Browsing by Subject "Stroke"

Now showing 1 - 20 of 21
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    Algorithms for Identification of Acute Stroke Hospitalizations in Medicare Data
    (2013-09) Fuller, Candace
    Medicare claims (CMS) are a source of nationwide data on various disease conditions including stroke. Development of acute stroke hospitalization identification algorithms in CMS data could allow these data to be used more widely. Our aims were: 1) Link a validated, population-based, acute stroke hospitalization database to CMS data; 2) Validate the CMS Chronic Conditions Warehouse (CCW) stroke definition; 3) Develop and test algorithms to identify acute stroke hospitalizations in CMS data. Aim 1: We linked 90% of year 2000 Minnesota Stroke Survey (MSS) hospitalizations to CMS enrollment data and 74% to CMS hospitalization claims. No CMS claim was located for 16% of MSS hospitalizations linked to CMS enrollment data; 84% of these patients were enrolled in an HMO plan. Inclusion of the working aged and Medicare ineligible patients in MSS may account for inabilities to link some hospitalizations to CMS claims. Aim 2: When the CCW stroke definition was compared to acute stroke hospitalizations in MSS, sensitivity [SEN] was 97% and specificity [SPE] was 99%. However, we observed many false positives (positive predictive value [PPV] 78%). False positives increased when both CMS hospitalization and physician claims identified stroke cases. Aim 3: We used the Classification and Regression Tree (CART) modeling framework to develop and test algorithms to identify stroke in CMS data. The algorithm with best discriminative performance identifies cases with an acute stroke hospitalization discharge code in their hospital record in CMS hospitalization claims (Test data [TD]: SEN=90%, SPE=96%, area under the receiver operating curve [AUC]=0.94). Discriminative performance was also high for the algorithm identifying CMS hospitalizations for cases meeting the World Health Organization stroke definition (TD: SEN=91%, SPE=95%, AUC=0.93). Our CART algorithms are available for validation with other data sets. Potential utility of developed algorithms has broader implications for stroke epidemiology and health services research.
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    Association of Caffeine Use on Mortality in Survivors of Stroke and Myocardial Infarction. An analysis of Third National Health and Nutrition Examination Survey Mortality Follow-up Study
    (2015-05) Suri, Muhammad
    To study if there is any association of caffeine with mortality secondary to cardiovascular disease in survivors of myocardial infarction (MI) and stroke, we used the Third National Health and Nutrition Examination Survey and the Linked Mortality File. Out of 1083 survivors of stroke or MI, 51 died of stroke, 117 of MI and 305 of ischemic heart disease, during a mean follow-up of 9.0 ± 5.2 years. Using Cox-proportional hazard model adjusted for vascular risk factors, among survivors of cardiovascular disease relative risk (RR) for fatal stroke (RR=0.3), fatal cardiovascular disease (RR=0.5) and all-cause mortality (RR=0.7) was significantly lower among those with caffeine consumption of 3+ cups per day (vs no caffeine). Similarly, among survivors of stroke, RR for stroke related mortality was lower in those with 3+ cups of caffeine consumption per day. In conclusion, caffeine consumption may be associated with lower risk of cardiovascular death.
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    Atrial Fibrillation and Warfarin
    (2012-07-23) Kreuser, Lucas Jordan
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    Carotid Stenosis: Information for Patients
    (2010-07-29) Briese, Nick
    Carotid stenosis increases your risk of stroke and transient ischemic attack (TIA). Aspirin, along with control of blood pressure and cholesterol and smoking cessation, can help lower the risk of stroke. This pamphlet briefly describes carotid stenosis, risk factors for carotid stenosis, and steps that patients can take to reduce their risk for carotid stenosis and the problems that come with it.
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    Constraint Induced Movement Therapy (CIMT) and Stroke Recovery
    (2009-05-04) Henry-Socha, Nancy A.
    Constraint Induced Movement Therapy (CIMT) is a therapy modality which can provide greater improvements in motor performance and functional use of affected upper limbs than traditional interventions. It is also showing efficacy in improvement up to two years post stroke.
