Pubmed du 15/08/14

Pubmed du jour

2014-08-15 12:03:50

1. Barbosa MR, Fernandes FD. {{Comparing the results of DAADD and ABC of children included in Autism Spectrum Disorders}}. {Codas}. 2014; 26(3): 208-12.

PURPOSE: To verify if there are characteristic behaviors of the different diagnosis included in the autism spectrum according to the Differential Assessment of Autism and Other Developmental Disorders (DAADD) and to the Autism Behavior Checklist (ABC). METHOD: Participants were 45 individuals and their respective speech-language therapists. All therapists are graduate students working with the children for at least 1 year. This time was considered sufficient to the therapists to have the information required by the DAADD questionnaire. It is comprised by 3 protocols specifically designed to children with 2 to 4 years, 4 to 6 years and 6 to 8 years, the same criteria used to separate the research groups, G1, G2 and G3, respectively. Data referring to the ABC were retrieved from the subject’s files at the Laboratorio de Investigacao Fonoaudiologica nos Disturbios do Espectro do Autismo (Research Laboratory on Language Disorders in the Autism Spectrum) of the School of Medicine, Universidade de Sao Paulo, where it is routinely applied during the annual assessment. RESULTS: Answers to the different areas of DAADD are similar to the different areas of ABC. These data show data the diagnosis by DAADD is easier in older children. Although there is no significant difference, the large occurrence of Rett’s syndrome diagnosis according to the DAADD was associated to higher risk for autism according to the ABC in G1. With increasing age this tendency decreases and either in G2 and G3 Autism is the most frequent diagnosis. CONCLUSION: Although the results of both questionnaires tend to agree more with increasing age, the DAADD is more sensitive in the different ages while the ABC if more specific only to older children.

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2. Duda M, Kosmicki JA, Wall DP. {{Testing the accuracy of an observation-based classifier for rapid detection of autism risk}}. {Transl Psychiatry}. 2014; 4: e424.

Current approaches for diagnosing autism have high diagnostic validity but are time consuming and can contribute to delays in arriving at an official diagnosis. In a pilot study, we used machine learning to derive a classifier that represented a 72% reduction in length from the gold-standard Autism Diagnostic Observation Schedule-Generic (ADOS-G), while retaining >97% statistical accuracy. The pilot study focused on a relatively small sample of children with and without autism. The present study sought to further test the accuracy of the classifier (termed the observation-based classifier (OBC)) on an independent sample of 2616 children scored using ADOS from five data repositories and including both spectrum (n=2333) and non-spectrum (n=283) individuals. We tested OBC outcomes against the outcomes provided by the original and current ADOS algorithms, the best estimate clinical diagnosis, and the comparison score severity metric associated with ADOS-2. The OBC was significantly correlated with the ADOS-G (r=-0.814) and ADOS-2 (r=-0.779) and exhibited >97% sensitivity and >77% specificity in comparison to both ADOS algorithm scores. The correspondence to the best estimate clinical diagnosis was also high (accuracy=96.8%), with sensitivity of 97.1% and specificity of 83.3%. The correlation between the OBC score and the comparison score was significant (r=-0.628), suggesting that the OBC provides both a classification as well as a measure of severity of the phenotype. These results further demonstrate the accuracy of the OBC and suggest that reductions in the process of detecting and monitoring autism are possible.

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3. Elsabbagh M, Yusuf A, Prasanna S, Shikako-Thomas K, Ruff CA, Fehlings MG. {{Community engagement and knowledge translation: Progress and challenge in autism research}}. {Autism}. 2014.

