Maria Breda, Maristella Lucchini, Natalie Barnett, Oliviero Bruni
Presented at World Sleep, Rio de Janeiro, 2023
Abstract
Introduction
Sleep in infancy is associated with various aspects of development and physical health. Although general trajectories of infant sleep in the first year of life have been well characterized, not all infants follow the same trajectory. Several factors contribute to different sleep behaviors in infancy, including infant characteristics, parent-infant dynamics, as well as environmental characteristics. Among infant characteristics, temperament has received a lot of attention and previous studies have shown that difficult temperament appears related to more sleep awakenings and sleep problems in general. Nonetheless, results are far from being conclusive due to several limitations of previous studies, including the reliance on parental reports for sleep metrics, small sample sizes and use of heterogeneous questionnaires to evaluate temperament. In this study we propose to address this knowledge gap by investigating the relationship between infant sleep and temperament at 12 months of age, relying on objective sleep metrics.
Materials and Methods
Caregivers of 623 infants aged 9-13 mos (M=10.3 mos ± 1.1, 52.0% females) were recruited among users of Nanit baby-monitor in the United States. Caregivers reported on their baby’s sleep habits by completing the Brief Infant Sleep Questionnaire (BISQ-R) and on their temperament completing the Infant Behavior Questionnaire (IBQ-R). Objective infant sleep metrics were obtained from the Nanit (1 week of data averaged). Sleep metrics analyzed were: total sleep time, number of night-wakings, sleep efficiency, bedtime, wake up time, time awake at night and parent interventions. Person correlation between each sleep metric and IBQR global score (Orienting/ Effortful control; Surgency/extraversion; Negative Affectivity) and subscales were calculated.
Results
Higher infant negative affectivity was significantly associated with shorter total sleep time (r=-0.25, p<0.01), lower sleep efficiency (r=-0.13, p<0.01), longer time awake at night (r=0.1, p<0.001), later bedtime (r=0.12, p<0.01), more night-wakings (r=0.12, p<0.01) and parental interventions (r=0.17, p<0.01). Although Orienting/ Effortful control and Surgency/Extraversion global scores were not significantly associated with any sleep metric, some of their subscales were. Lower soothability was associated with shorter total sleep time (r=-0.09, p<0.05), poorer sleep efficiency (r=-0.1, p<0.01), and less parental interventions (r--0.08, p<0.05). Higher Perceptual Sensitivity was associated with more night awakenings (r=0.13, p<0.01), and high approachability to later bedtime (r=0.09, p<0.05).
Conclusions
This study adds to the current literature on sleep and development thanks to a large sample size and objective sleep metrics. Our findings support previous research, highlighting that negative affectivity is associated with poor sleep across multiple domains and that, on the other hand, sleep disturbances may predict internalizing problems.
About the researchers
The authors include Maria Breda, Maristella Lucchini, Natalie Barnett, and Oliviero Bruni.
- Dr. Maristella Lucchini serves as Senior Clinical Researcher at Nanit. In her role, Maristella works to secure grant funding in collaboration with Nanit’s university research partners and supports the development of the company’s research collaborations around the world. Previously, Maristella served as an Assistant Research Scientist in the Division of Developmental Neuroscience, Department of Psychiatry at Columbia University Irving Medical Center where she led projects across several cohorts focusing on sleep health for pregnant and postpartum women and their children. Maristella’s research focused on underserved communities and sleep health disparities in the perinatal period. During her years as a postdoctoral researcher at Columbia University Irving Medical Center in the Department of Psychiatry, Maristella was selected to participate in the American Academy of Sleep Medicine Young Investigator Research Forum. She holds a Ph.D. in Biomedical Engineering from Politecnico di Milano.
- Dr. Natalie Barnett serves as VP of Clinical Research at Nanit. Natalie initiated sleep research collaborations at Nanit and in her current role, Natalie oversees collaborations with researchers at hospitals and universities around the world who use the Nanit camera to better understand pediatric sleep and leads the internal sleep and development research programs at Nanit. Natalie holds a Ph.D. in Genetics from the University of New England in Australia and a Postgraduate Certificate in Pediatric Sleep Science from the University of Western Australia. Natalie was an Assistant Professor in the Neurogenetics Unit at NYU School of Medicine prior to joining Nanit. Natalie is also the voice of Nanit's science-backed, personalized sleep tips delivered to users throughout their baby's first few years.