliation: Department of Neuroscience, Norwegian University of Science and Technology (NTNU), MTFS, N-7489 Trondheim, Norway. marte.bjork@ntnu.no
authors.forename: M H
authors.initials: MH
authors.lastname: Bjørk
authors.forename: L J
authors.initials: LJ
authors.lastname: Stovner
authors.forename: B M
authors.initials: BM
authors.lastname: Nilsen
authors.forename: M
authors.initials: M
authors.lastname: Stjern
authors.forename: K
authors.initials: K
authors.lastname: Hagen
authors.forename: T
authors.initials: T
authors.lastname: Sand
mesh_terms: D000328:Adult; D000513:Alpha Rhythm; D017281:Cost of Illness; D004569:Electroencephalography / Q000379:methods*; D005071:Evoked Potentials / Q000502:physiology; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D008881:Migraine Disorders / Q000175:diagnosis / Q000503:physiopathology*; D009778:Occipital Lobe / Q000503:physiopathology*; D010147:Pain Measurement / Q000379:methods; D020795:Photophobia / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D012720:Severity of Illness Index; D013997:Time Factors; D055815:Young Adult