The last decade has seen significant growth in scientific understanding and public awareness of autism. There is still a long road ahead before this awareness can be matched with parallel improvements in evidence-based practice. The process of translating evidence into community care has been hampered by the seeming disconnect between the mainstream scientific research agenda and the immediate priorities of many communities. The need for community engagement in the process of translating knowledge into impact has been recognized. However, there remains little consensus or empirical data regarding the process of such engagement and how to measure its impact. We shed light on a number of engagement models and tools, previously advocated in health research, as they apply to autism research. Furthermore, we illustrate the utility of such tools in supporting identification of knowledge gaps and priorities, using two community-based case studies. The case studies illustrate that information generated from research is indeed relevant and critical for knowledge users in the community. Simple and systematic methods can support the translation and uptake of knowledge in diverse communities, therefore enhancing engagement with research and bridging research findings with immediate community needs.

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4. Filliter JH, Longard J, Lawrence MA, Zwaigenbaum L, Brian J, Garon N, Smith IM, Roncadin C, Roberts W, Bryson SE. {{Positive Affect in Infant Siblings of Children Diagnosed with Autism Spectrum Disorder}}. {J Abnorm Child Psychol}. 2014.

Research on the expression of positive affect in young children with Autism Spectrum Disorder (ASD) suggests that differences in this domain emerge late in the first year or early in the second year. However, many previous studies in this area employed retrospective research methods and global rating schemes. In the current study, the expression of positive affect was examined prospectively at ages 6, 12, and 18 months in three groups: infant siblings with ASD, infant siblings without ASD, and low-risk comparison infants. Infant siblings were the younger brothers or sisters of children diagnosed with ASD and, therefore, had a higher familial risk of ASD. The frequency and duration of smiles were coded from video excerpts from the Autism Observation Scale for Infants (Bryson, Zwaigenbaum, McDermott, Rombough, and Brian 2008), a standardized, play-based assessment of early signs of ASD. Results indicated that at 12 months, infant siblings with ASD had a lower rate of smiling than the other two groups. At 18 months, infant siblings with ASD continued to display a lower rate of smiling than infant siblings without ASD, but not comparison infants. Overall, these results indicate that infant siblings with ASD demonstrate less positive affect than infant siblings without ASD and low-risk comparison infants at 12 months. This suggests that reduced smiling may be an informative behavioural risk marker for ASD by children’s first birthdays and may have implications for our understanding of atypical social development in children with ASD.

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5. Foti F, De Crescenzo F, Vivanti G, Menghini D, Vicari S. {{Implicit learning in individuals with autism spectrum disorders: a meta-analysis}}. {Psychol Med}. 2014: 1-14.

BACKGROUND: Individuals with autism spectrum disorders (ASDs) are characterized by social communication difficulties and behavioural rigidity. Difficulties in learning from others are one of the most devastating features of this group of conditions. Nevertheless, the nature of learning difficulties in ASDs is still unclear. Given the relevance of implicit learning for social and communicative functioning, a link has been hypothesized between ASDs and implicit learning deficit. However, studies that have employed formal testing of implicit learning in ASDs provided mixed results. METHOD: We undertook a systematic search of studies that examined implicit learning in ASDs using serial reaction time (SRT), alternating serial reaction time (ASRT), pursuit rotor (PR), and contextual cueing (CC) tasks, and synthesized the data using meta-analysis. A total of 11 studies were identified, representing data from 407 individuals with ASDs and typically developing comparison participants. RESULTS: The results indicate that individuals with ASDs do not differ in any task considered [SRT and ASRT task: standardized mean difference (SMD) -0.18, 95% confidence interval (CI) -0.71 to 0.36; PR task: SMD -0.34, 95% CI -1.04 to 0.36; CC task: SMD 0.27, 95% CI -0.07 to 0.60]. CONCLUSIONS: Based on our synthesis of the existing literature, we conclude that individuals with ASDs can learn implicitly, supporting the hypothesis that implicit learning deficits do not represent a core feature in ASDs.

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6. Ju A, Hammerschmidt K, Tantra M, Krueger D, Brose N, Ehrenreich H. {{Juvenile manifestation of ultrasound communication deficits in the neuroligin-4 null mutant mouse model of autism}}. {Behav Brain Res}. 2014; 270: 159-64.

