Diagnostic investigations in paediatric respiratory and sleep medicine are often challenging due to patient size (due to prematurity), tolerability, and compliance with gold standard equipment. Children with sensory/behavioural issues, at increased risk of sleep disordered breathing (SDB), often find tolerating standard diagnostic equipment difficult. There is a need to develop non-invasive, wireless, devices designed for the paediatric population. Devices must address health in-equalities as high-risk children, with low birth weights, genetic syndromes, or complex neuro-disabilities, are often unable to undergo current investigations, particularly in sleep medicine. Prompt and accurate diagnosis of SDB is important to facilitate early intervention and improve outcomes Infants in the neonatal period can have immature breathing control which manifests as excessive central breathing pauses, apnoea's, whilst asleep requiring oxygen therapy. There is also a risk to newborn term infants of sudden unexpected neonatal collapse, even in low risk babies. Diagnosis of breathing issues in babies can be challenging since babies are often too small for standard monitoring equipment. Effective monitoring and appropriate treatment of apnoea's has been shown to improve prognosis in terms of 5-year mortality and neurodevelopmental outcomes. Children with epilepsy are at risk of epileptic apnoea during a seizure (ictal) or post-ictal apnoea following an epileptic seizure. Epileptic and post-ictal apnoea have been implicated as causes of sudden unexpected death in epilepsy (SUDEP). Epilepsy affects approx. 50 million people worldwide. The risk of SUDEP varies in different underlying causes of epilepsy but is estimated to be the cause of 1.2 deaths for every 1,000 children with epilepsy each year. This observational study is part of a phased clinical program of research that aims to validate a small wearable biosensor developed by PneumoWave Ltd in a paediatric clinical setting with the overall primary endpoints of monitoring and assessing respiratory pattern as an aid to sleep diagnostics, and as a device to monitor apnoea in neonatal patients and children with epilepsy at risk of SUDEP.