title: Increase in alpha rhythm frequency after carotid endarterectomy.
abstract: OBJECTIVE
  Besides preventing stroke, carotid endarterectomy (CEA) is reported to improve cerebral circulation and brain function. We tested whether this improvement is reflected by changes in the qEEG.
  
  
  METHODS
  qEEG changes in 166 patients with a >70% stenosis of the internal carotid artery (ICA) were assessed after subtraction of the preoperative and postoperative spectra (eyes closed condition) before and 3 months after CEA. The mean frequency of the alpha band (MFA), the peak frequency of the alpha band (F alpha), and bands with limits relative to each patient's F alpha were studied in relation to neurological symptoms, patency or occlusion of the contralateral ICA, shunt requirement, and side of surgery.
  
  
  RESULTS
  MFA and F alpha significantly increased over both hemispheres. After alignment on F alpha, a decrease of spectral band power was seen below F alpha, and a band power increase above F alpha. The group of patients with a contralateral ICA occlusion showed significantly more improvement than the group without. The group of patients with neurological deficits showed a tendency for improvement. No differences were found concerning shunt requirement or the side of surgery.
  
  
  CONCLUSIONS
  After CEA the alpha rhythm frequency increases. In general, patients with a contralateral ICA occlusion improve more than other patients, in agreement with data from the literature on cerebral circulation and brain function.
authors.affiliation: Department of Clinical Neurophysiology, University Medical Centre Utrecht, The Netherlands.
authors.forename: E M
authors.initials: EM
authors.lastname: Vriens
authors.forename: G H
authors.initials: GH
authors.lastname: Wieneke
authors.forename: A C
authors.initials: AC
authors.lastname: Van Huffelen
authors.forename: G H
authors.initials: GH
authors.lastname: Visser
authors.forename: B C
authors.initials: BC
authors.lastname: Eikelboom
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000513:Alpha Rhythm; D001921:Brain / Q000503:physiopathology*; D002545:Brain Ischemia / Q000503:physiopathology*; D016894:Endarterectomy, Carotid / Q000009:adverse effects; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged