Problem-solving ability of inner-city children with and without in utero cocaine exposure

Effect of socioeconomic status disparity on child language and neural outcome: how early is early?

It is not news that poverty adversely affects child outcome. The literature is replete with reports of deleterious effects on developmental outcome, cognitive function, and school performance in children and youth. Causative factors include poor nutrition, exposure to toxins, inadequate parenting, lack of cognitive stimulation, unstable social support, genetics, and toxic environments. Less is known regarding how early in life adverse effects may be detected. This review proposes to elucidate "how early is early" through discussion of seminal articles related to the effect of socioeconomic status on language outcome and a discussion of the emerging literature on effects of socioeconomic status disparity on brain structure in very young children. Given the young ages at which such outcomes are detected, the critical need for early targeted interventions for our youngest is underscored. Further, the fiscal reasonableness of initiating quality interventions supports these initiatives. As early life adversity produces lasting and deleterious effects on developmental outcome and brain structure, increased focus on programs and policies directed to reducing the impact of socioeconomic disparities is essential.

Continued effects of prenatal cocaine use: preschool development

The relationship between prenatal cocaine use and preschooler's physical and cognitive development and behavioral characteristics was examined, controlling for other influences on child development. On average, children were 38.5 months old, women were 29.4 years old, had 12.3 years of education, and 47% were African American. During the first trimester, 18% of the women were frequent cocaine users (> or = 1 line/day). First trimester cocaine exposure predicted decreased head circumference at 3 years and lower scores on the short-term memory subscale of the Stanford-Binet Intelligence Scale (SBIS) [74]. There was no significant relationship between prenatal cocaine use and the other SBIS scales. First trimester cocaine use also predicted more total, internalizing, and externalizing behavior problems on the Child Behavior Checklist [3] and higher scores on the fussy/difficult scale of the Infant Characteristics Questionnaire [6]. Children who were exposed to cocaine throughout pregnancy had more behavior problems and were more fussy compared to children of women who never used cocaine prenatally. A repeated measures analysis showed that children of first trimester cocaine users became more fussy over time. These detrimental effects on growth and behavior are consistent with other reports in the literature and with the hypothesis that prenatal cocaine exposure affects development through changes in neurotransmitter systems.

Executive functioning at ages 5 and 7 years in children with prenatal cocaine exposure

This prospective longitudinal study evaluated the effect of prenatal cocaine exposure (PCE) on executive functioning in 5- and 7-year-old children. In total, 154 pregnant cocaine users, identified by urine toxicology and structured interviews, were matched to 154 nonusers. Children were assessed by certified masked evaluators, and caregivers were interviewed by experienced staff during home visits. In approximately 90% of the surviving sample tested at ages 5 and 7 years, structural equation modeling demonstrated that an increased head circumference at birth (adjusted for gestation) significantly predicted better performance on executive functioning, and that PCE was indirectly related to executive functioning through its significant negative effect on head circumference at birth. At age 5 years, quality of environment also predicted executive functioning, and the R(2) for the total model was 0.24. At 7 years, caregiver functioning predicted quality of environment, which in turn was positively related to executive functioning, and girls had better executive functioning. The total model at age 7 years accounted for 30% of the variance in executive functioning.

Functional magnetic resonance imaging and working memory in adolescents with gestational cocaine exposure

OBJECTIVE

To assess the effect of gestational cocaine exposure on the prefrontal cortex (PFC) with functional magnetic resonance imaging (fMRI).

STUDY DESIGN

Using an n-back task, we obtained fMRI with a 3T Siemens scanner on 49 adolescents, 25 who were exposed to cocaine and 24 who were not exposed. The primary outcome was PFC activation during task performance. Five functionally derived regions of interest (ROI) were defined; in addition, 2 a priori anatomical ROIs were generated for Brodmann regions 10 and 46.

RESULTS

Of the 49 adolescents who underwent imaging, data from 17 who were exposed to cocaine and 17 who were not exposed were in the final analysis. Groups had similar performance on the n-back task (P >/= .4), with both showing a fewer number of correct responses on the 2-back than the 1-back (P < .001), indicating increased demands on working memory with greater task difficulty. In functionally derived ROIs, imaging results showed increased activation for both groups in the 2-back versus the 1-back condition. In anatomical ROIs, both groups showed greater activation in the 2-back versus the 1-back condition, with activation in the non-exposed group proportionally greater for the left prefrontal region (P = .05).

CONCLUSION

In this sample of adolescents, participants who were exposed to cocaine and participants who were not exposed were similar in performance on an executive function task and in fMRI activation patterns during task performance.

A meta-analysis of animal studies on disruption of spatial navigation by prenatal cocaine exposure

Water-maze testing has been used to assess prenatal cocaine (PCOC)-induced deficits in behavioral studies of spatial navigation and memory abilities. Effects of PCOC in acquisition or in probe trials over water-maze testing days were rarely detected. Despite an absence of effects of PCOC when data were collapsed over multiple days, there was a potential difference when examined during the first day of acquisition training, characterized by a PCOC-associated decrease in learning efficiency but not capacity. Here, we review studies of PCOC-related changes in day-1 water-maze acquisition training and examine the relationship between experimental methodologies and PCOC-treatment procedures and the variability in effect size estimates across studies. The results revealed a significant increase in latencies to goal platform on acquisition training day-1 in PCOC-exposed offspring vs. controls (effect size: r=0.44). Significant effects attributable to variations in the PCOC-treatment procedures across studies were also identified. The moderating variable of PCOC "dose" was significant as lower doses of PCOC exposure yielded larger treatment effects. "Duration" of PCOC exposure was not significant, although a trend for greater effects was observed in studies that employed longer daily treatment schedules or schedules administered in later gestational periods. This analysis identified a consistent difference in acquisition training day-1 of water-maze testing in PCOC-exposed offspring indicating a PCOC-induced deficiency in spatial learning. These findings of impaired spatial learning efficiency are of particular interest given clinical scenarios involving acutely impaired spatial memory and related learning in PCOC-exposed children that highlight the potential consequences in classroom learning.

