1. Bohm HV, Stewart MG. {{Brief report: on the concordance percentages for Autistic Spectrum Disorder of twins}}. {J Autism Dev Disord};2009 (May);39(5):806-808.
In the development of genetic theories of Autistic Spectrum Disorder (ASD) various characteristics of monozygotic (MZ) and dizygotic (DZ) twins are often considered. This paper sets forth a possible refinement in the interpretation of the MZ twin concordance percentages for ASD underlying such genetic theories, and, drawing the consequences from that refinement, a possible early environmental factor in the later development of ASD.
2. Casanova MF, El-Baz A, Mott M, Mannheim G, Hassan H, Fahmi R, Giedd J, Rumsey JM, Switala AE, Farag A. {{Reduced gyral window and corpus callosum size in autism: possible macroscopic correlates of a minicolumnopathy}}. {J Autism Dev Disord};2009 (May);39(5):751-764.
Minicolumnar changes that generalize throughout a significant portion of the cortex have macroscopic structural correlates that may be visualized with modern structural neuroimaging techniques. In magnetic resonance images (MRIs) of fourteen autistic patients and 28 controls, the present study found macroscopic morphological correlates to recent neuropathological findings suggesting a minicolumnopathy in autism. Autistic patients manifested a significant reduction in the aperture for afferent/efferent cortical connections, i.e., gyral window. Furthermore, the size of the gyral window directly correlated to the size of the corpus callosum. A reduced gyral window constrains the possible size of projection fibers and biases connectivity towards shorter corticocortical fibers at the expense of longer association/commisural fibers. The findings may help explain abnormalities in motor skill development, differences in postnatal brain growth, and the regression of acquired functions observed in some autistic patients.
3. Constantino JN, Abbacchi AM, Lavesser PD, Reed H, Givens L, Chiang L, Gray T, Gross M, Zhang Y, Todd RD. {{Developmental course of autistic social impairment in males}}. {Dev Psychopathol};2009 (Winter);21(1):127-138.
Recent research has suggested that autistic social impairment (ASI) is continuously distributed in nature and that subtle autistic-like social impairments aggregate in the family members of children with pervasive developmental disorders (PDDs). This study examined the longitudinal course of quantitatively characterized ASI in 3- to 18-year-old boys with and without PDD. We obtained assessments of 95 epidemiologically ascertained male-male twin pairs and a clinical sample of 95 affected children using the Social Responsiveness Scale (SRS), at two time points, spaced 1-5 years apart. Longitudinal course was examined as a function of age, familial loading for PDD, and autistic severity at baseline. Interindividual variation in SRS scores was highly preserved over time, with test-retest correlation of 0.90 for the entire sample. SRS scores exhibited modest general improvement over the study period; individual trajectories varied as a function of severity at baseline and were highly familial. Quantitative measurements of ASI reflect heritable traitlike characteristics. Such measurements can serve as reliable indices of phenotypic severity for genetic and neurobiologic studies, and have potential utility for ascertaining incremental response to intervention.
4. Groen WB, van Orsouw L, Huurne N, Swinkels S, van der Gaag RJ, Buitelaar JK, Zwiers MP. {{Intact spectral but abnormal temporal processing of auditory stimuli in autism}}. {J Autism Dev Disord};2009 (May);39(5):742-750.
The perceptual pattern in autism has been related to either a specific localized processing deficit or a pathway-independent, complexity-specific anomaly. We examined auditory perception in autism using an auditory disembedding task that required spectral and temporal integration. 23 children with high-functioning-autism and 23 matched controls participated. Participants were presented with two-syllable words embedded in various auditory backgrounds (pink noise, moving ripple, amplitude-modulated pink noise, amplitude-modulated moving ripple) to assess speech-in-noise-reception thresholds. The gain in signal perception of pink noise with temporal dips relative to pink noise without temporal dips was smaller in children with autism (p = 0.008). Thus, the autism group was less able to integrate auditory information present in temporal dips in background sound, supporting the complexity-specific perceptual account.
5. Handen BL, Melmed RD, Hansen RL, Aman MG, Burnham DL, Bruss JB, McDougle CJ. {{A double-blind, placebo-controlled trial of oral human immunoglobulin for gastrointestinal dysfunction in children with autistic disorder}}. {J Autism Dev Disord};2009 (May);39(5):796-805.
