Browsing by Subject "stroke"
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Item Aspirin May Help Prevent Heart Attack and Stroke(2010-07-21) Merkle, AlexanderAspirin can help prevent heart disease and stroke for some people. The aspirin used for prevention is affordable and found over-the-counter. Aspirin may not be the right choice for some people, especially those who are at risk for bleeding. Talk to your doctor before beginning to take aspirin to prevent heart disease and stroke.Item Atrial Fibrillation: Prevention of Strokes(2009-09-18) Anderson, SarahAtrial fibrillation is the most common arrhythmia seen in the clinical setting. This so called, irregularly irregular rhythm is associated with thrombosis, or clot formation, in the heart. These clots have the potential to break free and travel to different places in the body, including the brain. Clots traveling to the brain prevent adequate circulation, resulting in a stroke. This pamphlet describes atrial fibrillation, why it has the increased potential to form thromboses, which patients are at increased risks of strokes, and the treatment options including antithrombotic therapies.Item Beta Blockers: A Guide for Patients(2009-09-18) Sharpe, EmilyIn patients who are at risk for heart disease, beta blockers started during surgery prevented heart attack but increased the risk of stroke and death. The current guidelines that recommend the initiation of beta-blocker therapy in patients having noncardiac surgery should be reevaluated. However, patients who have been treated with beta blockers for a long time should continue their medication throughout the perioperative period.Item Carotid Artery Stenosis: what you should know.(2008-11-24) Mitchell, JamieThis is a patient education tool explaining the risk factors, symptoms, and various treatment options for carotid artery stenosis. Patient’s who are at high risk for surgery can benefit from a less invasive procedure called stenting.Item Combining TMS and EEG for Characterizing Motor Network Interactions and Improving Motor Recovery after Stroke(2016-12) Johnson, NessaImaging of electrophysiological activity within the brain is crucial to understanding function in both healthy and disease conditions. The overall goal of this dissertation is to use both non-invasive neuromodulation and non-invasive neuroimaging to characterize and manipulate underlying neurological network dynamics in both healthy and stroke affected subjects. The two main applications of work are for the evaluation of peripheral motor activity on motor network dynamics in healthy subjects, and as a brain-based treatment for motor recovery after stroke. Combined transcranial magnetic stimulation (TMS) and electroencephalography (EEG) imaging can be used to analyze cortical reactivity and connectivity of underlying brain networks. However, the effect of corticospinal and peripheral muscle activity on TMS-evoked potentials (TEPs), particularly in motor areas, is not well understood. One aim of the present dissertation is to evaluate the relationship between cortico-spinal activity, in the form of peripheral motor-evoked potentials (MEPs), and the TEPs from motor areas, along with the connectivity among activated brain areas. This research demonstrates that TMS-EEG, along with adaptive connectivity estimators, can be used to evaluate the cortical dynamics associated with sensorimotor integration and proprioceptive manipulation. Stroke is a devastating neurological disorder which can result in lasting impairment affecting quality-of-life. Combining contralesional repetitive TMS (rTMS) with EEG-based brain-computer interface (BCI) training can address motor impairment after stroke by down-regulating exaggerated inhibition from the contralesional hemisphere and encouraging ipsilesional activation. Another aim of this dissertation was to evaluate the efficacy of combined rTMS+BCI, compared to sham rTMS+BCI, and BCI alone, on motor recovery after stroke in subjects with lasting motor paresis. As evaluated in a series of stroke patients, such a brain-based neuromodulatory and imaging approach for rehabilitation could potentially lead to greater understanding of the influence of brain network dynamics in recovery and design of optimal treatment strategies for individual patients. Our findings demonstrate the feasibility and efficacy of not only combined rTMS+BCI but also BCI alone, as demonstrated by significant improvements over time in behavioral and electrophysiological measures. In summary, the present dissertation research developed and evaluated the combination of neuromodulation and neuroimaging for the non-invasive mapping of motor network activities in the diseased and normal brain. Evaluations were conducted in healthy controls to evaluate the influence of peripheral muscle activity on resulting neural network activity, as well as in stroke patients to provide a brain-based treatment for motor rehabilitation. The results obtained suggest the importance of non-invasive spatiotemporal neuroimaging, along with non-invasive neuromodulation, for providing insight into neuroscience questions and providing novel treatments for clinical problems in a brain-based manner.Item Infection and Cardiovascular Disease: The Atherosclerosis Risk in Communities Study(2017-07) Cowan, LoganInfection has been identified as both a chronic and acute risk factor of