Objective: To determine the stability of the scores obtained on tests of motor development from birth until school age in healthy, term singletons and to determine if early motor scores are associated with more complex cognitive functions at school age, such as attention and memory.
Patients and methods: This longitudinal, prospective cohort study included 77 infants. The motor development of these infants was assessed during the neonatal period with Prechtl's neurologic examination; in early infancy with Touwen's neurologic examination and general movement assessment; at toddler age with Hempel's neurologic examination and the Psychomotor Developmental Index from the Bayley Scales of Infant Development; and at school age with the Movement Assessment Battery for Children. Cognition was determined at toddler age with the Mental Developmental Index from the Bayley Scales of Infant Development; and at school age with an intelligence test and attention and memory tests.
Results: The mean absolute difference in standardized motor scores for all time points was 1.01 SD (95% confidence interval: 0.91-1.11). Only the explained proportions of variance of maternal socioeconomic status and verbal intelligence were significant for sustained attention and verbal memory (r(2) = 0.104, P = .030 and r(2) = 0.074, P = .027), respectively. The children's scores on early motor tests added little value for their motor and cognitive development at school age.
Conclusions: In healthy children the stability of motor development from birth until school age is low. Maternal socioeconomic status and verbal intelligence rather than the infants' scores on early motor tests signified added value for complex cognitive functions at school age.