Lihua Xue

Longitudinal influence of prenatal cocaine exposure on child language functioning.

The present study estimates the longitudinal effects of in utero cocaine exposure on language functioning at 3, 5 and 7 years of age in an urban sample of 443 full-term children (236 cocaine-exposed and 207 noncocaine-exposed) participating in the Miami Prenatal Cocaine Study. The sample was enrolled prospectively at birth, with documentation of prenatal drug exposure status through maternal interview and urine and meconium toxicology assays. 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 Generalized Linear Model and Generalized Estimating Equations (GLM/GEE) analyses revealed an association between prenatal cocaine exposure and deficits in total language functioning after statistically controlling for child sex, visit age, prenatal exposure to alcohol, marijuana and tobacco and over 20 additional medical and sociodemographic covariates drawn from potentially confounding influences assessed at birth and follow-up visits (D=-0.17; 95% CI=-0.32, -0.03; P=.019). The link from prenatal cocaine exposure to later language deficits does not appear to be mediated by cocaine-associated deficits in birth weight, length or head circumference. Overall, the evidence tends to support an inference of a stable cocaine-specific effect on indicators of language functioning during early childhood through age 7 years.

Maternal Cocaine Use: Estimated Effects on Mother-Child Play Interactions in the Preschool Period

ABSTRACT. The study objective was to evaluate the quality of parent-child interactions in preschool-aged children exposed prenatally to cocaine. African-American mothers and their full-term newborns (n = 343) were enrolled prospectively at birth and classified as either prenatally cocaine-exposed (n = 157) or non–cocaine-exposed (n = 186) on the basis of maternal self-report and bioassays. Follow-up evaluations at 3 years of age (mean age, 40 mo) included a videotaped dyadic play session and maternal interviews to assess ongoing drug use and maternal psychological distress. Play interactions were coded using a modified version of Egeland et al’s Teaching Task coding scheme. Regression analyses indicated cocaine-associated deficits in mother-child interaction, even with statistical adjustment for multiple suspected influences on interaction dynamics. Mother-child interactions were most impaired in cocaine-exposed dyads when the mother continued to report cocaine use at the 3-year follow-up. Multivariate profile analysis of the Egeland interaction subscales indicated greater maternal intrusiveness and hostility, poorer quality of instruction, lower maternal confidence, and diminished child persistence in the cocaine-exposed dyads.

Impact of Prenatal Cocaine Exposure on Attention and Response Inhibition as Assessed by Continuous Performance Tests

Objective: This study examined the influence of prenatal cocaine exposure on attention and response inhibition measured by continuous performance tests (CPTs) at ages 5 and 7 years. Methods: The baseline sample consisted of 253 cocaine-exposed and 223 non–cocaine-exposed children enrolled prospectively at birth and assessed comprehensively through age 7 years in the longitudinal Miami Prenatal Cocaine Study. This report includes a subsample of 415 children (219 cocaine-exposed, 196 non–cocaine-exposed) who completed at least one CPT assessment at ages 5 and/or 7 years. Prenatal cocaine exposure was measured by maternal self-report and maternal and infant bioassays. Deficits in attention and response inhibition are estimated in relation to prenatal cocaine exposure using generalized estimating equations within the general linear model. Results: Results indicate cocaine-associated increases in omission errors at ages 5 and 7 as well as increases in response times for target tasks (i.e., slower reaction times) and decreased consistency in performance at age 7. There were no demonstrable cocaine-associated deficits in commission errors. Estimates did not change markedly with statistical adjustment for selected prenatal and postnatal covariates. Conclusion: Evidence supports cocaine-associated deficits in attention processing through age 7 years.

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 childs 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 childs intellectual functioning, and other birth and postnatal influences, including language stimulation in the home environment.

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.

Influence of prenatal cocaine exposure on full-term infant neurobehavioral functioning

This study investigated infant neurobehavioral functioning during the newborn period in 334 full-term, African American neonates (187 cocaine exposed, 147 non-cocaine exposed) enrolled prospectively at birth, with documentation of drug exposure status through maternal interview and urine and meconium toxicology assays. Infants were assessed using the Brazelton Neonatal Behavioral Assessment Scale (BNBAS) during the newborn period (0-6 postnatal days). Findings from multivariate profile analyses support a consistent, modest effect of prenatal cocaine exposure on neurobehavioral functioning in full-term neonates. All of the BNBAS cluster scores, with the exception of abnormal reflexes, were similarly affected, sharing a common slope (D=-0.14; 95% CI=-0.27, -0.003; P=.046) representing a -0.14 point difference between cocaine-exposed and non-cocaine-exposed infants after controlling for prenatal exposure to alcohol, tobacco, and marijuana (ATM); maternal age, education, employment, primigravida status, and prenatal care visits; and infant sex and postnatal age in days. Fetal growth was also related to neurobehavioral functioning and, in part, mediated the relationship between cocaine exposure and the BNBAS cluster scores. Cocaine exposure during each trimester similarly influenced infant neurobehavioral profiles, with cocaine-associated deficits most pronounced in infants with exposure in all three trimesters. Results from qualitative and quantitative urine and meconium bioassay indicators further substantiated these results. Findings, while significant, represent modest effect sizes in full-term infants.

