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Biomedical subjects

P D Sampson

Publications and source records attributed to P D Sampson.

At least 19 recordsLinked to original sources
PubMed1994

Prenatal alcohol and offspring development: the first fourteen years.

This report summarizes findings from a prospective longitudinal study of the effects of prenatal alcohol exposure on a birth cohort of 500 offspring selected from 1,529 consecutive pregnant women in prenatal care by mid-pregnancy at two representative community hospitals. Effects of prenatal alcohol observable on size measures at birth were insignificant after 8 months. Morphometric analysis of facial features identified effects only at the very highest alcohol exposure levels. By contrast, dose-dependent effects on neurobehavioral function from birth to 14 years have been established using partial least squares (PLS) methods jointly analysing multiple measures of both alcohol dose and outcome. Particularly salient effects included problems with attention, speed of information processing, and learning problems, especially arithmetic.

Adolescent↗
PubMed1994

Drinking during pregnancy decreases word attack and arithmetic scores on standardized tests: adolescent data from a population-based prospective study.

Women (1529) were interviewed in midpregnancy, and a cohort of their children has been examined at various ages. The two standardized tests presented herein are part of a large battery of tests administered when the children were 14 years old. "Word Attack" (n = 462) measures phonological processing on a task involving the reading of pseudowords in nontimed performance. "Arithmetic" (n = 191) measures auditorily processed mental computations in timed performance. Scores on both tests were associated with prenatal alcohol exposure in a dose-dependent fashion. These effects were robust when considered in relation to a wide variety of potentially confounding variables, such as prenatal exposure to tobacco and other drugs, sociodemographic characteristics, and traumatic postnatal events. A variety of alcohol scores were related to these two performance measures, but those involving a massing of drinks on a given occasion had the strongest association. The higher the average number of drinks/occasion, the poorer the offspring performance on tasks thought to underlie numerical problem solving and reading proficiency. Earlier reports of prenatal, alcohol-related neurobehavioral deficits in childhood have now been extended into adolescence.

Adolescent↗
PubMed1994

Maternal drinking during pregnancy: attention and short-term memory in 14-year-old offspring--a longitudinal prospective study.

A large and compelling experimental literature has documented the adverse impact of prenatal alcohol exposure on the developing brain of the offspring. This is the first report of adolescent attention/memory performance and its relationship with prenatal alcohol exposure in a population-based, longitudinal, prospective study (n = 462) involving substantial covariate control and "blind" examiners. Prenatal alcohol exposure was significantly related to attention/memory deficits in a dose-dependent fashion. A latent variable reflecting 13 measures of maternal drinking was correlated 0.26 with a latent variable representing 52 scores from 6 tests measuring various components of attention and short-term memory performance. The number of drinks/occasion was the strongest alcohol predictor. Fluctuating attentional states, problems with response inhibition, and spatial learning showed the strongest association with prenatal alcohol exposure. A latent variable reflecting the pattern of attention/memory deficits observed at 14 years correlated 0.67 with a composite pattern of deficits previously detected on neurobehavioral tests administered during the first 7 years of life. The 14-year attention/memory deficits observed in the present study appear to be the adolescent sequelae of deficits observed earlier in development. As is usual in such studies, not all exposed offspring showed deficits.

Adolescent↗
PubMed1994

Prenatal alcohol exposure, birthweight, and measures of child size from birth to age 14 years.

OBJECTIVES: The purpose of the study was to examine the effect of prenatal alcohol exposure on offspring's weight, height, and head circumference from birth through 14 years of age. METHODS: This longitudinal prospective study examined a cohort of approximately 500 offspring (oversampled for heavier drinkers and stratified for smoking from a population of 1529 women in prenatal care at the 5th gestational month) at birth; 8 and 18 months; and 4, 7, and 14 years of age. Covariates were examined by means of multiple regression. Birth size measures were also examined as predictors of 7-year neurodevelopmental outcomes. RESULTS: Effects of alcohol were observed on weight, length, and head circumference at birth; these effects were not altered by adjustment for covariates including smoking. However, the birthweight effect is clearly transient: although alcohol effects remained observable at 8 months, they were not measurable thereafter through age 14 years. CONCLUSIONS: In this population-based sample, neither birthweight nor any later size measure was as useful an indicator of the enduring effects of prenatal alcohol exposure as were certain neurodevelopmental outcomes.

