1. Christ SE, Kester LE, Bodner KE, Miles JH. {{Evidence for selective inhibitory impairment in individuals with autism spectrum disorder}}. {Neuropsychology};2011 (Jul 4)
Objective: The social and communicative challenges faced by individuals with autism spectrum disorder (ASD) are often compounded by additional difficulties with executive function. It remains unclear, however, to what the extent individuals with ASD experienced impairment in inhibitory control. The objective of the present study was to assess the three main subtypes of executive inhibitory control within a single ASD sample thus providing new insight into the unique ASD-related pattern of sparing and impairment observed across different aspects of inhibitory control. Method: A sample of 28 children with ASD (mean age = 13.1 years) and a comparison group of 49 neurologically uncompromised children (mean age = 13.3 years) participated. A prepotent response inhibition task, a flanker visual filtering task, and a proactive interference memory task were used to evaluate prepotent response inhibition, resistance to distracter interference, and resistance to proactive interference, respectively. Results: After accounting for individual differences in noninhibition abilities (e.g., processing speed) and overall level of functioning, there was no evidence of group-related differences in inhibitory performance on the prepotent response inhibition test or proactive interference test. ASD-related impairments in inhibitory control were evident, however, on the flanker visual filtering task. Conclusions: Taken together, the present findings indicate that ASD is associated with impairments in some, but not all, aspects of inhibitory control. Individuals with ASD appear to have difficulty ignoring distracting visual information, but prepotent response inhibition and resistance to proactive interference are relatively intact. The current findings also provide support for a multitype model of inhibitory control. (PsycINFO Database Record (c) 2011 APA, all rights reserved).
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2. Levitt P. {{Serotonin and the Autisms: A Red Flag or a Red Herring?}}. {Arch Gen Psychiatry};2011 (Jul 5)
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3. McPartland JC, Crowley MJ, Perszyk DR, Naples A, Mukerji CE, Wu J, Molfese P, Bolling DZ, Pelphrey KA, Mayes LC. {{Temporal dynamics reveal atypical brain response to social exclusion in autism}}. {Dev Cogn Neurosci};2011 (Jul);1(3):271-279.
Despite significant social difficulties, children with autism spectrum disorder (ASD) are vulnerable to the effects of social exclusion. We recorded EEG while children with ASD and typical peers played a computerized game involving peer rejection. Children with ASD reported ostracism-related distress comparable to typically developing children. Event-related potentials (ERPs) indicated a distinct pattern of temporal processing of rejection events in children with ASD. While typically developing children showed enhanced response to rejection at a late slow wave indexing emotional arousal and regulation, those with autism showed attenuation at an early component, suggesting reduced engagement of attentional resources in the aversive social context. Results emphasize the importance of studying the time course of social information processing in ASD; they suggest distinct mechanisms subserving similar overt behavior and yield insights relevant to development and implementation of targeted treatment approaches and objective measures of response to treatment.
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4. Niederhofer H. {{Efficacy of Duloxetine and Agomelatine Does Not Exceed That of Other Antidepressants in Patients With Autistic Disorder: Preliminary Results in 3 Patients}}. {Prim Care Companion CNS Disord};2011;13(1)
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5. Poustka L, Jennen-Steinmetz C, Henze R, Vomstein K, Haffner J, Sieltjes B. {{Fronto-temporal disconnectivity and symptom severity in children with autism spectrum disorder}}. {World J Biol Psychiatry};2011 (Jul 6)
Abstract Objectives. There is increasing evidence that many of the core behavioural impairments in autism spectrum disorders (ASD) emerge from disconnectivity of networks that are important for social communication. The present study aimed at investigating which specific fibre tracts are impaired in ASD and if possible alterations of white matter are associated with clinical symptomatology. Methods. Eighteen children with ASD and 18 carefully matched typically developing controls aged 6-12 years were examined using diffusion tensor imaging (DTI) and voxel-based morphometry (VBM). Fractional anisotropy (FA) values were correlated with symptom severity as indexed by the children’s scores on the Autisms Diagnostic Observation Schedule (ADOS) and the Autism Diagnostic Interview-Revised (ADI-R). Results. Decreased FA values were identified for the fornix (FO), the superior longitudinal fasciculus (SLF) the corpus callosum and the uncinate fasciculus (UF) in the ASD group compared to controls, with most prominent differences in the UF bilaterally and the right SLF. FA values of affected fibre tracts were negatively associated with clinical measures of autistic symptomatology. We did not observe significantly altered grey or white matter concentration after correction for multiple comparisons. Conclusion. Our findings support the hypothesis of abnormal white matter microstructure of fronto-temporal cortical networks in ASD, which are associated with core symptoms of the disorder.
