Differentiating Among Children with PDD-NOS,ADHD, and those with a Combined Diagnosis on the Basis of WISC-III Profiles

Pervasive Developmental Disorder-Not Otherwise Specified (PDD-NOS) and Attention Deficit/Hyperactivity Disorder (ADHD) have partly overlapping symptoms. It can also be debated whether a third diagnostic category exists: children with a combined diagnosis. In this study an attempt was made to distinguish among the three groups on the basis of intelligence (WISC-III) profiles. It was found that the PDD-NOS group had higher verbal and performance IQ’s, as well as higher WISC-III index scores than the ADHD group. Subtests Block Design and Mazes discriminated best. It was concluded that based on intelligence scores, only PDD-NOS and ADHD emerged as distinct categories, whereas the combined diagnosis did not. Future research on the distinctiveness of these diagnostic groups, however, should include variables other than IQ.     

Sex Differences in WISC-III Profiles of Children with High-functioning Pervasive Developmental Disorders

Using the Japanese version of the Wechsler Intelligence Scale for Children-Third Edition (WISC-III), 26 girls with high-functioning (IQ ≥ 70) pervasive developmental disorders (HFPDD) (mean age, 8.2 years) were compared with 116 boys with HFPDD (mean age, 9.0 years). Compared with the boys, the girls scored significantly higher on the Processing Speed index, Coding, and Symbol Search, but scored significantly lower on Block Design. Although both groups showed weakness on Comprehension in the verbal domain, the girls’ subtest profile in the performance domain was relatively even and significantly different from the boys’, which was characterized by a peak on Block Design. Such differences should be replicated, and possible behavioral, neurological, and genetic links to these sex differences should be clarified.     

Serial changes of prefrontal lobe growth in the patients with benign childhood epilepsy with centrotemporal spikes presenting with cognitive impairments/behavioral problems

Several studies have reported a higher incidence of learning and behavioral difficulties in association with frontal lobe dysfunctions in children with benign childhood epilepsy with centrotemporal spikes (BCECTS). We studied serial changes in frontal and prefrontal lobe volumes using three-dimensional magnetic resonance imaging in BCECTS with or without cognitive impairments and behavioral problems and evaluated correlations between prefrontal lobe growth and active seizure period. Serial changes in regional cerebral volumes were measured in two patients with cognitive impairments and behavioral problems (BCECTS(+)) and five patients without neuropsychiatric deficits (BCECTS(−)). Eleven normal subjects (4-13 years old) served as controls. Volumes of the frontal and prefrontal lobes were determined using a workstation, and the prefrontal-to-frontal lobe volume ratio was calculated. Frontal and prefrontal lobe volumes revealed growth disturbance in BCECTS(+) compared with BCECTS(−) and control subjects. In addition, prefrontal-to-frontal lobe volume ratio increased serially in BCECTS(−) similarly to controls, but was stagnant or decreased in BCECTS(+). Prefrontal growth also revealed more rapid recovery in a BCECTS(+) patient with shorter active seizure period. These findings suggest that longer active seizure period as frequent spike-waves coupled with the occurrence of frequent seizures may be associated with prefrontal lobe growth disturbance, which relates to neuropsychological problems.     

The relationship between prenatal PCB exposure and intelligence (IQ) in 9-year-old children

Background

Several epidemiologic studies have demonstrated relationships between prenatal exposure to polychlorinated biphenyls (PCBs) and modest cognitive impairments in infancy and early childhood. However, few studies have followed cohorts of exposed children long enough to examine the possible impact of prenatal PCB exposure on psychometric intelligence in later childhood. Of the few studies that have done so, one in the Great Lakes region of the United States reported impaired IQ in children prenatally exposed to PCBs, whereas another found no association.

Objectives

This study was designed to determine whether environmental exposure to PCBs predicts lower IQ in school-age children in the Great Lakes region of the northeastern United States.

Methods

We measured prenatal exposure to PCBs and IQ at 9 years of age in 156 subjects from Oswego, New York. We also measured > 50 potential predictors of intelligence in children, including repeated measures of the home environment [Home Observation for Measurement of the Environment (HOME)], socioeconomic status (SES), parental IQ, alcohol/cigarette use, neonatal risk factors, and nutrition.

Results

For each 1-ng/g (wet weight) increase in PCBs in placental tissue, Full Scale IQ dropped by three points (p = 0.02), and Verbal IQ dropped by four points (p = 0.003). The median PCB level was 1.50 ng/g, with a lower quartile of 1.00 ng/g and an upper quartile of 2.06 ng/g. Moreover, this association was significant after controlling for many potential confounders, including prenatal exposure to methylmercury, dichlorodiphenyldichloroethylene, hexachlorobenzene, and lead.