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    Data used for the RUMM2030 Rasch analysis of the scale Warwick-Edinburgh Mental Well-being Scale (WEMWBS)
    (2022-02-28) Deng, Wei; Carpentier, Sydney; Blackwood, Jena; Van de Winckel, Ann; avandewi@umn.edu; Van de Winckel, Ann; Brain Body Mind Lab
    This datafile is connected to a planned manuscript submission for the journal BMC Health and Quality of Life Outcomes. This xls file contains brief demographic and clinical data as well as the scoring of the 14 items of the Warwick-Edinburgh Mental Well-being Scale (WEMWBS) in Community-Dwelling Adults and in Adults with Stroke in the US.
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    Effects of Cutaneous Cueing on Step Initiation Anticipatory Postural Adjustments in Stroke Survivors
    (2015-05) Dowdal-Osborn, Megan
    Step initiation is preceded by a series of electrical and mechanical events that constitute what are commonly termed anticipatory postural adjustments (APAs). These APAs are highly predictable in persons without neuromuscular or musculoskeletal impairments and are known to be advantageously influenced with sural nerve stimulation. Anticipatory postural adjustments in the stroke survivor population have been rarely studied and are poorly understood. Furthermore, the influence of sural nerve cueing on step initiation in stroke survivors has not been explored. This study investigated step initiation APAs in stroke survivors (n=15) in a reaction time paradigm under two "go" cues: (1) sural nerve stimulation; (2) visual light onset. Subjects performed 30 steps with each leg given randomly assigned go cues. Four primary outcomes were assessed: (1) Loading forces; (2) COP excursions; (3) EMG activity in bilateral tibialis anterior and gluteus medius muscles; (4) Reaction times of loading forces, COP and EMG onsets. Sural cueing significantly increased vertical loading, COP and EMG reaction times across all conditions of the stepping trials. The sural cue also produced significantly faster vertical loading compared to a visual cue. The loading amount and speed, EMG activity and net COP displacement were significantly influenced by the stepping condition (paretic or non-paretic). The results of this study are the first to report the ability to improve both reaction times and various aspects of the APA with sural cueing in a stroke population. In that prolonged reaction times are believed to be a major predictor of falls and APAs are diminished in stroke survivors, these results encourage training studies for improving reaction times and APAs.
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    Effects of occupational therapy task-oriented approach in upper extremity post-stroke rehabilitation.
    (2011-08) Almhdawi, Khader
    There is a need for effective Upper Extremity (UE) post-stroke rehabilitation approaches. The Occupational Therapy Task-Oriented (TO) approach was described early in the nineties of the past century. Many of the TO principles were supported in the literature. However, the TO as a whole was only evaluated in case studies. This study aimed to evaluate the functional and the impairment effects of this approach and to refine its treatment protocol. Twenty participants with stroke of three months or more fulfilled the minimal affected UE active movements of at least 10° of shoulder flexion and abduction and elbow flexion-extension and volunteered for this study. Participants were randomized into two order groups. The immediate group got 3 hours of TO treatment per week for six weeks and then got six weeks of no treatment control while the delayed intervention group underwent the reversed order. Participants were evaluated before the first phase, at the cross over, and after the second phase by trained, blinded evaluators. The treatment change scores from both groups were compared with those of the control. The results supported the TO functional superiority as indicated by significant and clinically meaningful changes in the Canadian Occupational Performance Measure (COPM), the Motor Activity Log (MAL), and the time scale of the Wolf Motor Function Test (WMFT). The result failed to support hypothesis of the impairment effects superiority of the TO. We conclude that the TO approach is an effective UE post-stroke rehabilitation approach in improving the UE functional abilities. More studies are needed to provide more evidence for this approach and to illuminate more of its therapeutic abilities with different stroke severity and chronicity levels.
