Prenatal fever and autism risk.

Some studies suggest that prenatal infection increases risk of autism spectrum disorders (ASDs). This study was undertaken in a prospective cohort in Norway to examine whether we could find evidence to support an association of the prenatal occurrence of fever, a common manifestation of infection, with ASD risk. Prospective questionnaires provided maternal exposure data; case status was established from clinical assessments and registry linkages. In a large, prospectively ascertained cohort of pregnant mothers and their offspring, we examined infants born ⩾32 weeks for associations between fever exposure in each trimester and ASD risk using logistic regression. Maternal exposure to second-trimester fever was associated with increased ASD risk, adjusting for presence of fever in other trimesters and confounders (adjusted odds ratio (aOR), 1.40; 95% confidence interval, 1.09-1.79), with a similar, but nonsignificant, point estimate in the first trimester. Risk increased markedly with exposure to three or more fever episodes after 12 weeks' gestation (aOR, 3.12; 1.28-7.63). ASD risk appears to increase with maternal fever, particularly in the second trimester. Risk magnified dose dependently with exposure to multiple fevers after 12 weeks' gestation. Our findings support a role for gestational maternal infection and innate immune responses to infection in the pathogenesis of at least some cases of ASD.

The Autism Birth Cohort: a paradigm for gene-environment-timing research.

The reported prevalence of autism spectrum disorders (ASDs) has increased by 5- to 10-fold over the past 20 years. Whether ASDs are truly more frequent is controversial; nonetheless, the burden is profound in human and economic terms. Although autism is among the most heritable of mental disorders, its pathogenesis remains obscure. Environmental factors are proposed; however, none is implicated. Furthermore, there are no biomarkers to screen for ASD or risk of ASD. The Autism Birth Cohort (ABC) was initiated to analyze gene x environment x timing interactions and enable early diagnosis. It uses a large, unselected birth cohort in which cases are prospectively ascertained through population screening. Samples collected serially through pregnancy and childhood include parental blood, maternal urine, cord blood, milk teeth and rectal swabs. More than 107,000 children are continuously screened through questionnaires, referral, and a national registry. Cases are compared with a control group from the same cohort in a 'nested case-control' design. Early screening and diagnostic assessments and re-assessments are designed to provide a rich view of longitudinal trajectory. Genetic, proteomic, immunologic, metagenomic and microbiological tools will be used to exploit unique biological samples. The ABC is a paradigm for analyzing the role of genetic and environmental factors in complex disorders.

Maternal attachment and sensitivity in an at-risk sample.

This study investigated the relationship between adult attachment status and maternal sensitivity in a sample of 30 at-risk mother-child dyads. The children were 18-42 months old with an equal distribution of boys and girls that were at risk for compromised development due to a number of social, emotional and environmental factors. Using the Adult Attachment Interview (AAI; George, Kaplan, & Main, 1985) it was found that only 17% of the mothers were classified as autonomous, while 83% were classified as anxious regarding attachment. Sensitivity was measured using the Emotional Availability Scales (EAS) (Biringen, Robinson, & Emde, 1993). Each mother-child pair was video-taped in their home during a 30-minute interactional sequence in which they played with a given set of toys. Only the results from the Maternal Sensitivity Scale are reported here. Mothers who were free to evaluate their attachment experiences on the AAI were most sensitive. Mothers who showed anxiety in evaluating attachment, as a group, while undoubtedly caring and concerned, were less sensitive. There was, however, wide variability within the group of mothers with anxious attachment representations, Preoccupied mothers showing the least optimal interactions.

Recall performance on a central-incidental memory task by profoundly deaf children.

Bebko (1984) reported that deaf children tend not to use spontaneously active memory strategies such as rehearsal in tasks requiring recall of ordered, temporal information. The present study investigated whether this tendency is task specific or generalized to other experimental paradigms. A central-incidental paradigm was used with profoundly deaf children and hearing children 6 to 13 years of age. The results for the hearing students replicated previous studies: central recall increased with age, but incidental recall changed little. For the deaf children, the results initially appeared very similar to those of the hearing children. However, on closer examination, the rehearsal strategies of the deaf students seemed less effective in mediating their recall. They apparently compensated for these difficulties by capitalizing on unique spatial features of the task, leading to recall levels comparable to those of the hearing students. Therefore, similar performance may not have been the result of equal strategy use but, rather, of the use of additional strategies by the deaf students. This study reinforced the need to provide additional training for deaf students in the use of memory strategies such as rehearsal when information is to be remembered in a sequential manner.