Developing language skills of cocaine-exposed infants

The association of prenatal cocaine exposure with expressive and receptive language skills, phonological processing and reading ability at age 17

OBJECTIVE

Prenatal cocaine exposure (PCE) has been associated with small but significant effects on language development in childhood and early adolescence. This study examined whether this association persists into later adolescence and what relationship language skills may have with reading proficiency in this population.

METHODS

Enrolled were 338 (167 with PCE, 171 with NCE or no cocaine exposure) 17-year-olds recruited at birth who, together with their current caregiver, were seen as part of a 17-year follow-up. Participants were given assessments of reading achievement (WIAT-III), receptive and expressive language (CELF-IV), and phonological processing (CTOPP). Relationships between PCE status and language outcomes were modeled using multiple linear regression controlling for environmental and caregiver factors, and other prenatal substance exposures.

RESULTS

Adolescents with PCE scored lower in areas of phonological processing and reading related skills compared to adolescents with NCE. PCE by sex interactions were identified on language, memory and spoken language comprehension, with lower scores for girls with PCE compared to girls with NCE.

CONCLUSION

These findings suggest the persistence of PCE's relationship with phonological awareness well into adolescence. PCE was also associated with lower scores on measures of skills related to reading ability, which may be a manifestation of the observed deficits in phonological processing.

Cumulative Risk, Protection, and Early Intervention: Neurodevelopment in Sibling Groups Exposed Prenatally to Substances

Mothercraft's Breaking the Cycle is an early intervention program for substance-exposed children with neurodevelopmental vulnerabilities. Within three substance-exposed sibling groups (N = 8; 0-6 years), we 1) described longitudinal neurodevelopmental trajectories, 2) explored the balance of cross-domain cumulative risk and protection on neurodevelopment, and 3) generated hypotheses on how cumulative risk, protection, and early intervention impact neurodevelopment. Neurodevelopment is potentially shaped by the balance of risk and protection. Postnatal risk (birth/postnatal, child, parent-child interaction) and relational protection (family, parent-child interaction) appear to have the most salient impact on neurodevelopment. Early intervention is thought to be important as soon as possible and before age 3 years.

Effects of Fetal Substance Exposure on Offspring Substance Use

Prenatal exposure to alcohol and drugs is associated with physical, cognitive, and behavioral problems across the offspring's lifespan and an increased risk of alcohol and drug use in adolescent and young adult offspring. These prenatal effects continue to be evident after control for demographic background and parental alcohol and drug use. Behavior problems in childhood and adolescence associated with prenatal exposures may serve as a mediator of the prenatal exposure effects on offspring substance use.

Prenatal Cocaine Exposure Impacts Language and Reading Into Late Adolescence: Behavioral and ERP Evidence

Extant research documents impaired language among children with prenatal cocaine exposure (PCE) relative to nondrug exposed (NDE) children, suggesting that cocaine alters development of neurobiological systems that support language. The current study examines behavioral and neural (electrophysiological) indices of language function in older adolescents. Specifically, we compare performance of PCE (N = 59) and NDE (N = 51) adolescents on a battery of cognitive and linguistic assessments that tap word reading, reading comprehension, semantic and grammatical processing, and IQ. In addition, we examine event related potential (ERP) responses in in a subset of these children across three experimental tasks that examine word level phonological processing (rhyme priming), word level semantic processing (semantic priming), and sentence level semantic processing (semantic anomaly). Findings reveal deficits across a number of reading and language assessments, after controlling for socioeconomic status and exposure to other substances. Additionally, ERP data reveal atypical orthography to phonology mapping (reduced N1/P2 response) and atypical rhyme and semantic processing (N400 response). These findings suggest that PCE continues to impact language and reading skills into the late teenage years.

Alcohol Interactions with Psychostimulants: An Overview of Animal and Human Studies

Alcohol consumption with psychostimulants is very common among drug addicts. There is little known about the possible pharmacological interactions between alcohol and psychostimulants. Among most commonly co-abused psychostimulants with alcohol are methamphetamine, cocaine, 3,4-methylenedioxymethamphetaminen, and nicotine. Co-abuse of alcohol with psychostimulants can lead to several neurophysiological dysfunctions such as decrease in brain antioxidant enzymes, disruption of learning and memory processes, cerebral hypo-perfusion, neurotransmitters depletion as well as potentiation of drug seeking behaviour. Moreover, co-abuse of alcohol and psychostimulants can lead to increase in heart rate, blood pressure, myocardial oxygen consumption and cellular stress, and the risk of developing different types of cancer. Co-abuse of alcohol with psychostimulants during pregnancy can lead to fetal brain abnormalities. Further studies are needed to investigate the pharmacokinetics, pharmacodynamics, and neurochemical changes on co-abuse of alcohol and psychostimulants.

Cocaine-induced neurodevelopmental deficits and underlying mechanisms

Exposure to drugs early in life has complex and long-lasting implications for brain structure and function. This review summarizes work to date on the immediate and long-term effects of prenatal exposure to cocaine. In utero cocaine exposure produces disruptions in brain monoamines, particularly dopamine, during sensitive periods of brain development, and leads to permanent changes in specific brain circuits, molecules, and behavior. Here, we integrate clinical studies and significance with mechanistic preclinical studies, to define our current knowledge base and identify gaps for future investigation. Birth Defects Research (Part C) 108:147-173, 2016. © 2016 Wiley Periodicals, Inc.

Prenatal cocaine exposure and child outcomes: a conference report based on a prospective study from Cleveland

OBJECTIVE

The study aims to describe developmental outcomes from a longitudinal prospective cohort (Cleveland study) of prenatally cocaine-exposed (CE) infants.

METHODS

Two hundred eighteen CE and 197 nonexposed infants were enrolled at birth and followed through mid-adolescence. Birth CE status was determined by interview and biologic measures. Multiple demographic, drug, and environmental correlates were controlled. Standardized, normative, reliable measures of fetal growth, intelligence quotient (IQ), behavior, executive function, and language were given at each age and risk for substance misuse assessed in adolescence. A subset of children received volumetric magnetic resonance imaging (MRI) at 7 years and functional MRI at 14 years. The effect of CE was determined through multiple regression analyses controlling for confounders.

RESULTS

Cocaine exposed had significant negative effects on fetal growth, attention, executive function, language, and behavior, while overall IQ was not affected. CE had significant negative effects on perceptual reasoning IQ and visual-motor skills and predicted lower volume of corpus callosum and decreased gray matter in the occipital and parietal lobes. CE children had higher risk for substance misuse. Confounding risk factors had additive effects on developmental outcomes.

CONCLUSIONS

Prenatal exposure to cocaine was related to poorer perceptual organization IQ, visual-spatial information processing, attention, language, executive function, and behavior regulation through early adolescence.

