Standardization of the Denver developmental screening test on infants from Yucatan, Mexico

The DDST was standardized on 288 babies ranging in age from 2 to 54 weeks from Yucatan, Mexico. They were divided equally by age, sex and socio-cultural group (as defined by the health care center attended). all were full-term according to gestational age and birthweight, if known. Prior to developmental assessment, each baby had been rated as normal after examination by a Yucatecan health center physician. Subtest scores increased with age. No sex differences were found. Significant differences among socio-cultural groups occurred only on the language subtest, with middle-to-upper class babies obtaining higher scores. With the variable of age controlled, intercorrelations among DDST subtests were fairly low, suggesting that these subtest measure different functions. Split-half reliability correlations were lower than other published infant tests. Compared with other cross-cultural studies using the DDST, Yucatecan infants were advanced in fine motor skills, but by the end of their first year showed delay in gross motor locomotion. The DDST failed to identify as "questionable" 16 of 17 babies whose Bayley Motor Scores were borderline (PDI less than or equal to 80), thus, the DDST may be of limited use in diagnosing developmental delay in Yucatecan infants. Cross-cultural differences in infant development reaffirm the need for continuing test standardization to aid clinicians, researchers, and, especially, the babies themselves.