Study objectives: Unobtrusive monitoring of sleep and sleep disorders in children presents challenges. We investigated the possibility of using Ultra-Wide band (UWB) radar to measure sleep in children. Methods: Thirty-two children scheduled to undergo a clinical polysomnography participated; their ages ranged from 2 months to 14 years. During the polysomnography, the children's body movements and breathing rate were measured by an UWB-radar. A total of 38 features were calculated from the motion signals and breathing rate obtained from the raw radar signals. Adaptive boosting was used as machine learning classifier to estimate sleep stages, with polysomnography as gold standard method for comparison. Results: Data of all participants combined, this study achieved a Cohen's Kappa coefficient of 0.67 and an overall accuracy of 89.8% for wake and sleep classification, a Kappa of 0.47 and an accuracy of 72.9% for wake, rapid-eye-movement (REM) sleep, and non-REM sleep classification, and a Kappa of 0.43 and an accuracy of 58.0% for wake, REM sleep, light sleep and deep sleep classification. Conclusion: Although the current performance is not sufficient for clinical use yet, UWB radar is a promising method for non-contact sleep analysis in children.

Ultrasound is a superb neonatal neuroimaging technique as it is non-invasive, easily accessible and safe. Ultrasound is still seen as complementary to other neonatal neuroimaging techniques (such as MRI) because it still lacks several important neuroimaging features such as quantitative tissue analysis. However, developments in ultrasound technology are predicted to follow each other in rapid succession and are expected to have a major impact on clinical neonatal cerebral ultrasound applications in the near future. Elastography, Ultrafast Doppler, Shear Wave imaging, Contrast Enhanced ultrasound and functional ultrasound are examples of techniques being discussed. The aim of this review is to provide a compact overview of current ultrasound developments which are likely to have an impact on neonatal cerebral ultrasound use.