Infant sleep time: A comparative analysis of assessment methods

Understanding sleep functions in early development remains challenging due to limitations in the available measurement methods. This study aims to provide a comprehensive description of night and day sleep patterns of Italian infants and toddlers between 5 and 25 months of age while evaluating the accuracy, reliability, and practicality of commonly used sleep assessment tools such as actigraphy, diaries, and questionnaires. From a methodological viewpoint, an exhaustive cross-method validation approach suggested that actigraphy represents a valuable and practical tool for assessing infant sleep. However, its use should be approached with caution in contexts where sleep-wake differentiation is less distinct, for instance when motor activity is recurrent during sleep or naps. In such cases, validation against other methods is recommended to ensure reliable outcomes; expert manual coding and environmental audio recordings might be appropriate, when available. Lowering the sensitivity threshold in actigraphy and integrating parental reports also offer viable approaches to enhancing data reliability. Next, following best practices, infants and toddlers sleep duration was estimated. In our cohort, participants typically took one or two naps per day, with total daytime sleep ranging from 56 min to 2.58 h. On average, overnight sleep lasted 8 h, with approximately 2 night-awakenings, totaling between 35 min and 1.65 h. Overnight sleep in this sample appears slightly lower than what has been reported in infants of similar ages from other geographical contexts. This highlights the importance of considering sociocultural and ecological vari- ability in pediatric sleep research and cautions against applying universal sleep conventions without contextual and methodological validation.