Prenatal cocaine effects on brain structure in early infancy

Prenatal cocaine exposure (PCE) is related to subtle deficits in cognitive and behavioral function in infancy, childhood and adolescence. Very little is known about the effects of in utero PCE on early brain development that may contribute to these impairments. The purpose of this study was to examine brain structural differences in infants with and without PCE. We conducted MRI scans of newborns (mean age = 5 weeks) to determine cocaine's impact on early brain structural development. Subjects were three groups of infants: 33 with PCE co-morbid with other drugs, 46 drug-free controls and 40 with prenatal exposure to other drugs (nicotine, alcohol, marijuana, opiates, SSRIs) but without cocaine. Infants with PCE exhibited lesser total gray matter (GM) volume and greater total cerebral spinal fluid (CSF) volume compared with controls and infants with non-cocaine drug exposure. Analysis of regional volumes revealed that whole brain GM differences were driven primarily by lesser GM in prefrontal and frontal brain regions in infants with PCE, while more posterior regions (parietal, occipital) did not differ across groups. Greater CSF volumes in PCE infants were present in prefrontal, frontal and parietal but not occipital regions. Greatest differences (GM reduction, CSF enlargement) in PCE infants were observed in dorsal prefrontal cortex. Results suggest that PCE is associated with structural deficits in neonatal cortical gray matter, specifically in prefrontal and frontal regions involved in executive function and inhibitory control. Longitudinal study is required to determine whether these early differences persist and contribute to deficits in cognitive functions and enhanced risk for drug abuse seen at school age and in later life.

Level of intrauterine cocaine exposure and neuropsychological test scores in preadolescence: subtle effects on auditory attention and narrative memory

Neuropsychological processes such as attention and memory contribute to children's higher-level cognitive and language functioning and predict academic achievement. The goal of this analysis was to evaluate whether level of intrauterine cocaine exposure (IUCE) alters multiple aspects of preadolescents' neuropsychological functioning assessed using a single age-referenced instrument, the NEPSY: A Developmental Neuropsychological Assessment (NEPSY) (Korkman et al., 1998), after controlling for relevant covariates. Participants included 137 term 9.5-year-old children from low-income urban backgrounds (51% male, 90% African American/Caribbean) from an ongoing prospective longitudinal study. Level of IUCE was assessed in the newborn period using infant meconium and maternal report. 52% of the children had IUCE (65% with lighter IUCE, and 35% with heavier IUCE), and 48% were unexposed. Infants with Fetal Alcohol Syndrome, HIV seropositivity, or intrauterine exposure to illicit substances other than cocaine and marijuana were excluded. At the 9.5-year follow-up visit, trained examiners masked to IUCE and background variables evaluated children's neuropsychological functioning using the NEPSY. The association between level of IUCE and NEPSY outcomes was evaluated in a series of linear regressions controlling for intrauterine exposure to other substances and relevant child, caregiver, and demographic variables. Results indicated that level of IUCE was associated with lower scores on the Auditory Attention and Narrative Memory tasks, both of which require auditory information processing and sustained attention for successful performance. However, results did not follow the expected ordinal, dose-dependent pattern. Children's neuropsychological test scores were also altered by a variety of other biological and psychosocial factors.

Neurobehavioral and Developmental Traiectories Associated with Level of Prenatal Cocaine Exposure

INTRODUCTION

In experimental models, prenatal cocaine exposure has been found to perturb GABA and dopamine development. Clinically, abnormalities in tone, posture and state regulation are noted in early infancy but the evolution of these findings over time is not well described. The current study assesses the longitudinal effects of prenatal cocaine exposure in dose-dependent fashion on developmental & behavioral and neurological trajectories over the first 2 years of life.

METHODS

Three hundred and eighty infants, 113 cocaine-exposed, were enrolled at birth from an urban hospital from 2000 to 2004. Exposure was determined by maternal interview, segmental hair analyses (RIAH^™) in all, and meconium and urine in a subset. Developmental, behavioral and neurological assessments were carried out blind to drug exposure at 6, 12 and 24 months of age in the 306 children who returned in follow-up. Mixed-effects linear modeling (developmental growth curve) assessed change in outcome over time.

RESULTS

The mental developmental growth curve showed a negative slope (2.2 points) in adjusted analyses among cocaine-exposed children over the first 2 years of life. (p=.04), while the slope of the motor development growth curve did not. Adjusting for microcephaly at 6 months diminished the strength of the association between cocaine exposure and mental developmental growth curve (effect modification). Cocaine exposure was marginally associated with behavioral outcomes in adjusted analyses. Total Behavior scores and Orientation/Engagement scores improved with age. At 1 year of age, prenatal cocaine exposure was significantly associated with lower motor development scores. High rates of hypertonia (global and diparesis) identified at the 6-month visit dropped dramatically in the first 2 years of life: cocaine-exposed children showed a more rapid rate of resolution of hypertonia than unexposed children, with hypertonia improving 2.2 times faster among those with heavy cocaine exposure.

CONCLUSION

We found differences in mental performance over the first 2 years of life associated with prenatal cocaine exposure that was mediated by microcephaly implying that cocaine exerts a sustained teratogenic effect on brain development. Early neurological (hypertonia) and behavioral findings associated with prenatal cocaine exposure improved over time. Hypertonia did not predict long-term development impairments. Conceivably, the transient nature of neurobehavioral manifestations reflects postnatally a tendency towards homeostasis of cocaine-related embryopathic perturbations of GABA and dopaminergic systems.

Language outcomes at 12 years for children exposed prenatally to cocaine

PURPOSE

In this study, the authors aimed to examine the long-term effects of prenatal cocaine exposure (PCE) on the language development of 12-year-old children using a prospective design, controlling for confounding prenatal drug exposure and environmental factors.

METHOD

Children who were exposed to cocaine in utero (PCE; n = 183) and children who were not exposed to cocaine (i.e., no cocaine exposure [NCE]; n = 181) were followed prospectively from birth to 12 years of age and were compared on language subtests of the Test of Language Development-Intermediate, Third Edition ( Hammill & Newcomer, 1997b), and phonological processing as measured by the Comprehensive Test of Phonological Processing ( Wagner & Torgesen, 1999). The authors evaluated the relationship of PCE to language development through a multivariate analysis of covariance and regression analyses while controlling for confounders.

RESULTS

Results show that PCE has small effects on specific aspects of language, including syntax and phonological processing. The caregiver variables of lower maternal vocabulary, more psychological symptoms, and a poorer home environment also had consistent effects on language and phonological processing scores.

CONCLUSIONS

These findings suggest that PCE continues to have small, subtle effects on specific aspects of language at age 12 years. Phonological processing skills were significantly related to the reading outcomes of letter-word identification, reading fluency, and reading comprehension, indicating that PCE also has small but lasting effects on the language skills that are related to later literacy skills.

Prenatal IV Cocaine: Alterations in Auditory Information Processing

One clue regarding the basis of cocaine-induced deficits in attentional processing is provided by the clinical findings of changes in the infants' startle response; observations buttressed by neurophysiological evidence of alterations in brainstem transmission time. Using the IV route of administration and doses that mimic the peak arterial levels of cocaine use in humans, the present study examined the effects of prenatal cocaine on auditory information processing via tests of the auditory startle response (ASR), habituation, and prepulse inhibition (PPI) in the offspring. Nulliparous Long-Evans female rats, implanted with an IV access port prior to breeding, were administered saline, 0.5, 1.0, or 3.0 mg/kg/injection of cocaine HCL (COC) from gestation day (GD) 8-20 (1×/day-GD8-14, 2×/day-GD15-20). COC had no significant effects on maternal/litter parameters or growth of the offspring. At 18-20 days of age, one male and one female, randomly selected from each litter displayed an increased ASR (>30% for males at 1.0 mg/kg and >30% for females at 3.0 mg/kg). When reassessed in adulthood (D90-100), a linear dose-response increase was noted on response amplitude. At both test ages, within-session habituation was retarded by prenatal cocaine treatment. Testing the females in diestrus vs. estrus did not alter the results. Prenatal cocaine altered the PPI response function across interstimulus interval and induced significant sex-dependent changes in response latency. Idazoxan, an α(2)-adrenergic receptor antagonist, significantly enhanced the ASR, but less enhancement was noted with increasing doses of prenatal cocaine. Thus, in utero exposure to cocaine, when delivered via a protocol designed to capture prominent features of recreational usage, causes persistent, if not permanent, alterations in auditory information processing, and suggests dysfunction of the central noradrenergic circuitry modulating, if not mediating, these responses.

