Pediatric sleep movements: a review of methodologies, normative data, disease associations, and research gaps.

Restless sleep is a common complaint among children, yet its quantification and clinical significance remain poorly defined. Polysomnography, the standard diagnostic tool for sleep disorders, often fails to fully explain restlessness, even when other conditions are excluded. Measuring body movement indices, proposed as an objective marker of sleep restlessness but lacking a standardized methodology, currently has limited clinical application. Recent efforts by the International Restless Legs Syndrome Study Group have led to consensus diagnostic criteria for restless sleep disorder that incorporate both self-reported and objective measures. We review various methodologies used to quantify body movements during sleep, including polysomnography with video recordings, actigraphy, and a less-invasive "contactless" device. Key discrepancies in measurement techniques and normative data reporting are identified. To advance the inclusion of this disorder into the clinical setting, we collated and compared studies providing normative values for sleep movements across different populations and explore their relevance to other disorders. Providing a historical perspective on how the measurements of sleep movement have evolved shows how technological advancements have influenced current approaches. In this context, the consequences of restless sleep and its potential impact on neurocognitive and behavioral outcomes are discussed. We conclude by highlighting key knowledge gaps and proposing future research directions. CITATION: Lu M, Fitzgerald DA, Norman MB, Sullivan CE, Waters KA. Pediatric sleep movements: a review of methodologies, normative data, disease associations, and research gaps.