Emergence of Selective Motor Control in Early Infancy: A Longitudinal Study of Infants Born Preterm with and without Cerebral Palsy.

OBJECTIVES: To characterize early developmental trajectories of selective motor control (SMC) in infants born very preterm and examine associations with later cerebral palsy (CP) diagnosis and gross motor function. STUDY DESIGN: Infants born very preterm (<32 weeks' gestation) were recorded every 2-4 weeks until 5 months post-term age. SMC was scored from 352 videos (n = 47 infants; 12 with CP) using BabyOSCAR, a validated observational tool. CP diagnosis was then confirmed at 2 years of age. Linear mixed models examined SMC trajectories by CP diagnosis and Gross Motor Function Classification System (GMFCS) level. Receiver operating characteristic curves tested the ability of early SMC change (40-45 weeks) to predict CP. RESULTS: SMC scores increased over time, but infants with CP showed slower gains. Between 41 and 63 weeks, group differences emerged and widened (P < .001). A change in BabyOSCAR score from 40-45 weeks predicted CP with 92% sensitivity and 100% specificity (area under the curve = 0.98). GMFCS groups showed distinct trajectories, with children classified as GMFCS III-V exhibiting less change in scores. Infants with unilateral CP showed increasing asymmetry from 42 weeks post-term age. CONCLUSIONS: SMC develops rapidly after term age but is altered in infants with CP, particularly among those later classified as GMFCS III-V. Early trajectories may reflect emerging corticospinal connectivity and offer a clinically useful marker of functional motor outcomes.