Prenatal alcohol exposure and academic achievement at age six: a nonlinear fit.

This is a report on the effects of prenatal alcohol exposure on the academic achievement of children at 6 years of age. In this longitudinal study, women were interviewed at the end of each trimester of pregnancy, at delivery, and at 8, 18, 36, and 72 months postpartum. The women were of lower socioeconomic status, high school-educated, and moderate users of alcohol. The offspring received age-appropriate physical and developmental assessments at each follow-up. Linear regression and nonlinear curve fitting were used to investigate the nature and shape of the relationship between prenatal alcohol exposure and achievement. In addition, the role of child IQ in this relationship was explored. Alcohol exposure during the second trimester predicted deficits in each of the three subtests of the Wide Range Achievement Test-Revised (WRAT-R): reading, spelling, and arithmetic. The relationship was partially reduced by the addition of IQ to the model, but prenatal alcohol exposure still predicted significant deficits in achievement, even after controlling for IQ. Tests for the shape of the relationship demonstrated that the effect of prenatal exposure on the arithmetic subtest of the WRAT-R was a linear or dose-response relationship. By contrast, the relationships between prenatal alcohol exposure and performance on the spelling and reading subtests of the WRAT-R were better modeled as threshold effects. The thresholds for both were approximately 1 drink/day in the second trimester.

Ultradian rhythms in performance on tests of specialized cognitive function.

Performance on cognitive tasks cycled at ultradian frequencies for 24 males over a test period of eight hours. The verbal task of written word production cycled at 80 minutes; the spatial task of locating points in space cycled at 96 minutes. Multiple cycles were seen for a perceptual speed task that factor loads on both the verbal and spatial task. Replication of the results for the first 12 and second 12 subjects demonstrated their robustness. The verbal and spatial tasks were chosen to reflect specialized functions of the left and right cerebral hemispheres, respectively. Accordingly, the results are interpreted as evidence that specialized task performances are associated with independent neurochemical systems. In addition, blood samples were taken at task performance to assess cyclicity of hormone levels. Luteinizing hormone had a period of 120 minutes, testosterone and cortisol were inconsistent and none seemed to be related to the cognitive tasks. However when subjects were divided according to a winter or summer testing schedule, the spatial periodicity was absent for the summer group and the verbal periodicity was absent for the winter peak.

Effect of prenatal marijuana exposure on the cognitive development of offspring at age three.

Marijuana is the most commonly used illicit substance among pregnant women. Although there has been substantial concern about the effects of substance use during pregnancy, few studies have assessed the effects of prenatal exposure to marijuana and even fewer have provided longitudinal data on the developmental outcome of offspring. This is a report from a longitudinal study of substance use during pregnancy. The women in the cohort were of lower socioeconomic status, most were single, half were white and half were African-American. Women were interviewed at the fourth and seventh prenatal months, and women and children were assessed at delivery, 8, 18, and 36 months. Pediatric assessment included physical and cognitive development. At each study phase, mothers were interviewed about life style, living situation, current substance use, sociodemographic, and psychological status. Findings are reported on 655 women and children who were assessed at the third year. There were significant negative effects of prenatal marijuana exposure on the performance of 3-year-old children on the Stanford-Binet Intelligence Scale. The effects were associated with exposure during the first and second trimesters of pregnancy. Among the offspring of white women, these effects were moderated by the child's attendance at preschool/day-care at age three.

Ultradian rhythms of right and left hemisphere function.

Two studies are described that demonstrate ultradian shifts in performance on tests of specialized function associated with the left or right cerebral hemispheres. The first study demonstrated that right-handed males who were tested upon wakening from Rapid Eye Movement sleep performed relatively better on visuospatial skills compared to themselves when tested upon wakening from Non-Rapid Eye Movement sleep. In the second study, subjects were tested continuously for eight hours on a written word production test, a test of point localization, and a test of symbol digit substitution. Each of the tests was performed cyclically but with different periods. The results from both studies suggest that underlying cerebral mechanisms for verbosequential and visuospatial function are neurochemical in nature and not neuroanatomical because of the rapid (ultradian) shifts in performance level.

The effects of prenatal alcohol and marijuana exposure: disturbances in neonatal sleep cycling and arousal.

Neonatal EEG and sleep findings are presented from a longitudinal study of the effects of maternal alcohol and marijuana use during pregnancy. Infant outcome has been examined relative to the trimester(s) of pregnancy during which use occurred. Disturbances in sleep cycling, motility, and arousals were noted that were both substance and trimester specific. Alcohol consumed during the first trimester of pregnancy was associated with disruptions in sleep and arousal, whereas marijuana use affected sleep and motility regardless of the trimester in which it was used. Although these findings are preliminary and based on a small sample of women exhibiting only moderate substance use during pregnancy, they do suggest that specific neurophysiological systems may be differentially affected by prenatal alcohol or marijuana exposure even in the absence of morphological abnormalities.