The availability of digital media devices such as smartphones, tablets, notebooks, etc. in households has become so commonplace today that we hardly think about our media use and its consequences. This also seems to be true for households with children. Even very young children come in contact with and use these devices from an early age on. For example, a study in the UK reported that children started using touchscreen media (smartphones, tablets) as early as six months of age (Cheung et al., 2017). As for the duration of media use, an Austrian study of parents with children up to the age of six years found that one-third of the children use digital media every day and around fifty percent use them several times a week (Institut für empirische Sozialforschung [IFES], 2020). The numbers are similar across Europe (e.g., Germany see Kieninger et al., 2020; UK see Bedford et al., 2016; France see Cristia & Seidl, 2015; Italy see Chindamo et al., 2019).

Parents face various educational challenges and must deliberate how to manage and regulate their children’s media use. For the investigation of parents’ educational strategies and behaviors, “parental mediation theory” has proven to be a valuable theoretical framework. Within this framework, the present study focused on children’s sleep and parents’ mediation of media use. The prevalence of digital media presents parents with several challenges, including the duration and frequency of media use but also concerns about possible harmful effects of media use itself. In this regard, parental mediation theory describes strategies parents use to minimize potentially harmful consequences of media use (Clark, 2011; Valkenburg et al., 1999).

One important area of research concerns the effects of media use on children’s development and health. In this context, sleep is an important variable. During the first years of life, sufficient and restful sleep is of particular importance, because sleep is essential for developmental processes (El-Sheik & Sadeh, 2015) such as neuronal and cognitive development processes (Ednick et al., 2009). Research suggests harmful effects of media use on children’s sleep (e.g., Hackl-Wimmer et al., 2021). Ensuring that children get sufficient and restful sleep is an important educational task for parents. Toddlers’ sleep may be influenced by a variety of factors, including digital media use (Hackl-Wimmer et al., 2021). There are diverse methods for quantifying sleep quantity and quality. However, research on children’s sleep suffers from methodological problems. Studies on young children’s sleep and media use mainly employ subjective data such as parent questionnaires to assess children’s sleep (e.g., Chindamo et al., 2019).

An approach that is often used in medicine is polysomnography (PSG). PSG comprises the recording of several physiological functions (e.g., heart rate and brain waves) in a sleep laboratory for clinical purposes. However, the methodology is not suitable for recording children’s sleep in daily situations at home. Therefore, we used and further developed a more practical approach, namely ECG (electrocardiogram) recordings with small portable devices. ECG is the recording of the electrical activity of the heart. ECG data allows the measurement of heart rate (HR) and the calculation of several parameters of heart rate variability (the variation in time between consecutive heartbeats). Due to technological progress, ECG data can be recorded using portable devices over a period of 24 hours or more. These devices are also suitable for studies with young children and allow recording of HR during sleep at home in the child’s familiar environment.

The aim of this study is to examine whether toddlers’ use of smartphones and audio media is related to their sleep quality (quantified as HR during restless sleep phases).

In the present study, two methodological approaches and their intertwining are used: a questionnaire on parental mediation behavior, children’s media use, and other variables plus long-term ECG monitoring. The questionnaire included several types of media (e.g., smartphone and audio media) for which the duration of use on weekdays and the weekend was asked. Furthermore, parents were asked what their objectives were for their children’s smartphone and audio media use and for which activities their children used these devices. To investigate toddlers’ sleep quality, long-term ECG monitoring was performed for approximately 30 hours. Data collection was performed as part of a field study at crèches in Austria and started in the morning at the crèches. The ECG device used is equipped with an integrated 3D acceleration sensor that provides information about body position and body movement. For the duration of the ECG measurement, parents and daycare educators were asked to keep an activity log to record the children’s activities with begin and end times (e.g., sleep during the day and night and other activities such as mealtimes and media use). Processing of the ECG Data and the quantification of sleep quality involved several steps. The two main steps comprised the following: First, ECG data, acceleration sensor data and the activity log recordings were used to determine restful and restless sleep phases. Major determinants for restful sleep are a lying position, little body movement and a calm, steady respiration pattern. Phases of restful sleep had to last at least ten consecutive minutes to be classified as restful sleep for further analysis. Otherwise, the sleep phases were classified as restless sleep. In the second step, heart rate (HR) was calculated for restless sleep. The statistical analysis comprised partial correlations to investigate potential relationships between media use and HR. The analysis included the children’s age (in months) and were calculated separately for smartphone and audio media use on weekdays, the weekend and the average weekly media use. Additionally, descriptive statistics are reported on the activities and objectives for the use of these devices.

