Association Between Sleep Quality and Functional Connectivity by Resting State Encephalogram in Preeclampsia

Abstract

ABSTRACT BACKGROND: Preeclampsia (PE) is the leading cause of maternal deaths in all tertiary hospitals in Ghana. Pregnancy is accompanied by changes in maternal physiology, which result in cerebral alterations and sleep disturbance. PE may exacerbate these cerebral changes and sleep disturbance beyond the effects of normal pregnancy. It is suspected that increased inflammation underlies the cerebral changes and sleep disturbances in PE. AIM: The study aims to investigate the resting state functional connectivity of the cerebral cortex and its association with sleep quality and markers of inflammation like IL-6 and CRP in preeclamptic and normal pregnancy. METHODOLOGY: This case-control design compared 50 preeclamptic and 50 normotensive pregnancies. A structured questionnaire was used to collect social, demographic, pregnancy and medical history data. Sleep quality and sleepiness were assessed using the Pittsburgh Sleep Quality Index and Epworth’s Sleepiness Scale. Resting-state 32-lead electroencephalography was conducted in all participants and the alpha power spectrum bands were converted to functional MRI correlates using the eLORETA software. Cerebral cortical functional connectivity was obtained from the power spectrum analysis. In addition, a 5 ml venous blood sample was collected to assay levels of highly sensitive CRP and IL-6. RESULTS: There was no significant difference in overall sleep quality (PSQI global score p= 0.95), but sleep efficiency and sleep duration categories were significantly different (habitual sleep efficiency p= 0.024, sleep duration categorization p= 0.023). EEG results showed significant differences in β2 and β3 bands ( p= 0.041 and p= 0.05, respectively), implying altered brain functional connectivity in women with PE which is supported heat and Brodmann Area mapping. Poor sleep quality significantly predicted higher IL-6, and CRP levels (p= 0.01 and p= 0.028 respectively) CONCLUSION: Sleep disorders dysregulate maternal inflammatory response in PE, evidenced by higher serum IL-6 and C-RP levels in cases than among controls, mediating vascular endothelial and multi-organ dysfunction in PE. Functional connectivity differences between cases and controls were detected by resting-state encephalogram, particularly alterations in current densities in the β2 and β3 frequency domains originating from Brodmann areas 19 and 8- suggesting impaired functional connectivity in PE.