1. Corbett BA, Constantine LJ, Hendren R, Rocke D, Ozonoff S. {{Examining executive functioning in children with autism spectrum disorder, attention deficit hyperactivity disorder and typical development}}. {Psychiatry Res};2009 (Apr 30);166(2-3):210-222.
Executive functioning (EF) is an overarching term that refers to neuropsychological processes that enable physical, cognitive, and emotional self-control. Deficits in EF are often present in neurodevelopmental disorders, but examinations of the specificity of EF deficits and direct comparisons across disorders are rare. The current study investigated EF in 7- to 12-year-old children with autism spectrum disorder (ASD), attention deficit hyperactivity disorder (ADHD) and typical development using a comprehensive battery of measures assessing EF, including response inhibition, working memory, cognitive flexibility, planning, fluency and vigilance. The ADHD group exhibited deficits in vigilance, inhibition and working memory relative to the typical group; however, they did not consistently demonstrate problems on the remaining EF measures. Children with ASD showed significant deficits in vigilance compared with the typical group, and significant differences in response inhibition, cognitive flexibility/switching, and working memory compared with both groups. These results lend support for previous findings that show children with autism demonstrate generalized and profound impairment in EF. In addition, the observed deficits in vigilance and inhibitory control suggest that a significant number of children with ASD present with cognitive profiles consistent with ADHD.
2. Fitzpatrick M. {{Treating autism appropriately}}. {Br J Gen Pract};2009 (May);59(562):379.
3. Maestrini E, Pagnamenta AT, Lamb JA, Bacchelli E, Sykes NH, Sousa I, Toma C, Barnby G, Butler H, Winchester L, Scerri TS, Minopoli F, Reichert J, Cai G, Buxbaum JD, Korvatska O, Schellenberg GD, Dawson G, Bildt AD, Minderaa RB, Mulder EJ, Morris AP, Bailey AJ, Monaco AP. {{High-density SNP association study and copy number variation analysis of the AUTS1 and AUTS5 loci implicate the IMMP2L-DOCK4 gene region in autism susceptibility}}. {Mol Psychiatry};2009 (Apr 28)
Autism spectrum disorders are a group of highly heritable neurodevelopmental disorders with a complex genetic etiology. The International Molecular Genetic Study of Autism Consortium previously identified linkage loci on chromosomes 7 and 2, termed AUTS1 and AUTS5, respectively. In this study, we performed a high-density association analysis in AUTS1 and AUTS5, testing more than 3000 single nucleotide polymorphisms (SNPs) in all known genes in each region, as well as SNPs in non-genic highly conserved sequences. SNP genotype data were also used to investigate copy number variation within these regions. The study sample consisted of 127 and 126 families, showing linkage to the AUTS1 and AUTS5 regions, respectively, and 188 gender-matched controls. Further investigation of the strongest association results was conducted in an independent European family sample containing 390 affected individuals. Association and copy number variant analysis highlighted several genes that warrant further investigation, including IMMP2L and DOCK4 on chromosome 7. Evidence for the involvement of DOCK4 in autism susceptibility was supported by independent replication of association at rs2217262 and the finding of a deletion segregating in a sib-pair family.Molecular Psychiatry advance online publication, 28 April 2009; doi:10.1038/mp.2009.34.
4. Noonan SK, Haist F, Muller RA. {{Aberrant functional connectivity in autism: Evidence from low-frequency BOLD signal fluctuations}}. {Brain Res};2009 (Jan 14)
A number of recent studies have examined functional connectivity in individuals with Autism Spectrum Disorders (ASD), generally converging on the finding of reduced interregional coordination, or underconnectivity. Underconnectivity has been reported between many brain regions and across a range of cognitive tasks, and has been proposed to underlie behavioral and cognitive impairments associated with ASD. The current study employed functional connectivity MRI (fcMRI) to examine interregional correlations of low-frequency BOLD signal fluctuations in 10 high-functioning participants with ASD and 10 typically developing control participants. Whole-brain connectivity with three seed regions of interest (left middle frontal, left superior parietal, and left middle occipital cortex) was evaluated using fMRI datasets acquired during performance of a source recognition task. While fcMRI patterns were found to be largely similar across the two groups, including many common areas, effects for the ASD group were generally more extensive. These findings, although inconsistent with generalized underconnectivity in ASD, are compatible with a model of aberrant connectivity in which the nature of connectivity disturbance (i.e., increased or reduced) may vary by region. Taking into consideration methodological factors that might influence measured fcMRI effects, we suggest that ASD is associated with an inefficiency in optimizing network connections to achieve task performance.
5. Perera H, Wijewardena K, Aluthwelage R. {{Screening of 18-24-Month-Old Children for Autism in a Semi-Urban Community in Sri Lanka}}. {J Trop Pediatr};2009 (Apr 28)
All children aged 18-24 months in a defined geographical area were initially screened for autism, using ‘Red Flag’ criteria. All the children with one or more positive ‘Red Flag’ signs were further screened using Modified Checklist for Autism in Toddlers (M-CHAT) translated to Sinhala, followed by a comprehensive clinical assessment. Of a sample of 374 children, ‘Red Flag’ signs were positive in 28 (7.4%). Four children received a diagnosis of autism on clinical assessment giving a prevalence of 1.07% or 1 per 93 in the 18-24-month age group. Sensitivity of M-CHAT was only 25%, and specificity 70%. The high prevalence detected strongly justifies early community-based screening, but a culturally sensitive screening tool needs to be developed for Sri Lanka.
6. Webb SJ, Sparks BF, Friedman SD, Shaw DW, Giedd J, Dawson G, Dager SR. {{Cerebellar vermal volumes and behavioral correlates in children with autism spectrum disorder}}. {Psychiatry Res};2009 (Apr 30);172(1):61-67.
Cerebellar histopathological abnormalities have been well documented in autism, although findings of structural differences, as determined by magnetic resonance imaging, have been less consistent. This report explores specific cerebellar vermal structures and their relation with severity of symptoms and cognitive functioning in young children with autism spectrum disorder (ASD). Children with ASD aged 3 to 4 years were compared with typically developing children (TD) matched to the ASD children on chronological age, and children with developmental delay (DD) matched to the ASD children on both chronological and mental age. Volumes of the cerebellum and midsagittal vermal areas were measured from 3-D T1-weighted magnetic resonance images. Children with ASD had reduced total vermis volumes compared with children with TD after controlling for age, sex, and overall cerebral volume or cerebellum volume. In particular, the vermis lobe VI-VII area was reduced in children ASD compared with TD children. Children with DD had smaller total vermis areas compared with children with ASD and TD. Within the ASD group, cerebellar measurements were not correlated with symptom severity, or verbal, non-verbal or full scale IQ. Within the DD group, larger cerebellar measurements were correlated with fewer impairments. The specific relation between altered cerebellar structure and symptom expression in autism remains unclear.