Adolescent initiation of licit and illicit substance use: Impact of intrauterine exposures and post-natal exposure to violence

Whether intrauterine exposures to alcohol, tobacco, marijuana, or cocaine predispose offspring to substance use in adolescence has not been established. We followed a sample of 149 primarily African American/African Caribbean, urban adolescents, recruited at term birth, until age 16 to investigate intrauterine cocaine exposure (IUCE). We found that in Kaplan-Meier analyses higher levels of IUCE were associated with a greater likelihood of initiation of any substance (licit or illicit), as well as marijuana and alcohol specifically. Adolescent initiation of other illicit drugs and cigarettes were analyzed only in the "any" summary variable since they were used too infrequently to analyze as individual outcomes. In Cox proportional hazard models controlling for intrauterine exposure to alcohol, tobacco, and marijuana and demographic and post-natal covariates, those who experienced heavier IUCE had a greater likelihood of initiation of any substance, and those with lighter intrauterine marijuana exposure had a greater likelihood of initiation of any substance as well as of marijuana specifically. Time-dependent higher levels of exposure to violence between ages of 8 and 16 were also robustly associated with initiation of any licit or illicit substance, and of marijuana, and alcohol particularly.

Prenatal drug exposure: infant and toddler outcomes

This manuscript provides an overview of the current scientific literature on the impact of maternal drug use, specifically opioids and cocaine, during pregnancy on the acute and long-term outcomes of infants and toddlers from birth through age 3 years. Emphasis with regard to opioids is placed on heroin and opioid substitutes used to treat opioid addiction, including methadone, which has long been regarded as the standard of care in pregnancy, and buprenorphine, which is increasingly being investigated and prescribed as an alternative to methadone. Controlled studies comparing methadone at high and low doses, as well as those comparing methadone with buprenorphine, are highlighted and the diagnosis and management of neonatal abstinence syndrome is discussed. Over the past two decades, attention of the scientific and lay communities has also been focused on the potential adverse effects of cocaine and crack cocaine, especially during the height of the cocaine epidemic in the United States. Herein, the findings are summarized from prospective studies comparing cocaine-exposed with non-cocaine-exposed infants and toddlers with respect to anthropometric growth, infant neurobehavior, visual and auditory function, and cognitive, motor, and language development. The potentially stigmatizing label of the so-called "crack baby" preceded the evidence now accumulating from well-designed prospective investigations that have revealed less severe sequelae in the majority of prenatally exposed infants than originally anticipated. In contrast to opioids, which may produce neonatal abstinence syndrome and infant neurobehavioral deficits, prenatal cocaine exposure appears to be associated with what has been described as statistically significant but subtle decrements in neurobehavioral, cognitive, and language function, especially when viewed in the context of other exposures and the caregiving environment which may mediate or moderate the effects. Whether these early findings may herald more significant learning and behavioral problems during school-age and adolescence when the child is inevitably confronted with increasing social and academic challenges is the subject of ongoing longitudinal research.

The effects of prenatal cocaine on language development at 10 years of age

OBJECTIVE

To examine the long term effects of prenatal cocaine exposure (PCE) on the language development of 10-year-old children utilizing a prospective design, controlling for confounding drug and environmental factors.

PARTICIPANTS

Children exposed to cocaine in utero (PCE; n=175) and non-exposed children (NCE; n=175) were followed prospectively to 10years of age and were compared on language subscales of the Test of Language Development-Intermediate 3rd Edition (TOLD-I:3) and phonological processing as measured by the Comprehensive Test of Phonological Processing (CTOPP).

METHODS

Multivariate analysis of covariance (MANCOVA), linear regression, and logistic regressions were used to evaluate the relationship of prenatal cocaine exposure to language development, while controlling for confounders.

RESULTS

After controlling for confounding variables, prenatal cocaine effects were observed for specific aspects of language including syntax (Sentence Combining subtest of the TOLD-I:3, p=0.001), semantics (Malopropism subtest of the TOLD-I:3, p=0.05) and phonological processing (Phonological Awareness subscale, p=0.01). The caregiver factors of vocabulary, HOME, and psychological symptoms also had consistent effects on language subtests and phonological processing scores. Children with PCE who experienced foster or adoptive care had enhanced language development compared to those living with birth mothers or in relative care. Cocaine exposed girls had lower scores on the phonological awareness subscale of the CTOPP than non-exposed girls.

CONCLUSIONS

PCE has subtle effects on specific aspects of language development and phonological processing at age 10, even after controlling for confounding variables. Environmental factors (i.e., postnatal lead exposure, home environment, and caregiver vocabulary and psychological symptoms) also impact language skills at 10years. Adoptive or foster care appears to enrich PCE children's linguistic environment and protects children against language delay in the PCE sample.

Prenatal cocaine exposure alters emotional arousal regulation and its effects on working memory

While prenatal cocaine exposure (PCE) has been associated with arousal dysregulation and attentional impairments in both human and animal studies, the neurobiological bases of these teratogenic effects have not been well characterized. In the current study, we report functional neuroimaging observations of these effects in exposed youth. Using functional magnetic resonance imaging (fMRI), we embedded task-irrelevant emotional distracters in a working memory task to examine the interaction of emotional arousal and memory in 33 PCE and 23 non-exposed adolescents. Though with similar behavioral performance, the two groups exhibited different activation patterns associated with emotion-memory interactions. On the one hand, higher memory load attenuated emotion-related amygdala activation in controls but not in the exposed adolescents; on the other hand, prefrontal activation associated with memory load decreased in the presence of emotional distraction in the controls but increased in the exposed group. These group interaction differences suggest neurobiological substrates for arousal-associated neuronal alterations related to prenatal cocaine exposure. Consistent with previous findings in behavioral and physiological studies, the present neuroimaging data provided more in-depth evidence supporting the view that PCE has significant long-term teratogenic effect on arousal regulation system.

Fetal substance exposure and cumulative environmental risk in an African American cohort

Two models of vulnerability to socioenvironmental risk were examined in 337 African American children (M = 7.8 years) recruited to overrepresent prenatal alcohol or cocaine exposure: The cumulative risk model predicted synergistic effects from exposure to multiple risk factors, and the fetal patterning of disease model predicted that prenatal insult will increase vulnerability to environmental risk. Four or more risks emerged as a threshold for poorer cognitive and behavioral outcome among the non-substance-exposed children, whereas substance-exposed children showed greater vulnerability to lower levels of environmental risk. Cumulative risk was associated with increased delinquent and internalizing behaviors only for the substance-exposed group. Results support the cumulative risk model for non-substance-exposed children and increased vulnerability to environmental risk among the substance-exposed group.

Prenatal cocaine and tobacco effects on children's language trajectories

OBJECTIVE

The objective of this study was to examine the effects of prenatal cocaine and polydrug exposure on language development of preschool children using a prospective longitudinal model, controlling for confounders.