Conclusions

These results, in combination with similar results obtained from a similar study in the Great Lakes conducted 10 years earlier, indicate that prenatal PCB exposure in the Great Lakes region is associated with lower IQ in children.     

Protective effects of the alcohol dehydrogenase-ADH1B allele in children exposed to alcohol during pregnancy

OBJECTIVES: To examine alcohol use for mothers with and without an ADH1B*3 allele and the moderating effects of the maternal and child ADH1B*3 allele on a broad range of infant and 7.5-year outcomes. STUDY DESIGN: Blood samples from 263 black mother/child pairs (217 mothers and 239 children) were analyzed to determine incidence of the ADH1B allele and the relation of the maternal allele to pregnancy drinking assessed at every prenatal clinic visit. Moderating effects of ADH1B were examined by dichotomizing the moderator variable and performing regression analyses on the 2 groups. RESULTS: Pregnancy drinking at conception was less frequent in the presence of the ADH1B*3 allele, and virtually no adverse effects were found in children whose mothers had at least one ADH1B*3 allele. By contrast to the maternal allele, we found no consistent pattern of greater vulnerability in children lacking the ADH1B*3 allele. CONCLUSIONS: These data are consistent with the hypothesis that the maternal ADH1B*3 allele provides some protection to the fetus from prenatal alcohol exposure.     

Prenatal exposure to perfluroalkyl substances and children's IQ: The Taiwan maternal and infant cohort study

BackgroundPerfluoroalkyl substances (PFASs) are a group of fluorinated organic substances that are widely used in consumer products and are often detectable in human tissues. Human studies on prenatal exposure to PFASs and neurodevelopment in children are few and inconsistent.MethodsIn the Taiwan Maternal and Infant Cohort Study, we collected serum samples from pregnant women during the third trimester and measured concentrations of 9 PFASs using a high performance liquid chromatography system. A subsample of their children was assessed with full scale intelligence quotient (FSIQ), verbal IQ (VIQ) and performance IQ (PIQ) at both age 5 (n = 120) and 8 years (n = 120). We used multivariate linear regression models to examine prenatal PFAS exposure in relation to IQ scores at each age period.ResultsPrenatal perfluoroundecanoic acid (PFUnDA) concentrations were inversely associated with children's PIQ scores at age 5 years, with an adjusted coefficient (β) of −1.6 (95% confidence interval [CI]: (−3.0, −0.2). When children reached 8 years, most of the prenatal PFASs showed inverse association with children's FSIQ, VIQ and PIQ scores. Among them, prenatal perfluorononanoic acid (PFNA) reached significance. Children with higher prenatal PFNA levels had lower VIQ with an adjusted β of −2.1 (95% CI: −3.9, −0.2).ConclusionsWe found two prenatal PFAS exposure, both long-chain PFASs, in association with decreased IQ test scores in children. Our findings suggest more studies on long-chain PFASs and children's neurodevelopment.     

Intellectual functioning in children with epilepsy: Frontal lobe epilepsy,childhood absence epilepsy and benign epilepsy with centro-temporal spikes

PurposeThe purpose of our study is to describe intellectual functioning in three common childhood epilepsy syndromes – frontal lobe epilepsy (FLE), childhood absence epilepsy (CAE) and benign epilepsy with centro-temporal spikes (BECTS). And also to determine the influence of epilepsy related variables, type of epilepsy, age at epilepsy onset, duration and frequency of epilepsy, and treatment on the scores.MethodsIntellectual functioning was examined in a group of 90 children with epilepsy (30 FLE, 30 CAE, 30 BECTS), aged 6–15 years, and compared with a control group (30). All subjects obtained a Full Scale IQ ≥ 70 and they were receiving no more than two antiepileptic medications. Participants completed the Wechsler Intelligence Scale for Children – Third Edition. The impact of epilepsy related variables (type of epilepsy, age at epilepsy onset, duration of epilepsy, seizure frequency and anti-epileptic drugs) on intellectual functioning was examined.ResultsChildren with FLE scored significantly worse than controls on WISC-III Verbal IQ, Full Scale IQ and Processing Speed Index. There was a trend for children with FLE to have lower intelligence scores than CAE and BECTS groups. Linear regression analysis showed no effect for age at onset, frequency of seizures and treatment. Type of epilepsy and duration of epilepsy were the best indicators of intellectual functioning.ConclusionIt is crucial that children with FLE and those with a longer active duration of epilepsy are closely monitored to allow the early identification and evaluation of cognitive problems, in order to establish adequate and timely school intervention plans.