cardiovascular disease (CVD). Despite the growing body of evidence, additional research elucidating the relationship between infection and CVD is needed. This dissertation employs longitudinal data from the Atherosclerosis Risk in Communities (ARIC) study, the Longitudinal Investigation of Thromboembolism Etiology (LITE) ancillary study, the Dental-ARIC (D-ARIC) ancillary study, and the corresponding ARIC study participant Centers for Medicare and Medicaid Services (CMS) data to examine the relationship between infection and CVD. In the first manuscript we assessed the longitudinal relationship between self-reported periodontal disease and clinical periodontal disease and incident venous thromboembolism (VTE). Self-reported periodontal disease was associated with 30% higher VTE risk that remained significant or borderline significant after adjustment. Crude associations between clinical periodontal disease classifications were attenuated with adjustment and were no longer significant. In the second manuscript we assessed the longitudinal relationship between history of endodontic therapy (ET) and incident coronary heart disease (CHD), ischemic stroke, heart failure, and VTE. We found no significant associations between self-reported history of ET and any of our outcomes of interest that remained after adjustment. In the final manuscript we used a case-crossover study design to evaluate infection as a potential trigger of CHD, ischemic stroke, and VTE. Infection was associated with higher odds of CHD, stroke, and VTE up to 90 days following the infection. The association between infection and CVD/VTE was graded such that the infection-CVD/VTE association was highest immediately following the infection and decreased as the time since the infection increased. Generally, outpatient infection was a weaker CVD/VTE trigger compared to all infections. Further research is needed to pinpoint if periodontal disease is independently associated with VTE risk and if periodontal prevention and treatment could reduce VTE risk. Our results do not support an independent association between endodontic therapy and CVD or VTE. The results of the third manuscript provide evidence in support of our hypothesis that infection is a CVD/VTE trigger. Patients with an infection who are at elevated risk of CVD should be considered potential candidates for CVD prophylaxis during and immediately after infection to reduce the otherwise elevated CVD/VTE risk.Item Investigation into the use of Pulsed Focused Ultrasound as a Method of Facilitating Homing of Umbilical Cord Blood Stem Cells after Systemic Administration in Ischemic Stroke Rat Models(2016-04) Hamborg, JoshuaStroke is a leading cause of mortality with no current therapies for chronic stroke victims. Our work investigates how to help chronic stroke patients regain function lost due to their stroke. This was accomplished by exploring how the use umbilical cord blood stem cells (UCBSCs), used in conjunction with pulsed focused ultrasound (pFUS), could provide a safe, efficient, and relatively noninvasive method for providing neuroregenerative therapy. Using rat stroke models that have undergone unilateral MCA occlusion, we propose that tail vein injections of UCBSCs, followed immediately afterwards by pFUS targeted to regions of ischemic damage, will result in functional improvements due to engraftment and neural differentiation of the stem cells. Initial immunohistochemical analysis of control rat brain tissue investigated how the local neuroenvironment may become therapeutically favorable after transcranial pFUS treatments. Results obtained so far are preliminary.Item Optimization of Repetitive Transcranial Magnetic Stimulation With Priming In Chronic Stroke(2014-12) Cassidy, JessicaPurpose: Stroke is leading cause of long-term disability in the United States. The direct destruction of neural tissue from stroke combined with imbalances in transcallosal-mediated interhemispheric inhibition complicate motor recovery. Repetitive transcranial magnetic stimulation (rTMS) is thought to condition surviving but dormant neurons in the ipsilesional primary motor cortex (M1) region to become more amenable to voluntary recruitment during affected extremity movement. Low-frequency rTMS suppresses hyperexcitability in the contralesional hemisphere which can "disinhibit" the ipsilesional hemisphere resulting in greater ipsilesional M1 excitability. A bout of high-frequency excitatory rTMS, referred to as priming, potentiates the suppressive effects of low-frequency rTMS in healthy individuals. The objective of this study was to compare changes in brain excitability and affected hand function following three different rTMS treatments to ascertain whether potential gains from priming stimulation translate to the stroke brain. Methods: Eleven adults (3 females, mean age ± SD = 66 ± 9.4 years) with chronic stroke received three treatments (active 6-Hz priming + active 1-Hz rTMS, active 1-Hz priming + active 1-Hz rTMS, and sham 6-Hz priming + active 1-Hz rTMS) to contralesional M1 in random order over a five-week course with a one-week washout period between treatments. Cortical excitability including interhemispheric inhibition, short-interval intracortical inhibition, intracortical facilitation, and cortical silent period measures along with affected hand function were analyzed using a mixed effects linear model. The