Establishing Brazilian Age Norms and Cross-Cultural Differences in Infant Motor Development Using the Test of Infant Motor Performance (TIMP)

AIMS: (1) to compare the motor development trajectories of infants from Brazil (BR) and the U.S.; (2) to propose normative cutoffs scores for BR infants and examine similarities and differences in motor performance relative to U.S. cutoff scores; (3) to investigate variations in TIMP motor performance among Brazilian infants according to medical risk. METHODS: A total of 724 BR infants from diverse geographic regions were assessed using the TIMP and classified into low-, moderate-, and high-risk groups on medical history. Bayesian linear regression and discriminative power analysis were conducted. RESULTS: U.S. infants demonstrated higher performance during the early age ranges (34-35 week postmenstrual age to 6-7 week post-term corrected age), whereas BR infants showed higher performance from 10 week post-term corrected-age onward. The use of U.S. cutoff scores overestimated motor delays. Brazilian norms were sensitive to differentiated risk groups. CONCLUSIONS: Brazilian norms improved screening, accuracy, and referral decisions.