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6. Ray B, Long JM, Sokol DK, Lahiri DK. {{Increased Secreted Amyloid Precursor Protein-alpha (sAPPalpha) in Severe Autism: Proposal of a Specific, Anabolic Pathway and Putative Biomarker}}. {PLoS One};2011;6(6):e20405.
Autism is a neurodevelopmental disorder characterized by deficits in verbal communication, social interactions, and the presence of repetitive, stereotyped and compulsive behaviors. Excessive early brain growth is found commonly in some patients and may contribute to disease phenotype. Reports of increased levels of brain-derived neurotrophic factor (BDNF) and other neurotrophic-like factors in autistic neonates suggest that enhanced anabolic activity in CNS mediates this overgrowth effect. We have shown previously that in a subset of patients with severe autism and aggression, plasma levels of the secreted amyloid-beta (Abeta) precursor protein-alpha form (sAPPalpha) were significantly elevated relative to controls and patients with mild-to-moderate autism. Here we further tested the hypothesis that levels of sAPPalpha and sAPPbeta (proteolytic cleavage products of APP by alpha- and beta-secretase, respectively) are deranged in autism and may contribute to an anabolic environment leading to brain overgrowth. We measured plasma levels of sAPPalpha, sAPPbeta, Abeta peptides and BDNF by corresponding ELISA in a well characterized set of subjects. We included for analysis 18 control, 6 mild-to-moderate, and 15 severely autistic patient plasma samples. We have observed that sAPPalpha levels are increased and BDNF levels decreased in the plasma of patients with severe autism as compared to controls. Further, we show that Abeta1-40, Abeta1-42, and sAPPbeta levels are significantly decreased in the plasma of patients with severe autism. These findings do not extend to patients with mild-to-moderate autism, providing a biochemical correlate of phenotypic severity. Taken together, this study provides evidence that sAPPalpha levels are generally elevated in severe autism and suggests that these patients may have aberrant non-amyloidogenic processing of APP.
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7. Robb AS, Andersson C, Bellocchio EE, Manos G, Rojas-Fernandez C, Mathew S, Marcus R, Owen R, Mankoski R. {{Safety and Tolerability of Aripiprazole in the Treatment of Irritability Associated With Autistic Disorder in Pediatric Subjects (6-17 Years Old):Results From a Pooled Analysis of 2 Studies}}. {Prim Care Companion CNS Disord};2011;13(1)
Background: With increasing use of atypical antipsychotics among pediatric patients, detailed information about safety and tolerability is crucial.Method: Data were pooled from two 8-week, randomized, double-blind, multicenter, parallel-group trials comparing aripiprazole versus placebo in subjects aged 6 to 17 years with irritability associated with DSM-IV-TR-diagnosed autistic disorder: one flexibly dosed (aripiprazole 2-15 mg/d; target of 5, 10, or 15 mg/d), the other fixed-dose (aripiprazole 5, 10, or 15 mg/d). The first was conducted from June 2006-April 2008, and the second, from June 2006-June 2008. Adverse events were characterized with respect to incidence, duration, severity, timing of peak incidence of onset, and dose-response relationship. Extrapyramidal symptoms, drooling, and metabolic parameters were evaluated.Results: Three hundred thirteen subjects comprised the safety sample (aripiprazole 212, placebo 101). Discontinuations due to adverse events with aripiprazole versus placebo were, overall, 10.4% versus 6.9%; subjects 6-12 years: 10.8% versus 5.1%; and subjects 13-17 years: 8.9% versus 13.6%. Common adverse events with aripiprazole versus placebo included sedation (20.8% vs 4.0%), fatigue (16.5% vs 2.0%), vomiting (13.7% vs 6.9%), increased appetite (12.7% vs 6.9%), somnolence (10.4% vs 4.0%), and tremor (9.9% vs 0.0%). Most adverse events were mild or moderate and occurred early. Only fatigue showed a dose-response relationship (P < .05). Mean body weight change (last observation carried forward, 1.6 vs 0.4 kg) was higher with aripiprazole than placebo (P < .001). There were no between-treatment differences in metabolic changes. The extrapyramidal symptom-related adverse event incidence with aripiprazole versus placebo was, overall, 20.8% vs 9.9%; the incidence of akathisia-related events was 3.3% vs 8.9%.Conclusions: Aripiprazole was generally safe and well tolerated in subjects (6-17 years) with irritability associated with autistic disorder in these 8-week studies; clinicians should be aware of this clinical profile and strategies to manage adverse events if they occur.Trial Registration:clinicaltrials.gov Identifiers NCT00332241 and NCT00337571.
