Environmental stimulation, parental nurturance and cognitive development in humans.

The effects of environmental stimulation and parental nurturance on brain development have been studied extensively in animals. Much less is known about the relations between childhood experience and cognitive development in humans. Using a longitudinally collected data set with ecologically valid in-home measures of childhood experience and later in-laboratory behavioral measures of cognitive ability, we were able to test hypotheses concerning the effects of environmental stimulation and parental nurturance. A double dissociation was found: On the one hand, there was a selective relation between parental nurturance and memory development, consistent with the animal literature on maternal buffering of stress hormone effects on hippocampal development. On the other hand, there was a selective relation between environmental stimulation and language development. The relevance of these findings to socioeconomic gradients in cognitive ability is discussed.

Childhood poverty: specific associations with neurocognitive development.

Growing up in poverty is associated with reduced cognitive achievement as measured by standardized intelligence tests, but little is known about the underlying neurocognitive systems responsible for this effect. We administered a battery of tasks designed to tax-specific neurocognitive systems to healthy low and middle SES children screened for medical history and matched for age, gender and ethnicity. Higher SES was associated with better performance on the tasks, as expected, but the SES disparity was significantly nonuniform across neurocognitive systems. Pronounced differences were found in Left perisylvian/Language and Medial temporal/Memory systems, along with significant differences in Lateral/Prefrontal/Working memory and Anterior cingulate/Cognitive control and smaller, nonsignificant differences in Occipitotemporal/Pattern vision and Parietal/Spatial cognition.

School performance of children with gestational cocaine exposure.

OBJECTIVE: To document school performance (pass/fail, grade point average, reading level, standardized test scores, absences) of cocaine-exposed and control children. DESIGN: A total of 135 children (62 with gestational cocaine exposure and 73 without), who were enrolled at birth, followed prospectively and have completed the fourth grade, were evaluated using report card data, standardized test results, teacher and parent report, and natal and early childhood data. Successful grade progression was defined as completing grades 1 through 4 without being retained. RESULTS: Cocaine-exposed (cocaine-exposed presented first) and control children were similar in school performance: successful grade progression (71% vs. 84%), Grade Point Average (2.4+/-0.8 vs. 2.6+/-0.7), reading below grade level (30% vs. 28%) and standardized test scores below average (reading [32% vs. 35%], math [57% vs. 44%], science [39% vs. 36%]); all p > or = 0.10. Children with successful progression, regardless of cocaine exposure, had higher Full Scale Intelligence Quotient and better home environments. CONCLUSION: In this inner-city cohort, cocaine-exposed and control children had similar poor school performance. Better home environment and higher Intelligence Quotient conferred an advantage for successful grade progression, regardless of gestational cocaine exposure.

Attentional functioning and impulse control in cocaine-exposed and control children at age ten years.

Children with gestational cocaine exposure may be at risk of difficulties in attentional functioning and impulse control. We administered the Gordon Diagnostic System and subtests of the Halstead-Reitan Battery to inner-city children with (COC) and without (CON) gestational cocaine exposure at age 10 years. Subtle differences were found between groups, with differences in Gordon Delay (Efficiency Ratio) and Gordon Distractibility (Total Commissions). With these two exceptions, children had similar performance, with both groups performing poorly. Attentional functioning and impulse control were also assessed in school. Teachers did not distinguish between COC and CON, although both groups presented behavioral problems. We conclude that gestational cocaine exposure may be associated with subtle problems in attention and impulse control, putting exposed children at higher risk of developing significant behavioral problems as cognitive demands increase.

Adolescents with and without gestational cocaine exposure: Longitudinal analysis of inhibitory control, memory and receptive language.

Preclinical studies of gestational cocaine exposure (GCE) show evidence of changes in brain function at the anatomical, physiological, and behavioral levels, to include effects on developing dopaminergic systems. In contrast, human studies have produced less consistent results, with most showing small effects or no effects on developmental outcomes. Important changes in brain structure and function occur through adolescence, therefore it is possible that prenatal cocaine exposure has latent effects on neurocognitive (NC) outcome that do not manifest until adolescence or young adulthood. We examined NC function using a set of 5 tasks designed to tap 4 different systems: inhibitory control, working memory, receptive language, and incidental memory. For each NC task, data were collected longitudinally at ages 12, 14.5 and 17 years and examined using generalized estimating equations. One hundred and nine children completed at least two of the three evaluations. Covariates included in the final model were assessment number, gender, participant age at first assessment, caregiver depression, and two composites from the Home Observation for Measurement of the Environment (HOME), Environmental Stimulation and Parental Nurturance. We found no cocaine effects on inhibitory control, working memory, or receptive language (p=0.18). GCE effects were observed on incidental face memory task (p=0.055), and GCE by assessment number interaction effects were seen on the incidental word memory task (p=0.031). Participant performance on inhibitory control, working memory, and receptive language tasks improved over time. HOME Environmental Stimulation composite was associated with better receptive language functioning. With a larger sample size smaller differences between groups may have been detected. This report shows no evidence of latent effects of GCE on inhibitory control, working memory, or receptive language. GCE effects were observed on the incidental face memory task, and GCE by assessment number interaction effects was seen on the incidental word memory task.

Children with and without gestational cocaine exposure: a neurocognitive systems analysis.

BACKGROUND: Concern for effects of gestational cocaine exposure (GCE) on human neurocognitive (NC) development is based on effects of cocaine on blood flow to the fetus and impact of cocaine on developing monoaminergic systems. GCE has been shown to affect language, attention and perceptual reasoning skills. OBJECTIVE: Our objective was to investigate effects of GCE on 7 NC systems, assessed behaviorally in middle school-aged, low socioeconomic status subjects followed prospectively since birth. METHODS: 55 GCE and 65 non-exposed Control subjects were tested with a battery of 14 tasks adapted from neuroimaging and lesion literature designed to tap 3 frontal systems (Cognitive Control, Working Memory, and Reward Processing) and 4 non-frontal systems (Language, Memory, Spatial Cognition, and Visual Cognition). Using multivariate analysis of covariance, we assessed the relation between NC functioning and GCE status with the following covariates: age at testing; gender; gestational exposure to cigarettes, alcohol and marijuana; foster care placement; caregiver current cocaine use; and two indices of childhood environment. RESULTS: None of the analyses showed an effect of GCE on NC function. In contrast, child characteristics, including age at testing and childhood environment, were associated with NC function. CONCLUSIONS: In this cohort there is either no effect of GCE on NC function at middle school age, or that effect is less pronounced than the effect of age or childhood environment.