Objectives: To establish the normative data of the Bayley Scales of Infant Development-Second Edition (BSID-II) on Taiwanese infants from age 6 to 24 months and to explore the factors that relate to their mental and motor development.
Methods: Five hundred and seven Taiwanese full-term infants were prospectively examined with the BSID-II at 6, 12, 18, and 24 months of age.
Results: Taiwanese infants' Bayley mental and motor raw scores were lower than the United States norms from age 6 to 24 months, however, the discrepancy gradually declined with increasing age. Gender, intrauterine growth status, birth order, region of residence, maternal education, and paternal occupation were shown to have longitudinal associations with their mental and/or motor scores.
Conclusions: Differences existed in the mental and motor development among Taiwanese and American infants. Our preliminary norms of the BSID-II may be more appropriate than the United States norms for Taiwanese children.