Autism Spectrum Disorders (ASDs) are characterized by difficulties in social interaction and communication. Recent studies within the social sciences have espoused a need to reconceptualize autism out of the domain of the intrapersonal and into the realm of the sociocultural. Semi-structured in-depth interviewing was used to examine the selfperceptions and experiences of twelve people who identified as on the autism spectrum. Social scientists have tended to grant the topic of autism to the domain of psychology; as a result autistic perception has been stigmatized resulting in the exclusion of autistic perspectives in knowledge production on the lived experiences of autistic actors. The first-hand accounts examined in this study lend support to the idea that symbolic interactionism provides a more nuanced framework for studying how autistic perception influences autistic experience in contrast to the functionalist-reductionist approach of cognitive psychology. From this perspective we can position autistic differences in disposition and interaction as socioculturally situated rather than as solely a result of individual cognitive impairment. The application of microsociological concepts to autistic perception and interaction has the potential to expand knowledge on both autistic experience and the social construction of normative order.

Children with Autism Spectrum Disorders (ASD), and their infant siblings (ASD-siblings), exhibit deficits in their ability to shift visual attention, and to initiate and respond to joint attention. The current study examined early associations between visual attention and joint attention, and between these types of attention and later language ability and ASD severity in ASD-siblings (n = 31). This study investigated the possibility that ASD-siblings, who are at-risk for atypical development, differed from infants who have an older sibling(s) with no evidence of an ASD (Comparison-siblings; n = 23) on the following: 1) means of visual and joint attention, 2) the associations between these constructs, and 3) developmental trajectories of joint attention. Early visual attention was measured using infants' gazes at and away their parents' faces during the Face-to-Face Still-Face Protocol at 6 months. Initiating joint attention (IJA) and responding to joint attention (RJA) were measured during the Early Social Communication Scales at 8, 10, 12, 15, and 18 months. Language ability was measured with the Mullen Scales of Early Learning language at 24 and 36 months. ASD severity was measured on the Autism Diagnostic Observation Schedule at 30 months. Results indicated that ASD-siblings and Comparison-siblings were comparable in their gaze shifting and mean durations of gazes away from their parents' faces. These two components of visual attention were associated with parent behaviors, and the type of chair infants sat in. There were group differences in IJA at 10 months and RJA at 8, 15, 18 months, with ASD-siblings performing fewer behaviors than Comparison-siblings. There were developmental associations between visual and joint attention, and joint attention and later language and ASD severity. ASD-siblings differed from Comparison-siblings in their RJA development. ASD-siblings also had lower language ability and greater ASD severity than Comparison-siblings. The current study's limitations included low statistical power, and a difficulty inherent to prospective studies, which are at a disadvantage because a high proportion ASD-siblings may not develop an ASD. Nevertheless, the findings have clinical implications for the development of interventions targeting RJA behaviors within the first year of life.

Thesis (M.S.)--University of North Texas, May, 2009. / Title from title page display. Includes bibliographical references.

Background: Prenatal ethanol exposure (PNEE) causes irreversible intellectual and behavioral disabilities, clinically known as fetal alcohol spectrum disorder. Few neuropathologic studies of human brain exist. Hypotheses: First, markers of oxidative stress persist following PNEE. Second, PNEE is associated with inhibitory and excitatory neuron changes. Methods: Human brain autopsies (153) with known PNEE were reviewed; 18 cases (fetus to adult) and controls were selected. Oxidative stress and neuronal differentiation markers were used for immunohistochemistry. Results: There were no obvious differences between control and PNEE brains using oxidative stress markers. In human PNEE brains, glutamatergic neurons were reduced 15.96 % and 18.03% in dentate gyrus and temporal cortex, respectively. GABAergic neurons reactive for parvalbumin were reduced in all hippocampal regions (CA1= 57.86%, CA3= 65.15%, and DG= 53.39%) and temporal cortex (44.13%) in all age groups. Conclusion: GABAergic neuron reduction in human following PNEE could explain motor and behavior distractibility in FASD individuals.

published_or_final_version / Paediatrics and Adolescent Medicine / Master / Master of Medical Sciences