Controversy exists regarding the extent and possible causal relationship between gastrointestinal symptoms and autism. A randomized, double-blind, placebo-controlled, parallel groups, dose-ranging study of oral, human immunoglobulin (IGOH 140, 420, or 840 mg/day) was utilized with 125 children (ages 2-17 years) with autism and persistent GI symptoms. Endpoint analysis revealed no significant differences across treatment groups on a modified global improvement scale (validated in irritable bowel syndrome studies), number of daily bowel movements, days of constipation, or severity of problem behaviors. IGOH was well-tolerated; there were no serious adverse events. This study demonstrates the importance of conducting rigorous trials in children with autism and casts doubt on one GI mechanism presumed to exert etiological and/or symptomatic effects in this population.
6. Hobson JA, Harris R, Garcia-Perez R, Hobson RP. {{Anticipatory concern: a study in autism}}. {Dev Sci};2009 (Mar);12(2):249-263.
There has been substantial research on children’s empathic responsiveness towards distressed people, and on the limited responsiveness of children with autism. To date, however, there have not been experimental studies to test how far children show concern towards someone who might be expected to feel badly, when that person has not (yet) expressed any negative feelings. We tested matched groups of children with autism and learning disability, and typically developing children of similar verbal mental age (approximately 6 years), with a novel procedure in which participants witnessed one person (E1) tearing the drawing of another (E2). In a comparison condition, a blank card was torn. In the torn-drawing condition, as predicted, fewer participants with autism orientated towards E2 with an immediate look, and as a group, they were rated as showing less concern for, and fewer concerned looks towards, E2. We discuss possible implications for theoretical perspectives on the early development of empathy in typically as well as atypically developing children.
7. Howlin P, Magiati I, Charman T. {{Systematic review of early intensive behavioral interventions for children with autism}}. {Am J Intellect Dev Disabil};2009 (Jan);114(1):23-41.
Recent reviews highlight limitations in the evidence base for early interventions for children with autism. We conducted a systematic review of controlled studies of early intensive behavioral interventions (EIBI) for young children with autism. Eleven studies met inclusion criteria (including two randomized controlled trials). At group level, EIBI resulted in improved outcomes (primarily measured by IQ) compared to comparison groups. At an individual level, however, there was considerable variability in outcome, with some evidence that initial IQ (but not age) was related to progress. This review provides evidence for the effectiveness of EIBI for some, but not all, preschool children with autism.
8. Mooney EL, Gray KM, Tonge BJ, Sweeney DJ, Taffe JR. {{Factor analytic study of repetitive behaviours in young children with Pervasive Developmental Disorders}}. {J Autism Dev Disord};2009 (May);39(5):765-774.
The aim of the current study was to investigate the manifestation of repetitive behaviour profiles in young children with a Pervasive Developmental Disorder. The sample consisted of 137 developmentally delayed children with a DSM-IV-TR Pervasive Developmental Disorder (PDD) and 61 developmentally delayed children without a PDD. An exploratory factor analytic investigation using 12 ADI-R repetitive behaviour items from parent report of children with a PDD reported the emergence of two factors. The first factor consisted of higher-level, « insistence on sameness » behaviours, and the second of lower-level, repetitive « sensory-motor » behaviours. This factor structure was also applicable to a more general group of young children with developmental delay, regardless of their diagnosis. Correlational analyses highlighted contrasting relationships between developmental variables and the different repetitive behaviour factors. These relationships were different for children with a PDD and those without a PDD. The findings have potential implications for the early assessment and diagnosis of PDDs in young children.
9. Mouridsen SE, Rich B, Isager T. {{Body mass index in male and female children with pervasive developmental disorders}}. {Pediatr Int};2008 (Aug);50(4):569-571.
BACKGROUND: The aim of the present study was to evaluate body mass index (BMI) of children with a pervasive developmental disorder (PDD) attending two university clinics during the 1960-84 period. METHODS: BMI derived from medical records of 83 consecutively admitted children with atypical autism and 115 children with Asperger syndrome were compared with the corresponding BMI percentiles in an age- and sex-matched reference population. RESULTS: The BMI distribution of the boys, but not the girls, in both diagnostic categories was significantly lower than those of the age-matched reference populations. Approximately 15% of the boys had a BMI below the fifth percentile. CONCLUSIONS: The present findings are comparable to the results of other studies. Particular attention is given to low BMI as a potential endophenotype in boys with PDD.
10. Nataf R, Skorupka C, Lam A, Springbett A, Lathe R. {{Porphyrinuria in childhood autistic disorder is not associated with urinary creatinine deficiency}}. {Pediatr Int};2008 (Aug);50(4):528-532.
