Motor assessment of cocaine/polydrug exposed infants at age 4 months.

Fifty nondrug-exposed infants and 74 cocaine/polydrug-exposed infants were evaluated on the Movement Assessment of Infants (MAI). The test provides an assessment of risk for motor dysfunction at age 4 months. There was a significant difference in total risk scores between the two groups of infants with cocaine-exposed infants having higher total risk scores (p less than .0001). Categorical risk scores revealed significant differences between the infants in muscle tone, primitive reflexes, and volitional movement with cocaine-exposed infants scoring more poorly in each category (p less than .0001). The groups scored differently on 11 of the 49 MAI items in those categories. Placement of infants within previously established ranges of risk scores (0-7 = no risk; 8-13 questionable risk; greater than 13 = high risk) revealed a significant difference in distribution between the two groups (p less than .0001). Earlier studies of the effects of intrauterine drug exposure have not revealed significant differences in motor development. The MAI demonstrated differential assessments of risk for motor dysfunction between cocaine-exposed and nondrug-exposed infants.