Traditional screen time (e.g. TV and videogaming) has been linked to sleep problems and poorer developmental outcomes in children. With the advent of portable touchscreen devices, this association may be extending down in age to disrupt the sleep of infants and toddlers, an age when sleep is essential for cognitive development. However, this association has not been demonstrated empirically. This study aims to examine whether frequency of touchscreen use is associated with sleep in infants and toddlers between 6 and 36 months of age. An online survey was administered to 715 parents reporting on child media use (daily exposure to TV and use of touchscreens), sleep patterns (night-time and daytime sleep duration, sleep onset – time to fall asleep, and frequencies of night awakenings). Structural equation models controlling for age, sex, TV exposure and maternal education indicated a significant association between touchscreen use and night-time sleep, daytime sleep and sleep onset. No significant effect was observed for the number of night awakenings. To our knowledge, this is the first report linking the use of touchscreen with sleep problems in infants and toddlers. Future longitudinal studies are needed to clarify the direction of effects and the mechanisms underlying these associations using detailed sleep tracking.

Sleep is the dominant activity of an infant and plays an important role in neurodevelopment and synaptic plasticity^1,2,3. Both the brain and sleep patterns undergo parallel and substantial developmental change during the first few years of life. Given that neural plasticity is at its greatest during infancy and toddlerhood⁴, sleep is likely to have the most impact on the brain and on cognition during this critical period of early development. Yet, around 20–30% of young children experience problems with sleep⁵. One known environmental contributor to poor sleep is the heavy use of screen media, such as TV and videogaming (see review ^6,7). In recent years, family ownership of touch screen devices has risen rapidly (from 7% in 2011 to 71% in 2014)⁸. Reports from 2016 indicated that 86% of UK family homes have access to the Internet, with access mainly via portable media devices⁹. For infants and toddlers, touchscreen devices offer an intuitive and attractive source of stimulation¹⁰, and their portability allows for a wide range of use across multiple settings¹¹. Yet, the widespread use in this age group has raised serious concerns for parents, educators and policy makers, as the potential impact of touchscreen use on toddler development, such as sleep, remains unknown. In this study, we use data from a large UK survey (see ref. 12 for details) to investigate the relationship between touchscreen use and sleep in infants and toddlers between 6 and 36 months of age.

Problematic sleep in children is not uncommon. A recent longitudinal study mapped the sleep trajectories in around 3000 children from birth to 7 years and found that 60% of the children have atypical sleeping patterns: the majority of whom were initially short sleepers (45%), others were either persistent short sleepers (12%) or poor sleepers (3%). Compared to the typical sleepers, all three groups showed some degree of impaired physical, emotional and social functioning¹³. The results suggest that, even though some infants with atypical sleep patterns early on eventually develop typical patterns of sleep by 6 or 7 years of age, reduced sleep duration in the first two years of life may have long-term consequences on later developmental outcomes. These findings are mirrored by several follow-up studies in children and adolescents, showing significant associations between sleep difficulties or irregular bedtime and later problems with mental and physical health and lower cognitive and academic performance^{13,14,15,16,17}. As such, specific guidelines have recommended screens to be kept out of a child’s bedroom specifically because of the potential impact they may have on sleep^9,18. To date, research into the long-term impact of poor sleep during early development remains limited. Yet, findings so far converge, linking shorter sleep duration to negative developmental outcomes.

Media use has frequently been linked with inadequate sleep in children and adolescents (see ^6,7 for review). The majority of studies (~90%) show a consistent pattern linking increased screen time with shorter total sleep time and delayed bedtime. This association was observed across various types of media including TV, computer and mobile phone devices. Research on touchscreen media and sleep in children is by comparison, more limited. A recent meta-analytic review identified 20 studies in children and adolescents aged between 6 and 19, and found strong and consistent evidence for detrimental effects of portable touchscreen devices on sleep quality and quantity¹⁹. Specifically, individuals who are exposed to or have access to a portable media device at bedtime have significantly reduced night-time sleep and increased poor quality of sleep (defined as difficulties in sleep initiation and maintenance). To date, only a handful of studies have explored the impact of screen media on sleep in preschool infants and toddlers – all of which included only TV as media type^{20,21,22,23,24}. All studies used parent questionnaires, and have reported a significant effect of screen time on sleep: increased amount of TV viewing was associated with parent-reported sleep problems²⁴, shorter night-time sleep duration^20,22, reduced quality of sleep²³, and irregular naptime and bedtime schedules²¹, adjusting for known confounds including socioeconomic status (SES). Other maternal or child characteristics were also included in some studies, including maternal age, education, pregnancy BMI; child’s ethnicity and gender^20,22. Portable touchscreen devices may exacerbate the problem by allowing small children to increase screen time throughout the day and carry the screen into their sleeping space. Yet, so far no studies have examined the impact of touchscreen use on infant and toddler sleep.

In our UK-based survey on 715 families, we reported that 75% of toddlers between 6 months and 3 years of age use a touchscreen on a daily basis¹². This figure is similar to another study from the UK²⁵ and to reports from other countries in both high¹⁰ and low SES communities²⁶. In our sample¹² we found that the prevalence of daily use increases substantially with age, from 51% in 6- to 11-month-old infants to 92.05% by 25–36 months. Even among the 25% of children who did not use a touchscreen daily, only 42% reported no prior use. Among users, daily usage increased with age from 8.53 minutes a day (6–11 months) to 45 minutes a day (26–36 months). Given the evidence that 1) media use is linked to poor sleep in older children and adults, 2) touchscreen use in infants/toddlers is highly prevalent, and 3) sleep plays a prominent role in early cognitive and brain development, it is critical to investigate whether touchscreen use is associated with sleep problems early in development.

Using a large online survey, this study aims to investigate whether the frequency of daily touchscreen use is associated with sleep in infants and toddlers between 6 and 36 months. Parents were asked to report on the average duration of their child’s daytime and night-time sleep, the time taken for their child to fall asleep, as well as the frequency of night awakenings, to obtain a comprehensive account of infant/toddler sleep patterns.

As we have reported in our previous study¹², the average touchscreen usage in this sample is 24.44 minutes Descriptive statistics for the sleep variables split by age quartiles are also presented . Modest but significant correlations are observed amongst the sleep variables, with the exception of daytime sleep and sleep onset, which were not significantly correlated