Increase In Alpha Rhythm Frequency After Carotid Endarterectomy

Objectives: 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. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.