Background: The negative effects of high-grade carotid stenosis on the brain are widely known. However, there are still insufficient data on the brain state in patients with small carotid stenosis and after isolated or combined coronary and carotid surgery. This EEG-based study aimed to analyze the effect of carotid stenosis severity on associated brain activity changes and the neurophysiological test results in patients undergoing coronary artery bypass grafting (CABG) with or without carotid endarterectomy (CEA). Methods: One hundred and forty cardiac surgery patients underwent a clinical and neuropsychological examination and a multichannel EEG before surgery and 7–10 days after surgery. Results: The patients with CA stenoses of less than 50% demonstrated higher values of theta2- and alpha-rhythm power compared to the patients without CA stenoses both before and after CABG. In addition, the patients who underwent right-sided CABG+CEA had generalized EEG “slowdown” compared with isolated CABG and left-sided CABG+CEA patients. Conclusions: The on-pump cardiac surgery accompanied by specific re-arrangements of frequency–spatial patterns of electrical brain activity are dependent on the degree of carotid stenoses. The information obtained can be used to optimize the process of preoperative and postoperative management, as well as the search for neuroprotection and safe surgical strategies for this category of patients.

The study investigated the changes in theta activity and localization of its sources by standardized low resolution brain electromagnetic tomography (sLORETA) in patients who have underwent two variants of multitasking cognitive training (CT) in the early postoperative period of coronary artery bypass grafting (CABG). Two groups were formed in a pseudo-random way, which differed according to the type of motor problem used: CT I (n = 27)—a postural balance task and CT II (n = 27)—a simple visual-motor reaction. Cognitive tasks were the same for both groups (counting backwards, verbal fluency, and unusual uses for common objects). Daily sessions of CT were held from the 3rd to 4th day after CABG, with a duration of 5 min on the 1st day of training and up to 20 min on the 6th to 7th day of training. The current density of theta-rhythm sources was lower before CABG than after surgery in the CT II group only. The most significant differences are in Brodmann area 31, the parietal occipital lobes, and precuneus, which may indicate damage associated with cardiac surgery. This effect was not observed in the CT I group. The results of our study demonstrated the informativeness of sLORETA indicators to determine an effective cognitive recovery option after CABG. The reduction of the severity of damaging effects of CABG during training using cognitive tasks and postural balance tasks was shown. Further research is needed to determine the optimal mode and duration of cognitive training to maximize the functional reserves of such patients.