Motor development in 3-month-old healthy term-born infants is associated with cognitive and behavioural outcomes at early school age.

Aim: To determine whether motor development at 3 months of age is associated with cognitive, motor, and behavioural outcomes in healthy children at early school age.

Method: In this cohort study, we included 74 term-born, healthy children (44 males, 30 females; median gestational age 40.1 wks, range 38.0-42.6 wks). From video recordings (median 12.9 wks, range 9.3-18.6 wks), we assessed the quality of fidgety movements, and calculated a motor optimality score. At school age (median 5 y 11 mo, range 5 y 8 mo-7 y 6 mo), we performed detailed cognitive, motor, and behavioural assessments. We examined whether aspects of motor development were associated with functional outcomes.

Results: An age-adequate motor repertoire, in particular the presence of antigravity, midline leg, and manipulation movements, was related to poorer cognition, whereas variable finger postures was related to better cognition. Children with a monotonous concurrent motor repertoire had better ball skills but experienced more behavioural problems. The presence of antigravity movements tended to be associated with abnormal recognition (odds ratio [OR] 4.4, 95% confidence interval [CI], 0.9-21; R(2) =0.17; p=0.070), where the absence of variable finger postures was associated with borderline and abnormal visual-spatial perception (OR 20, 95% CI, 1.7-238; R(2) =0.39; p=0.018).

Interpretation: Detailed aspects of motor development at 3 months of age are associated with cognition and behaviour, but not with motor outcome, in healthy children at early school age. Our findings suggest that early motor development may be the basis for later cognitive and behavioural performance. Since the associations were only moderate, possible environmental influences should be acknowledged.