METHODS

Children who were exposed to cocaine in utero (n = 209) and nonexposed children (n = 189) were followed prospectively at birth and at 1, 2, 4, and 6 years of age and were compared on receptive, expressive, and total language scores across time using random coefficient models, controlling for confounders.

RESULTS

A significant, stable effect of cocaine exposure on language development was observed over time for all language domains, with cocaine exposure related to poorer language performance. Cigarette exposure was related to lower receptive language scores. Environmental influences on language scores were also observed. Both the cocaine-exposed and nonexposed children declined in language performance over time.

CONCLUSIONS

Prenatal cocaine exposure has a stable negative effect on language skills during the first 6 years of life. Both cocaine-exposed and nonexposed children showed decreased language growth over time; however, cocaine-exposed children demonstrated linguistic deficits compared with nonexposed peers and did not catch up. Cigarette and environmental influences were also noted.

Consequences of prenatal toxin exposure for mental health in children and adolescents: a systematic review

Drug use during pregnancy is common and the developing foetus may be exposed to a range of environmental toxins that have long-term consequences for neurodevelopment. We conducted a systematic review of the literature to explore the results of longitudinal cohort studies that have examined this question. Out of 2,977 abstracts identified, 7 previous systematic reviews and 95 original articles met further selection criteria. These mostly addressed the neurodevelopmental effects of exposure to lead, polychlorinated biphenyls, mercury, cocaine, alcohol, marijuana, cigarettes and antidepressants. Radiation, opiates, steroids, amphetamines and caffeine have received much less attention. Findings are difficult to interpret because risk factors tend to cluster together and interact. However, some findings are consistent. Lead and PCB's have a general effect on brain development, whilst marijuana and alcohol appear to have long-term effects specifically on attentional skills. The effects of alcohol increase with maternal age and binge drinking is more important than average intake. The effects of cocaine diminish with age and are largely mediated through psychosocial factors, whilst the relation between smoking and later delinquency is largely mediated by genetically inherited factors. Exposure to toxins during pregnancy may constitute an important but relatively unacknowledged cause of child psychiatric morbidity.

Learning disabilities and intellectual functioning in school-aged children with prenatal cocaine exposure

Risk for developing a learning disability (LD) or impaired intellectual functioning by age 7 was assessed in full-term children with prenatal cocaine exposure drawn from a cohort of 476 children born full term and enrolled prospectively at birth. Intellectual functioning was assessed using the Wechsler Intelligence Scale for Children-Third Edition (Wechsler, 1991) short form, and academic functioning was assessed using the Wechsler Individual Achievement Test (WIAT; Wechsler, 1993) Screener by examiners blind to exposure status. LDs were categorized based on ability-achievement discrepancy scores, using the regression-based predicted achievement method described in the WIAT manual. The sample in this report included 409 children (212 cocaine-exposed, 197 non-cocaine-exposed) from the birth cohort with available data. Cumulative incidence proportions and relative risk values were estimated using STATA software (Statacorp, 2003). No differences were found in the estimate of relative risk for impaired intellectual functioning (IQ below 70) between children with and without prenatal cocaine exposure (estimated relative risk = .95; 95% confidence interval [CI] = 0.65, 1.39; p = .79). The cocaine-exposed children had 2.8 times greater risk of developing a LD by age 7 than non-cocaine-exposed children (95% CI = 1.05, 7.67; p = .038; IQ >/= 70 cutoff). Results remained stable with adjustment for multiple child and caregiver covariates, suggesting that children with prenatal cocaine exposure are at increased risk for developing a learning disability by age 7 when compared to their non-cocaine-exposed peers.

Prenatal drug exposure effects on subsequent vulnerability to drug abuse

Research has shown that both prenatal alcohol and tobacco exposure are associated with increased risk of significant adverse medical, developmental, and behavioral outcomes including substance abuse. Research on the outcomes of prenatal exposure to illicit drugs (PNDE) has also found increased physical and behavioral problems for gestationally drug-exposed children. However, a clear picture has not emerged on whether the consequences of PNDE are independent from those associated with having a substance abusing parent and whether PNDE increases vulnerability to drug abuse. Because of its typical co-occurrence with factors inherent in having a drug-abusing parent, PNDE is at least a marker of significant increased risk for a range of negative outcomes including greater vulnerability to substance abuse. Although a review of the relevant research literatures indicates that the direct consequences of PNDE appear to be generally both subtle and nonglobal, PNDE does appear to have negative developmental and behavioral outcomes, and there is evidence that it is a modest direct contributor to increased substance abuse vulnerability.

School-age outcome of children with prenatal cocaine exposure following early case management

The impact of prenatal cocaine exposure on neurodevelopmental outcome in childhood continues to be in question. Objectives of this study were to determine if there are differences in growth, behavioral, cognitive or verbal functioning or caregiver-child dyad interactions for inner-city, school-aged children with and without prenatal cocaine exposure, and if these measures would be affected by early family case management. From an initial sample of 118 cocaine-exposed children who were evaluated to 36 months of age, 47 were able to be contacted and 39 (83%) completed a follow-up evaluation at 84 +/- 11 months of age. Subjects had been assigned at birth to early case management (CM, 24) and routine care (RC, 15). Eighteen children from the initial non-cocaine-exposed comparison sample of 41 children were able to be contacted and 12 (67%) were evaluated at 85 +/- 16 months of age. Evaluation included growth measurements, Stanford-Binet IQ, receptive and expressive language quotients, parent-reported Child Behavior Checklists (CBCL), and assessment of caregiver-child interactions by scored videotaped free-play sessions. No differences were found in growth, mean IQ, language quotients, CBCL scores or videotaped caregiver-child play interactions as a function of cocaine exposure. Within the cocaine-exposed group, there were no outcome differences between CM and RC children. However, during the play sessions, CM caregivers had more positive affect in interactions with the child than RC. Within the RC dyads, birthmothers had significantly more positive interactions than non-birthmothers. In summary, no differences in growth, behavioral, cognitive, or language function were evident for inner-city, school-aged children related to prenatal cocaine exposure or early case management. CM caregivers demonstrated more positive interactions during a play session than RC; within the RC group, non birthmothers had the least positive affective interactions. Further study of influences on caregiver-child interactions may lead to effective intervention strategies for drug-exposed infants.

Prenatal cocaine exposure accelerates morphological changes and transient expression of tyrosine hydroxylase in the cochlea of developing rats

Prenatal cocaine exposure causes alterations in auditory brainstem response in children and experimental animals and has adverse effects on auditory information processing and language skills in children. These effects may result from lesions in the cochlea since this organ is particularly sensitive to chemical insults during the development. We have thus studied here the effect of prenatal cocaine exposure on the maturation of the rat cochlea using the transient non-catecholaminergic expression of tyrosine hydroxylase in spiral ganglion neurons as an index of cochlear maturation and morphometry to evaluate the maturation of primary auditory neurons and the organ of Corti. We showed that prenatal cocaine exposure accelerated the cochlear maturation. In the basal coil of cochleas from PND8 cocaine-treated pups, the Kölliker's organ had disappeared, the tunnel of Corti was opened, and the stria vascularis no longer contained undifferentiated marginal cells. The maximum expression of tyrosine hydroxylase in type I primary auditory neurons occurred at PND8 instead of PND12 in pair-fed controls. On the other hand, the prenatal cocaine exposure had no effect on the width and height of the organ of Corti, spiral ganglion volume and number and size of primary auditory neurons. In conclusion, our data suggest that prenatal cocaine exposure, though not lethal to primary auditory neurons, accelerates aspects of the cochlear sensorineural maturation. This accelerated cochlear maturation in cocaine-treated rat pups could cause auditory dysfunctions by desynchronizing the development of the whole auditory pathway.