Cocaine effects on the developing brain: current status

The present paper reports on the results obtained in a rabbit model of prenatal cocaine exposure that mimics the pharmacokinetics of crack cocaine in humans, and relates these findings to studies in other species including humans. A general finding is that prenatal exposure to cocaine during neurogenesis produces dysfunctions in signal transduction via the dopamine D(1) receptor and alterations in cortical neuronal development leading to permanent morphological abnormalities in frontocingulate cortex and other brain structures. Differences in the precise effects obtained appear to be due to the dose, route and time of cocaine administration. Related to these effects of in utero cocaine exposure, animals demonstrate permanent deficits in cognitive processes related to attentional focus that have been correlated with impairment of stimulus processing in the anterior cingulate cortex. The long-term cognitive deficits observed in various species are in agreement with recent reports indicating that persistent attentional and other cognitive deficits are evident in cocaine-exposed children as they grow older and are challenged to master more complex cognitive tasks.

Children prenatally exposed to cocaine: developmental outcomes and environmental risks at seven years of age

Data are equivocal regarding the long-term consequences of prenatal exposure to cocaine on school-aged children. We compared 101 children exposed prenatally to cocaine with 130 unexposed children on measures of intelligence, visual motor, and motor abilities at age 7 years. Bivariate analyses revealed that cocaine-exposed children scored significantly lower than comparison children on the abbreviated Wechsler Intelligence Scale for Children-Third Edition Verbal and Full Scale IQ scores, the Visual Motor Integration and Motor Coordination standardized scores, and the Bruininks-Oseretsky Fine Motor Composite score. Regression analyses indicated that the biological mother's vocabulary and home environment assessed at the same 7-year visit were stronger predictors of developmental outcome than prenatal drug exposure. Level of cocaine exposure, however, predicted visual motor and motor skills. The results indicate that although prenatal cocaine exposure may confer some degree of developmental disadvantage in the visual motor domain, it frequently occurs in the context of an inadequate rearing environment, which may be a stronger determinant than prenatal cocaine exposure of children's outcome.

Perinatal substance abuse and human subjects research: are privacy protections adequate?

Privacy incursions in the clinical care of substance abusing pregnant women have gained lay and professional attention recently as the result of a high-profile Supreme Court finding in Ferguson vs City of Charleston et al. In March, 2001 the Supreme Court determined that nonconsensual drug screening of pregnant women by clinicians in a public hospital violated the women's Fourth Amendment rights to be secure against unreasonable search and seizure. Coercive or punitive policy approaches to perinatal substance abuse are often based on mistaken assumptions about the nature of addiction and the outcomes of punitive interventions. Much attention has been given to efforts to criminalize pregnancy for drug using women, and civil laws are also coming under increasing scrutiny. Although no state has passed a law criminalizing pregnancy and drug use, an estimated 250 women in more than 30 states have been prosecuted around the country on theories of "fetal abuse." A growing number of states (eighteen to date) have amended their civil child welfare laws to address specifically the subject of a woman's drug use during pregnancy. No one has examined how these laws and social policies could affect research that includes pregnant and parenting women; women (and their families) who stand to lose a great deal should their drug use be brought to the attention of child welfare or criminal justice authorities. We examine the adequacy of current protective mechanisms, such as federal certificates of confidentiality, in protecting research subjects (and investigators) who may be subject to punitive civil or criminal sanctions. We determine that current protective mechanisms may be insufficient to protect research subjects and that investigators and IRB members are often ignorant of the risks imposed by punitive policy approaches to perinatal substance abuse or fall prey to the same mistaken assumptions that inform punitive policies. We conclude that investigators and IRB members have a moral responsibility to understand local, state and national policies and laws governing perinatal substance abuse. Investigators and IRB members should balance the harms of punitive interventions against the protections that may, or may not be afforded to prospective research subjects as well as the prospective benefits, individual and social, of the research. In situations where criminal or punitive policies are in effect, investigators and IRB members should consider whether adequate protections can be achieved. In the context of inadequate protections, potential risks to prospective research subjects and their families may outweigh the individual or social benefits that accrue from the research. Clinical researchers are professionally obligated to work toward amending laws and policies that are not in the best interests of prospective research subjects.

Paved with good intentions: do public health and human service providers contribute to racial/ethnic disparities in health?

There is extensive evidence of racial/ethnic disparities in receipt of health care. The potential contribution of provider behavior to such disparities has remained largely unexplored. Do health and human service providers behave in ways that contribute to systematic inequities in care and outcomes? If so, why does this occur? The authors build on existing evidence to provide an integrated, coherent, and sound approach to research on providers' contributions to racial/ethnic disparities. They review the evidence regarding provider contributions to disparities in outcomes and describe a causal model representing an integrated set of hypothesized mechanisms through which health care providers' behaviors may contribute to these disparities.