1. Arvidsson O, Gillberg C, Lichtenstein P, Lundstrom S. {{Secular changes in the symptom level of clinically diagnosed autism}}. {J Child Psychol Psychiatry}. 2018.
BACKGROUND: The prevalence of autism has been reported to have increased worldwide. A decrease over time in the number of autism symptoms required for a clinical autism diagnosis would partly help explain this increase. This study aimed to determine whether the symptom level of clinically diagnosed autism cases below age 13 had changed over time. METHODS: Parents of Swedish 9-year old twins (n = 28,118) participated in a telephone survey, in which symptoms and dysfunction/suffering related to neurodevelopmental disorders [including autism, but also attention-deficit/hyperactivity disorder (ADHD), Developmental Coordination Disorder (DCD), and Learning Disabilities (LD)] in their children were assessed over a 10-year period. Survey data was merged with the National Patient Register containing clinically registered autism diagnoses (n = 271). RESULTS: In individuals who had been clinically diagnosed with autism before the age of 13, the symptom score for autism decreased on average 30% over more than a decade in birth cohorts 1992-2002. There was an average decrease of 50% in the autism symptom score from 2004 to 2014 in individuals who were diagnosed with autism at ages 7-12, but there was no decrease in those diagnosed at ages 0-6. CONCLUSIONS: Over time, considerably fewer autism symptoms seemed to be required for a clinical diagnosis of autism, at least for those diagnosed after the preschool years. The findings add support for the notion that the observed increase in autism diagnoses is, at least partly, the by-product of changes in clinical practice, and flag up the need for working in agreement with best practice guidelines.
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2. Berg EL, Copping NA, Rivera JK, Pride MC, Careaga M, Bauman MD, Berman RF, Lein PJ, Harony-Nicolas H, Buxbaum JD, Ellegood J, Lerch JP, Wohr M, Silverman JL. {{Developmental social communication deficits in the Shank3 rat model of phelan-mcdermid syndrome and autism spectrum disorder}}. {Autism Res}. 2018.
Mutations in the SHANK3 gene have been discovered in autism spectrum disorder (ASD), and the intellectual disability, Phelan-McDermid Syndrome. This study leveraged a new rat model of Shank3 deficiency to assess complex behavioral phenomena, unique to rats, which display a richer social behavior repertoire than mice. Uniquely detectable emissions of ultrasonic vocalizations (USV) in rats serve as situation-dependent affective signals and accomplish important communicative functions. We report, for the first time, a call and response acoustic playback assay of bidirectional social communication in juvenile Shank3 rats. Interestingly, we found that Shank3-deficient null males did not demonstrate the enhanced social approach behavior typically exhibited following playback of pro-social USV. Concomitantly, we discovered that emission of USV in response to playback was not genotype-dependent and emitted response calls were divergent in meaning. This is the first report of these socially relevant responses using a genetic model of ASD. A comprehensive and empirical analysis of vigorous play during juvenile reciprocal social interactions further revealed fewer bouts and reduced durations of time spent playing by multiple key parameters, including reduced anogenital sniffing and allogrooming. We further discovered that male null Shank3-deficient pups emitted fewer isolation-induced USV than Shank3 wildtype controls. Postnatal whole brain anatomical phenotyping was applied to visualize anatomical substrates that underlie developmental phenotypes. The data presented here lend support for the important role of Shank3 in social communication, the core symptom domain of ASD. By increasing the number of in vivo functional outcome measures, we improved the likelihood for identifying and moving forward with medical interventions. Autism Res 2018. (c) 2018 International Society for Autism Research, Wiley Periodicals, Inc. LAY SUMMARY: Clinically relevant outcomes are required to demonstrate the utility of therapeutics. We introduce findings in a rat model, and assess the impact of mutations in Shank3, an autism risk gene. We found that males with deficient expression of Shank3 did not demonstrate typical responses in a bi-directional social communication test and that social interaction was lower on key parameters. Outcome measures reported herein extend earlier results in mice and capture responses to acoustic calls, which is analogous to measuring receptive and expressive communication.
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3. Brandes-Aitken A, Anguera JA, Rolle CE, Desai SS, Demopoulos C, Skinner SN, Gazzaley A, Marco EJ. {{Characterizing cognitive and visuomotor control in children with sensory processing dysfunction and autism spectrum disorders}}. {Neuropsychology}. 2018; 32(2): 148-60.