model checked for carryover, treatment-by-period interactions, and baseline differences before analyzing within- and between-treatment differences from baseline. Results: Active 6-Hz primed 1-Hz rTMS produced significant within-treatment differences in short-interval intracortical inhibition and cortical silent period duration from baseline indicating reduced intracortical inhibition. Compared to active 1-Hz and sham 6-Hz primed 1-Hz rTMS, active 6-Hz priming generated significantly greater decreases in cortical silent period duration. Discussion: The utility of priming in stroke does not present in such a straightforward manner as it does in healthy individuals given that active 6-Hz priming did not potentiate all outcome measures. Several potential factors are discussed. Our significant findings support the existence of `synaptic wisdom' in the stroke brain involving the deployment of homeostatic and/or metaplastic processes that preserve synaptic function.Item Preliminary Rasch analysis of the Multidimensional Assessment of Interoceptive Awareness in adults with stroke(2023-11-16) Blackwood, Jena; Carpentier, Sydney; Deng, Wei; Van de Winckel, Ann; avandewi@umn.edu; Van de Winckel, Ann; Brain Body Mind LabThis datafile is connected to a planned manuscript submission for the journal PLOS ONE. This xls file contains brief demographic and clinical data as well as the scoring of the 32 items of the Multidimensional Assessment of Interoceptive Awareness in Adults with Chronic Stroke in the US.Item Refining Prediction Of Atrial Fibrillation-Related Stroke Using The P2-Cha2Ds2-Vasc Score(2018-02) Maheshwari, AnkitIntroduction: In people with atrial fibrillation (AF), periods of sinus rhythm present an opportunity to detect pro-thrombotic atrial remodeling through measurement of P-wave indices (PWIs)—prolonged P-wave duration, abnormal P-wave axis, advanced inter-atrial block, and abnormal P-wave terminal force in lead V1. We hypothesized that addition of PWIs to the CHA2DS2-VASc score would improve its ability to predict AF-related ischemic stroke. Methods: We included 2229 Atherosclerosis Risk in Communities (ARIC) study and 700 Multi-Ethnic Study of Atherosclerosis (MESA) participants with incident AF and without anticoagulant use within 1 year of AF diagnosis. PWIs were obtained from study visit ECGs before development of AF. AF was ascertained using study visit ECGs and hospital records. Ischemic stroke cases were based on physician adjudication of hospital records. We used Cox proportional hazards models to estimate hazard ratios (HRs) and 95% confidence intervals (95% CIs) of PWIs for ischemic stroke. Improvement in 1-year stroke prediction was assessed by C-statistic, categorical net reclassification improvement (NRI), and relative integrated discrimination improvement (IDI). Results: Abnormal P-wave axis was the only PWI associated with increased ischemic stroke risk (HR, 1.84; 95% CI, 1.33-2.55) independent of CHA2DS2-VASc variables and that resulted in meaningful improvement in stroke prediction. The beta estimate was approximately twice that of the CHA2DS2-VASc variables, thus abnormal P-wave axis was assigned 2 points to create the P2-CHA2DS2-VASc score. This improved the C-statistic (95% CI) from 0.60 (0.51-0.69) to 0.67 (0.60-0.75) in ARIC and 0.68 (0.52-0.84) to 0.75 (0.60-0.91) in MESA (validation cohort). In ARIC and MESA, the categorical NRI (95% CI) were 0.25 (0.13-0.39) and 0.51 (0.18-0.86), respectively, and the relative IDI (95% CI) were 1.19 (0.96-1.44) and 0.82 (0.36-1.39), respectively. Conclusions: Abnormal P-wave axis—an ECG correlate of left atrial abnormality— improves ischemic stroke prediction in AF. Compared with CHA2DS2-VASc, the P2-CHA2DS2-VASc is a better prediction tool for AF-related ischemic stroke.Item Robot-Aided Assessment of Ankle Motion Sense and Associated Lesion-Symptom Mapping Analysis in Chronic Stroke(2023-06) Huang, QiyinBackground: Compromised ankle proprioception is a strong predictor of balance dysfunction in chronic stroke. However, objective, accurate methods for testing ankle proprioceptive function in clinical settings are not established. Only sparse data on ankle position sense and no systematic data on ankle motion sense dysfunction in stroke are available. Moreover, the lesion sites underlying impaired ankle proprioception have not been comprehensively delineated.Objectives: To address these knowledge gaps, this study aimed: 1) To examine the feasibility and test-retest reliability of a newly developed robotic technology that uses an adaptive psychophysical forced-choice method to obtain quantitative data on ankle position and motion sense acuity in healthy young adults. 2) To determine the extent and magnitude of ankle motion sense impairment observed in adults with chronic stroke and how such impairment coincides with position sense dysfunction using the robotic system. 