Neuroligin-4 (Nlgn4) is a member of the neuroligin family of postsynaptic cell adhesion molecules. Loss-of-function mutations of NLGN4 are among the most frequent, known genetic causes of heritable autism. Adult Nlgn4 null mutant (Nlgn4(-/-)) mice are a construct valid model of human autism, with both genders displaying a remarkable autistic phenotype, including deficits in social interaction and communication as well as restricted and repetitive behaviors. In contrast to adults, autism-related abnormalities in neonatal and juvenile Nlgn4(-/-) mice have not been reported yet. The present study has been designed to systematically investigate in male and female Nlgn4(-/-) pups versus wildtype littermates (WT, Nlgn4(+/+)) developmental milestones and stimulus-induced ultrasound vocalization (USV). Neonatal development, followed daily from postnatal days (PND) 4 to 21, including physical development, neurological reflexes and neuromotor coordination, did not yield any differences between Nlgn4(-/-) and their WT littermates. USV in pups (PND8-9) in response to brief separation from their mothers revealed remarkable gender effects, and a genotype influence in females regarding latency to first call. In juveniles (PND22-23), USV monitoring upon exposure to an anesthetized female intruder mouse uncovered a clear genotype effect with reduced USV in Nlgn4(-/-) mice, and again a more prominent phenotype in females. Together, these data support an early manifestation of communication deficits in Nlgn4(-/-) mice that appear more pronounced in immature females with their overall stronger USV as compared to males.

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7. Key AP, Ibanez LV, Henderson HA, Warren Z, Messinger DS, Stone WL. {{Erratum to: Positive Affect Processing and Joint Attention in Infants at High Risk for Autism: An Exploratory Study}}. {J Autism Dev Disord}. 2014.

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8. Kumazaki H, Watanabe K, Imasaka Y, Iwata K, Tomoda A, Mimura M. {{Risperidone-Associated Urinary Incontinence in Patients With Autistic Disorder With Mental Retardation}}. {J Clin Psychopharmacol}. 2014.

We report several cases in which patients with autistic disorder with mental retardation who received risperidone experienced urinary incontinence. We retrospectively investigated the medical records of patients housed in facilities for patients with autistic disorder with mental retardation. Those who had undergone a medical examination at a hospital in Tokyo from April 1999 to March 2009 were included in the study.Retrospective data were gathered including age, sex, IQ, birth weight, dosage of risperidone, urinary density, as well as existence of urinary and fecal incontinence. We divided the participants into those who did and did not experience urinary incontinence after taking risperidone and compared the 2 groups. Risperidone had been prescribed to 35 patients. In spite of the fact that no patient had a history of urinary incontinence, 14 patients experienced urinary incontinence after receiving risperidone. Moreover, 4 of these 14 patients also had fecal incontinence. Among the variables we examined, the only significant difference between groups was in sex, with significantly more women experiencing incontinence compared with men. When the dose of risperidone was reduced or the patients switched to other drugs, urinary incontinence of the patients improved.Hence, risperidone may have a casual relationship with urinary incontinence. Further research is needed to understand the pathophysiology of possible effect.

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9. Latham GJ, Coppinger J, Hadd AG, Nolin SL. {{The role of AGG interruptions in fragile X repeat expansions: a twenty-year perspective}}. {Front Genet}. 2014; 5: 244.

In 1994, it was suggested that AGG interruptions affect the stability of the fragile X triplet repeat. Until recently, however, this hypothesis was not explored on a large scale due primarily to the technical difficulty of determining AGG interruption patterns of the two alleles in females. The recent development of a PCR technology that overcomes this difficulty and accurately identifies the number and position of AGGs has led to several studies that examine their influence on repeat stability. Here, we present a historical perspective of relevant studies published during the last 20 years on AGG interruptions and examine those recent publications that have refined risk estimates for repeat instability and full-mutation expansions.

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10. Lowenthal R, Zaqueu L, Rohde LA, Mari J, Paula CS. {{Developmental disability in schoolchildren from four Brazilian regions}}. {Rev Bras Psiquiatr}. 2014; 36(3): 273.

