1. Cleland J, Gibbon FE, Peppe SJ, O’Hare A, Rutherford M. {{Phonetic and phonological errors in children with high functioning autism and Asperger syndrome}}. {Int J Speech Lang Pathol} (Feb);12(1):69-76.
This study involved a qualitative analysis of speech errors in children with autism spectrum disorders (ASDs). Participants were 69 children aged 5-13 years; 30 had high functioning autism and 39 had Asperger syndrome. On a standardized test of articulation, the minority (12%) of participants presented with standard scores below the normal range, indicating a speech delay/disorder. Although all the other children had standard scores within the normal range, a sizeable proportion (33% of those with normal standard scores) presented with a small number of errors. Overall 41% of the group produced at least some speech errors. The speech of children with ASD was characterized by mainly developmental phonological processes (gliding, cluster reduction and final consonant deletion most frequently), but non-developmental error types (such as phoneme specific nasal emission and initial consonant deletion) were found both in children identified as performing below the normal range in the standardized speech test and in those who performed within the normal range. Non-developmental distortions occurred relatively frequently in the children with ASD and previous studies of adolescents and adults with ASDs shows similar errors, suggesting that they do not resolve over time. Whether or not speech disorders are related specifically to ASD, their presence adds an additional communication and social barrier and should be diagnosed and treated as early as possible in individual children.
2. Eagleson KL, Gravielle MC, Schluetermcfadyen-Ketchum LJ, Russek SJ, Farb DH, Levitt P. {{Genetic disruption of the autism spectrum disorder risk gene PLAUR induces GABAA receptor subunit changes}}. {Neuroscience} (Apr 7)
Disruption of the GABAergic system has been implicated in multiple developmental disorders, including epilepsy, autism spectrum disorder and schizophrenia. The human gene encoding uPAR (PLAUR) has been shown recently to be associated with the risk of autism. The uPAR(-/-) mouse exhibits a regionally selective reduction in GABAergic interneurons in frontal and parietal regions of the cerebral cortex as well as in the CA1 and dentate gyrus subfields of the hippocampus. Behaviorally, these mice exhibit increased sensitivity to pharmacologically-induced seizures, heightened anxiety, and atypical social behavior. Here, we explore potential alterations in GABAergic circuitry that may occur in the context of altered interneuron development. Analysis of gene expression for 13 GABA(A) receptor subunits using quantitative real-time PCR indicates seven subunit mRNAs (alpha(1), alpha(2), alpha(3), beta(2), beta(3), gamma(2S) and gamma(2L)) of interest. Semi-quantitative in situ hybridization analysis focusing on these subunit mRNAs reveals a complex pattern of potential gene regulatory adaptations. The levels of alpha(2) subunit mRNAs increase in frontal cortex, CA1 and CA3, while those of alpha3 decrease in frontal cortex and CA1. In contrast, alpha(1) subunit mRNAs are unaltered in any region examined. beta(2) subunit mRNAs are increased in frontal cortex whereas beta(3) subunit mRNAs are decreased in parietal cortex. Finally, gamma(2S) subunit mRNAs are increased in parietal cortex while gamma(2L) subunit mRNAs are increased in the dentate gyrus, potentially altering the gamma(2S):gamma(2L) ratio in these two regions. For all subunits, no changes were observed in forebrain regions where GABAergic interneuron numbers are normal. We propose that disrupted differentiation of GABAergic neurons specifically in frontal and parietal cortices leads to regionally-selective alterations in local circuitry and subsequent adaptive changes in receptor subunit composition. Future electrophysiological studies will be useful in determining how alterations in network activity in the cortex and hippocampus relate to the observed behavioral phenotype.
3. Green SA, Ben-Sasson A. {{Anxiety Disorders and Sensory Over-Responsivity in Children with Autism Spectrum Disorders: Is There a Causal Relationship?}}. {J Autism Dev Disord} (Apr 10)
Anxiety disorders and sensory over-responsivity (SOR) are common in children with autism spectrum disorders (ASD), and there is evidence for an association between these two conditions. Currently, it is unclear what causal mechanisms may exist between SOR and anxiety. We propose three possible theories to explain the association between anxiety and SOR: (a) SOR is caused by anxiety; (b) Anxiety is caused by SOR; or (c) SOR and anxiety are causally unrelated but are associated through a common risk factor or diagnostic overlap. In this paper, we examine support for each theory in the existing anxiety, autism, and neuroscience literature, and discuss how each theory informs choice of interventions and implications for future studies.
4. Kujala T, Kuuluvainen S, Saalasti S, Jansson-Verkasalo E, Wendt LV, Lepisto T. {{Speech-feature discrimination in children with Asperger syndrome as determined with the multi-feature mismatch negativity paradigm}}. {Clin Neurophysiol} (Apr 8)
OBJECTIVE: Asperger syndrome, belonging to the autistic spectrum of disorders, involves deficits in social interaction and prosodic use of language but normal development of formal language abilities. Auditory processing involves both hyper- and hypoactive reactivity to acoustic changes. METHODS: Responses composed of mismatch negativity (MMN) and obligatory components were recorded for five types of deviations in syllables (vowel, vowel duration, consonant, syllable frequency, syllable intensity) with the multi-feature paradigm from 8-12-year old children with Asperger syndrome. RESULTS: Children with Asperger syndrome had larger MMNs for intensity and smaller MMNs for frequency changes than typically developing children, whereas no MMN group differences were found for the other deviant stimuli. Furthermore, children with Asperger syndrome performed more poorly than controls in Comprehension of Instructions subtest of a language test battery. CONCLUSIONS: Cortical speech-sound discrimination is aberrant in children with Asperger syndrome. This is evident both as hypersensitive and depressed neural reactions to speech-sound changes, and is associated with features (frequency, intensity) which are relevant for prosodic processing. SIGNIFICANCE: The multi-feature MMN paradigm, which includes variation and thereby resembles natural speech hearing circumstances, suggests abnormal pattern of speech discrimination in Asperger syndrome, including both hypo- and hypersensitive responses for speech features.
5. Shukla DK, Keehn B, Muller RA. {{Regional Homogeneity of fMRI Time Series in Autism Spectrum Disorders}}. {Neurosci Lett} (Apr 7)
Functional magnetic resonance imaging (fMRI) and functional connectivity MRI (fcMRI) studies of autism spectrum disorders (ASD) have suggested atypical patterns of activation and long-distance connectivity for diverse tasks and networks in ASD. We explored the regional homogeneity (ReHo) approach in ASD, which is analogous to conventional fcMRI, but focuses on local connectivity. FMRI data of 26 children with ASD and 29 typically developing (TD) children were acquired during continuous task performance (visual search). Effects of motion and task were removed and Kendall’s coefficient of concordance (KCC) was computed, based on the correlation of the blood oxygen level dependent (BOLD) time series for each voxel and its 6 nearest neighbors. ReHo was lower in the ASD than the TD group in superior parietal and anterior prefrontal regions. Inverse effects of greater ReHo in the ASD group were detected in lateral and medial temporal regions, predominantly in the right hemisphere. Our findings suggest that ReHo is a sensitive measure for detecting cortical abnormalities in autism. However, impact of methodological factors (such as spatial resolution) on ReHo require further investigation.
