title: Paradoxical air microembolism induces cerebral bioelectrical abnormalities and occasionally headache in patent foramen ovale patients with migraine.
abstract: BACKGROUND
  Although controversial, paradoxical embolism via patent foramen ovale (PFO) may account for some of the migraine attacks in a subset of migraine with aura (MA) patients. Induction of MA attacks with air bubble injection during transcranial Doppler ultrasound in MA patients with PFO supports this view. It is likely that cerebral embolism in patients with right-to-left shunt induces bioelectrical abnormalities to initiate MA under some conditions.
  
  
  RESULTS
  We investigated changes in cerebral bioelectrical activity after intravenous microbubble injection in 10 MA patients with large PFO and right-to-left cardiac shunt. Eight PFO patients without migraine but with large right-to-left shunt and 12 MA patients without PFO served as controls. Four MA patients with PFO were reexamined with sham injections of saline without microbubbles. Bioelectrical activity was evaluated using spectral electroencephalography and, passage of microbubbles through cerebral arteries was monitored with transcranial Doppler ultrasound. Microbubble embolism caused significant electroencephalographic power increase in MA+PFO patients but not in control groups including the sham-injected MA+PFO patients. Headache developed in 2 MA with PFO patients after microbubble injection.
  
  
  CONCLUSIONS
  These findings demonstrate that air microembolism through large PFOs may cause cerebral bioelectrical disturbances and, occasionally, headache in MA patients, which may reflect an increased reactivity of their brain to transient subclinical hypoxia-ischemia, and suggest that paradoxical embolism is not a common cause of migraine but may induce headache in the presence of a large PFO and facilitating conditions.
authors: Department of Neurology, Faculty of Medicine, Hacettepe University,  Ankara, Turkey.
authors: Eser Başak
authors: EB
authors: Sevgi
authors: Sefik Evren
authors: SE
authors: Erdener
authors: Mehmet
authors: M
authors: Demirci
authors: Mehmet Akif
authors: MA
authors: Topcuoglu
authors: Turgay
authors: T
authors: Dalkara
mesh_terms: D000293:Adolescent; D000328:Adult; D016022:Case-Control Studies; D004553:Electric Conductivity; D004569:Electroencephalography; D004618:Embolism, Air; D005260:Female; D054092:Foramen Ovale, Patent / Q000150:complications* / Q000503:physiopathology; D006261:Headache / Q000209:etiology* / Q000503:physiopathology; D006801:Humans; D020766:Intracranial Embolism / Q000209:etiology / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D020325:Migraine with Aura / Q000150:complications* / Q000503:physiopathology; D017585:Ultrasonography, Doppler, Transcranial; D055815:Young Adult
keywords: PFO; cerebral ischemia; embolism; migraine; shunts