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 THE INFLUENCE OF CUMULATIVE SLEEP RESTRICTION ON HUMAN PERFORMANCE: EXAMINATION OF BRAIN DYNAMICS AND SUSTAINED ATTENTION(2024) Kahl, Steven; Hatfield, Bradley; Kinesiology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Sustained attention (SA) impacts nearly every aspect of human performance. From the exactness of performing brain surgery to safely driving from one location to another, the ability to concentrate on a task for a period of time is important for success in work, school, relationships, and individual activities. As a key component of executive function (EF) and psychomotor performance, SA can be affected by many mental and physical processes. One process that can impact SA is restricted sleep, which is becoming more relevant in our ever-evolving technological society. Numerous studies have examined the impact of short bouts of restricted sleep on response time, a measure of SA, but few studies have examined the impact of the accumulating effect of sleep restriction (SR) on response time and brain dynamics as measured with electroencephalography (EEG). As part of a larger 40-day study, eight healthy participants (five female, average age 27.75) were observed for seven consecutive days and nights in a sleep lab, where they spent five hours in bed per night and engaged in numerous psychomotor vigilance tests (PVT), an indicator of SA, as part of their daytime activities. Through multiple one-factor ANOVAs, response time significantly slowed, and brain dynamic changes occurred, measured by slow wave activity (SWA) maxima change in the Fz electrode, located in the midline frontal region, over the course of the entire week of continual SR compared to an extended sleep night. Employing mixed method effects revealed a statistically significant relationship between response time and SWA maxima differences. The data show that not only does response time increase the day after rising first and last SWA maxima levels converge (i.e., flattening of the line slope connecting these values) caused by short bouts of SR, but these phenomena continue this progression with prolonged SR. Over the course of the week-long SR, the final SWA maximum increased at a higher rate than the first SWA maximum, leading to the maxima difference shrinking as response time increases. These findings indicate that brain dynamics highlight less restorative sleep occurring alongside a lack of sustained attention when sleep is restricted on a consistent basis.Item Speech-language Pathologists' Services for Children with Co-occurring Language and Executive Function Deficits(2022) Senter, Reed; Chow, Jason C.; Special Education; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)There is a well-documented association between developmental language disorder (DLD) and executive function (EF) deficits. These co-occurring deficits pose risks to students’ short- and long-term academic and social outcomes. In the United States, school-based speech-language pathologists (SLPs) are tasked to ensure that students with DLD are able to achieve academic success, and though EF generally lies within their scope of practice, it remains unclear the extent to which SLPs are equipped to address these deficits. This dissertation consists of three related studies, the sum of which shall provide insight into the SLPs’ services. The first of these studies, Chapter 2, offers a systematic literature review of the evidence supporting intervention for children with co-occurring deficits, as well as a synthesis of the guidance for SLPs addressing EF deficits in their services. I found a dearth of empirical studies for interventions targeting this population, though a relative abundance of practitioner papers provides a foundation of best practices for direct and indirect services. Chapter 3 presents the second study, an exploratory latent profile analysis of 167 Kindergarteners’ receptive language, expressive language, and working memory (WM), as well as follow-up analyses of variance which examine children’s average behavior ratings by profile. I identified a suitably-fitted three-profile model of language and WM, and I found that low-performing children, on average, were rated lower in social competence. Finally, Chapter 4 contains a mixed-methods analysis of school-based SLPs’ interventions for children with EF deficits. Following an explanatory sequential design, I first surveyed 350 SLPs, then followed up with eight interviews designed to explain and contextualize the survey results. I found that most SLPs support EF deficits through indirect services or embedded strategies, though fewer provide direct intervention. However, direct intervention is feasible, and SLPs’ knowledge and confidence about EFs influence their service provision. Overall, the findings of this dissertation support the notion that SLPs can be active and involved service providers, addressing EF deficits that are abundant in children with DLD, and which may otherwise hinder students’ education. However, to optimize these services, the field of SLP requires further empirical intervention research and improved SLP preparation to ensure that SLPs can meet all the needs of students with co-occurring deficits.Item INFLUENCE OF EXECUTIVE FUNCTIONING ON MEMORY FOR CONTEXTUAL DETAILS AND FALSE RECOGNITION(2012) Rollins, Leslie Ann Hainley; Riggins, Tracy; Psychology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)No previous studies had examined how all constructs of executive functioning (i.e., conflict inhibition, delay inhibition, cognitive flexibility, and working memory) relate to memory for contextual details and false recognition in early childhood controlling for general intelligence. Three and six-year-old children performed a laboratory-based episodic memory task and a battery of neuropsychological tasks. The relation between executive functioning and false recognition was diminished taking general intellectual ability into account. Executive functioning did not predict memory for contextual details in the full sample. However, when children who were at chance at recalling contextual details were excluded from analysis, executive functioning showed a trend for accounting for variance beyond age group and general intellectual ability. The inability of this effect to reach conventional statistical significance was likely due low statistical power resulting from the sample size reduction. Specifically, accuracy on the day/night task, a measure of conflict inhibition, was a significant predictor.