Pubmed du 02/12/09

Pubmed du jour

2009-12-02 12:03:50

1. Bedogni F, Hodge RD, Nelson BR, Frederick EA, Shiba N, Daza RA, Hevner RF. {{Autism susceptibility candidate 2 (Auts2) encodes a nuclear protein expressed in developing brain regions implicated in autism neuropathology}}. {Gene Expr Patterns};2009 (Nov 27)

Autism susceptibility candidate 2 (Auts2) is a gene associated with autism and mental retardation, whose function is unknown. Expression of Auts2 mRNA and protein were studied in the developing mouse brain by in situ hybridization, immunohistochemistry, and western blotting. Auts2 mRNA was highly expressed in the developing cerebral cortex and cerebellum, regions often affected by neuropathological changes in autism, and a few other brain regions. On embryonic day (E) 12, Auts2 mRNA was expressed in the cortical preplate, where it colocalized with Tbr1, a transcription factor specific for postmitotic projection neurons. From E16 to postnatal day 21, Auts2 was expressed most abundantly in frontal cortex, hippocampus and cerebellum, including Purkinje cells and deep nuclei. High levels of Auts2 were also detected in developing dorsal thalamus, olfactory bulb, inferior colliculus and substantia nigra. Auts2 protein showed similar regional expression patterns as the mRNA. At the cellular level, Auts2 protein was localized in the nuclei of neurons and some neuronal progenitors.

2. Dawson G, Rogers S, Munson J, Smith M, Winter J, Greenson J, Donaldson A, Varley J. {{Randomized, Controlled Trial of an Intervention for Toddlers With Autism: The Early Start Denver Model}}. {Pediatrics};2009 (Nov 30)

Objective: To conduct a randomized, controlled trial to evaluate the efficacy of the Early Start Denver Model (ESDM), a comprehensive developmental behavioral intervention, for improving outcomes of toddlers diagnosed with autism spectrum disorder (ASD). Methods: Forty-eight children diagnosed with ASD between 18 and 30 months of age were randomly assigned to 1 of 2 groups: (1) ESDM intervention, which is based on developmental and applied behavioral analytic principles and delivered by trained therapists and parents for 2 years; or (2) referral to community providers for intervention commonly available in the community. Results: Compared with children who received community-intervention, children who received ESDM showed significant improvements in IQ, adaptive behavior, and autism diagnosis. Two years after entering intervention, the ESDM group on average improved 17.6 standard score points (1 SD: 15 points) compared with 7.0 points in the comparison group relative to baseline scores. The ESDM group maintained its rate of growth in adaptive behavior compared with a normative sample of typically developing children. In contrast, over the 2-year span, the comparison group showed greater delays in adaptive behavior. Children who received ESDM also were more likely to experience a change in diagnosis from autism to pervasive developmental disorder, not otherwise specified, than the comparison group. Conclusions: This is the first randomized, controlled trial to demonstrate the efficacy of a comprehensive developmental behavioral intervention for toddlers with ASD for improving cognitive and adaptive behavior and reducing severity of ASD diagnosis. Results of this study underscore the importance of early detection of and intervention in autism.

3. Esch BE, Carr JE, Grow LL. {{Evaluation of an enhanced stimulus-stimulus pairing procedure to increase early vocalizations of children with autism}}. {J Appl Behav Anal};2009 (Summer);42(2):225-241.

Evidence to support stimulus-stimulus pairing (SSP) in speech acquisition is less than robust, calling into question the ability of SSP to reliably establish automatically reinforcing properties of speech and limiting the procedure’s clinical utility for increasing vocalizations. We evaluated the effects of a modified SSP procedure on low-frequency within-session vocalizations that were further strengthened through programmed reinforcement. Procedural modifications (e.g., interspersed paired and unpaired trials) were designed to increase stimulus salience during SSP. All 3 participants, preschoolers with autism, showed differential increases of target over nontarget vocal responses during SSP. Results suggested an automatic reinforcement effect of SSP, although alternative interpretations are discussed, and suggestions are made for future research to determine the utility of SSP as a clinical intervention for speech-delayed children.

