Prenatal cocaine exposure places infants at risk for developmental delays, particularly language delays (Chapman, 2000; Lester, LaGasse, & Seifer, 1998), which increase the likelihood that they will require special education services as children and show poor developmental outcomes (Delgado, Vagi, & Scott, 2006). This study used second-order latent growth curve modeling to identify the trajectory of language development of infants from 12 to 36 months of age who had completed a three-year early intervention program. This study also investigated the predictive ability of six factors related to the child, family, and intervention. Child factors included sex, birthweight, and cognitive ability at 12 months, a family factor included mother's education level, and intervention factors included intervention type and age at enrollment. Results revealed that language growth across the two-year period was quadratic, with growth declining initially, then accelerating after 24 months, compared to the nationally normed sample upon which standardized language scores were based. Being a girl, being enrolled in the program soon after birth, and having higher cognitive ability at 12 months predicted higher initial language ability. Intervention group predicted growth in language, such that both intervention groups predicted less or no initial decline compared to the primary care non-intervention group, and the center-based intervention group showed faster acceleration after 24 months compared to the home-based intervention group. Implications of these results on the research literature and practical applications were discussed.

The current study examined the development of responding to joint attention (RJA), a prelinguistic skill, in a sample of children prenatally cocaine exposed. The sample used was part of a larger population of children randomly assigned to three levels of intervention. The growth of RJA in the current sample was best characterized by two linear growth groups determined by a semi-parametric growth modeling program. Each trajectory group was differentially associated with three language outcomes. Gender, treatment group, and birthweight were three risk factors that influenced the likelihood of belonging to either growth cluster. RJA?s predictive significance in terms of concurrent and subsequent language was also established, accounting for the variance associated with contemporaneous measures of cognition. The findings (regarding the relationship between RJA and language) were consistent with previous research examining joint attention behaviors in other types of samples. Additionally, this study contributed uniquely to the body of research on joint attention by exploring the growth of RJA, a precursor of language, in a sample of children at risk for language impairment.

Mutual regulation of attention was investigated in a group of prenatally cocaine-exposed and non-exposed mother-infant dyads during a 5-minute videotaped free play session. Mutual regulation was measured using a state-based coding scheme designed to categorize dyadic interactions into three mutually exclusive and exhaustive states: maternal bid, mutual engagement, and non-involved. Results revealed no significant differences between cocaine-exposed and non-exposed dyads in overall amount of mutual engagement displayed. Cocaine-exposed dyads exhibited significantly longer mutual engagement episodes. Mothers in the two groups did not differ in the number or quality of bids for mutual engagement, and infants in both groups were equally responsive to maternal bids. No ecological variables were found to predict mutual engagement.

Although the hazards of prenatal exposure to addictive substances have been documented for decades, it continues to be a prevalent social and health concern today. Alcohol and cocaine are two commonly abused substances during pregnancy, often leading to behavioral and cognitive disorders in exposed children. At present, the relationship between teratogenic effects of prenatal alcohol exposure (PAE) and prenatal cocaine exposure (PCE) on the brain and observed behavioral outcomes is still unclear. A primary reason for this incomplete understanding is the lack of information regarding neuronal functioning in these populations. Functional MRI, which measures real-time brain activation in response to certain stimuli, can be utilized to bridge the gap between known structural damage and observed behavioral outcomes. This thesis aims to examine structural and functional alterations in PAE and PCE populations as compared to unexposed, socio-economic status-matched populations. As the PAE population is highly affected by structural dysmorphology, the applicability of a newly developed diffeomorphic image registration method to this population is examined. Additionally, task-positive and task-negative functional connectivity and activity are investigated in the PAE population, and related to underlying structural alterations. Neural correlates of global arousal and emotional regulation are investigated in the PCE population, as these behavioral outcomes are most notable. Similarly, functional connectivity and activation in task-positive and task-negative networks, as well as correlated structural measures, are examined in the PCE population. The diffeomorphic image registration algorithm was found to improve both structural and functional image registration for the PAE population. In the examination of specific deficits in arithmetic processing, poorer performance in the PAE group was attributed to a multi-level effect produced by altered structural and functional connectivity and functional activity in calculation and default mode networks. Baseline arousal levels were found to be higher in adolescents with PCE as compared to healthy controls (by altered default mode network functioning); emotional regulation also appeared to be affected in the PCE group by a prefrontal-amygdala structural and functional disconnect. The findings of this thesis give insights into the relationship between task-positive and task-negative duality and cognitive impairment, and contribute to a more comprehensive understanding of the spectrum of clinical disorders caused by prenatal exposure to alcohol and cocaine.