The Structure of SleepDisordered Breathing and Cognitive Impairment in Cerebrovascular Diseases

Abstract

Abstract. Obstructive sleep apnea syndrome (OSAS) is considered one of the risk factors for cognitive impairment (CogI). The role of central apnea (CA) in the development of CI has not been established. Aim — to study the features of the structure of sleep-disordered breathing (SDB) in patients with chronic cerebrovascular disease (CVD) and clarify their significance as a risk factor for CogI. Material and methods. 100 patients (50 men, 50 women) at the age of 65 (58; 74.5) years were examined. Most had arterial hypertension (AH) and atherosclerosis of the brachiocephalic arteries; less commonly, stable forms of coronary artery disease and diabetes mellitus (DM) type 2. All patients were diagnosed with stage I–II dyscirculatory encephalopathy. Previously, non-disabling stroke was suffered by 37% of patients (mRS 0–2 points). Everyone completed the MoCA test. SDB was verified during cardiorespiratory monitoring (CT-04-3R (M), “INKART”, St. Petersburg). We estimated the number of episodes of SDB, obstructive apnea, CA, apnea/hypopnea index (AHI), duration and degree of desaturation. The correlation, discriminant and ROC analysis, the calculation of the odds ratio (OR) and the confidence interval (CI) of the occurrence of the event are performed. Results. SDB (AHI ≥ 5) according to the type of OSAS and CA were detected in 82% of patients. The average AHI was 13 (8; 21). CogI (MoCA < 26) were detected in 28% of patients without SDB and 52% of patients with SDB (p = 0.03). The relationship between the assessment of MoCA and AHI (Spearman, r = –0.24, p = 0.02) was established. A discriminant analysis with step-by-step inclusion of cardiovascular risk factors and SDB parameters revealed that CA, the degree of AH, age and DM are associated with the development of CN (Wilks’s Lambda: 0.75542; approx. F(4,73) = 5.9087, p < 0.0004). A threshold value of CA ≥ 5 was established (AUC 0.741, 95% CI 0.595–0.828; sensitivity 64%, specificity 76%), while the OR is 5.5 (95% CI 2.09–14.90). Conclusion. In 82% of patients with chronic CVD, SDB is detected, which is associated with a twofold increase in the frequency of CogI. Moreover, the most significant is the presence in the SDB structure of 5 or more episodes of CA, which serve not as a cause of CogI, but as a marker of more severe structural and functional cerebral changes.