Early Screen Exposure and Neurodevelopment: A Narrative Review of Longitudinal Evidence on Sleep, Brain Structure, and Cognition

Digital devices have become part of children's everyday experiences, raising important questions about how early and repeated screen exposure may influence development. These concerns are particularly relevant during early childhood, when sleep patterns, brain structures, and cognitive abilities are still developing. This narrative review examines evidence on the relationship between screen exposure and neurodevelopment, drawing particularly on longitudinal studies alongside relevant observational research, systematic reviews, meta-analyses, and selected grey literature. Literature was identified through searches of PubMed, Google Scholar, Scopus, ScienceDirect, and the Cochrane Library, with findings synthesized narratively because of differences in study designs, exposure measurements, and developmental outcomes. Across the reviewed literature, greater screen exposure, especially around bedtime, was frequently associated with shorter sleep duration, delayed sleep onset, and poorer sleep quality. Studies also reported associations with language development, attention, and cognitive performance, although these findings were not uniform and appeared to vary with children's ages, the nature of screen use, and caregiver involvement. Evidence concerning brain structure was less conclusive, as relatively few studies directly examined changes in brain volume over time. Taken together, the findings suggest that the developmental implications of screen exposure depend not simply on duration but also on timing and context. However, the largely observational evidence and differences in research methods make it difficult to establish causal relationships. Further longitudinal research is therefore needed to clarify how early screen exposure relates to sleep, brain development, and cognitive growth.