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    The Efficacy of a Forearm Rotation Orthosis for Persons with a Hemiparetic Arm
    (2018-06) Yu, Chih-Huang
    Objectives. To examine the efficacy of a dynamic forearm rotation orthosis used as the sole intervention and in combination with the Occupational Therapy Task-Oriented (OTTO) approach as well as to evaluate the efficacy of the OTTO approach on the functional performance of persons post-stroke with a hemiparetic arm. Method. A matched, randomized, two- group, single-blinded, repeated measures designed was used. Volunteer sample of persons with chronic stroke (N=14) were first matched on motor function and then randomly assigned to Group A or B. Group A (N=8) experienced six weeks of orthotic intervention followed by six weeks of orthosis plus OTTO intervention (3 hour/week for 6 weeks). Group B (N=6) experience no treatment for six weeks followed by another six weeks of OTTO intervention. The primary outcome measures were functional performance, including self-perceived performance and satisfaction (Canadian Occupational Performance Measure (COPM)), motor function (Wolf Motor Function Test (WMFT)), and self-reported use of the affected limb (Motor Activity Log (MAL)). The secondary outcome measures were impairments, including active range of motion and strength of the upper extremity, grip, and pinch. Participants were evaluated before and after each intervention phase. Results. No significant differences were found between participants who received orthotic intervention and those who had no treatment. By the end of study, participants who receive the OTTO intervention as the sole intervention and in combination with orthosis showed clinically important improvements in self-perceived performance and satisfaction on the COPM and statistical significant improvement in self-report amount and quality of use of the affected limb on the MAL. No significant differences in functional performance and impairment measures were found between participants who received the OTTO intervention as the sole intervention and in combination with the orthosis. Conclusions. The 6 weeks of functional training protocol provided clinically important benefits to persons post-stroke in self-perceived functional performance (COPM), but not in motor function (WMFT) and impairment measures (active ROM and strength of UE, grip, and pinch). However, due to technical failure for monitoring adherence to orthotic use, the efficacy of the forearm rotation orthosis for persons post-stroke remains unclear.
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    Investigation of intravenous administration of non-hematopoietic umbilical cord blood cells as a therapy for stroke
    (2013-05) Juliano, Mario
    Stroke is one of the leading causes of death in the United States. Limitations of currently available stroke treatment include a 3 hour time window for recombinant tissue plasminogen activator. Stem cells have become promising for the treatment of a variety of neurodegenerative diseases, including stroke. Therapies in this category include stimulation of endogenous neurogenesis, as well as the delivery of exogenous stem cells.This thesis focuses on the investigation of the intravenous delivery of a CD34 negative subset of umbilical cord blood stem cells as a therapy for stroke. Methods employed for this investigation include next generation sequencing technologies for gene expression profiling, 19-fluorine tracking of stem cells with MRI, and fluorescence biodistribution tracking.
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    Migraine with Aura: More Than Just a Bad Headache?
    (2010-07-22) Tyner, Harmony
    Migraine with aura is common among women in the primary care setting. In addition to being uncomfortable and inconvenient, migraine with aura is also an independent risk factor for stroke in some women, particularly those below the age of 55, with low blood pressure and cholesterol. This patient education tool is a tri-fold brochure designed to help the reader identify who is at risk, how big the risk is, and what can be done to mitigate the risk of stroke in women who experience migraine with aura.
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    Motor imagery retraining after stroke with virtual hands: an immersive sensorimotor rhythm-based brain-computer interface
    (2013-06) Doud, Alexander James
    The burden of stroke on the health care system at large and individual patients is profound, and current techniques for rehabilitation rely on the training and dedication of the rehabilitation specialist. Here we present an immersive, virtual reality environment for presenting feedback to subjects in the form of a set of virtual hands. By just imagining the use of the left or right hands, subjects could see movement in the virtual hands and learn to modulate their thoughts to control them. Allowing subjects task relevant motor feedback early could prove an effective means of early rehabilitation. The implications of this training are presented in 6 patients who had suffered cortical or basal ganglia stroke. Using the system described below, the subject's were able to achieve control accuracies of as high as 81% in a binary classification task and showed progression of skill in as little as three, two-hour experimental sessions.
