Nonverbal communication, cognitive, and language development in cocaine-exposed infants

The present study examined the developmental relations between early nonverbal communication skills and later cognitive and language outcome in prenatally cocaine-exposed infants (n = 81). Correlational analyses revealed a positive association between ability to follow the line of regard of a social partner (i.e., responding to joint attention or RJA) at 18 months and cognitive and language outcome at 36 months. Additionally, they revealed a surprising finding such that the tendency to initiate joint attention (IJA) with a social partner at 12 months was negatively associated with cognitive outcome at 36 months. Follow-up hierarchical regression analyses indicated that both IJA at 12 months and RJA at 18 months provided incremental validity in the prediction of cognitive outcome at 36 months, above and beyond birthweight, educational intervention, and cognitive status at 18 months. Additionally, discriminant function analyses were conducted using IJA at 12 months, RJA at 18 months, and cognitive status at 18 months to classify infants into delayed versus normative cognitive groups at 36 months. The results of these analyses indicated correct classification of 91% of the delayed infants and 83% of the normative infants at 36 months. Results of this study suggest that measures of infant joint attention, when combined with an assemblage of other assessment measures, may be utilized to provide unique, and clinically significant, information in the prediction of cognitive outcome in at-risk infants.