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Abstract
The pattern of motor and attention development was investigated in 21 preterm infants who were prenatally exposed to cocaine and compared to that of preterm non-cocaine-exposed and fullterm cocaine-exposed infants. Neurobehavioral development was measured by relevant clusters from the Neurobehavioral Assessment of the Preterm Infant (Korner, Thom & Forrest, 1991). The effect of cocaine exposure depended on infant conceptional age at evaluation, medical status, the pattern of development, and the neurobehavioral domain examined. Results suggested that prenatal cocaine exposure was associated with initial motor and attention deficits and faster rates of neurobehavioral development in preterm infants. These initial deficits may resolve with advancing conceptional age, with comparable neurobehavioral performance observed at 36 weeks conceptional age between cocaine-exposed and non-cocaine-exposed infants. The effects of cocaine exposure on motor development were stronger than those for attention development, as cocaine exposure did not predict the pattern of attention development when evaluation conditions were statistically controlled. In utero cocaine exposure moderated the effects of medical status on motor development, but not on attention development. Combined with the influence of cocaine exposure, the number of weeks of prematurity was the most salient predictor of motor outcome. Cocaine exposure was found to influence motor outcome directly and through the influence of prematurity. The differential results for the mechanism of action of cocaine on motor versus attention development may be a result of a more direct link of motor functioning with the underlying neuropathology of in utero cocaine exposure. The findings indicate that the impact of cocaine exposure on early neurobehavioral competence may be more complicated than previously considered. However, examination of the mechanism of action of prenatal cocaine exposure on motor and attention development can be fruitful in parsing the relations among cocaine exposure, medical status and neurobehavioral development.
