0492 Noninvasive Intracranial Pressure Monitoring and Cognitive Correlates in Obstructive Sleep Apnea

Abstract Introduction Obstructive sleep apnea syndrome (OSA) is a common sleep-related disorder with many consequences, including changes in cerebral hemodynamics related to blood flow and intracranial pressure regulation caused by respiratory pauses. Among OSA's effects, cognitive changes are common, particularly in attention, processing speed, memory, and executive function. Our goal is to noninvasively assess intracranial pressure dynamics in adults with OSA and their potential link to cognitive impairment. Methods On the night of the Type I polysomnography, intracranial pressure (P2/P1 ratio) was assessed before and after sleep using a noninvasive monitoring device. Cognitive function was evaluated using the Montreal Cognitive Assessment (MoCA) and the Clock Drawing Test. Clinical and demographic characteristics were also collected, including age, sex, body mass index, and years of education. A paired t-test was used to compare mean P2/P1 ratios, and Cohen’s d was calculated to estimate effect size. Associations between the P2/P1 ratio and cognitive test scores were examined using Spearman’s correlation coefficient. Results Seven patients were included. The mean age was 54.9 ± 7.2 years, and 85.7% were women. The mean educational level was 13.4 ± 2.9 years, and the mean BMI was 33.1 ± 3.9 kg/m2. We observed that before sleep onset, the P2/P1 ratio was already elevated, becoming significantly higher in the early morning (1.31 ± 0.21 vs. 1.57 ± 0.26; p = 0.0076; Cohen’s d = 1.49). The mean MoCA score was 23, whereas the expected score for this educational level was 26 or higher. The mean Clock Drawing Test score was 6 points (expected = 9). Analysis of the associations between the P2/P1 ratio and both the MoCA and Clock Drawing Test scores demonstrated a negative correlation. Conclusion Patients with OSA exhibited increased intracranial pressure even before sleep onset, which suggests a chronic alteration in cerebral compliance that further worsens after a night of sleep characterized by frequent obstructive events. Cognitive performance was slightly below the expected level for the participants’ mean educational attainment, which may be explained by OSA itself or by the associated cerebral hemodynamic impairment. Support (if any) National Council for Scientific and Technological Development (CNPq). Coordination for the Improvement of Higher Education Personnel (CAPES).