The Investigation of Motor Primitives During Human Reaching Movements and the Quantification of Post-Stroke Motor Impairment

Movement is a complex task, requiring precise and coordinated muscle contractions. The forces and torques produced during multi-segmental movement of the upper limbs in humans, must be controlled, in order for movement to be achieved successfully. Although a critical aspect of everyday life, there remain questions regarding the specific controller used by the central nervous system to govern movement. Furthermore, how this system is affected by neurological injuries such as stroke also remains in question. It was the goal of this thesis to examine the neurological control of movement in healthy individuals and apply these findings to the further investigation of chronically motor impaired stroke patients. Additionally, this work aimed at providing clinicians with a more reliable, easy to use, and inexpensive approach to quantify post-stroke motor impairment

Characterization of stroke-related upper limb motor impairments across various upper limb activities by use of kinematic core set measures

BACKGROUND Upper limb kinematic assessments provide quantifiable information on qualitative movement behavior and limitations after stroke. A comprehensive characterization of spatiotemporal kinematics of stroke subjects during upper limb daily living activities is lacking. Herein, kinematic expressions were investigated with respect to different movement types and impairment levels for the entire task as well as for motion subphases. METHOD Chronic stroke subjects with upper limb movement impairments and healthy subjects performed a set of daily living activities including gesture and grasp movements. Kinematic measures of trunk displacement, shoulder flexion/extension, shoulder abduction/adduction, elbow flexion/extension, forearm pronation/supination, wrist flexion/extension, movement time, hand peak velocity, number of velocity peaks (NVP), and spectral arc length (SPARC) were extracted for the whole movement as well as the subphases of reaching distally and proximally. The effects of the factors gesture versus grasp movements, and the impairment level on the kinematics of the whole task were tested. Similarities considering the metrics expressions and relations were investigated for the subphases of reaching proximally and distally between tasks and subgroups. RESULTS Data of 26 stroke and 5 healthy subjects were included. Gesture and grasp movements were differently expressed across subjects. Gestures were performed with larger shoulder motions besides higher peak velocity. Grasp movements were expressed by larger trunk, forearm, and wrist motions. Trunk displacement, movement time, and NVP increased and shoulder flexion/extension decreased significantly with increased impairment level. Across tasks, phases of reaching distally were comparable in terms of trunk displacement, shoulder motions and peak velocity, while reaching proximally showed comparable expressions in trunk motions. Consistent metric relations during reaching distally were found between shoulder flexion/extension, elbow flexion/extension, peak velocity, and between movement time, NVP, and SPARC. Reaching proximally revealed reproducible correlations between forearm pronation/supination and wrist flexion/extension, movement time and NVP. CONCLUSION Spatiotemporal differences between gestures versus grasp movements and between different impairment levels were confirmed. The consistencies of metric expressions during movement subphases across tasks can be useful for linking kinematic assessment standards and daily living measures in future research and performing task and study comparisons. TRIAL REGISTRATION ClinicalTrials.gov Identifier NCT03135093. Registered 26 April 2017, https://clinicaltrials.gov/ct2/show/NCT03135093

