Motivated by recent studies in motor control and therapy, in this thesis an existing computational framework is used to assess balance impairment and disease severity in people suffering from Parkinson's disease. The framework uses high-dimensional shape descriptors of the reconstructed phase space, of the subjects' center of pressure (CoP) tracings while performing dynamical postural shifts. The performance of the framework is evaluated using a dataset collected from 43 healthy and 17 Parkinson's disease impaired subjects, and outperforms other methods, such as dynamical shift indices and use of chaotic invariants, in assessment of balance impairment.
In this thesis, an unsupervised method is also proposed that measures movement quality assessment of simple actions like sit-to-stand and dynamic posture shifts by modeling the deviation of a given movement from an ideal movement path in the configuration space, i.e. the quality of movement is directly related to similarity to the ideal trajectory, between the start and end pose. The S^1xS^1 configuration space was used to model the interaction of two joint angles in sit-to-stand actions, and the R^2 space was used to model the subject's CoP while performing dynamic posture shifts for application in movement quality estimation.
For locating specific cognitive and behavioral information in different regions of the brain, neural recordings are processed using sequential Bayesian filtering methods to detect and estimate both the number of neural sources and their corresponding parameters. Time-frequency based feature selection algorithms are combined with adaptive machine learning approaches to suppress physiological and non-physiological artifacts present in neural recordings. Adaptive processing and unsupervised clustering methods applied to neural recordings are also used to suppress neurostimulation artifacts and classify between various behavior tasks to assess the level of neurostimulation in patients.
For pathogen detection and identification, random peptide sequences and their properties are first uniquely mapped to highly-localized signals and their corresponding parameters in the time-frequency plane. Time-frequency signal processing methods are then applied to estimate antigenic determinants or epitope candidates for detecting and identifying potential pathogens.
Introduction: Lateral reactive stepping is correlated with impairment in people with Parkinson’s Disease (PwPD). Despite this, there is little known of lateral stepping strategies and performance of these strategies in reactive stepping. Objective: To characterize step strategy in people with PD, characterize changes in these stepping strategies through training, and identify performance improvements in the lateral step strategies. Methods: A total of 31 PwPd who are currently at risk for falls took part in an 18-week various background reactive stepping intervention. The stepping strategies were assessed on two baseline assessments (B1 and B2) immediately followed by a 6- session step training intervention occurring over two weeks. Step strategies were again assessed immediately after training (P1) and two months later (P2). Initial outcomes were characterized step strategies, changes in step strategies, and improvement in performance of step strategies. Results: Three step strategies were established and split into two groups (no cross and cross). Changes in step strategies did not occur significantly both before and after training. Improvement in performance of the step strategies occurred at a significant amount (p=0.05) via a decrease in use of support after training occurred for any step strategies utilized. Conclusion: Step strategies were characterized, and performance of strategies was improved upon following the 2-week training. Lateral step strategies are defined and repeated throughout reactive step training with potential for improvement.
While REM Sleep Behavior disorder (RBD) has been linked with synucleinopathies, difficulties persist in clinically convenient diagnostic tools which can differentiate between underlying diseases. Identifying markers in the gait of RBD patients may ease the diagnostic process and indicate potential or status for developing more severe disorders. Individuals were referred to Movement Disorders Center of Arizona (MDCA) by a sleep specialist with a confirmed diagnosis of RBD, or those who were clinically indicated after questioning. All participants underwent a skin-biopsy test for α-synuclein, I-ioflupane dopamine transporter(DAT) scan, and had their gait velocity, cadence and stride dynamics assessed by an automated gait analysis system.