published_or_final_version / Public Health / Master / Master of Public Health

While a stable diagnosis of Autism Spectrum Disorders can be made as early as 2 years of age, the diagnosis of mild ASD cases are usually not made until primary school age or much later; and yet it is these milder cases that can benefit the most from early intervention. The present study aimed at pushing the identification of mild ASD children earlier to preschool age. A review of current screening tools revealed that they were not effective in identifying milder ASD variants. One reason perhaps is that the existing tools rely primarily on parental reports. Note that young children with mild ASD often function adequately interacting with an adult who knows them well; they typically face more difficulty in free play with other children. Parents as a result may not be in a good position to detect milder ASD. The present study therefore took a very different approach from existing screening tools by developing a more objective scale based on observation by of peer interaction in preschools. Considering peer interaction deficits are central for ASD, and deficits of these milder individuals might be more obvious in a setting that tax their social skills. A screening tool based on peer interaction observation in preschool, namely the Structured Classroom Observation Scale (SCOS), was thus developed. Drawing on existing screening tools and experts input, 84 items were compiled and pilot tested. An initial psychometric study of the scale was conducted using a community sample, with 304 preschoolers aged 3 and 4, from four English-language international schools in Hong Kong. The initial 84-item version was trimmed substantially to result in a user-friendly 13-item observation scale with good psychometric properties. The final SCOS includes 3 items depicting self-regulation challenges and 10 items describing difficulties in peer interaction. The initial psychometric study using a community sample indicated substantial interrater reliability (u= .76) and acceptable test-retest reliability (ICC = .72). The average agreement for individual items was less satisfactory (T = .40). Using Latent Class Analysis, the present scale delineated the children into 4 groups: Typical, Shy, Behavioral and High Risk of ASD. A subsequent validity study (n = 186) comparing the SCOS with ADOS scores showed that the class membership of the children based on SCOS predicted their ADOS results, after controlling for age and gender. Children from the High Risk group were found to have significantly higher Calibrated ADOS Severity scores than the other 3 groups; and their mean ADOS scores (i.e., 8.18) were above the cutoff for ASD on the ADOS. A 9-month follow found more reports of parental concerns in the High Risk group with ADOS scores above the cutoff. Discriminant validity of the SCOS was demonstrated between the scale and Head Start Competence Scale (parent version). In contrast to the usual portrayal of active but odd stereotypical children with Asperger Syndrome, the High Risk group identified by the SCOS consisted of children with infrequent interfering behaviors. They were relatively passive but not necessarily odd during social interactions, which might perhaps explain why early identification was difficult. The current scale also identified another two groups of children (Shy group and Behavioral group), which will require longitudinal follow up to ascertain educational or intervention implications. / published_or_final_version / Clinical Psychology / Doctoral / Doctor of Psychology

Background: The Weak Central Coherence (WCC) account of autism spectrum disorder (ASD) proposes a weakness of global integrative processing (i.e. central coherence) resulting in a strength in local, detailed, focused processing in individuals with ASD. However, because of the mixed findings regarding weaknesses in global integrative processing, recent literature had neglected this part of the WCC theory. Mixed findings about global integrative deficits in ASD came about because WCC was operationalized differently in different studies. This research’s primary aim was to delineate the nature of integrative processing that is impaired in ASD more precisely. Integrative processes were demarcated into first order and second order processes. Individuals with ASD were hypothesized to have problems in second order integrative processing only, which refers to the apprehension of inter-elemental relations that exist external to the individual elements. The hypothesis was investigated in both the visual-perceptual domain (Study One) and the verbal-conceptual domain (Study Two). In the visual-perceptual domain, first order and second order integrative processing refer to global processing and gestalt processing respectively. In the verbal-conceptual domain, they refer to the apprehension of taxonomic relations and thematic relations respectively. With better delineation of the construct of integrative processing in WCC, Study Three pursued the secondary aims of this research: to use the clarified constructs to study whether WCC exists as a central mechanism, and to test its predictive value on ASD symptomatology. Methods: Twenty high functioning adolescents with ASD (HFA, aged 12 to 15) and 20 matched typically developing (TD) counterparts (aged 12 to 15) participated in the three studies of this research. In Study One, participants were administered a first order task with hierarchical compound stimuli that aimed to tap their global processing, and a second order task that aimed to tap their apprehension of gestalt principles (gestalt processing). In Study Two, participants were administered a lexical decision priming task with half of the prime-target pairs denoting a taxonomic relation (first order task), and half of the prime-target pairs denoting a thematic relation (second order task). In Study Three, correlation analyses were done among the second order task measures of the two domains as well as HFA symptomatology indexed by the Autism Quotient (AQ). Results: For Study One, there was a trend showing that participants with HFA performed worse than TD peers in a subtask that tapped one gestalt principle (the principle of similarity). Contrary to prediction, in the global processing task, HFA individuals exhibited a reliable local bias. For Study Two, HFA participants were found to be primed to a significantly lesser extent by a thematic prime while exhibiting intact taxonomic priming. In Study Three, cross domain associations of second order processing measures were not significant, which was against the notion of a central mechanism of WCC. The priming extent by a thematic prime and a measure of gestalt processing were found to associate negatively with ASD symptoms in the TD group. Conclusions: All in all, the present research had partial success in clarifying the nature of WCC as a weakness in second order integrative processing. Theoretical and practical significance as well as future research directions were discussed. / published_or_final_version / Educational Psychology / Doctoral / Doctor of Psychology