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11. Martin BS, Corbin JG, Huntsman MM. {{Deficient tonic GABAergic conductance and synaptic balance in the fragile X syndrome amygdala}}. {J Neurophysiol}. 2014; 112(4): 890-902.

Fragile X syndrome (FXS) is the leading cause of inherited intellectual disability. Comorbidities of FXS such as autism are increasingly linked to imbalances in excitation and inhibition (E/I) as well as dysfunction in GABAergic transmission in a number of brain regions including the amygdala. However, the link between E/I imbalance and GABAergic transmission deficits in the FXS amygdala is poorly understood. Here we reveal that normal tonic GABAA receptor-mediated neurotransmission in principal neurons (PNs) of the basolateral amygdala (BLA) is comprised of both delta- and alpha5-subunit-containing GABAA receptors. Furthermore, tonic GABAergic capacity is reduced in these neurons in the Fmr1 knockout (KO) mouse model of FXS (1.5-fold total, 3-fold delta-subunit, and 2-fold alpha5-subunit mediated) as indicated by application of gabazine (50 muM), 4,5,6,7-tetrahydroisoxazolo[5,4-c]pyridin-3-ol (THIP, 1 muM), and alpha5ia (1.5 muM) in whole cell patch-clamp recordings. Moreover, alpha5-containing tonic GABAA receptors appear to preferentially modulate nonsomatic compartments of BLA PNs. Examination of evoked feedforward synaptic transmission in these cells surprisingly revealed no differences in overall synaptic conductance or E/I balance between wild-type (WT) and Fmr1 KO mice. Instead, we observed altered feedforward kinetics in Fmr1 KO PNs that supports a subtle yet significant decrease in E/I balance at the peak of excitatory conductance. Blockade of alpha5-subunit-containing GABAA receptors replicated this condition in WT PNs. Therefore, our data suggest that tonic GABAA receptor-mediated neurotransmission can modulate synaptic E/I balance and timing established by feedforward inhibition and thus may represent a therapeutic target to enhance amygdala function in FXS.

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12. Matthews NL, Pollard E, Ober-Reynolds S, Kirwan J, Malligo A, Smith CJ. {{Revisiting Cognitive and Adaptive Functioning in Children and Adolescents with Autism Spectrum Disorder}}. {J Autism Dev Disord}. 2014.

Profiles of performance on the Stanford Binet Intelligence Scales (SB5) and Vineland Adaptive Behavior Scales (VABS) were examined in 73 children and adolescents with autism spectrum disorder. SB5 cognitive profiles were observed to be similar between participants with and without early language delay, but different between participants with and without intellectual disability. With few exceptions, the distribution and cognitive profiles of participants with specific nonverbal IQ-verbal IQ and abbreviated IQ-full scale IQ discrepancy patterns paralleled previous reports. A cognitive functioning advantage over adaptive functioning was observed to be strongest in participants without intellectual disability and older participants. The previously reported VABS « autism profile » was not observed. Current findings clarify previous research and will inform the diagnostic process and treatment planning.

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13. Meilleur AA, Berthiaume C, Bertone A, Mottron L. {{Autism-Specific Covariation in Perceptual Performances: « g » or « p » Factor?}}. {PLoS One}. 2014; 9(8): e103781.

