[A comparative assessment of neurochemical and neurophysiological parameters of cardiac surgery patients who underwent different versions of multitasking cognitive training].

Objective: To compare biomarkers of neurovascular unit (NVU) - S100β, NSE, BDNF and indicators of the brain electrical activity in patients who underwent coronary artery bypass grafting (CABG) depending on the use of different versions of multi-tasking cognitive training (CT).

Material and methods: The study included 89 people, of whom 47 completed the CTI (postural and three cognitive tasks (counting backwards, verbal fluency and the open-ended task «Unusual use of an ordinary object») and 42 patients, who underwent CTII (visuomotor reaction and the same cognitive tasks) in the early postoperative CABG period. The patients of both groups underwent complex testing of psychomotor, executive functions, attention, short-term memory and EEG study in the perioperative period of CABG. Concentrations of NVU markers in peripheral blood serum were also analyzed.

Results: The highest values of S100β protein concentration in both patients with CTI and CTII were observed on the 1^st-2^nd days after CABG, followed by a significant decrease on the 10^th-12^th days to preoperative values only in the CTII group. Also, during CTI, low concentrations of S100β and NSE protein were associated with higher indicators of cognitive status, such as short-term memory and general integral index. In patients with CTI, the concentration of BDNF on days 10-12 of CABG was significantly higher compared to patients with CTII, and its higher levels were associated with higher levels of attention. Only if the training was successful, the patients with CTI had greater preoperative levels of EEG alpha-1 and alpha-2 activity compared to patients with CTII.

Conclusion: The version of multitasking CT using the postural motor component more actively triggered the processes of neuroplasticity due to the expression of BDNF and its success was due to the greater presence of alpha-activity in the preoperative period of CABG. Further research is needed to study the neurophysiological mechanisms of recovery of cognitive functions after cardiac surgery.