4. Hoekstra RA, Happe F, Baron-Cohen S, Ronald A. {{Association between extreme autistic traits and intellectual disability: insights from a general population twin study}}. {Br J Psychiatry};2009 (Dec);195(6):531-536.

BACKGROUND: Autism is associated with intellectual disability. The strength and origin of this association is unclear. AIMS: To investigate the association between extreme autistic traits and intellectual disability in children from a community-based sample and to examine whether the association can be explained by genetic factors. METHOD: Children scoring in the extreme 5% on measures of autistic traits, IQ and academic achievement were selected from 7965 7/8-year-old and 3687 9-year-old twin pairs. Phenotypic associations between extreme autistic traits and intellectual disability were compared with associations among the full-range scores. Genetic correlations were estimated using bivariate DeFries-Fulker extremes analyses. RESULTS: Extreme autistic traits were modestly related to intellectual disability; this association was driven by communication problems characteristic of autism. Although this association was largely explained by genetic factors, the genetic correlation between autistic traits and intellectual disability was only modest. CONCLUSIONS: Extreme autistic traits are substantially genetically independent of intellectual disability.

5. Karsten AM, Carr JE. {{The effects of differential reinforcement of unprompted responding on the skill acquisition of children with autism}}. {J Appl Behav Anal};2009 (Summer);42(2):327-334.

The recommendation to reserve the most potent reinforcers for unprompted responses during acquisition programming has little published empirical support for its purported benefits (e.g., rapid acquisition, decreased errors, and decreased prompt dependence). The purpose of the current investigation was to compare the delivery of high-quality reinforcers exclusively following unprompted responses (differential reinforcement) with the delivery of high-quality reinforcers following both prompted and unprompted responses (nondifferential reinforcement) on the skill acquisition of 2 children with autism. Results indicated that both were effective teaching procedures, although the differential reinforcement procedure was more reliable in producing skill acquisition. These preliminary findings suggest that the differential reinforcement of unprompted responses may be the most appropriate default approach to teaching children with autism.

6. Kenworthy L, Case L, Harms MB, Martin A, Wallace GL. {{Adaptive Behavior Ratings Correlate With Symptomatology and IQ Among Individuals With High-Functioning Autism Spectrum Disorders}}.{ J Autism Dev Disord};2009 (Dec 1)

Caregiver report on the Adaptive Behavior Assessment System-II (ABAS) for 40 high-functioning individuals with Autism Spectrum Disorders (ASD) and 30 typically developing (TD) individuals matched for age, IQ, and sex ratio revealed global adaptive behavior deficits in ASD, with social skills impairments particularly prominent. Within the ASD group, adaptive communication skills were positively related to IQ while global adaptive functioning was negatively associated with autism symptomatology. Autistic behavior ratings related negatively to ABAS scores in the TD but not the ASD group. This investigation demonstrates: the utility of an adaptive functioning checklist for capturing impairments, even in high-functioning individuals with ASD; and that a relationship between social abilities and autism exists independently of intelligence.

7. Kuhn DE, Hardesty SL, Sweeney NM. {{Assessment and treatment of excessive straightening and destructive behavior in an adolescent diagnosed with autism}}. {J Appl Behav Anal};2009 (Summer);42(2):355-360.

Repetitive behaviors such as excessive straightening are commonly observed among individuals with autism. Attempts to prevent these behaviors may increase the likelihood of other problem behaviors. The present study was designed to assess and treat the excessive straightening and associated destructive behaviors of a 16-year-old boy who had been diagnosed with autism and moderate mental retardation. Following a series of functional analyses, an intervention that incorporated functional communication, extinction of destructive behavior, and blocking of repetitive straightening was demonstrated to be effective in reducing straightening and destructive behavior.