Prenatal cocaine exposure and children's language functioning at 6 and 9.5 years: moderating effects of child age, birthweight, and gender

OBJECTIVE

To evaluate whether prenatal cocaine exposure (PCE), or the interaction between PCE and contextual variables, is associated with children's language at age 6 and 9.5 years, adjusting for relevant covariates.

METHODS

Analyses were based on 160 low-income, urban children from a prospective study who completed a standardized language assessment at 6 and 9.5 years. PCE was determined using neonatal meconium assays and maternal self-report.

RESULTS

Significant interaction effects of PCE on language outcomes were found in multivariate longitudinal analyses using generalized estimating equations (GEE). Children with PCE had lower receptive language than unexposed children at 6 but not at 9.5 years, lower expressive language if they had lower birthweight, and lower expressive and total language if they were female. Other risk (e.g., violence exposure) and protective factors (e.g., preschool experience) were related to language outcomes regardless of PCE status.

CONCLUSIONS

Age, birthweight, and gender moderated the relation between PCE and school-aged children's language.

Low birth weight and preterm births: etiologic fraction attributable to prenatal drug exposure

OBJECTIVES

To determine the factors that would increase the likelihood of outcomes: low birth weight (LBW), preterm births and intrauterine growth restriction (IUGR).

STUDY DESIGN

Secondary data analysis from a multi-center study. Risk factors for each outcome were derived from logistic regression models. Odds ratios (OR), 95% confidence intervals, and population-attributable risk proportions (PAR%) were estimated.

RESULTS

Prenatal cocaine exposure increased the likelihood of LBW (OR: 3.59), prematurity (OR: 1.25), and IUGR (OR: 2.24). Tobacco, but not marijuana, significantly influenced these outcomes. Alcohol had an effect on LBW and IUGR. Etiologic fractions (PAR%) attributable to tobacco for LBW, prematurity, and IUGR were 5.57, 3.66, and 13.79%, respectively. With additional drug exposure including cocaine, estimated summary PAR% increased to 7.20% (LBW), 5.68% (prematurity), and 17.96% (IUGR).

CONCLUSION

Disease burden for each outcome increases with each added drug exposure; however, etiologic fraction attributable to tobacco is greater than for cocaine.

Fatty Acid ethyl esters: quantitative biomarkers for maternal alcohol consumption

OBJECTIVE

To develop a laboratory marker to identify newborns exposed to alcohol.

STUDY DESIGN

Meconium was collected from 30 infants from Jordan who were unexposed and from 248 Cleveland study infants of varying exposure status. Retrospective maternal alcohol histories were obtained. Fatty acid ethyl esters (FAEEs) were quantified with gas chromatography/flame ionization and compared between abstainers and non-abstainers to identify FAEEs of interest. The area under the receiver operating characteristic curve, sensitivity, specificity, and positive and negative predictive values were calculated by using definitions of drinking obtained from a graphical representation.

RESULTS

Six of 7 FAEEs were significantly different between the non-abstainers and at least 1 of 2 of the abstaining groups. FAEEs best predicted drinks per drinking day, and ethyl linoleate had the greatest area under the curve (76%), with a sensitivity rate of 88%, a specificity rate of 64%, a positive predictive value of 9%, and a negative predictive value of 99%. No combination of FAEEs was better than a single ester for identifying drinkers.

CONCLUSION

Ethyl linoleate in meconium is a useful biological marker for identifying infants not exposed in utero to high levels of alcohol in a high-risk, substance-abusing, clinic-based sample.

Expressive and receptive language functioning in preschool children with prenatal cocaine exposure

OBJECTIVE

To estimate the relationship between severity of prenatal cocaine exposure and expressive and receptive language skills in full-term, African American children at age 3 years.

METHODS

Language was assessed at age 3 using the Clinical Evaluation of Language Fundamentals-Preschool (CELF-P). The sample included 424 children (226 cocaine exposed, 198 non-cocaine exposed) who received preschool language assessments at age 3, drawn from a cohort of 476 children enrolled prospectively at birth.

RESULTS

Structural equation modeling was used to regress expressive and receptive language as intercorrelated response variables on level of prenatal cocaine exposure, measured by a latent construct including maternal self-report of cocaine use and maternal/infant urine toxicology assays and infant meconium. Results indicated a.168 SD decrease in expressive language functioning for every unit increase in exposure level (95% CI = -.320, -.015; p =.031) after consideration for fetal growth and gestational age as correlated response variables. Receptive language was more modestly related to prenatal cocaine exposure and was not statistically significant. Results for expressive language remained stable with inclusion of the McCarthy general cognitive index as a response variable (expressive language beta = -.173, 95% CI = -.330, -.016; p =.031), and with adjustment for maternal age and prenatal exposures to alcohol, tobacco, and marijuana (expressive language beta = -.175, 95% CI = -.347, -.003; p =.046). Additional child and caregiver environmental variables assessed at age 3 were also evaluated in varying statistical models with similar results.

CONCLUSION

The evidence from this study supports a gradient relationship between increased level of prenatal cocaine exposure and decreased expressive language functioning in preschool-aged cocaine-exposed children.

Neurological and developmental outcomes of prenatally cocaine-exposed offspring from 12 to 36 months

Second generation studies of prenatal cocaine exposure failed to find gross deficits after controlling for confounders. Concern remained that exposure could cause subtle deficits. This prospective, cohort study evaluated effects of cocaine on development at 12, 18, 24, and 36 months. From 1991-1993, 361 mother-infant pairs were recruited from the Children's Hospital of New York, Presbyterian Medical Center's prenatal clinic or delivery room suite. Mothers were assigned to the cocaine group based on report of prenatal cocaine use or positive urine toxicology. Control mothers were enrolled from the same clinic and matched for age and socioeconomic status (SES). Women with serious medical problems were excluded from either group. Of the retained cohort, at 12 months, 147 infants were exposed and 89 were unexposed case controls. Both groups were raised in impoverished environments with few supports. Developmental evaluations were conducted blinded to group. Cross-sectional analysis revealed cocaine-related deficits in neurological exams and speech across all time periods, in spite of catch up in weight, length, and head circumference. Overall analysis of development was evaluated using Generalized Estimating Equations regression analysis. Bayley Mental [Badj = -6.5 (CI--9.4, -3.5, p < or = 0.001)] and Psychomotor [Badj = -3.9 (CI--7.4, -0.5, p = 0.02)] Developmental Indices showed deficits after controlling for confounders. Males were more vulnerable to cocaine exposure for height, motor development, and emotional regulation. Dose-response relationships existed for abnormal neurological exams (Ptrends < 0.08), Mental Development Index (MDI) (Ptrend < 0.001), and Psychomotor Development Index (PDI) (Ptrend < 0.001) deficits. Although nonexposed children performed poorly, cocaine-exposed children showed worse performance. Both groups showed declines at 18 months in mental and psychomotor development from which only nonexposed children rebounded. Overall, cocaine exposure adds an additional risk to disadvantaged children's development. Cocaine-exposed children are less resilient to effects of these multiple risks.

