Background: The morphology of the intracranial pressure pulse consists of three waves: P1, corresponding to arterial pulsation; P2, corresponding to cerebral compliance; and P3, corresponding to aortic valve closure. Under normal conditions, P1> P2> P3. Reversal of the P2/P1 ratio represents impaired cerebral compliance (CC) and, indirectly, increased intracranial pressure (ICP). Objective: To evaluate cerebral compliance during normal sleep. Methods: Cerebral compliance analysis was performed using the Brain4care device placed on patients along with type 1 polysomnography. We evaluated CC during the all-night sleep period and analyzed it according to NREM and REM sleep stages. Results: We analyzed CC from 3 participants without sleep disorders. The mean age was 33 years (±3 years). Two participants were female. All participants denied comorbidities and medication use. The mean CC recording time was 363 minutes (minimum = 333; maximum = 385), totalizing 1,088 minutes analyzed. Participant 1. With 370 minutes of CC recording, it exhibited 22.5% REM sleep, 77.5% NREM sleep, and SE of 92%. The mean P2/P1 ratio during sleep was 1.28; 1.29 during REM sleep and 1.30 during NREM sleep. Participant 2. With 385 minutes of CC recording, it demonstrated 14.4% REM sleep, 85.6% NREM sleep, and SE of 84%. The mean P2/P1 ratio during sleep was 0.88; 0.84 during REM sleep and 0.87 during NREM sleep. Participant 3. With 333 minutes of CC recording, showed 28.8% REM sleep; 71.2% NREM sleep, and SE of 87%. The mean P2/P1 ratio during sleep was 0.83; 0.77 during REM sleep and 0.91 during NREM sleep. Only one participant showed P2/P1 ratio values above 1.0 during sleep, suggesting reduced cerebral compliance. We are just starting to understand this new technology, and this sort of result can be somehow explainable by variables that we do not are aware of. After conducting studies comparing invasive and non-invasive methods of ICP assessment, it was possible to establish values to stratify the risk of intracranial hypertension: green zone (P2/P1 0.65 to 1.00); yellow zone (P2/P1 1.00 to 1.20); red zone (P2/P1 >1.21). The higher the ratio, the greater the cerebral compliance disturbance. One of the components influencing ICP is cerebral blood flow, which varies according to the brain‘s metabolic demand, correlates with the dominant frequency of the electroencephalogram, and is higher during wakefulness. During NREM sleep, blood flow decreases by approximately 10 to 20%. This flow increases by 20 to 35% in REM sleep, compared to wakefulness. The main mechanism justifying this variation is the synergy between cortical activity and perfusion, which represents cerebral metabolism, which is decreased or increased during NREM and REM sleep, respectively. Thus, in normal sleep, an increase in compliance is expected during REM sleep and a reduction during NREM sleep. Conclusion: Normal sleep maintains cerebral compliance within the bounds of normality.