Theses and Dissertations from UMD
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New submissions to the thesis/dissertation collections are added automatically as they are received from the Graduate School. Currently, the Graduate School deposits all theses and dissertations from a given semester after the official graduation date. This means that there may be up to a 4 month delay in the appearance of a give thesis/dissertation in DRUM
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Item Literacy Based Behavioral Interventions for Autistic and Neurotypical Children(2024) Pepkin Dataram, Sara Anne; Kang, Veronica; Special Education; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)The neurodiversity model of disability is a relatively new approach to teaching and working with autistic individuals. As a result, many interventions align with earlier models of disability, such as the medical and social models, and aim to assimilate autistic individuals among their neurotypical peers rather than celebrate their differences as one of life’s natural diversities. This study investigates how educators can create Literacy Based Behavioral Interventions (LBBIs) that align with the neurodiversity paradigm and foster equitable friendships between autistic and neurotypical children. I conducted focus groups with 34 autistic middle school and high school students and eight educators to determine how to feasibly meet autistic students’ social needs. Themes found across these focus groups included autism education for teachers and neurotypical peers, barriers to communication, and the impact of social stigma against autistic individuals. These findings indicate a need for LBBIs and overall classroom environments that amplify autistic perspectives and are not rooted in neurotypical standards.Item Library and Information Science Research and Neurodiversity: So Much Potential if We'd Just Apply Ourselves(2023) Hoffman, Kelly M.; Jaeger, Paul T; St. Jean, Beth; Library & Information Services; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Neurodivergent people consistently face less optimal outcomes than neurotypical people in education, their careers, and other areas of life. Anecdotally, personal knowledge management (PKM) is a useful tool for neurodivergent individuals. However, there is sparse research involving the information practices of neurodivergent adults in the field of library andinformation science (LIS). A survey with both close-ended and open-ended questions, partially based on Dervin's Sense-Making Methodology (Dervin, 1992, 2000), was distributed online and received over 300 self-identifying neurodivergent participants. The results indicated that neurodivergent people use PKM most heavily in the Learning, Job, and Everyday domains for the purposes of Managing Tasks and Projects, Building Knowledge, Creating, and Self-Improvement. Common PKM activities engaged included Storing Information and Using It Later, Remembering What Needs to be Done, Understanding and Ideating, and Planning and Prioritizing. The most helpful benefits of PKM that were described were Connecting Ideas, Improving Thinking, and Having Fun. Overall, key themes regarding neurodivergent individuals’ PKM usage included Reducing Stress, Memory, and Externalizing. These findings provide a foundation for a much-needed LIS research agenda exploring the PKM practices of neurodivergent adults.Item THE ROLE OF THEORY OF MIND IN SOCIAL INTERACTION(2021) Alkire, Diana; Redcay, Elizabeth; Neuroscience and Cognitive Science; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Theory of mind (ToM) is assumed to be instrumental to social interactions, yet it is typically studied using non-interactive laboratory tasks. Standard measures are thus limited in their ability to characterize the cognitive and neural substrates of ToM in naturalistic social interactions, as well as the mechanisms explaining social-interactive difficulties in autism spectrum disorder (ASD). Across three studies, this dissertation aimed to highlight and bridge the disconnect between the study of ToM and its real-world implementation. Study 1 assessed the relative importance of a range of social-cognitive, social-perceptual, and social-affective constructs in explaining variance in the social symptoms of ASD. Three standard, non-interactive ToM measures together explained only 6% of the variance in social symptoms, reinforcing the need for interactive approaches to studying ToM. Study 2 applied such an approach using a socially interactive neuroimaging paradigm to measure brain activation associated with both ToM and social interaction. In typically developing children aged 8-12, interacting with a peer, even in the absence of explicit ToM demands, engaged many of the same regions as did non-interactive ToM reasoning, consistent with the idea that social interaction elicits spontaneous ToM-related processes. Study 3 also investigated ToM in social interaction, this time at the behavioral level, by introducing a novel observational coding system that measures the use of (or failure to use) ToM in naturalistic conversation. Among dyads of typically developing and autistic children and adolescents, conversational ToM (cToM) did not predict interaction success. However, the cToM Negative subscale—capturing ToM-related violations of conversational norms—was negatively associated