The results showed that smartphone use is associated with poorer night’s sleep (i.e., higher HR during restless sleep). However, audio media use is associated with more favorable sleep (i.e., lower HR during restless sleep), indicating that the investigation of media effects benefits from differentiating between media types. The joint consideration of physiological data and parents’ educational behavior gives more insights into possible causes. Regarding the objectives of media use, parents most often reported that smartphones and audio media are used by their children for entertainment purposes or out of boredom. While parents most often reported that their children used the smartphone for activities such as watching movies, listening to music, and playing educational games, audio media were mainly used for listening to music and books. A possible explanation for the present results could be that smartphone use is related to sustained arousal due to its interactive component and the emitted blue light. On the other hand, assuming that calming content is played, using audio media to listen to music and books could help children to relax and unwind. However, the possible selectivity of the sample must be taken into account. Media use was lower compared to other studies (e.g., Cheung et al., 2017), as some toddlers did not use smartphones or audio media at all. In conclusion, not every type of media is detrimental to children’s sleep, so further research on media content is needed. ECG monitoring during the use of different types of media content allows the detection of psychophysiological processes that young children are unable to reflect and report on. Implications for education and development comprise the selection of media content appropriate to the situation, meaning arousing or exciting content for playtime, for example, and calming content for relaxing situations such as before bedtime.

Bedford, R., Saez de Urabain, I.R., Cheung, C.H.M., Karmiloff-Smith, A., & Smith, T. J. (2016). Toddlers’ fine motor milestone achievement is associated with early touchscreen scrolling. Frontiers in Psychology, 7, 1108. Cheung, C.H.M., Bedford, R., Saez De Urabain, I.R., Karmiloff-Smith, A., & Smith, T.J. (2017). Daily touchscreen use in infants and toddlers is associated with reduced sleep and delayed sleep onset. Scientific Reports, 7, 46104. Chindamo, S., Buja, A., DeBattisti, E., Terraneo, A., Marini, E., Gomez Perez, L.J., Marconi, L., Baldo, V., Chiamenti, G., Doria, M., Ceschin, F., Malorgio, E., Tommasi, M., Sperotto, M., Buzzetti, R., & Gallimberti, L. (2019). Sleep and new media usage in toddlers. European Journal of Pediatrics, 178(4), 483–490. Clark, L.S. (2011). Parental mediation theory for the digital age. Communication Theory, 21, 323–343. Cristia, A., & Seidl, A. (2015). Parental reports on touch screen use in early childhood. PloS ONE, 10(6), e0128338. Ednick, M., Cohen, A.P., McPhail, G.L., Beebe, D., Simakajornboon, N., & Amin, R.S. (2009). A review of the effects of sleep during the first year of life on cognitive, psychomotor, and temperament development. Sleep, 32(11), 1449–1458. El‐Sheikh, M., & Sadeh, A. (2015). I. Sleep and development: Introduction to the monograph. Monographs of the Society for Research in Child Development, 80(1), 1–14. Hackl-Wimmer, S., Eglmaier, M.T.W., Eichen, L., Rettenbacher, K., Macher, D., Walter-Laager, C., Helmut K.L., Papousek, I., & Paechter, M. (2021). Effects of touchscreen media use on toddlers’ sleep: Insights from longtime ECG monitoring. Sensors, 21(22), 7515. Institut für empirische Sozialforschung. (2020). Die Allerjüngsten (0-6 J.) & digitale Medien [The very young (0–6 years) & digital media]. https://www.saferinternet.at/fileadmin/redakteure/Projekt-Seiten/Safer_Internet_Day/Safer_Internet_Day_2020/Praesentation_PK_Safer_Internet_Day_2020.pdf Kieninger, J., Feierabend, S., Ratgeb, T., Kheredmand, H., & Glöckler, S. (2020): miniKIM-Studie 2020. Kleinkinder und Medien: Basisuntersuchung zum Medienumgang 2- bis 5-Jähriger in Deutschland. www.mpfs.de/fileadmin/files/Studien/miniKIM/2020/lfk_miniKIM_2020_211020_WEB_barrierefrei.pdf Valkenburg, P.M., Krcmar, M., Peeters, A.L., & Marseille, N.M. (1999). Developing a scale to assess three styles of television mediation: “Instructive mediation,” “restrictive mediation,” and “social coviewing”. Journal of Broadcasting & Electronic Media, 43(1), 52–66.