Adolescent↗
PubMed1992

Analysis of facial shape in children gestationally exposed to marijuana, alcohol, and/or cocaine.

The association between fetal marijuana and/or alcohol exposure and facial features resembling fetal alcohol syndrome was investigated in a sample of 80 children. Standardized lateral and frontal facial photographs were taken of 40 children, 5 to 7 years of age, whose mothers reported frequent use of marijuana during the first trimester of pregnancy and 40 children whose mothers reported no use of marijuana during pregnancy. The marijuana-exposed and unexposed children were group-matched on alcohol exposure prior to and during pregnancy, sex, race, and age at the time of assessment. The photographs were assessed clinically by a study staff dysmorphologist and morphometrically by computerized landmark analysis. Fetal alcohol syndrome-like facial features were not associated with prenatal marijuana exposure in this study sample. No consistent patterns of facial features were identified among the marijuana-exposed group. Maternal consumption of two or more ounces of alcohol per day, on average, in early gestation was found to be associated with fetal alcohol syndrome-like facial features identified both clinically and morphometrically. Cocaine use reported by 13 of the 80 women was independently associated with mild facial dysmorphic features of hypertelorism and midfacial flattening. The results demonstrate the usefulness of this diagnostic technique for quantifying anomalies apparently unique to fetal alcohol syndrome and for targeting clusters of anomalies in new conditions for future evaluation.

Alcohol Drinking↗
PubMed1990

Measuring interrater reliability among multiple raters: an example of methods for nominal data.

This paper reviews and critiques various approaches to the measurement of reliability among multiple raters in the case of nominal data. We consider measurement of the overall reliability of a group of raters (using kappa-like statistics) as well as the reliability of individual raters with respect to a group. We introduce modifications of previously published estimators appropriate for measurement of reliability in the case of stratified sampling frames and we interpret these measures in view of standard errors computed using the jackknife. Analyses of a set of 48 anaesthesia case histories in which 42 anaesthesiologists independently rated the appropriateness of care on a nominal scale serve as an example.

Reproducibility of Results↗
PubMed1990

"Size" and "shape" variables in the presence of covariates: an application to the sudden infant death syndrome.

A "size measure independent of shape" is used to investigate differences in "size" and "shape" variables, defined as functions of weight and length at birth, between a random control group and victims of the Sudden Infant Death Syndrome (SIDS). At birth, the SIDS group has a lower mean size than the control group. After adjusting for maternal and environmental factors (covariates), there is a lessened but persistent difference in size, suggesting the existence of some undetected factor linked to sudden death in infants.

Birth Weight↗
PubMed1990

Moderate prenatal alcohol exposure: effects on child IQ and learning problems at age 7 1/2 years.

This longitudinal, prospective, population-based study examined the long-term effects of moderate prenatal alcohol exposure on 482 school aged children. Maternal reports of alcohol use obtained during pregnancy were significantly related to child IQ, achievement test scores, and classroom behaviors in second grade children, even after statistical adjustment for appropriate covariates. Consumption of two drinks per day or more on the average was related to a 7-point decrement in IQ in 7-year-old children even after statistically adjusting for appropriate covariates. Low paternal education and more children in the household were identified as environmental factors exacerbating the effect of prenatal alcohol exposure on child IQ. Learning problems were associated with the alcohol "BINGE" pattern of five or more drinks on at least one occasion. This study shows that alcohol use patterns within the social drinking range can have long lasting effects on IQ and learning problems in young school aged children. These patterns should not be interpreted as biologic thresholds. It should also be noted that these are group effects of prenatal alcohol exposure, not necessarily predictable in the individual child, and that for the most part these children were functioning within the normal range of intelligence.

Achievement↗
PubMed1989

Cardiovascular control by arterial and cardiopulmonary baroreceptors in awake dogs with atrioventricular block.

We studied reflex responses to pressure changes at arterial and cardiopulmonary baroreceptors in five awake dogs with atrioventricular block before and after baroreceptor denervation. We changed ventricular pacing rate and blood volume to vary cardiac output and arterial (MAP) and central venous pressure (CVP). We determined peripheral resistance (TPR) and atrial rate (HRA) as responses. In the intact animal, regression analysis showed an average relationship across dogs of TPR = 169-0.69 MAP-1.952 CVP + error. Correlation (r) between observed and predicted TPR was 0.83. For HRA, regression indicated HRA = 291.66-2.319 MAP + 8.144 CVP + error (r = 0.899). TPR and MAP are percent of control at 90 beats/min; CVP is in mmHg; HRA, in beats/min. Although its coefficient is smaller, MAP explains approximately 69% of the variation in TPR. After arterial baroreceptor denervation, effects of MAP on TPR were insignificant and the coefficient for CVP increased. Subsequent vagal block eliminated all reflex responses. Effects from the two receptor sites sum linearly. They act cooperatively with changes in blood volume, but oppose one another with cardiac output changes.