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8. Rojas DC, Teale PD, Maharajh K, Kronberg E, Youngpeter K, Wilson L, Wallace A, Hepburn S. {{Transient and steady-state auditory gamma-band responses in first-degree relatives of people with autism spectrum disorder}}. {Mol Autism};2011 (Jul 5);2(1):11.
ABSTRACT: BACKGROUND: Stimulus-related gamma-band oscillations, which may be related to perceptual binding, are reduced in persons with autism spectrum disorders (ASD). The purpose of this study was to examine auditory transient and steady-state gamma-band findings in 1st degree relatives of persons with ASD to assess their potential familiality in ASD. METHODS: Magnetoencephalography (MEG) recordings in 21 parents of a child with an autism spectrum disorder (pASD) and 20 healthy adult control subjects (HC) were obtained. Gamma-band phase locking factor (PLF), evoked and induced amplitudes to 32, 40 and 48 Hz amplitude-modulated sounds were measured for transient and steady-state responses. Participants were also tested on a number of behavioral and cognitive assessments related to the broad autism phenotype (BAP). RESULTS: Reliable group differences were observed primarily for steady-state responses. In the left hemisphere, pASD subjects exhibited lower phase-locked steady-state amplitudes in all three conditions. Total gamma-band amplitude, including the non-phase-locked component, was also reduced in the pASD group. In addition, pASD subjects had significantly lower PLF than the HC group. Correlations were observed between MEG measures and BAP measures. CONCLUSIONS: The reduction in steady-state gamma-band responses in the pASD group is consistent with prior results for children with ASD. Steady-state responses may be more sensitive to phase-locking errors in ASD than transient responses. Together with the lower PLF and phase-locked amplitudes in 1st degree relatives, correlations between gamma-band measures and behavioral measures relevant to the BAP highlight the potential of gamma-band deficits as a potential new autism endophenotype.
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9. Szatmari P. {{Is Autism, at Least in Part, a Disorder of Fetal Programming?}}. {Arch Gen Psychiatry};2011 (Jul 5)
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10. Tavassoli T, Baron-Cohen S. {{Olfactory Detection Thresholds and Adaptation in Adults with Autism Spectrum Condition}}. {J Autism Dev Disord};2011 (Jul 6)
Sensory issues have been widely reported in Autism Spectrum Conditions (ASC). Since olfaction is one of the least investigated senses in ASC, the current studies explore olfactory detection thresholds and adaptation to olfactory stimuli in adults with ASC. 80 participants took part, 38 (18 females, 20 males) with ASC and 42 control participants (20 males, 22 females). A subgroup of participants (N = 19 in each group) also conducted an adaptation task. Standardized « Sniffin’ Sticks » were used to measure olfactory detection levels and adaptation. Adults with and without ASC showed similar olfactory detection thresholds, and similar adaptation to an olfactory stimulus. Since diminished adaptation in ASC has been previously suggested, future research needs to examine adaptation in other modalities as well.