Four-year language outcomes of children exposed to cocaine in utero

A large cohort of children exposed to cocaine in utero (n=189) were followed prospectively from birth to 4 years of age and compared to nonexposed children (n=185) on the Clinical Evaluation of Language Fundamentals-Preschool (CELF-P), a measure of receptive and expressive language abilities. Children exposed to cocaine in utero performed more poorly on the expressive and total language measures than nonexposed children after controlling for confounding variables, including prenatal exposure to alcohol, marijuana, and tobacco, as well as medical and sociodemographic variables. Children exposed to cocaine had more mild receptive language delays than nonexposed children and were less likely to have higher expressive abilities. Also, maternal factors such as language ability, performance IQ, race, and education correlated with child language abilities. Prenatal cigarette and marijuana exposure were related to deficits in specific language skills. Children placed in adoptive or foster care who were cocaine exposed demonstrated superior language skills compared to children exposed to cocaine who remained in biological relative or mother's care. These findings support a cocaine-specific effect on language skills in early childhood that may be modified with an enriched environment.

The maternal lifestyle study: cognitive, motor, and behavioral outcomes of cocaine-exposed and opiate-exposed infants through three years of age

OBJECTIVE

To evaluate the direct effects of prenatal cocaine exposure and prenatal opiate exposure on infant mental, motor, and behavioral outcomes longitudinally between 1 and 3 years old.

METHODS

As part of a prospective, longitudinal, multisite study, the Bayley Scales of Infant Development II were administered to 1227 infants who were exposed to cocaine (n = 474), opiates (n = 50), cocaine and opiates (n = 48), and neither substance (n = 655) at 1, 2, and 3 years of corrected age by certified, masked examiners. Hierarchic linear modeling of the 1-, 2-, and 3-year scores was conducted using cocaine and opiate exposure as predictors with and without controlling for covariates.

RESULTS

Overall retention was 88.4% and did not differ by cocaine or opiate exposure. Overall (at 1, 2, and 3 years), cocaine-exposed infants scored 1.6 Mental Development Index points below infants who were not exposed to cocaine. Opiate-exposed infants scored 3.8 Psychomotor Development Index points below infants who were not exposed to opiates. Neither the cocaine nor the opiate effect remained significant after controlling for covariates. Neither cocaine nor opiate exposure was associated with the Behavioral Record Score during the examination. Low birth weight and indices of nonoptimal caregiving were associated with lower Mental Development Index, Psychomotor Development Index, and Behavioral Record Score scores for all groups of infants.

CONCLUSIONS

In the largest at-risk sample observed longitudinally to date, infant prenatal exposure to cocaine and to opiates was not associated with mental, motor, or behavioral deficits after controlling for birth weight and environmental risks.

Prenatal cocaine exposure alters potassium-evoked dopamine release dynamics in rat striatum

The emerging profile for the effects of prenatal cocaine exposure presents two prominent features in the exposed offspring: cognitive/attention deficits and an age-associated trend toward motor/tone abnormalities up to 2 years of age. One candidate mechanism underlying these clinical features is long-lasting alterations to dopamine (DA) neuron function. However, the impact of prenatal cocaine exposure on DA release in dopaminergic terminal fields in vivo in mature offspring is poorly understood. Long-Evans female rats were implanted with an i.v. access port, bred, and given saline or cocaine-HCl (3 mg/kg/ml) for gestational days (GD) 8-14 (1x/day), GD 15-21 (2x/day), or GD 8-21 (1x/day-GD 8-14, 2x/day-GD 15-21). Using in vivo high-speed chronoamperometric recordings, potassium-stimulated DA release was measured in striatum of anesthetized male offspring 90-150 days after birth. There was a trend toward increased potassium-evoked DA signal amplitudes in offspring exposed to cocaine at any time period examined. In offspring exposed to cocaine during GD 8-21 and GD 15-21, but not at GD 8-14, there were significant decreases in the clearance capacity of the potassium-evoked DA signal compared with control offspring. The time required to clear 80% of the evoked DA signal (T(80)) in striatum for DA was significantly prolonged (approximately 150% of control) and this effect was further increased in the mean-evoked DA concentration range for these two groups. We also measured total dopamine transporter (DAT) and tyrosine hydroxylase protein levels in these offspring by blot immunolabeling and found a small, but significant, decrease in DAT protein in striatum from offspring exposed at GD 8-21 and GD 15-21. Collectively, these data demonstrate that prenatal cocaine exposure during dopamine neuron neurogenesis has long-lasting effects on DA neuron function lasting into early adulthood which may be related in part to steady state DAT protein levels. These molecular events may be associated with established cognitive deficits and perhaps the trends seen in altered motor behavior.

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.

Cocaine, anemia, and neurodevelopmental outcomes in children: a longitudinal study

This longitudinal study investigated the rates of iron-deficiency (ID) and iron-deficiency anemia (IDA) among prenatally cocaine-exposed and nonexposed two- and four-year-old children and assessed their relationships to neurodevelopmental outcomes. The sample consisted of 143 two-year-old (70 exposed and 73 nonexposed) and 274 four-year-old (139 exposed and 135 nonexposed) low socioeconomic status children recruited from an ongoing longitudinal study. Hematological assessments included hemoglobin, serum ferritin, mean corpuscular volume, transferrin saturation, and blood lead levels. The neurodevelopmental outcomes consisted of the Bayley Mental (MDI) and Motor (PDI) Development indices at two years, and the Wechsler Preschool and Primary Scales of Intelligence (WPPSI) and the Peabody Developmental Motor Scales (PDMS) at four years. The rate of IDA in four-year-old children was significantly greater among the cocaine-exposed compared to the nonexposed group (p =.026), while the rates at two years were not significant. Exposure to IDA at two years was associated with a significant decrease in concurrent motor scores (p =.011) after adjustment for relevant covariates. Peak exposure to IDA, defined as being anemic at 2 and/or 4 years of age, was associated with a significant (p <.05) decrease in Full Scale IQ after adjustment. Cocaine exposure was not a significant predictor of Full Scale IQ with the inclusion of peak IDA and lead in the model. These findings indicate the need for greater pediatric surveillance of IDA and lead in cocaine-exposed infants, in order to reduce long-term neuropsychological deficits.

Severity of prenatal cocaine exposure and child language functioning through age seven years: a longitudinal latent growth curve analysis

The current study estimates the longitudinal effects of severity of prenatal cocaine exposure on language functioning in an urban sample of full-term African-American children (200 cocaine-exposed, 176 noncocaine-exposed) through age 7 years. The Miami Prenatal Cocaine Study sample was enrolled prospectively at birth, with documentation of prenatal drug exposure status through maternal interview and toxicology assays of maternal and infant urine and infant meconium. Language functioning was measured at ages 3 and 5 years using the Clinical Evaluation of Language Fundamentals--Preschool (CELF-P) and at age 7 years using the Core Language Domain of the NEPSY: A Developmental Neuropsychological Assessment. Longitudinal latent growth curve analyses were used to examine two components of language functioning, a more stable aptitude for language performance and a time-varying trajectory of language development, across the three time points and their relationship to varying levels of prenatal cocaine exposure. Severity of prenatal cocaine exposure was characterized using a latent construct combining maternal self-report of cocaine use during pregnancy by trimesters and maternal and infant bioassays, allowing all available information to be taken into account. The association between severity of exposure and language functioning was examined within a model including factors for fetal growth, gestational age, and IQ as intercorrelated response variables and child's age, gender, and prenatal alcohol, tobacco, and marijuana exposure as covariates. Results indicated that greater severity of prenatal cocaine exposure was associated with greater deficits within the more stable aptitude for language performance (D = -0.071, 95% CI = -0.133, -0.009; p = 0.026). There was no relationship between severity of prenatal cocaine exposure and the time-varying trajectory of language development. The observed cocaine-associated deficit was independent of multiple alternative suspected sources of variation in language performance, including other potential responses to prenatal cocaine exposure, such as child's intellectual functioning, and other birth and postnatal influences, including language stimulation in the home environment.

