Changes in inter- and intrahemispheric connectivity in patients with cardiovascular diseases and obstructive sleep apnea

Objective: to analyse the measure of EEG connectivity in patients with cardiovascular diseases and obstructive sleep apnea. Material and methods. The patients (n=133) underwent polysomnography and were divided into 4 groups depending on the apnea-hypopnea index (AHI). Wavelet bicoherence method were used to assess the level of EEG connectivity for the whole duration of night sleep. Results. The mean value of interhemispheric connectivity decreases significantly with increasing severity of apnea syndrome almost at all frequency ranges. The mean values of occipital interhemispheric connectivity show an inversely proportional trend as AHI increases in Af6 [4.0-8.0 Hz]: 0.472 [0.391; 0.585], 0.439 [0.402; 0.509], 0.418 [0.384; 0.483], 0.395 [0.359; 0.433] (p=0.012). Intrahemispheric connectivity, both in the left and right hemispheres, is higher to interhemispheric connectivity and demonstrates heterogeneous dynamics. Conclusions. With increasing AHI, interhemispheric connectivity decreases and intrahemispheric connectivity increases selectively. At the same time, in the group of patients with AHK10 ep/h, this pattern is broken, and their measures of EEG connectivity correspond to the most severe cases of apnea.