Anatomy and Aging of the Amygdala and Hippocampus in Autism Spectrum Disorder: An In Vivo Magnetic Resonance Imaging Study of Asperger Syndrome
Clodagh M. Murphy, Q. Deeley, E.M. Daly, C. Ecker, F.M. O'Brien, B. Hallahan, E. Loth, F. Toal, S. Reed, S. Hales, D. Robertson, M.C. Craig, D. Mullins, G.J. Barker, T. Lavender, P. Johnston, K.C. Murphy, and D.G. Murphy
The amygdala and hippocampus play a role in emotion, reward, learning, and memory. It has been suggested that perhaps some of the behavioral difficulties that individuals with autism spectrum disorder (ASD) have may be associated with differences in the shape and development of their amygdala and hippocampus. A number of studies have measured the amygdala and hippocampus of people with ASD. However, results to date are contradictory—perhaps because they included people from different parts of the ASD spectrum, of different ages and ability. We compared, using magnetic resonance imaging, the anatomy of the amygdala and hippocampus in 32 healthy individuals with Asperger syndrome (12–47 years old) and 32 healthy controls. We compared the volume of amygdala and hippocampus between individuals with Asperger syndrome and controls and then investigated whether the age of people contributed to differences in the volume of their amygdala and hippocampus.
We found that individuals with Asperger syndrome had a significantly larger volume of amygdala than controls. We also found that the development of the amygdala appeared to be different across groups. The amygdala of controls continued to increase with age, whereas the amygdala of individuals with Asperger syndrome did not. Results of this study suggest that both volume and ageing of the amygdala is significantly different in individuals with Asperger syndrome from controls. The cause of these differences is unknown. Future studies of amygdala and hippocampus development, combining brain imaging with clinical measures of behaviour are warranted. © 2011 INSAR/Wiley Periodicals, Inc.
Article citation:Autism Res2012,5:3–12. DOI: 10.1002/aur.227
Evidence for Broader Autism Phenotype Characteristics in Parents from Multiple Incidence Autism Families
Raphael Bernier, Jennifer Gerdts, Jeff Munson, Geraldine Dawson, and Annette Estes
Autism Spectrum Disorders (ASD) are characterized by impairments in social communication and the presence of restricted and repetitive interests and behaviors. Studies indicate that parents of children with ASD, on average, are more likely to have impairments in areas related to ASD such as language and conversational skills and social relations, referred to as the broader autism phenotype. In this paper we assessed the broader autism phenotype in parents who have two or more children with ASD, as compared to parents who have only one child with autism, parents who have a child with developmental delay without autism, and parents who have typically developing children. Clinicians, naive to parent group membership status, rated broader autism phenotype characteristics from videotaped administrations of the Broader Autism Phenotype Symptom Scale (BPASS). Parents with two or more children with autism showed significantly elevated scores on the BPASS as compared to the parents in the other groups across three of the four domains assessed: social motivation, conversation, expressiveness, and restricted interests. Further, the parents of children with one child with autism did not differ from the parents of children with developmental delay or typical development. These findings suggest that characteristics of the broader autism phenotype are present in parents with two or more children with autism to a greater degree than comparison group parents. Further, the results provide support for the notion that genetic transmission mechanisms may differ between families with more than one child with autism and families with only one child with autism. © 2011 INSAR/Wiley Periodicals, Inc.
Article citation:Autism Res2012,5:13–20. DOI: 10.1002/aur.226
Pregnancy Complications and Obstetric Suboptimality in Association with Autism Spectrum Disorders in Children of the Nurses’ Health Study II
Kristen Lyall, David L. Pauls, Donna Spiegelman, Alberto Ascherio, and Susan L. Santangelo
Complications during pregnancy, including toxemia, gestational diabetes, and hypertension, as well as obstetric suboptimality, have been previously associated with autism, but it is not clear whether specific complications influence risk. We examined such factors in a large cohort of nurses in the United States, the Nurses’ Health Study II. Our study included 793 mothers reporting a child with an autism spectrum disorder (ASD) and 65,652 mothers who did not report a child with ASD. Mothers of ASD children were significantly more likely to have had pregnancy complications and a greater number of obstetric complications than mothers of unaffected children. We saw similar associations between complications and different types of autism, indicating that Asperger syndrome, autistic disorder, and other autism spectrum conditions were all significantly associated with maternal pregnancy complications. Gestational diabetes in particular was associated with an approximately 75% increase in the odds of having a child with ASD, and should be investigated in more detail in future studies. © 2011 INSAR/Wiley Periodicals, Inc.
Article citation:Autism Res2012,5:21–30. DOI: 10.1002/aur.228
Accuracy of Phenotyping Children with Autism Based on Parent Report: What Specifically Do We Gain Phenotyping “Rapidly”?
