1. Bellando J, Fussell J. {{Part 2: Components of a comprehensive diagnostic evaluation for autism spectrum disorders}}. {J Ark Med Soc};2011 (Feb);107(9):180-182.

Part two in this series will discuss the American Academy of Pediatrics suggestions for the components of a comprehensive autism assessment. A better understanding about the critical components of a comprehensive assessment for ASD can help the PCP be an informed consumer of the information provided in report(s) from the referral source. This information also helps the PCP have a better understanding of what additional evaluations might be needed to provide a complete clinical picture of the child. This knowledge will guide the PCP in translating these evaluation components into a meaningful treatment plan for the child.

2. Buhler E, Bachmann C, Goyert H, Heinzel-Gutenbrunner M, Kamp-Becker I. {{Differential Diagnosis of Autism Spectrum Disorder and Attention Deficit Hyperactivity Disorder by Means of Inhibitory Control and ‘Theory of Mind’}}. {J Autism Dev Disord};2011 (Mar 4)

Autism spectrum disorders (ASD) and attention deficit hyperactivity disorders (ADHD) are both associated with deficits in executive control and with problems in social contexts. This study analyses the variables inhibitory control and theory of mind (ToM), including a developmental aspect in the case of the latter, to differentiate between the disorders. Participants with an ASD (N = 86), an ADHD (N = 84) and with both disorders (N = 52) in the age range of 5-22 years were compared. Results were differences in inhibitory control (ADHD < ASD) and in the ToM performance among younger (ASD < ADHD) but not among older children. We discuss whether common deficits in ToM differ in the developmental course.

3. Lo YC, Soong WT, Gau SS, Wu YY, Lai MC, Yeh FC, Chiang WY, Kuo LW, Jaw FS, Tseng WY. {{The loss of asymmetry and reduced interhemispheric connectivity in adolescents with autism: A study using diffusion spectrum imaging tractography}}. {Psychiatry Res};2011 (Mar 4)

Evidence from neuroimaging and neurobiological studies suggests that abnormalities in cortical-cortical connectivity involving both local and long-distance scales may be related to autism. The present study analyzed the microstructural integrity of the long-range connectivity related to social cognition and language processing with diffusion tractography among adolescents with autism compared with neurotypical adolescents. Tract-specific analyses were used to study the long-range connectivity responsible for integrating social cognition and language processing. Specifically, three pairs of association fibers and three portions of callosal fiber tracts were analyzed. Generalized fractional anisotropy (GFA) values were measured along individual targeted fiber tracts to investigate alterations in microstructure integrity. The asymmetry patterns were also assessed in three pairs of association fibers. In neurotypical participants, we found a consistent leftward asymmetry in three pairs of association fibers. However, adolescents with autism did not demonstrate such asymmetry. Moreover, adolescents with autism had significantly lower mean GFA in three callosal fiber tracts than neurotypical participants. The loss of leftward asymmetry and reduction of interhemispheric connection in adolescents with autism suggest alterations of the long-range connectivity involved in social cognition and language processing. Our results warrant further investigation by combining developmental and neurocognitive data.

4. Muller RA, Shih P, Keehn B, Deyoe JR, Leyden KM, Shukla DK. {{Underconnected, but How? A Survey of Functional Connectivity MRI Studies in Autism Spectrum Disorders}}. {Cereb Cortex};2011 (Mar 4)

Growing consensus suggests that autism spectrum disorders (ASD) are associated with atypical brain networks, thus shifting the focus to the study of connectivity. Many functional connectivity studies have reported underconnectivity in ASD, but results in others have been divergent. We conducted a survey of 32 functional connectivity magnetic resonance imaging studies of ASD for numerous methodological variables to distinguish studies supporting general underconnectivity (GU) from those not consistent with this hypothesis (NGU). Distinguishing patterns were apparent for several data analysis choices. The study types differed significantly with respect to low-pass filtering, task regression, and whole-brain field of view. GU studies were more likely to examine task-driven time series in regions of interest, without the use of low-pass filtering. Conversely, NGU studies mostly applied task regression (for removal of activation effects) and low-pass filtering, testing for correlations across the whole brain. Results thus suggest that underconnectivity findings may be contingent on specific methodological choices. Whereas underconnectivity reflects reduced efficiency of within-network communication in ASD, diffusely increased functional connectivity can be attributed to impaired experience-driven mechanisms (e.g., synaptic pruning). Both GU and NGU findings reflect important aspects of network dysfunction associated with sociocommunicative, cognitive, and sensorimotor impairments in ASD.

5. Volders K, Nuytens K, Creemers JW. {{The Autism Candidate Gene Neurobeachin Encodes a Scaffolding Protein Implicated in Membrane Trafficking and Signaling}}. {Curr Mol Med};2011 (Mar 4)

Autism is a developmental disorder of the central nervous system characterized by impairments in social interaction, communication and restricted repetitive and stereotyped behavior. It is generally assumed that in most cases autism has a polygenic cause, but the pathogenesis is still unknown. Neurobeachin (NBEA) has recently been identified as a candidate gene for autism in a patient with a de novo chromosomal translocation and three patients with a monoallelic deletion. This multidomain scaffolding protein has been suggested to be involved in neuronal post-Golgi membrane traffic. Knockout of Nbea in two independent mouse models has demonstrated a role in neurotransmitter release and synaptic functioning. Knockdown in a cell line has shown a role as negative regulator of secretion of large dense-core vesicles (LDCVs) and haploinsufficiency in blood platelets results in dense granules with an aberrant morphology. A potential role in vesicle transport is further supported by a study of SEL-2, the C.elegans homologue of NBEA. This protein was identified as a negative regulator of LIN-12/Notch activity, probably due to defects in endosomal trafficking. Members of the Notch pathway have also been shown to be modifiers of the NBEA homologue in Drosophila, rugose. These new insights in the function of NBEA may help identifying novel pathways affected in autistic patients. In particular, it suggests that impaired functionality of LDCVs, which contain neurotrophins, neuropeptides and monoamines, might contribute to the pathogenesis of autism in at least a subgroup of patients.

6. Yama B, Freeman T, Graves E, Yuan S, Karen Campbell M. {{Examination of the Properties of the Modified Checklist for Autism in Toddlers (M-CHAT) in a Population Sample}}. {J Autism Dev Disord};2011 (Mar 4)

This study examines the following properties of the Modified Checklist for Autism in Toddlers (M-CHAT) in an unselected low-risk sample: (a) the maximum age for screen administration; (b) the positive screen rate in the absence of follow-up telephone interviews and; (c) the distributional properties of positive screens. Data came from a prospective cohort study (n = 1,604). Results suggest that the M-CHAT can appropriately be administered to children aged 20-48 months. Documented explanations provided by mothers during screening, appear to effectively identify potential screen misclassifications in the absence of the follow-up telephone interviews. This further emphasizes the importance of clinician expertise in verifying positive M-CHAT screens. Results have implications for the administration of the M-CHAT in clinical and research settings.