with two forms of non-interactive ToM: 1) recognizing complex emotions from facial expressions, and 2) spontaneously attributing mental states when describing abstract social animations. Furthermore, exploratory analyses revealed associations between cToM and brain activation during the socially interactive neuroimaging task used in Study 2. Findings across the three studies highlight the multifaceted nature of the ToM construct, the value of socially interactive approaches to studying ToM, and the importance of considering ToM alongside other social-cognitive and affective processes when investigating social interaction.Item Estimating the Prevalence and Timing of Events Along the Pathway to Identification of Autism in the US 2016–2018(2021) Hanley, Allison; Nguyen, Quyhn; Public and Community Health; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)The prevalence of autism spectrum disorder (ASD) has risen rapidly in the past decade. Estimates on factors associated with developmental screening and the timing of events along the diagnostic pathway can inform early identification efforts. This dissertation uses cross-sectional data from the 2016–2018 National Survey of Children’s Health to achieve 3 aims: 1) evaluate individual- and state-level sources of variance between states in developmental screening rates via multilevel models, 2) evaluate characteristics associated with the ages at which children with ASD are first diagnosed, receive an intervention plan, and begin intervention, and 3) evaluate differences in lengths of time between these events by cohort. Aim 1: The national rate of developmental screening for children ages 9 months to 5 years is 34.4% (95% Confidence Interval (CI), [34.3, 34.4]). Rates varied between states by 38%. Individual-level factors explained 6% of the variance, while income inequality and a state’s choice to track developmental screening did not explain any variance between states. Aim 2: Linear regression models adjusted for individual and household characteristics showed that compared to children aged 3–5 years at the time of the survey, children 6–11 were 18 months older at first services (? =1.49, 95% CI, [1.18, 1.81] and children aged 12–17 were 38 months older at first ASD diagnosis (? =3.16, 95% CI, [2.72, 3.60]. Aim 3: Analyses using identical models showed that compared to children aged 3–5 at the time of the survey, the interval between first plan and first services was 4 months longer for children 6–11 (? =0.34, 95% CI, [0.07, 0.61]; and 8 months longer between first ASD diagnosis and first services for children aged 12–17 (? =0.67, 95% CI, [0.28, 1.06]. Today’s children with autism receive their first diagnosis, intervention plans, and developmental services at younger ages than in the past and are moving between events with less delay compared to older children. However, the low rate of developmental screening nationwide represents missed opportunities for even earlier identification. Research is needed to identify the macro-level factors that explain the variance between states on developmental screening rates.Item Developmental Alterations in Inhibitory Neurotransmission in the Fragile X Syndrome Mouse Basolateral Amygdala(2012) Kratovac, Sebila; Corbin, Joshua G; Biology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Fragile X Syndrome, caused by Fmr1 gene inactivation, is characterized by symptoms including enhanced fear, hyperactivity, social anxiety, and autism, pointing to synaptic and neural circuit defects in the amygdala. Previous studies in Fmr1 knockout (KO) mice have demonstrated alterations in GABAA receptor (GABAAR) function in the basolateral amygdala during early postnatal development. In this study, we sought to determine whether these early defects in GABAAR function are accompanied by changes in protein expression of GABAAR alpha 1, 2, and 3 subunits, the pre-synaptic GABA-synthesizing proteins GAD65 and 67 (GAD65/67), and the post-synaptic GABAAR-clustering protein gephyrin. We found that the developmental trajectory of protein expression is altered in knockout mice for all tested proteins except GABAAR alpha 3 and GAD 65/67. Our results suggest that alterations in the timing of inhibitory synapse protein expression in early postnatal development could contribute to observed inhibitory neurotransmission deficits in the KO mouse basolateral amygdala.Item Autism Spectrum Disorder and Hazardous Air Pollutants in the U.S. and Maryland(2010) Trousdale, Kristie; Dabney, Betty J; Maryland Institute for Applied Environmental Health; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)The prevalence of Autism Spectrum Disorder (ASD) diagnoses in the United States has increased dramatically over the past 20 years, fueling investigations into possible environmental triggers for the disorder. Exposures to pesticides, persistent pollutants, prescription medications, and heavy metals through various routes have been examined, but very few studies have examined the potential role of chronic inhalation of hazardous air pollutants (HAPs) in the etiology of ASD. This thesis was designed to examine possible relationships between HAPs and ASD prevalence on a statewide level for the U.S., with sub-analyses on a finer, countywide level within the state of Maryland. Findings suggest consistent, positive associations between ASD prevalence and HAPs at the statewide