BACKGROUND: Autistic perception is characterized by atypical and sometimes exceptional performance in several low- (e.g., discrimination) and mid-level (e.g., pattern matching) tasks in both visual and auditory domains. A factor that specifically affects perceptive abilities in autistic individuals should manifest as an autism-specific association between perceptual tasks. The first purpose of this study was to explore how perceptual performances are associated within or across processing levels and/or modalities. The second purpose was to determine if general intelligence, the major factor that accounts for covariation in task performances in non-autistic individuals, equally controls perceptual abilities in autistic individuals. METHODS: We asked 46 autistic individuals and 46 typically developing controls to perform four tasks measuring low- or mid-level visual or auditory processing. Intelligence was measured with the Wechsler’s Intelligence Scale (FSIQ) and Raven Progressive Matrices (RPM). We conducted linear regression models to compare task performances between groups and patterns of covariation between tasks. The addition of either Wechsler’s FSIQ or RPM in the regression models controlled for the effects of intelligence. RESULTS: In typically developing individuals, most perceptual tasks were associated with intelligence measured either by RPM or Wechsler FSIQ. The residual covariation between unimodal tasks, i.e. covariation not explained by intelligence, could be explained by a modality-specific factor. In the autistic group, residual covariation revealed the presence of a plurimodal factor specific to autism. CONCLUSIONS: Autistic individuals show exceptional performance in some perceptual tasks. Here, we demonstrate the existence of specific, plurimodal covariation that does not dependent on general intelligence (or « g » factor). Instead, this residual covariation is accounted for by a common perceptual process (or « p » factor), which may drive perceptual abilities differently in autistic and non-autistic individuals.

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14. Patten E, Belardi K, Baranek GT, Watson LR, Labban JD, Oller DK. {{Erratum to: Vocal Patterns in Infants with Autism Spectrum Disorder: Canonical Babbling Status and Vocalization Frequency}}. {J Autism Dev Disord}. 2014.

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15. Pollard JS, Higbee TS, Akers JS, Brodhead MT. {{An evaluation of interactive computer training to teach instructors to implement discrete trials with children with autism}}. {J Appl Behav Anal}. 2014.

Discrete-trial instruction (DTI) is a teaching strategy that is often incorporated into early intensive behavioral interventions for children with autism. Researchers have investigated time- and cost-effective methods to train staff to implement DTI, including self-instruction manuals, video modeling, and interactive computer training (ICT). ICT combines the best components of self-instruction manuals and video models, and have the same benefits; however, there is limited research on this training method. Therefore, the purpose of this study was to investigate ICT to teach university students to implement DTI with children with autism. All participants’ teaching fidelity increased during both role-plays with an adult and instructional sessions with a child with autism. In addition, participants demonstrated an increase in teaching fidelity with untrained instructional programs. All participants were able to complete training in an average of 2 hr, and social validity ratings were high.

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16. Pragnya B, Kameshwari JS, Veeresh B. {{Ameliorating effect of piperine on behavioral abnormalities and oxidative markers in sodium valproate induced autism in BALB/C mice}}. {Behav Brain Res}. 2014; 270: 86-94.

Post natal exposure to VPA (valproic acid) in mice induces behavioral deficits, abnormal sensitivity to sensory stimuli and self-injurious behavior, observed in autism. Piperine has been reported to have protective effect on brain. The present study aimed at evaluating effect of piperine on VPA induced neurobehavioral and biochemical alterations in BALB/c mice. Young BALB/c mice 13 days old were procured from five different litters and segregated into five groups (n=6; 3 male, 3 female) i.e., Group I served as control group, received physiological saline on PND (Post natal day) 14 & Tween 80 p.o. from PND13-40. Group II served as normal treated group and received piperine (20mg/kg p.o.) from PND 13-40 and saline s.c. on PND 14. Group III served as valproate treated group received VPA (400mg/kg s.c.) on PND 14 and Tween 80 p.o. from PND 13-40. Group IV & V served as disease treated group received VPA (400mg/kg s.c.) on PND 14 & piperine (5 & 20mg/kg p.o.) from PND 13-40 respectively. BALB/c mice pups were subjected to behavioral testing to assess motor skill development, nociceptive response, locomotion, anxiety, and cognition on various postnatal days up to PND 40. At the end of behavioral evaluation, mice were sacrificed; brain was isolated for biochemical estimations (serotonin, glutathione, MDA and nitric oxide) and histopathological examination. Our study revealed that treatment with piperine significantly improved behavioral alterations, lowered oxidative stress markers, and restored histoarchitecture of cerebellum. This ameliorating effect of piperine is attributed to its anti-oxidant activity, cognition enhancing and neuroprotective activity.