Animals↗
PubMed1988

Morphometric analysis of Macaca nemestrina exposed to ethanol during gestation.

This study was part of a multidisciplinary investigation of the effects of gestational ethanol exposure in nonhuman primates. Thirty-one pregnant Macaca nemestrina were exposed to weekly ethanol doses of 0.0, 0.3, 0.6, 1.2, 1.8, 2.5, 3.3, or 4.1 g/kg maternal weight. Dose cohorts 0.0 through 1.8 were exposed to the initial ethanol dose within 10 days postconception. Dose cohorts 2.5 through 4.1 received their initial dose after the fifth week of gestation. Morphometric analyses performed on cranial radiographs showed that animals exposed to high doses of gestational ethanol had, on average, slightly smaller, distorted crania than control animals. A dysmorphic, flat face characteristic of fetal alcohol syndrome was recognized in one animal of the 1.8 g/kg cohort. The animal that received the highest doses of gestational ethanol was microcephalic. Similar malformations were not seen with low ethanol exposures or in controls. These data suggest a pattern of cranial distortion that may be recognizable and characteristic of ethanol teratogenesis.

Animals↗
PubMed1987

Facial effects of fetal alcohol exposure: assessment by photographs and morphometric analysis.

This study was designed to assess the limits of alcohol-related facial dysmorphogenesis. Standard full face and lateral facial photographs were obtained on 21 7-year-old children who had been exposed gestationally to known, heavy quantities of ethanol. Only two of these children had been previously considered to have definite fetal alcohol syndrome (FAS). Similar photographs of 21 other 7-year-old children with negligible gestational ethanol exposure were obtained for control purposes. Copies of the 42 photographs were given to each of seven expert clinicians who were asked to select any child with an FAS-related facial appearance. Six of seven judges were accurate in identifying children with high levels of alcohol exposure as having a fetal alcohol-affected face. A set of homologous points on the photographs were then digitized and analyzed by newly developed morphometric methods to determine the facial shape characteristics that distinguish the selected photographs of highly exposed children. The analysis confirmed that the judges specifically identified children with facial changes consistent with those previously published as defining the face of the FAS: short palpebral fissures, a relatively long and flat midface, and a retrusive mandible. This methodology may be useful in more accurately delineating the facial phenotype in other conditions diagnosed primarily on the basis of subjective clinical criteria.

Anthropometry↗
PubMed1987

Aspirin and acetaminophen use by pregnant women and subsequent child IQ and attention decrements.

In a longitudinal prospective study of 1,529 women pregnant in 1974-1975, aspirin and acetaminophen were the two medications most frequently taken during the first half of pregnancy (46 and 41%, respectively). In a selected cohort of 421 offspring of these women, examined at 4 years of age, maternal aspirin use during the first half of pregnancy was significantly related to IQ and attention decrements in the exposed children. Multiple regression analyses were used to statistically adjust for a variety of potentially confounding factors including demographic characteristics, child characteristics, other exposures, and lifestyle/environmental variables. Continuous dose-response and step-function parameterizations of aspirin exposure were both statistically significant and not clearly distinguishable from each other. The estimated aspirin effect is significantly greater for girls than boys. Aspirin effects on offspring function were found in the absence of effects on physical size both at birth and at 4 years. Maternal acetaminophen use was not significantly related to child IQ or attention. As this exploratory research originated from observations of a data set gathered for other purposes, it would be desirable to have these findings replicated in other studies. Further follow-up of the children at a later age is planned.

Acetaminophen↗
PubMed1986

Fetal growth and moderate drinking in early pregnancy.