level for the U.S. The findings do not persist at the county level in the Maryland sub-analyses. These results reinforce the concept of ASD as a spectrum of phenotypes best explained through multifactorial etiological models.Item Factors Affecting the Generalization of "wh-" Question Answering by Children with Autism(2007-04-25) Barthold, Christine Hoffner; Egel, Andrew L; Special Education; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)The purpose of this study was to examine whether Relational Frame Theory (Hayes, Barnes-Holmes, & Roche, 2001b) could be applied to increase generalization of "wh-" question answering (e.g., what, why, how) by children with autism. Students (N=6) from two self-contained classrooms for children with autism were taught to answer "wh-" questions in the presence of magazine pictures, pictures from storybooks, and actions in the natural context depicting a scenario related to the question asked. Generalization to novel questions was then assessed. If students were not able to answer generalized "wh-" questions to criterion, a matching-to-sample procedure with exclusion was used to increase associations between stimuli. A multiple probe design across subjects was used for this study. A baseline of "wh-" question answering, matching to sample, and receptive identification of answers to questions were conducted prior to training. In addition, students were observed in the classroom environment prior to training. A descriptive analysis of their verbal behavior, in which antecedents, student responses, and consequences were recorded, was conducted to determine the students' verbal behavior ability in the absence of a particular training program. Two students, one in each school, were able to generalize to novel "wh-" questions after training. Both of these students were able to spontaneously tact items and had a higher number of tacts in relation to mands in the descriptive analysis. Individuals who did not generalize did not acquire relations using a matching to sample with exclusion procedure. They also emitted either an equal number of tacts and mands during the descriptive analysis or more mands than tacts. Implications for practice include the consideration of waiting to include "wh-" question answering until students are able to emit a high number of spontaneous tacts and possibly early intraverbal behavior such as greetings, the elimination of visual stimuli when teaching "wh-" questions, and the expansion of matching-to-sample goals in behavioral curricula. Suggestions for future research include the continued research into the development of verbal behavior in children with autism, refinement of matching techniques to teach relations, and expansion of the descriptive analysis of verbal behavior.Item The Social Engagement System: Functional Differences in Individuals with Autism(2004-05-03) Denver, John William; Porges, Stephen W; Human DevelopmentThe Polyvagal Theory links the evolution of the autonomic nervous system to affective experience, emotional expression, facial gestures, vocalization and social engagement behavior. Therefore, the theory provides a plausible explanation for the bio-behavioral indices of several psychiatric disorders. The vagus as a "system" provides a rich organizing principle to investigate several of the behavioral, psychological, and physiological features associated with compromised social behavior in several psychiatric disorders. The Polyvagal Theory describes this integrated system as the Social Engagement System. Observations of the behaviors and physiological responses of autistic individuals suggest that they have great difficulties in recruiting the neural circuit that regulates the social engagement system. This model predicts that a deficit in the system would produce atypical social behaviors such as social withdrawal; improper communication (i.e., poor intonation and prosody); difficulty listening (inability to extract human voice from background noise); poor eye contact; inappropriate facial expressivity (i.e., flat affect); and atypical visceral functioning (i.e., low cardiac vagal tone). These indices are directly related to the atypical behaviors associated with autism, and several other psychiatric disorders. In the current study, measures related to the functioning of these components were obtained to test the hypothesis that autistic individuals have a compromised social engagement system. Forty subjects participated in the study (20 autistic, 31 males, ages 9-24). Data were collected to assess autonomic functioning (i.e., cardiac vagal tone), the ability to extract human voice from a compromised environment, an estimate of right ear advantage, and looking behavior (i.e., eye contact). Analyses showed that autistic individuals scored poorer on all measures assessing social engagement system functioning. Compared to controls, the autistic group had lower mean cardiac vagal tone and shorter heart periods, performed poorer on extracting human voice from a compromised environment, on a dichotic listening task, and on a measure of right ear advantage. They also spent significantly less time fixating on the eyes and more time fixating off of the face when viewing a movie of a person telling them a story. Results support the hypothesized relation between a compromised social engagement system and the atypical features associated with autism.