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17. Ray S, Miller M, Karalunas S, Robertson C, Grayson DS, Cary RP, Hawkey E, Painter JG, Kriz D, Fombonne E, Nigg JT, Fair DA. {{Structural and functional connectivity of the human brain in autism spectrum disorders and attention-deficit/hyperactivity disorder: A rich club-organization study}}. {Hum Brain Mapp}. 2014.

Attention-deficit/hyperactive disorder (ADHD) and autism spectrum disorders (ASD) are two of the most common and vexing neurodevelopmental disorders among children. Although the two disorders share many behavioral and neuropsychological characteristics, most MRI studies examine only one of the disorders at a time. Using graph theory combined with structural and functional connectivity, we examined the large-scale network organization among three groups of children: a group with ADHD (8-12 years, n = 20), a group with ASD (7-13 years, n = 16), and typically developing controls (TD) (8-12 years, n = 20). We apply the concept of the rich-club organization, whereby central, highly connected hub regions are also highly connected to themselves. We examine the brain into two different network domains: (1) inside a rich-club network phenomena and (2) outside a rich-club network phenomena. The ASD and ADHD groups had markedly different patterns of rich club and non rich-club connections in both functional and structural data. The ASD group exhibited higher connectivity in structural and functional networks but only inside the rich-club networks. These findings were replicated using the autism brain imaging data exchange dataset with ASD (n = 85) and TD (n = 101). The ADHD group exhibited a lower generalized fractional anisotropy and functional connectivity inside the rich-club networks, but a higher number of axonal fibers and correlation coefficient values outside the rich club. Despite some shared biological features and frequent comorbity, these data suggest ADHD and ASD exhibit distinct large-scale connectivity patterns in middle childhood. Hum Brain Mapp, 2014. (c) 2014 Wiley Periodicals, Inc.

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18. Razavi M, Fathi M, Savabi O, Vashaee D, Tayebi L. {{Improvement of Biodegradability, Bioactivity, Mechanical Integrity and Cytocompatibility Behavior of Biodegradable Mg Based Orthopedic Implants Using Nanostructured Bredigite (CaMgSi O ) Bioceramic Coated via ASD/EPD Technique}}. {Ann Biomed Eng}. 2014.

This research explored the influence of surface modification of AZ91 Mg alloy on the biodegradation, bioactivity, mechanical integrity and cytocompatibility of the alloy. For this purpose, a nanostructured bredigite (Ca7MgSi4O16) ceramic coating was prepared on biodegradable AZ91 Mg alloy through anodic spark deposition and electrophoretic deposition method. The phase composition and surface morphology of the coated alloy were characterized by X-ray diffraction, scanning electron microscope and transmission electron microscope. The properties of samples were investigated by electrochemical measurements, immersion test, compression examination and cell culturing. The results showed that the degradation resistance, bioactivity, mechanical integrity and cytocompatibility of biodegradable Mg alloy were improved by the anodic spark deposition and electrophorretic deposition of the nanostructured bredigite coating. Therefore, the nanostructured bredigite ceramic coating is identified as a good coating for AZ91 Mg alloy for the purpose of making biodegradable metallic orthopedic implants.

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19. Segatto M, Trapani L, Di Tunno I, Sticozzi C, Valacchi G, Hayek J, Pallottini V. {{Cholesterol metabolism is altered in rett syndrome: a study on plasma and primary cultured fibroblasts derived from patients}}. {PLoS One}. 2014; 9(8): e104834.