OBJECTIVE: Children with autism spectrum disorders (ASD) and sensory processing dysfunction (SPD) are reported to show difficulties involving cognitive and visuomotor control. We sought to determine whether performance on computerized, behavioral measures of cognitive control aimed at assessing selective attention, as well as visuomotor abilities differentiated children with ASD (n = 14), SPD (n = 14) and typically developing controls (TDC; n = 28). METHOD: Cognitive control differences were measured by assessing selective attention-based abilities both with and without distracting stimuli, and visuomotor differences were measured by characterizing visuomotor tracking and tracing skills. Performance in cognitive control and visuomotor domains were investigated globally as composite scores, and specifically within each task. RESULTS: Our results indicated that though the ASD group showed the most impaired selective attention performance, the SPD group had intermediate abilities-performing above the ASD group but below the TDC group. Furthermore, both the SPD and ASD groups demonstrated equally impaired visuomotor abilities relative to the TDC group. A correlational analysis between cognitive and visuomotor control suggest a relationship between these overlapping control networks. CONCLUSIONS: This study supports the importance of direct, phenotypic characterizations of control-based abilities in children with ASD and SPD to personalize characterization and treatment interventions for at-risk children. (PsycINFO Database Record
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4. Hendry A, Jones EJH, Bedford R, Gliga T, Charman T, Johnson MH. {{Developmental change in look durations predicts later effortful control in toddlers at familial risk for ASD}}. {J Neurodev Disord}. 2018; 10(1): 3.
BACKGROUND: Difficulties with executive functioning (EF) are common in individuals with a range of developmental disorders, including autism spectrum disorder (ASD). Interventions that target underlying mechanisms of EF early in development could be broadly beneficial, but require infant markers of such mechanisms in order to be feasible. Prospective studies of infants at high familial risk (HR) for ASD have revealed a surprising tendency for HR toddlers to show longer epochs of attention to faces than low-risk (LR) controls. In typical development, decreases in look durations towards the end of the first year of life are driven by the development of executive attention-a foundational component of EF. Here, we test the hypothesis that prolonged attention to visual stimuli (including faces) in HR toddlers reflects early differences in the development of executive attention. METHODS: In a longitudinal prospective study, we used eye-tracking to record HR and LR infants’ looking behaviour to social and non-social visual stimuli at ages 9 and 15 months. At age 3 years, we assessed children with a battery of clinical research measures and collected parental report of effortful control (EC)-a temperament trait closely associated with EF and similarly contingent on executive attention. RESULTS: Consistent with previous studies, we found an attenuated reduction in peak look durations to faces between 9 and 15 months for the HR group compared with the LR group, and lower EC amongst the HR-ASD group. In line with our hypothesis, change in peak look duration to faces between 9 and 15 months was negatively associated with EC at age 3. CONCLUSIONS: We suggest that for HR toddlers, disruption to the early development of executive attention results in an attenuated reduction in looking time to faces. Effects may be more apparent for faces due to early biases to orient towards them; further, attention difficulties may interact with earlier emerging differences in social information processing. Our finding that prolonged attention to faces may be an early indicator of disruption to the executive attention system is of potential value in screening for infants at risk for later EF difficulties and for evaluation of intervention outcomes.
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5. Knoth IS, Lajnef T, Rigoulot S, Lacourse K, Vannasing P, Michaud JL, Jacquemont S, Major P, Jerbi K, Lippe S. {{Auditory repetition suppression alterations in relation to cognitive functioning in fragile X syndrome: a combined EEG and machine learning approach}}. {J Neurodev Disord}. 2018; 10(1): 4.
BACKGROUND: Fragile X syndrome (FXS) is a neurodevelopmental genetic disorder causing cognitive and behavioural deficits. Repetition suppression (RS), a learning phenomenon in which stimulus repetitions result in diminished brain activity, has been found to be impaired in FXS. Alterations in RS have been associated with behavioural problems in FXS; however, relations between RS and intellectual functioning have not yet been elucidated. METHODS: EEG was recorded in 14 FXS participants and 25 neurotypical controls during an auditory habituation paradigm using repeatedly presented pseudowords. Non-phased locked signal energy was compared across presentations and between groups using linear mixed models (LMMs) in order to investigate RS effects across repetitions and brain areas and a possible relation to non-verbal IQ (NVIQ) in FXS. In addition, we explored group differences according to NVIQ and we probed the feasibility of training a support vector machine to predict cognitive functioning levels across FXS participants based on single-trial RS features. RESULTS: LMM analyses showed that repetition effects differ between groups (FXS vs. controls) as well as with respect to NVIQ in FXS. When exploring group differences in RS patterns, we found that neurotypical controls revealed the expected pattern of RS between the first and second presentations of a pseudoword. More importantly, while FXS participants in the 42 NVIQ group showed a delayed RS response after several presentations. Concordantly, single-trial estimates of repetition effects over the first four repetitions provided the highest decoding accuracies in the classification between the FXS participant groups. CONCLUSION: Electrophysiological measures of repetition effects provide a non-invasive and unbiased measure of brain responses sensitive to cognitive functioning levels, which may be useful for clinical trials in FXS.