Influence of Prenatal Cocaine Exposure on Early Language Development: Longitudinal Findings from Four Months to Three Years of Age

ABSTRACT. 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.

Estimated effects of in utero cocaine exposure on language development through early adolescence.

The potential longitudinal effects of prenatal cocaine exposure (PCE) on language functioning were estimated from early childhood through early adolescence in a large, well-retained urban sample of 451 full-term children (242 cocaine-exposed, 209 non-cocaine-exposed) participating in the Miami Prenatal Cocaine Study (MPCS). The 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. Age-appropriate versions of the Clinical Evaluation of Language Fundamentals (CELF) were used to measure total, expressive, and receptive language at ages 3, 5, and 12years. Longitudinal latent growth curve (LLGC) modeling of the data revealed an association between PCE (measured dichotomously as yes/no) and lower functioning in expressive and total language scores, after considering other sources of variation including childs age at testing, sex, prenatal exposure to alcohol, marijuana, and tobacco, and additional medical and social-demographic covariates. Analyses of level of PCE showed a gradient, i.e. dose-dependent, relationship between PCE level and expressive, receptive, and total language scores in the models controlling for age, childs sex, and other prenatal drug exposures. With additional covariate control these findings were most stable for the total language score. The evidence supports an inference about an enduring stable cocaine-specific effect on childrens language abilities, with no effect on language growth over time in the longitudinal trajectory of language development.

Prenatal cocaine exposure: An examination of childhood externalizing and internalizing behavior problems at age 7 years

AIM This study examines the relationship between prenatal cocaine exposure and parent-reported child behavior problems at age 7 years. METHODS Data are from 407 African-American children (210 cocaine-exposed, 197 non-cocaine-exposed) enrolled prospectively at birth in a longitudinal study on the neurodevelopmental consequences of in utero exposure to cocaine. Prenatal cocaine exposure was assessed at delivery through maternal self-report and bioassays (maternal and infant urine and infant meconium). The Achenbach Child Behavior Checklist (CBCL), a measure of childhood externalizing and internalizing behavior problems, was completed by the childs current primary caregiver during an assessment visit scheduled when the child was seven years old. RESULTS Structural equation and GLM/GEE models disclosed no association linking prenatal cocaine exposure status or level of cocaine exposure to child behavior (CBCL Externalizing and Internalizing scores or the eight CBCL subscale scores). CONCLUSIONS This evidence, based on standardized ratings by the current primary caregiver, fails to support hypothesized cocaine-associated behavioral problems in school-aged children with in utero cocaine exposure. A next step in this line of research is to secure standardized ratings from other informants (e.g., teachers, youth self-report).

Longitudinal effects of prenatal cocaine use on mother-child interactions at ages 3 and 5 years.

Objective: To assess the effect of maternal prenatal and past-year cocaine use on mother-child interactions across preschool years. Methods: The sample is drawn from the Miami Prenatal Cocaine Study, a longitudinal follow-up of prenatal cocaine exposure (PCE) in a large cohort of African-American infants prospectively enrolled at birth. Analyses are based on the 366 children (168 PCE and 198 non-cocaine-exposed) in the care of their biological mothers and with completed mother-child interaction measures at the 3- and/or 5-year assessments. Videotaped interactions were coded using a modified Egeland Teaching Task scheme. Generalized linear models with a generalized estimating equations approach were used to evaluate the effect of PCE on the overall quality of maternal-child interaction, measured by the Egeland total score at both study visits, and on the individual Egeland subscales at the 5-year visit, while adjusting for other suspected influences on interactions. Results: PCE dyads demonstrated less optimal overall mother-child interactions compared with non-cocaine-exposed dyads. The estimated PCE-associated difference did not shift appreciably with statistical adjustment for child sex, child age at examination, or other birth covariates. PCE dyads with past-year maternal cocaine use had significantly lower Egeland summary scores compared with children with neither exposure. In subscale analyses, PCE was most strongly associated with greater maternal intrusiveness and boundary dissolution at the 5-year visit. Conclusions: Prenatal and past-year maternal cocaine use seems to be associated with poorer quality in mother-child interaction during early childhood. These dynamics should be considered when examining the association between PCE and child cognitive, behavioral, and academic outcomes.