3) To identify the brain lesions associated with ankle position and motion sense dysfunction. Methods: To verify aim 1, experiments 1 and 2 were conducted successively. Forty healthy adults (20 in each experiment, mean ± SD age 24 ± 3.9 years, F: 17) were recruited. The feasibility and test-retest reliability of the system were determined in Experiment 1. Experiment 2 was conducted to improve the motion sense test paradigm that controlled for confounding factors (time and position) that a person might use as motion cues to make a perceptual judgment of ankle joint motion. To verify aim 2 and 3, twelve stroke survivors (mean ± SD age, 54 ± 10.9 years, on average 6 years post-stroke, 10 ischemic, 2 hemorrhagic lesions), and 13 neurotypical adults participated. During the testing, the robot passively plantarflexed a participant’s ankle to two distinct positions or at two distinct velocities. Participants subsequently indicated which of the two movements was further/faster. Based on the stimulus-response data, a psychometric function was obtained, and just-noticeable-difference (JND) thresholds, as a measure of bias, and intervals of uncertainty (IU), as a measure of precision were derived. For adults with stroke (n = 11), lesion-symptom analyses identified the brain lesions associated with observed proprioceptive deficits in adults with stroke. Results: For aim 1, objective data on position sense acuity (JND threshold: 0.80° ± 0.10°, IU: 0.84° ± 0.41°) and motion sense acuity (JND threshold: 0.73°/s ± 0.11°/s, IU: 0.60°/s ± 0.29°/s) were obtained in experiment 1. Additionally, moderate-to-excellent test-retest reliability of the system has been established based on the JND threshold for position sense (average intraclass correlation coefficient (ICC) = 0.86 [0.50 - 0.98], standard error of measurement (SEM) = 0.0173°) and motion sense (average ICC = 0.88, SEM = 0.0197°/s). In experiment 2, the results showed that the mean JND motion sense threshold increased almost linearly from 0.53°/s at the 10°/s reference to 1.6°/s at 20°/s (p < 0.0001). Perceptual uncertainty increased similarly (median IU = 0.33°/s at 10°/s and 0.97°/s at 20°/s; p < 0.0001). Both measures were strongly correlated (rs = 0.70). For aim 2, 83% of adults with stroke exhibited abnormalities in either position or motion sense, or both. JND and IU measures were significantly elevated compared to the control group (JNDPosition: +77%, p = 0.03; JNDMotion: +153%, IUPosition: +148%, and IUMotion: +78%, all p < 0.01). The JND and IU values of both senses were strongly positively correlated (rs = 0.56-0.62). For aim 3, lesions in the primary somatosensory, posterior parietal, motor cortices, insula, and temporoparietal regions (supramarginal, superior temporal, Heschl's gyri) were associated with deficits in both senses. Meanwhile, lesions in the medial/lateral occipital cortex were linked to impaired position sense, and temporal pole lesions were associated with impaired motion sense. Moreover, temporal pole lesions were significantly related to motion sense deficit (z-score = 3.26). Conclusion: This research demonstrated that the proposed robot-aided test produces quantitative data on human ankle position and motion sense acuity. It yields two distinct measures of proprioceptive acuity (i.e., bias and precision) as part of a comprehensive analysis of proprioceptive function. Using the robot-aided assessment, this study documented the initial data on the magnitude and prevalence of ankle position and motion sense impairment in adults with chronic stroke. Proprioceptive dysfunction was characterized by elevated JND thresholds and increased uncertainty in perceiving ankle position/motion. Associated cortical lesions for both proprioceptive senses were largely overlapping, but temporal pole lesions were independently linked to motion sense dysfunction.Item Supporting Care Partner Mental Health: Feasibility of a Behavioral Intervention Tailored for Stroke Survivor-Care Partner Dyads(2020-04) Hultman, MeghanThis dissertation begins with an introduction to the current state of the science in patient-caregiver dyad research. Current studies have largely focused on cancer and dementia, and additional research is needed in other chronic conditions. Evidence suggests that various factors may impact caregiver outcomes such as caregiver burden, depression, and quality of life (QOL), and these outcomes may improve with intervention. Three manuscripts are presented, the first presenting a review of the literature related to characteristics of stroke survivors that are associated with depressive symptoms in their caregivers. The findings offer support for dyad-focused interventions to manage depressive symptoms in stroke survivor-caregiver dyads. This led to development of a two-arm randomized feasibility study exploring the use of problem-solving therapy (PST) compared to stroke-related health education for depressive symptoms and QOL in stroke survivor-caregiver dyads. Dyad-focused PST is a novel approach. The second manuscript describes challenges and lessons learned tailoring PST to dyads. These include: personalizing the intervention, balancing participation, maintaining focus, managing conflict, and addressing ethical concerns. Considerations for future research involving dyad-focused interventions are presented. The third manuscript illustrates the design, methods and results of the study. Recruitment required substantial efforts, yielding a recruitment rate of 14.4%. Overall attrition was 25%. Dyads completing the study showed excellent protocol adherence and provided positive experiential feedback, especially for PST, supporting intervention acceptability. No significant changes in outcome measures were seen over time for care partners or stroke survivors. Finally, the work is synthesized, highlighting key takeaways and implications for research and practice.