Pubmed du 21/09/10

Pubmed du jour

2010-09-21 12:03:50

1. Churches O, Wheelwright S, Baron-Cohen S, Ring H. {{The N170 is not modulated by attention in autism spectrum conditions}}. {Neuroreport} (Apr 21);21(6):399-403.

Face processing deficits are characteristic of autism spectrum conditions. However, event-related potential studies of autism spectrum conditions have found inconsistent results for the face selective N170 component. In this study, 15 adult males with autism spectrum conditions and 15 matched, typically developing controls completed a task in which pictures of faces were either attended to or ignored. In the control group, the N170 was larger when faces were attended to. However, there was no such modulation in the autism spectrum conditions group. This finding helps clarify the results from the earlier event-related potential studies of face processing in autism spectrum conditions and suggests that visual attention does not enhance face processing in autism spectrum conditions as it does in typical development.

2. Halayem S, Bouden A, Halayem MB, Tabbane K, Amado I, Krebs MO. {{[Neurological soft signs in pervasive developmental disorders.]}}. {Encephale} (Sep);36(4):307-313.

BACKGROUND: Many studies have focused on specific motor signs in autism and Asperger’s syndrome, but few has been published on the complete range of neurological soft signs (NSS) in children with pervasive developmental disorder (PDD). Scarce are the studies evaluating NSS in children suffering from PDD not otherwise specified (PDDNOS). METHODS: This study compared performance of 11 autistic children (AD) and 10 children with PDDNOS, with controls matched on age, sex and cognitive performance on Krebs et al.’s NSS scale. Because of the duration of the assessments and specific difficulties encountered in managing some items, an adaptation of the scale had to be made during a pilot study with the agreement of the author. To be eligible, patients had to meet the following inclusion criteria: an age range of 6-16 years, a diagnosis of autistic disorder or PDDNOS based on the DSM IV criteria (American Psychiatric Association 1994). The autism diagnostic interview-revised (ADI-R) was used in order to confirm the diagnosis and to evaluate the association of the symptoms to the severity of the NSS. The childhood autism rating scale (CARS) was completed for the patients in order to evaluate symptoms at the time of the NSS examination. Cognitive ability was assessed with Raven’s progressive matrices. Were excluded patients with: history of cerebral palsy, congenital anomaly of the central nervous system, epilepsy, known genetic syndrome, tuberous sclerosis, neurofibromatosis, antecedent of severe head trauma, Asperger’s syndrome, obvious physical deformities or sensory deficits that would interfere with neurological assessment, deep mental retardation and recent or chronic substance use or abuse. Healthy controls shared the same exclusion criteria, with no personal history of neurological, psychiatric disorder or substance abuse, no family history of psychiatric disorder and normal or retardation in schooling. All study procedures were approved by the local Ethics Committee (Comite d’ethique, Razi Hospital), according to the declaration of Helsinki. RESULTS: There was no difference between patients and controls with respect to sex, age and cognitive function. All children had an IQ higher than 81. Significant differences were found between AD children and control group in the motor integration function and sensory integration function. Different NSS scores were significantly higher in the PDDNOS group than in controls: the total scores, motor coordination, motor integration function, sensory integration and abnormal movements. Lower performance in motor coordination skills was associated with higher ADI-R communication score in the AD group. No relationship was found between NSS and CARS’ total sore. CONCLUSION: This study confirms the impaired neurological functioning in autistic as well as PDDNOS children. The association of motor impairment with autistic symptoms highlights the argument that motor control problems can be part of the autism spectrum disorders. The lack of relationship between NSS and intellectual aptitude in the clinical sample provides new elements for the neurodevelopment model of the autism spectrum.

3. May T, Brewer WJ, Rinehart NJ, Enticott PG, Brereton AV, Tonge BJ. {{Differential Olfactory Identification in Children with Autism and Asperger’s Disorder: A Comparative and Longitudinal Study}}. {J Autism Dev Disord} (Sep 18)

Key theories of autism implicate orbitofrontal cortex (OFC) compromise, while olfactory identification (OI) deficits are associated with OFC dysfunction. This study aimed to complete a 5-year follow-up of children with high-functioning autism (HFA) who previously lacked the normal age-OI association; and compare unirhinal-OI in children with HFA, Asperger’s disorder (ASP), and controls. While both HFA and controls had improved birhinal-OI at follow-up, reduced OI in some HFA participants suggested OFC deterioration and heterogeneous OFC development. Unirhinal-OI was impaired in HFA but not ASP relative to controls, suggesting orbitofrontal compromise in HFA but integrity in ASP. Differing IQ-OI relationships existed between HFA and ASP. Findings support the hypothesis of separate neurobiological underpinnings in ASP and HFA, specifically differential orbitofrontal functioning.

4. Tamura R, Kitamura H, Endo T, Hasegawa N, Someya T. {{Reduced thalamic volume observed across different subgroups of autism spectrum disorders}}. {Psychiatry Res} (Sep 15)

We measured the thalamic volumes of 38 subjects with autism spectrum disorders (ASD), including autism, Asperger’s disorder, and pervasive developmental disorder not otherwise specified, and 16 matched healthy controls. Thalamic volume in all ASD subgroups was significantly smaller compared with volume in the control subjects.

5. Wimmer MC, Doherty MJ. {{Children with autism’s perception and understanding of ambiguous figures: evidence for pictorial metarepresentation, a research note}}. {Br J Dev Psychol} (Sep);28(Pt 3):627-641.

A large body of autism research over the last 20 years has shown that people with autism have difficulties understanding mental states. This has been conceived of as a metarepresentational deficit. An open question is whether people with autism’s metarepresentational deficit is limited to the mental domain. This research explores individuals with autism’s understanding of the representational nature of pictures. With the use of ambiguous figures, where a single stimulus is capable of representing two distinct referents, we compared metarepresentational abilities in the pictorial and mental domains and the perception of pictorial ambiguity. Our findings indicate that individuals with autism are impaired in mental metarepresentation but not in pictorial metarepresentation. These findings suggest that children with autism understand the representational nature of pictures. We conclude that children with autism’s understanding of the representational nature of pictures is in advance of their metarepresentational understanding of mind. Their perception of figure ambiguity is comparable to the typical population.