Heavy maternal drinking during pregnancy has consistently been linked to decreased intrauterine growth, but the effect of smaller amounts of alcohol is less clear. In this study, the relationship between fetal growth and "moderate" drinking by low-risk, nonsmoking prenatal patients is explored. The sample consists of 144 women seen for the first time at the prenatal clinic of University College Obstetrics Hospital, London, England, between July 1979 and May 1980 and meeting the following criteria: white, aged 19-35 years, 8-16 weeks gestation at first prenatal visit, nonsmoker, nonalcoholic, lower middle class or higher, and in general good health. Average daily consumption of 10 g of ethanol (about one drink) in the week prior to recognition of pregnancy is related to a decrease in infant birth weight of 225 g, after adjustment for gestational age, sex of child, and maternal age, weight, height, pregnancy weight gain, social class, gravidity, and parity. In addition, consumption of this amount in the week before first prenatal visit is related to a comparable decrease in birth weight for male but not for female infants. These findings suggest that risk of decreased intrauterine growth begins very early in pregnancy, and that fetal response to later alcohol use may vary with sex of the child.

Alcohol Drinking↗
PubMed1986

Studying alcohol teratogenesis from the perspective of the fetal alcohol syndrome: methodological and statistical issues.

Alcohol is a teratogenic drug and the effects appear to be grossly dose related. The severest effects are observable clinically as the fetal alcohol syndrome and are associated with heavy prenatal alcohol exposure and a history of chronic maternal abuse of alcohol. Hypotheses for subtler behavioral effects associated with lower levels of exposure can be generated from observation of the behavioral effects in FAS. Behavioral effects associated with various levels of prenatal alcohol exposure in humans include poor sucking and poor habituation in the newborn, poorer mental and motor development in infancy, and attentional and reaction time effects at four and seven years of age. Human behavioral teratology studies are necessarily complex due to the large number of covariates that affect behavior, modify the effects of teratogens, and influence interpretation. Challenging problems exist in assessing exposure, outcomes, and covariates. Common to assessment of all these classes of variables are the multiplicity of measurement and the indirect nature of the measurement. Answering specific questions about timing and dose effects demands careful statistical modeling procedures and large, complex data bases. Large data bases and indirect measurement problems suggest factor analytic extensions of current regression methodology, which we have proposed in this paper.

Child, Preschool↗
PubMed1983

Statistical analysis of arch shape with conic sections.

Arcs of conic sections are used to model the shapes of human dental arches and to provide a basis for the statistical and graphical analysis of a population of shapes. The Bingham distribution, an elliptical distribution on a hypersphere, is applied in order to model the coefficients of the conic arcs. It provides a definition of an 'average shape' and it quantifies variation in shape. Geometric envelopes of families of conic arcs whose coefficients satisfy a quadratic constraint are used to depict the distribution of shapes in the plane and to make graphical inferences about the average shape. The methods are demonstrated with conic arcs fitted to a sample of 66 maxillary dental arches.

Dental Arch↗
PubMed1981

Dental arch shape: a statistical analysis using conic sections.

This report addresses two problems in the study of the shape of human dental arches; (1) the description of arch shape by mathematical functions and (2) the description of variation among the dental arch shapes in a population. A new algorithm for fitting conic sections is used to model the maxillary dental arches of a sample of sixty-six subjects. A statistical model for shapes represented by arcs of conic sections is demonstrated on the sample of sixty-six dental arches. It permits the definition of an "average shape" and the graphic representation of variation in shape. The model and methods of analysis presented should help dental scientists to better define and quantify "normal" or "ideal" shapes and "normal ranges of variation" for the shape of the dental arch.

Adolescent↗
PubMedDate not supplied

Neurobehavioral effects of prenatal alcohol: Part I. Research strategy.

This paper, Part I of a three-part series, reviews the literature on the neurobehavioral effects of prenatal alcohol exposure and describes a large group of tests assembled to assess neurobehavioral outcomes of alcohol teratogenesis in 7-year-old children. This paper presents the distribution of these test scores for our sample and discusses their relationships with an alcohol binge score and with full-scale IQ. This group of tests is suitable for children with a wide range of abilities and provides a broad assessment of neurobehavioral deficits. Part II of this series describes a new method of statistical analysis, Partial Least Squares (PLS), which is particularly well suited to complex multivariate data sets such as these, and with its aid, examines the effects of prenatal alcohol exposure on IQ, achievement, vigilance and classroom behavior, a total of 43 outcome scores. Part III examines prenatal alcohol effects on outcomes from the broad group of 164 scores deriving from 17 neuropsychologic tests, using the Partial Least Squares methodology, and summarizes the implications of our findings for the behavioral teratology of alcohol.

Child↗