The relation between age of attainment of motor milestones and future cognitive and motor development in Bangladeshi children.

There is a need for easily administered, low-cost measures to assess child development in large field studies. Many researchers evaluate the age of attainment of motor milestones, but there is little information on their validity. A large longitudinal study (MINIMat) was conducted in a poor rural area of Bangladesh and we assessed the age of attainment of motor milestones in a subsample of over 2000 children. We examined their association with scores on the Bayley psychomotor development index (PDI) and mental development index (MDI) at 18 months and with scores on the Movement Assessment Battery for Children and with intelligence quotient (IQ) on the Wechsler Preschool and Primary Scale of Intelligence at 64 months. A field worker visited the children's homes monthly from 3 to 12 months of age and then at 15 months and examined the children. Mothers recorded the date of attainment of the milestones. Age of attainment of walking and standing alone was moderately correlated with the PDI and had significant but low associations with later motor development. They were as good as the PDI in predicting later motor development and could be used in field studies for that purpose. Milestone age of attainment had significant but low correlations with MDI and later IQ. Height for age at 15 months was related to milestones and later IQ and motor development and accounted for some of the association between milestones and IQ. Milestone age of attainment may not be sensitive enough to be used as an indicator of later IQ.