Impaired sustained attention and altered reactivity to errors in an animal model of prenatal cocaine exposure

Although correlations have been reported between maternal cocaine use and impaired attention in exposed children, interpretation of these findings is complicated by the many risk factors that differentiate cocaine-exposed children from SES-matched controls. For this reason, the present dose-response study (0, 0.5, 1.0, or 3.0 mg/kg cocaine HCl) was designed to explore the effect of prenatal cocaine exposure on visual attention in a rodent model, using an intravenous injection protocol that closely mimics the pharmacokinetic profile and physiological effects of human recreational cocaine use. In adulthood, animals were tested on an attention task in which the duration, location, and onset time of a brief visual cue varied randomly between trials. The 3.0 mg/kg exposed males committed significantly more omission errors than control males during the final 1/3 of each testing session, specifically on trials that followed an error, which implicates impaired sustained attention and increased reactivity to committing an error. During the final 1/3 of each testing session, the 0.5 and 1.0 mg/kg exposed females took longer to enter the testing alcove at trial onset, and failed to enter the alcove more frequently than control females. Because these effects were not seen in other tasks of similar duration and reinforcement density, these findings suggest an impairment of sustained attention. This inference is supported by the finding that the increase in omission errors in the final block of trials in each daily session (relative to earlier in the session) was significantly greater for the 1.0 mg/kg females than for controls, a trend also seen for the 0.5 mg/kg group. Unlike the cocaine-exposed males, who remain engaged in the task when attention is waning, the cocaine-exposed females appear to opt for another strategy; namely, refusing to participate when their ability to sustain attention is surpassed.

Executive functioning in preschool-age children prenatally exposed to alcohol, cocaine, and marijuana

BACKGROUND

Reports from clinical and experimental (animal) research converge on the suggestion that prenatal exposure to alcohol, cocaine, or marijuana undermines executive functioning (EF) and its neurological underpinnings. However, large, adequately controlled, prospective studies of alcohol and marijuana effects on EF have reported conflicting findings, and there have been no such studies of cocaine exposure.

METHODS

EF was investigated in a cohort (n = 316) of 4-year-old children the majority of whose mothers had used varying combinations of cocaine, alcohol, and marijuana during pregnancy. With use of postpartum maternal report and biological assay, children were assigned to overlapping prenatal cocaine-exposed, alcohol-exposed, and marijuana-exposed groups and to complementary control groups. The postnatal environmental assessment included measures of maternal intellectual and psychosocial functioning, current drug or alcohol use, and home environment.

RESULTS

The children in the alcohol-exposed group had worse tapping-inhibition performance than children in the non-alcohol-exposed group, and this effect persisted when potential confounding environmental variables, other drug variables, and concurrent verbal intelligence were controlled for.

CONCLUSIONS

Prenatal alcohol is predictive of decreased EF in early childhood that could not be attributed to environmental factors. The results are discussed in terms of the age and overall high-risk status of the children.

Executive functioning in preschool-age children prenatally exposed to alcohol, cocaine, and marijuana

BACKGROUND

Reports from clinical and experimental (animal) research converge on the suggestion that prenatal exposure to alcohol, cocaine, or marijuana undermines executive functioning (EF) and its neurological underpinnings. However, large, adequately controlled, prospective studies of alcohol and marijuana effects on EF have reported conflicting findings, and there have been no such studies of cocaine exposure.

METHODS

EF was investigated in a cohort (n = 316) of 4-year-old children the majority of whose mothers had used varying combinations of cocaine, alcohol, and marijuana during pregnancy. With use of postpartum maternal report and biological assay, children were assigned to overlapping prenatal cocaine-exposed, alcohol-exposed, and marijuana-exposed groups and to complementary control groups. The postnatal environmental assessment included measures of maternal intellectual and psychosocial functioning, current drug or alcohol use, and home environment.

RESULTS

The children in the alcohol-exposed group had worse tapping-inhibition performance than children in the non-alcohol-exposed group, and this effect persisted when potential confounding environmental variables, other drug variables, and concurrent verbal intelligence were controlled for.

CONCLUSIONS

Prenatal alcohol is predictive of decreased EF in early childhood that could not be attributed to environmental factors. The results are discussed in terms of the age and overall high-risk status of the children.

Children's intellectual and emotional-behavioral adjustment at 4 years as a function of cocaine exposure, maternal characteristics, and environmental risk

The authors examined 223 children at age 4 years for the effects of prenatal cocaine exposure, exposure to other substances, maternal and environmental risk factors, and neonatal medical problems on IQ, externalizing problems, and internalizing problems. Regression analyses showed that maternal verbal IQ and low environmental risk predicted child IQ. Cocaine exposure negatively predicted children's overall IQ and verbal reasoning scores, but only for boys. Cocaine exposure also predicted poorer short-term memory. Maternal harsh discipline, maternal depressive symptoms, and increased environmental risk predicted externalizing problems. In contrast, only maternal depressive symptoms predicted internalizing problems. These findings indicate that early exposure to substances is largely unrelated to subsequent IQ or adjustment, particularly for girls.

Influence of prenatal cocaine exposure on early language development: longitudinal findings from four months to three years of age

The influence of prenatal cocaine exposure on children's language functioning was evaluated longitudinally at six time points from 4 months to 3 years of age. The Miami Prenatal Cocaine Study prospectively enrolled 476 full-term African-American infants at birth, categorized as cocaine-exposed (n = 253) or non-cocaine-exposed (n = 223) by maternal self-report and bioassays (maternal/infant urine, meconium). The Bayley Scales of Infant Development, scored using the Kent Scoring Adaptation for language, was administered at 4, 8, 12, 18, and 24 months. The Clinical Evaluation of Language Fundamentals-Preschool was administered at 3 years. In longitudinal analyses using Generalized Estimating Equations, cocaine-exposed children had lower overall language skills than non-cocaine-exposed children (D = -0.151; 95% CI = -0.269, -0.033; p =.012). Longitudinal findings remained stable after evaluation of potential confounding influences including other prenatal substance exposures and sociodemographic factors. Preliminary evidence also indicated possible mediation through an intermediary effect involving cocaine-associated deficits in fetal growth.

The maternal lifestyle study: effects of substance exposure during pregnancy on neurodevelopmental outcome in 1-month-old infants

OBJECTIVE

This was a prospective longitudinal multisite study of the effects of prenatal cocaine and/or opiate exposure on neurodevelopmental outcome in term and preterm infants at 1 month of age.