Valproic acid (VPA) is a broad-spectrum anticonvulsant and antiepileptic drug and widely used in many neurological conditions and psychiatric disorders as well as in cancer and HIV treatment. However, despite all its many benefits, VPA also has side effects. It is a strong fetal teratogen that can induce congenital malformation and neurodevelopmental problems. Case reports and population studies have revealed that prenatal exposure to VPA is associated with a higher risk of autism in postnatal life. Animal models also have confirmed that VPA can induce autistic-like features in rodents. Yet, there are some questions remaining unanswered by existing animal studies of prenatal VPA exposure. The embryotoxicity of a drug is not only determined by its own chemical, physiological or pharmacological properties, but also on the dose and the time in development that the exposure happens. The majority of studies investigating the behavioral, neuroanatomical and physiological impact of VPA in animals have examined early gestational exposure to relatively high doses that can cause significant malformation or loss of offspring. Thus, although there are behavioral alterations considered similar to autistic symptoms in humans, these are found in the offspring that have survived a very toxic insult, leading to problems of interpretation. Low dose exposure has not been widely studied, nor has the impact of VPA exposure late in gestation. Moreover, how the age and sex of offspring influences the phenotypic outcome has rarely been considered. Therefore, in the present series of studies, a battery of behavioral tests and in vivo magnetic resonance imaging (MRI) was used to investigate the postnatal consequences of prenatal exposure to lower doses of VPA in mice in early and late gestation. The effects of VPA were examined in female and male mice at juvenile and adult ages. The main findings were, that low doses of VPA in early or late gestation cause no physical malformation and no gross neurological functional impairments, but induce behavioral abnormalities and neuroanatomical differences related to autism. Generally, VPA-treated mice exhibited lower motor activities and higher anxiety levels in the open field test; dislike of novelty in the novel abject exploration test; higher startle response and sensorimotor gating differences; decreased responses to non-social and social odors in the olfactory test; and volumetric changes in brain structures similar to those found in autism. However, the timepoint of exposure, dose of VPA, sex and age of testing influenced the phenotypic outcome. Although largely neglected in previous studies, late gestation exposure to VPA elicited an autistic phenotype. Surprisingly, given the male bias in autism, female mice were often more ‘sensitive’ to VPA. Although the present studies had some limitations, these experiments confirmed that low dose VPA in pregnancy could trigger behavioral abnormalities and brain anatomical differences in mice that resembled a range of features of autism. Importantly, these behaviors were unconfounded by ‘gross’ neurological or physical abnormalities. Further studies to investigate the cellular mechanisms underlying the low dose VPA phenotype will therefore be helpful to shed light on possible causal pathways with specific relevance to autism. / published_or_final_version / Psychiatry / Doctoral / Doctor of Philosophy

Objective: To present a systematic review of existing literature that investigates biological plausibility of prenatal hazardous air pollutants’ (HAPs) exposure, in the etiology of autism spectrum disorder (ASD) and related outcomes. Method: Electronic databases Pubmed, Biomed Central and National Database for Autism Research, and grey literature pertaining to air pollution association with ASD and related outcomes were searched using specific keywords. The search included 190 HAPs as defined by The Clean Air Act Amendments of 1990 [U.S.Environmental Protection Agency (EPA) 1994] including air pollutants CO, SO2, NOx, O3 and Particulate Matter (PM). Studies selected for systematic review were assessed on quality and causality. Result: Total of 628 articles from electronic search and 16 articles from grey literature were retrieved. 12 studies that cleared the inclusion and exclusion criteria were systematically reviewed using the PRISMA checklist. Outcomes considered included ASD, Attention Deficit Hyperactivity Disorder, social behavior, social interaction, child behavior, communication, cognitive development, attention problems, mental and psychomotor development, and social competence. Studies were from two countries, United States of America and Spain. Study design was case control and cohort study. Follow up duration for cases ranged from in-utero to less than 9 years. Exposure was measured in ambient air using predictive models and cord blood. Although there were discrepancies in the studies, related to strength of association, analysis and covariates adjusted, the association between air pollution and ASD related outcomes could not be dismissed. Most studies lacked information on blinding when quality was assessed and lacked consistency when assessed on causality, while scored well on temporality and biological plausibility. Discussion: Evidence suggests HAPs are capable of transplacentally affecting cognitive function, especially traffic related pollutants. Study design, sample size, response rate, exposure misclassification, failing to adjusting covariates related to lifestyle, nutrition and other chemical exposures have influenced the estimates and the strength of association. Shortcomings of this review are the English language restriction and single reviewer on study selection process and assessments. Immuno-toxic, neuro-toxic and endocrine disrupting properties of these HAPs necessitates comprehensive prospective studies especially in Hong Kong with the rising prevalence of ASD and ever high reported air pollution indexes. Conclusion: Repeated studies were carried out on the same cohorts and studies were concentrated in U.S.A. On account of a lack of consistency, it is difficult to confirm whether air pollution is a plausible candidate for prenatal exposure in ASD. (Abstract of 391 words) / published_or_final_version / Public Health / Master / Master of Public Health