[Clinical features in autism]

Prenatal maternal stress and risk of neurodevelopmental disorders in the offspring: a systematic review and meta-analysis

PURPOSE

Exposure to prenatal stress has been reported to affect the risk of adverse neurodevelopmental outcomes in the offspring; however, there is currently no clear consensus. The aim of this systematic review and meta-analysis was to examine the existing literature on the association between prenatal stress and autism spectrum disorder (ASD) and attention-deficit hyperactivity disorder (ADHD) in the offspring.

METHODS

Based on a registered protocol, we searched several electronic databases for articles in accordance with a detailed search strategy. We performed this study following the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA).

RESULTS

Prenatal stress was significantly associated with an increased risk of both ASD (pooled OR 1.64 [95% CI 1.15-2.34]; I² = 90%; 15 articles) and ADHD (pooled OR 1.72 [95% CI 1.27-2.34]; I² = 85%; 12 articles).

CONCLUSIONS

This study suggests that prenatal stress may be associated with ASD and ADHD; however, several limitations in the reviewed literature should be noted including significant heterogeneity and there is a need for carefully controlled future studies in this area.

Prenatal maternal stress and risk of neurodevelopmental disorders in the offspring: A systematic review and meta-analysis protocol

Background: Prenatal maternal stress (PNMS) is defined as the experience of significant levels of prenatal stress, depression or anxiety during pregnancy. PNMS has been associated with increased risk of autism spectrum disorder (ASD) and attention-deficit hyperactivity disorder (ADHD) in exposed offspring. However, these findings are inconsistent and other studies found no association, meaning a clear consensus on the impact of PNMS on ASD and ADHD risk is required. The purpose of this systematic review and meta-analysis is to summarize and critically review the existing literature on the effects of PNMS on ASD and ADHD risk. Methods: Electronic databases (PubMed, PsycINFO, Web of Science, Scopus and EMBASE) will be searched for articles following a detailed search strategy. We will include cohort and case-control studies that assessed maternal exposure to psychological and/or environmental stress and had ASD or ADHD as an outcome. Two reviewers will independently screen the titles, abstracts and full articles to identify eligible studies. We will use a standardised data extraction form for extracting data and a bias classification tool for assessing study quality. This systematic review will be reported according to the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA). The generic inverse variance method will be used if possible to perform meta-analyses. Ethics and dissemination: Ethical approval is not required for this study because it will not involve the conduct or inclusion of any experimental or personal data that would require informed consent.  The systematic review will be disseminated in peer-reviewed journals. PROSPERO registration number: CRD42018084222.

Prenatal maternal stress and risk of neurodevelopmental disorders in the offspring: A systematic review and meta-analysis protocol

Background: Prenatal maternal stress (PNMS) is defined as the experience of significant levels of prenatal stress, depression or anxiety during pregnancy. PNMS has been associated with increased risk of autism spectrum disorder (ASD) and attention-deficit hyperactivity disorder (ADHD) in exposed offspring. However, these findings are inconsistent and other studies found no association, meaning a clear consensus on the impact of PNMS on ASD and ADHD risk is required. The purpose of this systematic review and meta-analysis is to summarize and critically review the existing literature on the effects of PNMS on ASD and ADHD risk. Methods: Electronic databases (PubMed, PsycINFO, Web of Science, Scopus and EMBASE) will be searched for articles following a detailed search strategy. We will include cohort, case-control and cross-sectional studies that assessed maternal exposure to psychological and/or environmental stress and had ASD or ADHD as an outcome. Two reviewers will independently screen the titles, abstracts and full articles to identify eligible studies. We will use a standardised data extraction form for extracting data and a bias classification tool for assessing study quality. This systematic review will be reported according to the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA). The generic inverse variance method will be used if possible to perform meta-analyses. Ethics and dissemination: Ethical approval is not required for this study because it will not involve the conduct or inclusion of any experimental or personal data that would require informed consent.  The systematic review will be disseminated in peer-reviewed journals. PROSPERO registration number: CRD42018084222.

Individuals with autism have higher 8-Iso-PGF2α levels than controls, but no correlation with quantitative assay of Paraoxonase 1 serum levels

Autism spectrum disorder (ASD) represents a very large set of neurodevelopmental issues with diverse clinical outcomes. Various hypotheses have been put forth for the etiology of autism spectrum disorder, including issues pertaining to oxidative stress. In this study, we conducted measurements of serum 8-Iso-Prostaglanding F2 α (8-iso-PGF2α, which is the results of non-enzimatically mediated polyunsaturated fatty acid oxidation) in a population of individuals with autism and a control group of age and sex matched controls. A quantitative assay of Paraoxonase 1 (PON1) was conducted. Data regarding comorbidities, structural MRI scans, medication, intelligence quotient (IQ) and Childhood Autism Rating Scale scores (CARS) were also included in our study. Our results show that patients diagnosed with autism have higher levels of 8-iso-PGF2α than their neurotypical counterparts. Levels of this particular metabolite, however, do not correlate with quantitative serum levels of Paraoxonase 1, which has been shown to be altered in individuals with autism. Neither 8-iso-PGF2α nor quantitative levels of PON1 provide any meaningful correlation with clinical or neuroimaging data in this study group. Future research should focus on providing data regarding PON 1 phenotype, in addition to standard quantitative measurements, in relation to 8-iso-PGF2α as well as other clinical and structural brain findings.

Can pupil size and pupil responses during visual scanning contribute to the diagnosis of autism spectrum disorder in children?

The purpose of this study was to determine whether baseline pupil size and pupil responses during visual scanning with eye-tracking technology could discriminate children with autism spectrum disorder (ASD) from mental age-matched and chronological age-matched controls. To this end, we used stimuli consisting in still color photographs presented centrally to the participant's midline on a stimulus monitor. Each child was presented with a series of neutral faces, virtual faces (avatars) and different objects, separated by black slides. We recorded the mean pupil size and pupil size changes over time in each of the three categories of stimuli and during exposure to the black slides. Fifty-seven children participated in study (19 ASD, mean age 118 months; 19 mental age-matched controls, mean age 87 months; and 19 chronological age-matched controls, mean age 118 months). We compared the baseline pupil size and pupil responses during visual scanning among the three diagnostic groups. During the presentation of slides, the mean pupil size in the ASD group was clearly smaller than in the MA-matched and CA-matched groups. Discriminate analysis of pupil size during the presentation of black slides and slides with visual stimuli successfully predicted group membership in 72% of the participants. Group membership was correctly classified in 89% of the participants in the ASD group, in 63% in the MA-matched group and in 63% in the CA-matched group. These potential biomarkers may contribute to our understanding of the differences in neurological development in the brain in autism and could prove useful as indicators of ASD.

Catecholamines and their metabolites in children with asperger and kanner syndromes

Children with Asperger and Kanner syndromes in the stable state demonstrate similar decrease in plasma norepinephrine. In the aggravated state, these changes become more expressed and are characterized by a decrease in plasma tyrosine, norepinephrine, normetanephrine and by an increase in dopamine and homovanylic acid and a decrease in excretion of norepinephrine and an increase in excretion of homovanylic acid, epinephrine and MHPG. Only in children with Kanner syndrome in the aggravated state plasma MHPG increases, excretion of tyrosine decreases and excretion of normetanephrine increases. The observed imbalance in dopamine and epinephrine/norepinephrine systems justifies combined analysis of changes in catecholamines and their metabolites levels as the most informative approach in the study of the effect of autistic disorders.