BACKGROUND: Urinary metabolite measurements are often normalized to levels of the ubiquitous metabolite creatinine (CRT) to take account of variations in fluid export. Following CRT normalization, excesses of porphyrins and isoprostanes have been reported in the urines of children with neurodevelopmental disorders. It was suggested (Whiteley et al., 2006, Pediatr. Int. 2006; 48: 292-297) that urinary CRT levels may be depressed in children with autism spectrum disorders. This prompted re-evaluation of CRT levels in such children. METHODS: First matinal urinary CRT levels were compared between subjects in different diagnostic categories including autistic disorder, pervasive developmental disorder not otherwise specified (PDD-NOS) and hyperactivity, before and after correction for age and gender. A larger reference group, consisting of subjects with unrelated disorders and Asperger disorder, with no reported porphyrin excess, was also compared to the group with autistic disorder, both for CRT and for porphyrin (coproporphyrin, COPRO) excess. RESULTS: No significant difference in CRT was observed between any of the categories analyzed, also when corrected for age and gender. In contrast, urinary COPRO levels were significantly higher in autistic disorder versus reference groups, either when expressed as absolute values (independent of CRT levels) or when normalized to CRT. CONCLUSIONS: These data do not support a systematic reduction in urinary CRT levels in subjects with autism spectrum disorders including autistic disorder and PDD-NOS. Urinary COPRO excess in autistic disorder was not associated with or consequent upon urinary CRT deficiency. Differences between affected and control subjects in age and sampling time, as reported by Whiteley et al., may underlie the apparent CRT reduction.
11. Singh J, Illes J, Lazzeroni L, Hallmayer J. {{Trends in US autism research funding}}. {J Autism Dev Disord};2009 (May);39(5):788-795.
This study shows that the number of autism research grants funded in the US from 1997 to 2006 significantly increased 15% per year. Although the majority of projects were concentrated in basic science (65%) compared to clinical (15%) and translational research (20%), there is a significant decrease in the proportion of basic research grants per year and a significant increase in the proportion of translational projects per year. The number of translational projects funded by the National Alliance for Autism Research and Cure Autism Now increased significantly, whereas the number of clinical projects significantly increased for the National Institutes of Health. In conclusion, this study demonstrates the shifting landscape of autism research from basic science to clinical and translational research.
12. Wallace GL, Anderson M, Happe F. {{Brief report: information processing speed is intact in autism but not correlated with measured intelligence}}. {J Autism Dev Disord};2009 (May);39(5):809-814.
Speed of information processing, as measured by inspection time (IT), is a robust predictor of intellectual functioning. However, among individuals with autism and low IQ scores, IT has been reported to be discrepantly fast, and equal to that of high IQ typically developing children (Scheuffgen et al. in Dev Psychopathol 12: 83-90, 2000). The present investigation replicates and extends this study by examining IT and its relationship to IQ in a higher functioning (average range mean IQ) group of children with autism spectrum disorders (ASD) versus matched controls. Though IT was not significantly faster in the ASD group than in the matched control group, the relationship between IT and IQ was uniquely discrepant for the ASD group, partially corroborating and extending previous findings.
13. White S, O’Reilly H, Frith U. {{Big heads, small details and autism}}. {Neuropsychologia};2009 (Apr);47(5):1274-1281.
Autism is thought to be associated with a bias towards detail-focussed processing. While the cognitive basis remains controversial, one strong hypothesis is that there are high processing costs associated with changing from local into global processing. A possible neural mechanism underlying this processing style is abnormal neural connectivity; specifically reduced structural or functional connectivity between brain regions might lead to good exemplar-based processing but poor generalisation. Abnormal neural connectivity has also been suggested to account for the increased incidence of macrocephaly in autism (increased head/brain size). The present study therefore investigated the effect of head size on the ability to switch between global and local processing in autism. 49 high-functioning 7-12 year olds with autism (12 with macrocephaly) were compared to 25 normally developing children in their performance on a Local-Global Switching task. Those children with autism who also had macrocephaly showed a greater processing cost when switching into global processing, or ‘zooming out’, than both the remaining children with autism and the control children. A second experiment revealed that macrocephaly in the context of normal development is not associated with difficulty switching into global processing but rather occurs in children who are physically large. Macrocephaly in the context of autism may therefore be a biological marker of abnormal neural connectivity, and of a local processing bias.
