Thesis (Ph. D.)--Ohio State University, 2009. / Title from first page of PDF file. Includes vita. Includes bibliographical references (p. 101-112).

Previous research demonstrates an uneven pattern of cognitive abilities in children diagnosed with autism spectrum disorders (ASD). This study examined whether this uneven pattern exists in preschool children. Participants include 24 children with high-functioning ASD and 28 typically developing (TD) children aged 4 to 6 with comparable average age and development level. No significant group difference in cognitive abilities was found between the ASD and TD group on the MANOVA. Patterns of cognitive functioning found include better performance on memory, weaker performance on language comprehension and expression, fine motor and speed of processing. Nonverbal and visual motor abilities were comparable between groups. Language expression was less impaired than language comprehension, and fine motor abilities were correlated with more cognitive abilities. / published_or_final_version / Educational Psychology / Master / Master of Social Sciences

People with autism spectrum disorders (ASDs) have difficulty empathizing with others, contributing to deficits in social interaction and communication. The degree of difficulty empathizing may be related to the level of impairment associated with the ASD. Little is known about the early development of empathy prior to ASD diagnosis. A novel way of studying the early development of ASDs is to study the development of younger siblings of children with ASDs, who are at an increased genetic risk for these disorders, and compare them to children with typically developing older siblings. The current study examined how empathic responding and cooperation, a measure of prosocial functioning, at 24 and 30 months of age differed between children who later received a diagnosis of autism or pervasive developmental disorder-not otherwise specified, and those who did not. Overall, children engaged in more empathic responding at 30 months than at 24 months. As expected, children later diagnosed with autism engaged in less empathic responding than children with no diagnosis. Additionally, lower empathic responding at 24 months predicted higher autism symptomatology at 30 months. In terms of cooperation, children tended to engage in less noncompliant behavior at 30 months than at 24 months. However, no age differences were found for compliant behavior. Contrary to expectations, there were no diagnostic group differences in cooperative behavior nor was there a relation between empathic responding and cooperation. This was one of the first studies to investigate empathic responding in young children prior to diagnosis with an ASD. Results show that empathy deficits are present from an early age, and may be an important predictor for later diagnosis. Implications for these findings and future directions are discussed.

Autism Spectrum Disorder (ASD) is a complex neurodevelopmental disorder affecting individuals along a continuum of severity in communication, social interaction and behaviour. The impact of ASD significantly varies amongst individuals, and the cause of ASD can originate broadly between genetic and environmental factors. Previous ASD researches indicate that early identification combined with a targeted treatment plan involving behavioural interventions and multidisciplinary therapies can provide substantial improvement for ASD patients. Currently there is no cure for ASD, and the clinical variability and uncertainty of the disorder still remains. Hence, the search to unravel heterogeneity within ASD by subgroup classification may provide clinicians with a better understanding of ASD and to work towards a more definitive course of action. In this study, a norm of physical measurements including height, weight, head circumference, ear length, outer and inner canthi, interpupillary distance, philtrum, hand and foot length was collected from 658 Typical Developing (TD) Chinese children aged 1 to 7 years (mean age of 4.19 years). The norm collected was compared against 80 ASD Chinese children aged 1 to 12 years (mean age of 4.36 years). We then further attempted to find subgroups within ASD based on identifying physical abnormalities; individuals were classified as (non)dysmorphic with the Autism Dysmorphology Measure (ADM) from physical examinations of 12 body regions. Our results show that there were significant differences between ASD and TD children for measurements in: head circumference (p=0.009), outer (p=0.021) and inner (p=0.021) canthus, philtrum length (p=0.003), right (p=0.023) and left (p=0.20) foot length. Within the 80 ASD patients, 37(46%) were classified as dysmorphic (p=0.00). This study attempts to identify subgroups within ASD based on physical measurements and dysmorphology examinations. The information from this study seeks to benefit ASD community by identifying possible subtypes of ASD in Chinese population; in seek for a more definitive diagnosis, referral and treatment plan. / published_or_final_version / Paediatrics and Adolescent Medicine / Master / Master of Philosophy

Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by communication difficulties, social interaction impairments, and stereotyped patterns of behavior. Prior studies have shown that ASD is associated with differences in neuroanatomy in the cerebral cortex and the subcortical regions as well as the connectivity among these regions. However, findings have been mixed due to the varying age group sampled and the methods used to measure these brain structures. In view of the heterogeneous findings in ASD, three cross-sectional design studies were conducted in this thesis to examine brain structural pathologies that may be related to the clinical and behavioural phenotype of the disorder across development. In the childhood and adolescent sample, two studies were carried out. The first one examined cortical thickness using a vertex-wise approach. Results revealed thinner cortex in the occipital, parietal and frontal regions, and thicker cortex in the inferior parietal and caudal anterior cingulate regions. These regions also showed age-related differences that deviated markedly from the typical developmental trajectories observed in the control group. Some of these regions with significant differences in cortical thickness were found to be associated with clinical symptoms in ASD. The second study in the childhood and adolescent sample examined the volume of subcortical structures and CSF using a spatially non-biased parcellation approach. It was found that intracranial volume was enlarged in children with ASD, accompanied by smaller bilateral cerebellum and left thalamus. These regions showed an age-related increase in volume in children with ASD, whereas the typically developing children showed a general age-related decrease in volume of the same regions. The volumes of the cerebellum, thalamus and basal ganglia structures were associated with relatively weaker motor control in ASD, and in particular greater volume of the left thalamus rather than age predicted worse motor performance in the clinical group. The third study was carried out in a large adult sample. The cerebellar white matter system, that interconnects cortical and subcortical targets, was examined. Using a diffusion-tensor imaging tractography approach, the cerebellar input and output white matter pathways were dissected. Both the input and output pathways were observed to be disrupted in ASD, supporting the hypothesis that ASD may be a “disconnectivity disorder”. Lower fractional anisotropy of the left middle cerebellar peduncles was associated with increased difficulties in communication and social interaction, and lower fractional anisotropy in the right superior cerebellar peduncle was linked to worse motor performance in adults with ASD. Therefore, my studies confirmed differences in neuroanatomy of cortical and subcortical regions with altered brain developmental trajectories in children and adolescence with ASD, and revealed disrupted cerebellar network system in adults with ASD. Dysmaturation of cortical and subcortical regions as well as cerebellar white matter pathways may contribute to clinical and motor phenotype of the disorder. Lastly, postmortem and early life imaging studies, together with evidence that prenatal stressors during 21 to 32 weeks of gestation may increase incidence of ASD, lead me to speculate whether the abnormalities reported here may have origins prior to 31 weeks of gestation. / published_or_final_version / Psychiatry / Doctoral / Doctor of Philosophy

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Attentional abnormalities are one of the earliest signs of Autism Spectrum Disorders (ASD). Despite flourishing attention studies in autism, relatively little is known about attentional performance among young children with high-functioning autism (HFA). The present study compared 23 preschool children with HFA and 28 typically-developing children on attention network efficiencies, selective attention to social or non-social information and attention switching, with age, cognitive and language abilities matched or controlled. Compared with typically-developing children, young children with HFA showed comparative attention network efficiencies, slower orienting to face and better attention switching. Alternative explanations for their strength in attention switching are given based on superior focused attention to visual details and hyper-systemizing skills. Implications on future research and practice are discussed. / published_or_final_version / Educational Psychology / Master / Master of Social Sciences