8. Kuschner ES, Bodner KE, Minshew NJ. {{Local vs. global approaches to reproducing the Rey Osterrieth complex figure by children, adolescents, and adults with high-functioning autism}}. {Autism Res};2009 (Nov 30)

Individuals with autism have an atypical pattern of visual processing. Various studies have provided evidence that individuals with autism perceive the details of stimuli before the gestalt, the reverse of the typical pattern of visual processing. This study used the Rey Osterreith Complex Figure (ROCF) task and an objective scoring system to examine local/global processing approaches to its reproduction in 37 individuals diagnosed with high-functioning autism (HFA) compared to 49 age-, IQ-, and gender-matched typically developing controls (TD). The sample was divided into children (aged 8-14 years) and adolescents/adults (aged 15-47 years) to assess age effects. Results showed no difference in overall performance on the ROCF between HFA and TD children. TD participants displayed improved organizational and planning skills with age and a shift to global processing approaches, but there were no differences in performance between children and adolescents/adults with HFA. There was no evidence of enhanced local processing in either HFA group. These findings suggest that HFA individuals with average IQ scores do not have the clinically demonstrable evidence of the enhanced local processing thought to reflect increased local brain connectivity in more severely autistic individuals. The deficient global processing of the HFA adults reflects dependence of performance on impaired strategic problem-solving abilities, which has been demonstrated to result from under development of neural connectivity between visuo-spatial and frontal brain regions in HFA adults.

9. Marcus A, Wilder DA. {{A comparison of peer video modeling and self video modeling to teach textual responses in children with autism}}. {J Appl Behav Anal};2009 (Summer);42(2):335-341.

Peer video modeling was compared to self video modeling to teach 3 children with autism to respond appropriately to (i.e., identify or label) novel letters. A combination multiple baseline and multielement design was used to compare the two procedures. Results showed that all 3 participants met the mastery criterion in the self-modeling condition, whereas only 1 of the participants met the mastery criterion in the peer-modeling condition. In addition, the participant who met the mastery criterion in both conditions reached the criterion more quickly in the self-modeling condition. Results are discussed in terms of their implications for teaching new skills to children with autism.

10. Murphy C, Barnes-Holmes D. {{Derived more-less relational mands in children diagnosed with autism}}. {J Appl Behav Anal};2009 (Summer);42(2):253-268.

In Experiment 1, more and less relations were trained for arbitrary Stimuli A1 and A2 with 3 children with autism. The following conditional discriminations were then trained: A1-B1, A2-B2, B1-C1, B2-C2. In subsequent tests, participants showed derived more-less mands (mand with C1 for more and mand with C2 for less). A training procedure reversed the B-C conditional discriminations, and participants then showed derived reversed more-less mands (mand with C1 for less, C2 for more). Baseline B-C relations were retrained, and participants subsequently demonstrated a return to the original derived manding. A second experiment with 1 prior participant and 1 naive participant removed a possible confounding effect. Establishing derived manding may be an advantageous component when teaching a mand repertoire in applied settings.

11. Owen R, Sikich L, Marcus RN, Corey-Lisle P, Manos G, McQuade RD, Carson WH, Findling RL. {{Aripiprazole in the treatment of irritability in children and adolescents with autistic disorder}}. {Pediatrics};2009 (Dec);124(6):1533-1540.

OBJECTIVE: The objective of this study was to evaluate short-term efficacy and safety of aripiprazole in the treatment of irritability in children and adolescents with autistic disorder who were manifesting behaviors such as tantrums, aggression, self-injurious behavior, or a combination of these. METHODS: This 8-week, double-blind, randomized, placebo-controlled, parallel-group study was conducted of children and adolescents (aged 6-17 years) with autistic disorder. Patients were randomly assigned (1:1) to flexibly dosed aripiprazole (target dosage: 5, 10, or 15 mg/day) or placebo. Efficacy outcome measures included the Aberrant Behavior Checklist irritability subscale and the Clinical Global Impression-Improvement score (CGI-I). Safety and tolerability were also assessed. RESULTS: Ninety-eight patients were randomly assigned to receive placebo (n = 51) or aripiprazole (n = 47). Mean improvement in Aberrant Behavior Checklist irritability subscale score was significantly greater with aripiprazole than with placebo from week 1 through week 8. Aripiprazole demonstrated significantly greater global improvements than placebo, as assessed by the mean CGI-I score from week 1 through week 8; however, clinically significant residual symptoms may still persist for some patients. Discontinuation rates as a result of adverse events (AEs) were 10.6% for aripiprazole and 5.9% for placebo. Extrapyramidal symptom-related AE rates were 14.9% for aripiprazole and 8.0% for placebo. No serious AEs were reported. Mean weight gain was 2.0 kg on aripiprazole and 0.8 kg on placebo at week 8. CONCLUSIONS: Aripiprazole was efficacious in children and adolescents with irritability associated with autistic disorder and was generally safe and well tolerated.