Rett (RTT) syndrome is a severe neurological disorder that affects almost exclusively females. Several detectable mutations in the X-linked methyl-CpG-binding protein 2 gene (MECP2) are responsible for the onset of the disease. MeCP2 is a key transcription regulator involved in gene silencing via methylation-dependent remodeling of chromatin. Recent data highlight that lipid metabolism is perturbed in brains and livers of MECP2-null male mice. In addition, altered plasma lipid profile in RTT patients has been observed. Thus, the aim of the work is to investigate the protein network involved in cholesterol homeostasis maintenance on freshly isolated fibroblasts and plasma from both RTT and healthy donors. To this end, protein expression of 3-hydroxy-3methyl glutaryl Coenzyme A reductase (HMGR), sterol regulatory element binding proteins (SREBPs), low density lipoprotein receptor (LDLr) and scavenger receptor B-1 (SRB-1) was assessed in cultured skin fibroblasts from unaffected individuals and RTT patients. In addition, lipid profile and the abundance of proprotein convertase subtilisin/kexin type 9 (PCSK9) were analyzed on plasma samples. The obtained results demonstrate that the main proteins belonging to cholesterol regulatory network are altered in RTT female patients, providing the proof of principle that cholesterol metabolism may be taken into account as a new target for the treatment of specific features of RTT pathology.

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20. Stasolla F, Damiani R, Perilli V, Di Leone A, Albano V, Stella A, Damato C. {{Technological supports to promote choice opportunities by two children with fragile X syndrome and severe to profound developmental disabilities}}. {Res Dev Disabil}. 2014; 35(11): 2993-3000.

This study was aimed at assessing whether technological supports (i.e. optic sensors such as photocells) were successful enabling two boys with fragile X syndrome and severe to profound developmental disabilities to perform occupation and choice opportunities. A second goal of the study was to reduce stereotyped behaviours (i.e. hand mouthing and eye poking) exhibited by the participants. Finally, the third purpose of the study was to verify the rehabilitative effects of the intervention program on the indices of happiness of the participants. The study has been conducted according to a non-concurrent multiple baseline design across participants followed by intervention and cross over phases, where the associations between behavioural responses and environmental consequences were systematically inverted. Moreover, a maintenance phase was assessed. The results demonstrated that the technology is useful to facilitate employment and opportunities of choice, showing a growth of the indices of happiness and a decrease of stereotyped behaviours, from both participants involved. Clinical, practical and psychological implications of the findings are discussed.

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21. Ye AX, Leung RC, Schafer CB, Taylor MJ, Doesburg SM. {{Atypical resting synchrony in autism spectrum disorder}}. {Hum Brain Mapp}. 2014.

Autism spectrum disorder (ASD) is increasingly understood to be associated with aberrant functional brain connectivity. Few studies, however, have described such atypical neural synchrony among specific brain regions. Here, we used magnetoencephalography (MEG) to characterize alterations in functional connectivity in adolescents with ASD through source space analysis of phase synchrony. Resting-state MEG data were collected from 16 adolescents with ASD and 15 age- and sex-matched typically developing (TD) adolescents. Atlas-guided reconstruction of neural activity at various cortical and subcortical regions was performed and inter-regional phase synchrony was calculated in physiologically relevant frequency bands. Using a multilevel approach, we characterized atypical resting-state synchrony within specific anatomically defined networks as well as altered network topologies at both regional and whole-network scales. Adolescents with ASD demonstrated frequency-dependent alterations in inter-regional functional connectivity. Hyperconnectivity was observed among the frontal, temporal, and subcortical regions in beta and gamma frequency ranges. In contrast, parietal and occipital regions were hypoconnected to widespread brain regions in theta and alpha bands in ASD. Furthermore, we isolated a hyperconnected network in the gamma band in adolescents with ASD which encompassed orbitofrontal, subcortical, and temporal regions implicated in social cognition. Results from graph analyses confirmed that frequency-dependent alterations of network topologies exist at both global and local levels. We present the first source-space investigation of oscillatory phase synchrony in resting-state MEG in ASD. This work provides evidence of atypical connectivity at physiologically relevant time scales and indicates that alterations of functional connectivity in adolescents with ASD are frequency dependent and region dependent. Hum Brain Mapp, 2014. (c) 2014 Wiley Periodicals, Inc.

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