  Background: While the relations between sleep, cognition and behavior have
been extensively studied in adolescents and school-aged children, very little
attention has been given to preschoolers. Objective: In this systematic review,
our aim was to survey articles that address the link between sleep and both
cognition and behavior in preschoolers (24 to 72 months old). Methods: Four
electronic databases were searched, namely Medline, Web of Science, PsycINFO
and ERIC, completed by forward and backward citation search. Results: Among the
1590 articles identified (minus duplicates), 26 met the inclusion criteria.
Globally, studies with the largest sample sizes (N=13) found that a greater
quantity or quality of sleep was associated with better behavioral and
cognitive outcomes, while the others were less consistent. Conclusion: Although
the current literature seems to indicate that sleep is related to behavioral
and cognitive development as early as preschool years, the strength of the
associations (i.e. effect sizes) was relatively small. In addition to taking
stock of the available data, this systematic review identifies potential
sources of improvement for future research.