12. Rhine D, Tarbox J. {{Chewing gum as a treatment for rumination in a child with autism}}. {J Appl Behav Anal};2009 (Summer);42(2):381-385.

Rumination involves regurgitation of previously ingested food, rechewing the food, and reswallowing it. In the current study, a child with autism displayed chronic rumination, resulting in the decay and subsequent removal of several teeth. After several treatments failed, including thickened liquids and starch satiation, the participant was taught to chew gum. His rumination decreased significantly when gum was made available. Results suggest that access to chewing gum may be an effective treatment for rumination in some individuals.

13. Sawyer MG, Bittman M, La Greca AM, Crettenden AD, Harchak TF, Martin J. {{Time Demands of Caring for Children with Autism: What are the Implications for Maternal Mental Health?}} {J Autism Dev Disord};2009 (Dec 1)

This study examined the relationship between maternal mental health problems and both caregiving time and experience of time pressure for 216 mothers of children with autism. Data describing caregiving time was obtained using 24-h time-diaries. Standard questionnaires were used to assess time pressure, social support, children’s emotional and behavioural problems, and maternal mental health problems. After adjusting for the effect of children’s age, maternal social support, and children’s behaviour problems, time pressure but not hours of caregiving, had a significant positive relationship with maternal mental health problems. Findings suggest that the quality of home-based care for children with autism may be adversely affected if time pressure experienced by caregivers compromises their mental health and well being.

14. Tiger JH, Fisher WW, Bouxsein KJ. {{Therapist- and self-monitored dro contingencies as a treatment for the self-injurious skin picking of a young man with asperger syndrome}}. {J Appl Behav Anal};2009 (Summer);42(2):315-319.

The use of differential reinforcement of other behavior (DRO) has decreased, at least partially due to the development of less effortful alternative behavioral interventions (e.g., noncontingent reinforcement; Vollmer, Iwata, Zarcone, Smith, & Mazaleski, 1993). The effort associated with DRO contingencies may be lessened by incorporating self-monitoring components in which clients are responsible for the delivery of reinforcers for their own behavior. The current study evaluates the effectiveness of DRO in the treatment of self-injury when implemented first by the therapist and subsequently by the client.

15. Whelan PJ. James {{Joyce and Asperger syndrome}}. {Br J Psychiatry};2009 (Dec);195(6):555-556.

16. Zafeiriou DI, Ververi A, Vargiami E. {{The serotonergic system: its role in pathogenesis and early developmental treatment of autism}}. {Curr Neuropharmacol};2009 (Jun);7(2):150-157.

Autism is a severe childhood disorder already presenting in the first 3 years of life and, therefore, strongly correlated with neurodevelopmental alterations in prenatal, as well as postnatal period. Neurotransmitters hold a pivotal role in development by providing the stimulation needed for synapses and neuronal networks to be formed during the critical period of neuroplasticity. Aberrations of the serotonergic system modify key processes in the developing brain and are strongly implicated in the pathophysiology of developmental disorders. Evidence for the role of serotonin in autism emerges from neuropathological, imaging and genetic studies. Due to its developmental arrest, autism requires early intervention that would, among others, target the disrupted serotonergic system and utilize brain plasticity to elicit clinically important brain changes in children.