RESUMEN
BACKGROUND: The neurocognitive consequences of exposure to screens in school-aged children have been the subject of multiple studies. However, the relationship between screen exposure and neurocognitive development, especially attentional functions, remains unclear in preschool children. The aim of this systematic review was to evaluate the immediate and long-term impact of screen exposure on attentional functions in preschoolers. METHODS: Three electronic databases (PubMed, COCHRANE, and SCOPUS) were searched for studies published between January 1, 2000, and November 30, 2020. Two reviewers independently selected studies. Inclusion criteria were observational studies, inclusion of children aged less than seven years with no neurodevelopmental disorders, evaluation of screen time, and evaluation of attentional functions. Data extracted including participants' ages, number of participants, screen exposure time, attention assessment tool, and confounding factors. Study quality was evaluated using the Newcastle-Ottawa Scale. RESULTS: Five cross-sectional studies were included: all reported significant, positive associations between high levels of screen exposure and attention difficulties. Ten longitudinal studies were included: six found a significant impact of earlier screen exposure on subsequent attentional function and four found no relationship. Eight of the studies included evaluated the direction of the relationship between screen exposure and attentional difficulties: seven suggested the relationship is bidirectional. CONCLUSIONS: These findings support current guidelines to limit screen time in preschoolers to prevent the development of attention difficulties.
