Abstract
OBJECTIVE: To compare the motor development of infants from three population samples (Brazil, Canada and Greece), to investigate differences in the percentile curves of motor development in these samples, and to investigate the prevalence of motor delays in Brazilian children. METHODS: Observational, descriptive and cross-sectional study with 795 Brazilian infants from zero to 18 months of age, assessed by the Alberta Infant Motor Scale (AIMS) at day care centers, nurseries, basic health units and at home. The Brazilian infants' motor scores were compared to the results of two population samples from Greece (424 infants) and Canada (2,400 infants). Descriptive statistics was used, with one-sample t-test and binomial tests, being significant p ≤ 0.05. RESULTS: 65.4% of Brazilian children showed typical motor development, although with lower mean scores. In the beginning of the second year of life, the differences in the motor development among Brazilian, Canadian and Greek infants were milder; at 15 months of age, the motor development became similar in the three groups. A non-linear motor development trend was observed. CONCLUSIONS: The lowest motor percentiles of the Brazilian sample emphasized the need for national norms in order to correctly categorize the infant motor development. The different ways of motor development may be a consequence of cultural differences in infant care.