Zachary Warren, Alison Vehorn, Elizabeth Dohrmann, Amy Nicholson, James Sutcliffe, and Jeremy Veenstra-Vander Weele
Autism Spectrum Disorder (ASD) is considered among the most heritable of all developmental disorders. Despite strong genetic influence the percentage of ASD cases that can be causally attributed to identifiable genetic causes is quite low. Numerous scientific groups have advocated collecting large samples of families in order to improve our understanding of the genetics of ASD. Some researchers have proposed focusing on using parent questionnaires to build large samples in order to bypass financial and time barriers commonly associated with large collections. We assessed the accuracy of this parent-report methodology in comparison to results obtained from extensive assessments through clinical experts. Results indicated concerns about the accuracy of parent questionnaires as they often included children who did not have ASD and they failed to identify many children with ASD. © 2011 INSAR/Wiley Periodicals, Inc.
Article citation:Autism Res2012,5:31–38. DOI: 10.1002/aur.230
Audiovisual Speech Integration in Autism Spectrum Disorder: ERP Evidence for Atypicalities in Lexical-Semantic Processing
Odette Megnin, Atlanta Flitton, Catherine Jones, Michelle de Haan, Torsten Baldeweg, and Tony Charman
Language and communicative impairments are among the primary characteristics of autism spectrum disorders (ASD). Previous studies have examined auditory language processing in ASD. However, during face-to-face conversation, auditory and visual speech inputs provide complementary information, and little is known about audiovisual (AV) speech processing in ASD. It is possible to elucidate the neural correlates of AV integration by examining the effects of seeing the lip movements accompanying the speech (visual speech) on electrophysiological event-related potentials (ERP) to spoken words. Moreover, electrophysiological techniques have a high temporal resolution and thus enable us to track the time-course of spoken word processing in ASD and typical development (TD). The present study examined the ERP correlates of AV effects in three time windows that are indicative of hierarchical stages of word processing. We studied a group of TD adolescent boys (n = 14) and a group of high-functioning boys with ASD (n = 14). Significant group differences were found in AV integration of spoken words in the 200–300 ms time window when spoken words start to be processed for meaning. These results suggest that the neural facilitation by visual speech of spoken word processing is reduced in individuals with ASD. © 2011 INSAR/Wiley Periodicals, Inc.
Article citation:Autism Res2012,5:39–48. DOI: 10.1002/aur.231
Regional Differences in Grey and White Matter in Children and Adults with Autism Spectrum Disorder: An Activation Likelihood Estimate (ALE) Meta-Analysis
Emma G. Duerden, Kathleen M. Mak-Fan, Margot J. Taylor, and S. Wendy Roberts
Autism spectrum disorders (ASD) are associated with environmental and genetic influences that change the structure of the brain during development. Previous neuroimaging studies have explored these changes in children and adults with ASD using magnetic resonance imaging (MRI) and the reports are inconsistent in terms of the regions of the brain that are affected in this disorder. However, findings from children and adults should be examined separately as the brain undergoes many changes during development. We examined existing structural neuroimaging data using meta-analyses to determine the brain regions that exhibit changes in childhood and adulthood separately. Results showed that both children and adults with ASD had common decreases and also increases in brain regions involved in repetitive behavior and executive functioning; however, children showed greater decreases in other brain areas relative to adults. Additionally, only children showed decreased white matter in brain regions that project to the frontal cortex. These results will help us understand the current literature examining brain changes in autism and highlight the importance of targeted developmental studies. © 2011 INSAR/Wiley Periodicals, Inc.
Article citation:Autism Res2012,5:49–66. DOI: 10.1002/aur.235
The Visual Rooting Reflex in Individuals with Autism Spectrum Disorders and Co-occurring Intellectual Disability
Annelies de Bildt, Erik J. Mulder, Natasja D.J. Van Lang, S.A.Jytte de With, Ruud B. Minderaa, Sherin S. Stahl, and George M. Anderson
The rooting reflex is seen in infants and is defined as an orientation towards touch in the area around the mouth. In adults, a rooting reflex to visual stimulation around the face is associated with neurological dysfunction. Previously, an increased occurrence of the visual rooting reflex (VRR) in children and young adults with autism was reported. In the present study, the VRR was investigated in 155 individuals with autism spectrum disorders (ASD) and co-occurring intellectual disability (ID), and in 65 individuals with ID only. The VRR occurred more often in the ASD + ID group than in the ID-only group. Within the ASD + ID group, the VRR presented more often in individuals with autism than in individuals with Pervasive Developmental Disorder-Not Otherwise Specified (PDD-NOS). A positive VRR was associated with lower IQ and lower adaptive functioning, and in the ASD + ID group autism symptom scores were significantly higher in the VRR+ subgroup. The results replicate and extend the finding of an increased occurrence of the VRR in autism. Although an association with IQ was observed, the VRR occurred substantially more often in the autism group compared to an intellectually disabled group indicating some degree of specificity. Additional studies of infants and children with typical development, ASD and ID are needed to determine the utility of the VRR in ASD risk assessment and in order to elucidate possible specific behavioral associations. © 2011 INSAR/Wiley Periodicals, Inc.
Article citation:Autism Res2012,5:67–72. DOI: 10.1002/aur.225