Exploring the Complexities of Real World Upper Limb Performance after Stroke

Stroke is the leading cause of long-term disability in the United States. Hemiparesis, or weakness on one side of the body, is a common impairment following a stroke. Approximately 80% of individuals with stroke will experience upper limb paresis, with only a small percentage regaining full functional use of their paretic upper limb. Individuals report ongoing difficulties with incorporating their paretic upper limb into routine activities after a stroke. Rehabilitation interventions often try to increase real world upper limb use by improving what an individual is capable of doing (i.e. capacity) in the rehabilitation clinic. Both clinicians and researchers assume that improving in-clinic capacity translates to increased use (i.e. performance) in daily life. For this dissertation, we explicitly tested the assumption that improved upper limb capacity translates to increased upper limb performance, or use, in daily life. Additionally, we explored known factors that influence human behavior (e.g. confidence, motivation) as they relate to upper limb performance, or use, in adults with stroke. Using sensors (i.e. wrist-worn accelerometers), we tested the assumption that improved in-clinic upper limb capacity translates to increased upper limb performance, or use, in daily life in adults with chronic (≥ 6 months) upper limb paresis post-stroke. Testing this common assumption provided important insights into the efficacy of an in-clinic intervention for improving upper limb use in the free-living environment. Many personal, environmental, biological, and psychosocial factors influence human behavior and the activities individuals choose to engage in throughout their day. There is a growing emphasis on the potentially powerful role self-efficacy and other psychosocial factors may play in the stroke recovery process. Currently, there are limited data on how psychosocial factors, specifically related to the upper limb, evolve over the critical period of motor recovery (\u3c 6 months post-stroke). Here, we quantified the natural time course of belief further improvement of the paretic upper limb is possible, confidence, and motivation to use the paretic upper limb in daily life, as well as self-reported barriers to upper limb recovery. These data provide a more robust understanding of how psychosocial factors evolve as overall recovery improves. Additionally, these data provide important information about potential mechanisms for action for future upper limb interventions. The final project of this dissertation maps the natural trajectory of upper limb performance over the first 12 weeks post-stroke. Presently, no studies have examined the natural trajectory of sensor-measured upper limb performance over the same period of time when majority of upper limb motor recovery occurs. We sought to characterize the relationship between upper limb performance and psychosocial factors by testing belief, confidence, and motivation as potential moderators of upper limb performance in daily life. The reported findings show that in-clinic improvements in upper limb capacity do not directly translate to increased upper limb performance, or use, in daily life in the chronic phase of stroke recovery. Indeed, improving what someone is capable of doing does not indicate their behavior will change in daily life. These results help distinguish between upper limb capacity and upper limb performance. While conceptually similar, they are distinct constructs. Belief, confidence, and motivation to use the paretic upper limb in daily life are remarkably high early, and remain high over the first 24 weeks (6 months) post-stroke. Upper limb performance in daily life does improve early (\u3c12 weeks) after stroke. This change, however, is not moderated by belief, confidence, and motivation. Together, this dissertation provides multi-dimensional information related to upper limb performance after stroke. These results will lead to a more integrated approach for optimizing upper limb performance outcomes, a top priority for people post-stroke

Physical Activity Comparison Between Body Sides in Hemiparetic Patients Using Wearable Motion Sensors in Free-Living and Therapy: A Case Series

Background: Physical activity (PA) is essential in stroke rehabilitation of hemiparetic patients to avoid health risks, and moderate to vigorous PA could promote patients' recovery. However, PA assessments are limited to clinical environments. Little is known about PA in unguided free-living. Wearable sensors could reveal patients' PA during rehabilitation, and day-long long-term measurements over several weeks might reveal recovery trends of affected and less-affected body sides.Methods: We investigated PA in an observation study during outpatient rehabilitation in a day-care center. PA of affected and less-affected body sides, including upper and lower limbs were derived using wearable motion sensors. In this analysis we focused on PA during free-living and clinician guided therapies, and investigated differences between body-sides. Linear regressions were used to estimate metabolic equivalents for each limb at comparable scale. Non-parametric statistics were derived to quantify PA differences between body sides.Results: We analyzed 102 full-day movement data recordings from eleven hemiparetic patients during individual rehabilitation periods up to 79 days. The comparison between free-living and clinician guided therapy showed on average 16.1 % higher PA in the affected arm during therapy and 5.3 % higher PA in the affected leg during therapy. Average differences between free-living and therapy in the less-affected side were below 4.5 %.Conclusion: We analyzed PA of patients with a hemiparesis in two distinct rehabilitation settings, including free-living and clinician guided therapies over several weeks and compared MET values of affected and less-affected body sides. In particular, we investigated PA using individual regression models for each limb. We demonstrated that wearable motion sensors provide insights in patient's PA during rehabilitation. Although, no clear PA trends were found, our analysis showed patients' tendency to sedentary behavior, confirming previous lab study results. Our PA analysis approach could be used beyond clinical rehabilitation to devise personalized patient and limb-specific exercise recommendations in future remote rehabilitation