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6. Ring M, Gaigg SB, Altgassen M, Barr P, Bowler DM. {{Allocentric Versus Egocentric Spatial Memory in Adults with Autism Spectrum Disorder}}. {J Autism Dev Disord}. 2018.
Individuals with autism spectrum disorder (ASD) present difficulties in forming relations among items and context. This capacity for relational binding is also involved in spatial navigation and research on this topic in ASD is scarce and inconclusive. Using a computerised version of the Morris Water Maze task, ASD participants showed particular difficulties in performing viewpoint independent (allocentric) navigation, leaving viewpoint dependent navigation (egocentric) intact. Further analyses showed that navigation deficits were not related to poor visual short-term memory or mental rotation in the ASD group. The results further confirm the need of autistic individuals for support at retrieval and have important implications for the design of signposts and maps.
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7. Saldarriaga W, Forero-Forero JV, Gonzalez-Teshima LY, Fandino-Losada A, Isaza C, Tovar-Cuevas JR, Silva M, Choudhary NS, Tang HT, Aguilar-Gaxiola S, Hagerman RJ, Tassone F. {{Genetic cluster of fragile X syndrome in a Colombian district}}. {Journal of human genetics}. 2018.
BACKGROUND: Fragile X syndrome (FXS) is the most common cause of inherited intellectual disabilities and autism. The reported prevalence of the full mutation (FM) gene FMR1 in the general population is 0.2-0.4 per 1000 males and 0.125-0.4 per 1000 females. Population screening for FMR1 expanded alleles has been performed in newborns and in an adult population. However, it has never been carried out in an entire town. Ricaurte is a Colombian district with 1186 habitants, with a high prevalence of FXS, which was first described by cytogenetic techniques in 1999. METHODS: Using a PCR-based approach, screening for FXS was performed on blood spot samples obtained from 926 (502 males and 424 females) inhabitants from Ricaurte, accounting for 78% of total population. RESULTS: A high prevalence of carriers of the expanded allele was observed in all FXS mutation categories. Using the Bayesian methods the carrier frequency of FM was 48.2 (95% Credibility Region CR: 36.3-61.5) per 1000 males and 20.5 (95% CR:13.5-28.6) per 1000 females; the frequency of premutation carrier was 14.1 (95% RC: 8.0-21.7) per 1000 males (95% RC: 8.0-21.7 per 1000 males) and 35.9 (95% RC: 26.5-46.2) per 1000 for females (95% RC: 26.5-46.2 per 1000 females), and gray zone carrier was 13.4 (95% RC: 7.4-20.7) per 1000 males (95% RC: 7.4-20.7 per 1000 males) and 42.2 (95% RC: 32.2-53.8) per 1000 for females (95% RC: 32.2-53.8 per 1000 females). Differences in carrier frequencies were observed for premutation and FM alleles between natives and non-natives. CONCLUSIONS: This study shows that in Ricaurte the carrier frequencies of FMR1 expanded alleles (premutations and FMs) are higher than those reported in the literature, suggesting that Ricaurte constitutes a genetic cluster of FXS.
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8. Yasue M, Nakagami A, Nakagaki K, Ichinohe N, Kawai N. {{Inequity aversion is observed in common marmosets but not in marmoset models of autism induced by prenatal exposure to valproic acid}}. {Behav Brain Res}. 2018; 343: 36-40.
Humans and various nonhuman primates respond negatively to inequity not in their favor (i.e., inequity aversion), when inequity between two individuals is introduced. Common marmosets, a highly prosocial species, further discriminated between human actors who reciprocated in social exchanges, and those who did not. Conversely, marmoset models of autism, induced via prenatal exposure to valproic acid (VPA marmosets), did not discriminate. Interestingly, previous studies of inequity aversion in marmosets have produced negative results, or were limited to males. Recent studies suggest that inequity aversion is highly influenced by the tasks employed. Here we show inequity aversion in both male and female marmosets using a novel task which required a relatively long duration of response. Marmosets were required to hold a spoon for 2s to receive a reward. Marmosets successfully performed the task when they observed an unfamiliar conspecific partner obtaining the same reward (equity test). However, when they witnessed the partner receiving a more attractive reward for equal effort (inequity test), unexposed marmosets, which were not exposed to either valproic acid or saline during the fetal period refused to respond. This inequity aversion was not observed in unexposed marmosets when the partner was absent.In contrast, marmosets with fetal exposure to valproic acid (VPA marmosets) successfully executed the task irrespective of their partners’ reward conditions. As prenatal exposure to valproic acid is a well-known procedure to induce autism spectrum disorder (ASD)-like behaviors in rodents, we propose that VPA marmosets failed to show inequity aversion due to weak social motivation or interest towards others.
