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
More information is available at Theses and Dissertations at University of Maryland Libraries.
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Item THE CONTRIBUTION OF EXECUTIVE FUNCTION TO READING COMPREHENSION FOR LINGUISTICALLY DIVERSE LEARNERS(2018) Meyer, Anna; Silverman, Rebecca D; Special Education; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Research suggests that EF can aid in the prediction of RC. However, much of the existing research into the relationship between these two variables has relied on statistical correlations and simple linear regression, neither of which fully capture the complexity of their theoretical relationship and other known contributors to RC, such as decoding and linguistic comprehension. Accordingly, this dissertation study investigated the relationship between EF and RC through a synthesis of the literature and two separate empirical studies. The first empirical study investigate whether (1) a latent construct of EF, measured by separate assessments of working memory, shifting, and inhibition, makes unique direct contribution to the prediction of RC and (2) whether EF’s latent construct mediates the prediction of RC through decoding and a latent construct of linguistic comprehension. The second empirical study investigated whether (1) a latent construct of EF, measured by separate assessments of working memory, shifting, and inhibition, makes unique direct contribution to the prediction of RC and (2) whether EF’s latent construct mediates the prediction of RC through decoding and a latent construct of linguistic comprehension. Both empirical studies examined this relationship in linguistically diverse learners (LDLs) as an understudied population to extend the current research base. Specifically, the sample included three groups of LDL students: (a) English Learners (ELs), or students who speak a language other than or in addition to English in the home and who are receiving school-based English language services because they have not passed an English language proficiency exam, (b) R-ELs, or students who speak a language other than or in addition to English in the home but have passed an English language proficiency exam and have thus been recently exited from EL services, and (c) EL students from the above cohorts who the school identified as having a disability. Language and disability status, respectively, were entered as moderators in the above models to test for significant differences by group. Limitations of the dissertation study and directions for future research are discussed.Item Decoding of walking kinematics from non-invasively acquired electroencephalographic signals in stroke patients(2012) Nathan, Kevin; Contreras-Vidal, Jose L; Electrical Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Our group has recently shown the feasibility of decoding kinematics of controlled walking from the lower frequency range of electroencephalographic (EEG) signals during a precision walking task. Here, we turn our attention to stroke survivors who have had lesions resulting in hemiparetic gait. We recorded the EEG of stroke recovery patients during a precision treadmill walking task while tracking bilaterally the kinematics of the hips, knees, and ankles. In offline analyses, we applied a Wiener Filter and two unscented Kalman filters of 1st and 10th orders to predict estimates of the kinematic parameters from scalp EEG. Decoding accuracies from four patients who have had cortical and subcortical strokes were comparable with previous studies in healthy subjects. With improved decoding of EEG signals from damaged brains, we hope we can soon correlate activity to more intentional and normal-form walking that can guide users of a powered lower-body prosthetic or exoskeleton.Item Decoding Repetitive Finger Movements with Brain Signals Acquired Via Noninvasive Electroencephalography(2011) Paek, Andrew Young; Contreras-Vidal, Jose L; Bioengineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)We investigated how well finger movements can be decoded from electroencephalography (EEG) signals. 18 hand joint angles were measured simultaneously with 64-channel EEG while subjects performed a repetitive finger tapping task. A linear decoder with memory was used to predict continuous index finger angular velocities from EEG signals. A genetic algorithm was used to select EEG channels across temporal lags between the EEG and kinematics recordings, which optimized decoding accuracies. To evaluate the accuracy of the decoder, the Pearson's correlation coefficient (r) between the observed and predicted trajectories was calculated in a 10-fold cross-validation scheme. Our results (median r = .403, maximum r = .704), compare favorably with previous studies that used electrocorticography (ECoG) to decode finger movements. The decoder used in this study can be used for future brain machine interfaces, where individuals can control peripheral devices through EEG signals.Item The Effectiveness of a Color-Coded, Onset-Rime Reading Intervention With First Grade Students At Serious Risk For Reading Disabilities(2007-04-25) Hines, Sara Jane; Speece, Deborah L.; Special Education; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Beginning readers who are weak decoders usually continue to fall behind in reading as they progress through school, negatively affecting their overall academic performance, self-esteem, and motivation. Therefore, it is imperative to develop instructional practices to assist the acquisition of effective decoding skills. Although existing remedial approaches have proven effective with a number of students with reading problems, they have not been successful with those students most at risk and have generally not resulted in transfer of skills to decoding novel words not targeted in instruction. I used a single-subject multiple probe design across participants to investigate the effectiveness of a color-coded, onset-rime based decoding intervention. The participants were first grade students determined to be at serious risk for reading disabilities based on their performance on screening measures. All four of the students made strong progress in learning the instructional words, increasing on average 73% over baseline (range 66%-78%). In addition, for novel words from instructed rime patterns, students increased their scores from baseline to post-intervention by an average of 56% (range 50% to 62%). There was limited transfer at the vowel level to uninstructed rime patterns, with students improving their scores by an average of 29% (range 17% to 50%). All students maintained their improvement in decoding skills for both instructional and transfer words at one week and one month maintenance. The fact that the children were able not only to master instructional words but also to use their knowledge of rime patterns to decode uninstructed words is important given the difficulty of students most at-risk for reading disabilities to master instructional words and transfer decoding gains. Furthermore, the three participants with the lowest performance prior to instruction showed strong improvement on a standardized measure of reading achievement (Woodcock-Johnson Reading Mastery Test-Revised, Normative Update). The effectiveness of the program in improving the decoding skills of readers who are significantly at-risk is a promising first step in finding an instructional approach that is successful with students who have been left behind not just by traditional classroom instruction but by remedial approaches as well.