METHODS

The sample included 658 exposed and 730 comparison infants matched on race, gender, and gestational age (11.7% born <33 weeks' gestational age). Mothers were recruited at 4 urban university-based centers and were mostly black and on public assistance. Exposure was determined by meconium assay and self-report with alcohol, marijuana, and tobacco present in both groups. At 1 month corrected age, infants were tested by masked examiners with the NICU Network Neurobehavioral Scale and acoustical cry analysis. Exposed and comparison groups were compared adjusting for covariates (alcohol, marijuana, tobacco, birth weight, social class, and site). Separate analyses were conducted for level of cocaine exposure.

RESULTS

On the NICU Network Neurobehavioral Scale, cocaine exposure was related to lower arousal, poorer quality of movement and self-regulation, higher excitability, more hypertonia, and more nonoptimal reflexes with most effects maintained after adjustment for covariates. Some effects were associated with heavy cocaine exposure, and effects were also found for opiates, alcohol, marijuana, and birth weight. Acoustic cry characteristics that reflect reactivity, respiratory, and neural control of the cry sound were also compromised by prenatal drug exposure, including cocaine, opiates, alcohol, and marijuana and by birth weight. Fewer cry effects remained after adjustment for covariates.

CONCLUSIONS

Cocaine effects are subtle and can be detected when studied in the context of polydrug use and level of cocaine exposure. Effects of other drugs even at low thresholds can also be observed in the context of a polydrug model. The ability to detect these drug effects requires a large sample and neurobehavioral tests that are differentially sensitive to drug effects. Long-term follow-up is necessary to determine whether these differences develop into clinically significant deficits.

Autonomic alterations in cocaine-exposed infants

BACKGROUND

Heart rate variability (HRV) reflects autonomic control of the heart. After intrauterine cocaine exposure, asymptomatic newborn infants within 72 hours of life have decreased HRV. It is unknown whether these alterations are transient (acute effect) or persist in older infants and possibly reflect a teratogenic effect of cocaine.

METHODS

This study prospectively evaluated HRV in 2- to 6-month-old infants who were exposed to cocaine in-utero (Group 1, n = 71). Their data were compared to normal controls (Group 3, n = 77) and to newborns exposed to drugs other than cocaine (Group 2, n = 89). Based on our previous study, heavy and light cocaine exposure was also defined a priori as the amount of cocaine used during the pregnancy that was more than or less than the 70th percentile, respectively.

RESULTS

At the age of 2 to 6 months, infants with in-utero cocaine exposure had higher vagal tone and higher HRV (total power) than normal controls (no exposure to drugs). Most of this increase in vagal tone occurred in the light-cocaine-exposure group. HRV and vagal tone in the heavy-cocaine-exposure group were similar to the noncocaine-exposed group.

CONCLUSIONS

At 2 to 6 months of age, asymptomatic infants exposed to cocaine in-utero have recovered from lower HRV seen within 72 hours of age. Infants exposed to light cocaine recovered by a rebound by increasing their vagal tone to above-normal levels. A similar response was blunted in heavily-cocaine-exposed infants. These alterations noted at follow up suggest a possible teratogenic effect of cocaine on the developing autonomic system.

Level of prenatal cocaine exposure and scores on the Bayley Scales of Infant Development: modifying effects of caregiver, early intervention, and birth weight

OBJECTIVES

The objectives of this study were 1) to assess whether there is an independent association between the level of prenatal cocaine exposure and infants' developmental test scores after control of potential confounding variables; and 2) if such an association exists, to determine which biological and social variables, individually and in interaction with each other, may modify it.

METHODS

In a prospective, longitudinal study of 203 urban term infants, 3 cocaine exposure groups were defined by maternal report and infant meconium assay: unexposed, heavier cocaine exposure (>75th percentile self-reported days of use or meconium benzoylecognine concentration), or lighter cocaine exposure (all others). Examiners, masked to exposure history, tested infants at 6, 12, and 24 months of age with the Bayley Scales of Infant Development.

RESULTS

The final mixed linear regression model included as fixed covariates level of prenatal exposure to cocaine, alcohol, and cigarettes; prenatal marijuana exposure; gestational age and birth weight z score for gestational age; and gender. Age at test, caregiver at time of each test (biological mother, kinship caregiver, unrelated foster caregiver), and any previous child-focused early intervention were included as time-dependent covariates. There were no significant adverse main effects of level of cocaine exposure on Mental Development Index (MDI), Psychomotor Development Index (PDI), or Infant Behavior Record. Child-focused early intervention interacted with level of cocaine exposure such that heavily exposed children who received such intervention showed higher adjusted mean MDI scores than all other groups. Although the sample was born at or near term, there was also a significant interaction of cocaine exposure and gestational age on MDI scores, with those in the heavier exposure group born at slightly lower gestational age having higher mean MDI scores compared with other children born at that gestational age. There was also a significant interaction on MDI between child's age and caregiver. At 6 months, the adjusted MDI of children living with a kinship caregiver was 15.5 points lower than that of children living with their biological mother, but this effect was diminished and was no longer significant at 24 months (difference in means: 4.3 points). The adjusted mean MDI of children in unrelated foster care at 6 months was 8.2 points lower than children of biological mothers, whereas it was 7.3 points higher at 24 months. Early intervention attenuated the age-related decline in PDI scores for all groups. Birth weight <10th percentile was associated with lower PDI scores for children with heavier cocaine exposure and with lower MDI scores for all groups.

CONCLUSIONS

Heavier prenatal cocaine exposure is not an independent risk factor for depressed scores on the Bayley Scales of Infant Development up to 24 months of age when term infants are compared with lighter exposed or unexposed infants of the same demographic background. Cocaine-exposed infants with birth weight below the 10th percentile for gestational age and gender and those placed with kinship caregivers are at increased risk for less optimal developmental outcomes. Pediatric clinicians should refer cocaine-exposed children to the child-focused developmental interventions available for all children at developmental risk.

Children's intellectual and emotional-behavioral adjustment at 4 years as a function of cocaine exposure, maternal characteristics, and environmental risk

The authors examined 223 children at age 4 years for the effects of prenatal cocaine exposure, exposure to other substances, maternal and environmental risk factors, and neonatal medical problems on IQ, externalizing problems, and internalizing problems. Regression analyses showed that maternal verbal IQ and low environmental risk predicted child IQ. Cocaine exposure negatively predicted children's overall IQ and verbal reasoning scores, but only for boys. Cocaine exposure also predicted poorer short-term memory. Maternal harsh discipline, maternal depressive symptoms, and increased environmental risk predicted externalizing problems. In contrast, only maternal depressive symptoms predicted internalizing problems. These findings indicate that early exposure to substances is largely unrelated to subsequent IQ or adjustment, particularly for girls.

Randomized clinical trials in infancy: methodologic issues

Randomized clinical trials of early nutritional interventions in infants are necessary to establish safety and efficacy of supplementation of infant formulas with LCPUFAS for term and preterm infants. Such trials pose significant methodologic difficulties when applied to infants because of the rapidly changing development of the infant's central nervous system and its interdependence with multiple environmental factors. Current assessments of infant cognitive development in the first year of life lack stability and predictive relationships to later outcomes. Thus, intervention trials need to extend beyond the first two years of life. Small sample sizes, high attrition rates, and lack of attention to confounding variables known to be related to child outcomes are additional problems in the majority of studies to date, especially for preterm populations. Attention to selection and attrition biases and the roles of mediating and moderating factors in affecting intervention effects are also necessary to determine the benefits vs risks of LCPUFA supplementation of infant formula.