Background/objectives: The first year of life represents a critical developmental stage in which the foundations for motor, cognitive, language, and social-emotional development are set. During this time, development occurs rapidly, making early detection of developmental disorders essential for timely intervention. The Bayley Scales of Infant and Toddler Development-Third Edition (Bayley-III) is an effective tool for assessing language, motor, and cognitive development in children aged 1 to 42 months. This study aimed to investigate whether or not the results of the Bayley-III in healthy one-year-old children are predictive for their later motor skills and school performance.
Methods: This study had a prospective, longitudinal design. The study participants were healthy children having performed Bayley-III at 1 year with information on motor performance (n = 170) at age 5-10 and school grades (n = 69) at age 7-10. Linear or logistic regression analysis was performed for data analysis.
Results: Below-average performance in the cognitive part of the Bayley-III at age 1 was significantly associated with poorer performance in balancing backwards (b = -0.45), sideways jumping (b = -0.42), standing long jump (b = -0.54), and forward bends (b = -0.59) at age 5-10 (all p < 0.05). Performance in other parts of the Bayley-III was not significantly associated with later motor skills. Furthermore, we did not observe any significant associations between performance in the Bayley-III and grades in school. The associations were not moderated by age, sex, or socioeconomic status (all p > 0.05).
Conclusions: The cognitive scale of the Bayley-III may be used as a predictive tool for later motor skills. Regarding school performance, the Bayley-III cannot be considered predictive.
Keywords: Bayley-III; cognitive skills; motor skills; predictive validity.