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    Niacin
    (2012-04-10) Bryan, Andrew
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    Should I take a blood thinner after a stroke?
    (2012-04-10) Vlasak, Andrea
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    So I have atrial fibrillation…
    (2011-08-03) Edin, Colt
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    Stroke disparities and selection bias in an American Indian cohort: the Strong Heart and Strong Heart Stroke Studies
    (2015-12) Muller, Clemma
    Abstract Background. American Indians experience higher stroke morbidity and mortality compared to US general population, but are underrepresented in public health research. Data on incident stroke in American Indians derive mainly from the Strong Heart Study (SHS), a population-based cohort study of cardiovascular disease in 4549 American Indians who were 45-74 years old when baseline exams were conducted from 1988-1990. The SHS had higher stroke rates than reported for Whites and African Americans in external comparisons to other cohorts. These findings suggested similar disparities in covert vascular brain injury (VBI), an often asymptomatic form of cerebrovascular disease that precedes clinical events. Accordingly, from 2010-2013 the Strong Heart Stroke Study (SHSS) used structural cranial magnetic resonance imaging to assess covert VBI in 1033 surviving members of the SHS. Goals. In this dissertation we addressed three limitations to using SHS and SHSS data for analysis of stroke and covert VBI in American Indians: Manuscript 1) lack of research that directly compares stroke incidence and mortality in American Indians vs. other racial groups, and which limits current knowledge to external comparisons that do not account for differences in stroke risk factors; Manuscript 2) potential selection bias in SHSS data when survival and participation of cohort members depends on both the exposures and outcomes of interest; and Manuscript 3) an inherent limitation in effect measures estimates that condition on categories defined by progressively older age or longer time since exposure, and which leads to observed point estimates that are potentially biased estimates of the true effects. Manuscript 1. Methods: We pooled data from the SHS and the Atherosclerosis Risk in Communities Study (ARIC) to compare stroke risk and post-stroke mortality in American Indians vs. Blacks and Whites. We used Cox regression to estimate hazard ratios (HR) with attained age as the time scale to account for differences in baseline age at enrollment, and adjusted estimates for baseline factors that included prevalent hypertension and diabetes. Due to effect modification, analyses were stratified by birth year tertile (1914-1930, 1931-1937, and 1938-1947). We used logistic regression to compare 30-day and 1-year post-stroke mortality among participants from both studies who experienced stroke during follow-up. Results: Stroke risk among American Indians in the SHS was lower than among Blacks for all birth year tertiles (1914-1930: HR = 0.9 (95% CI = 0.7, 1.1); 1931-1937: HR = 0.9 (95% CI = 0.7, 1.2); 1938-1947: HR = 0.9 (95% CI = 0.7, 1.2)), but higher than among Whites (1914-1930: HR = 1.6 (95% CI = 1.3, 2.0); 1931-1937: HR = 2.2 (95% CI = 1.7, 2.8); 1938-1947: HR = 2.7 (95% CI = 2.0, 3.6)) in ARIC. Adjusting for risk factors including prevalent diabetes at baseline resulted in strengthening of associations compared to Blacks (oldest to youngest tertile HR = 0.8 (95% CI = 0.6-1.0); 0.7 (95% CI = 0.5-1.0); and 0.6 (95% CI = 0.4-0.8)), and attenuation of associations compared to Whites (oldest to youngest tertile HR = 1.1 (95% CI = 0.9-1.5); 1.2 (95% CI = 0.9-1.6); and 1.1 (95% CI = 0.8-1.5)). American Indians had higher risk of 30-day and 1-year mortality compared to Blacks (relative risk = 2.2 (95% CI = 1.4-3.0) and 1.4 (95% CI = 1.1-1.8), respectively) and Whites (relative risk = 1.8 (95% CI = 1.2-2.3) and 1.5 (95% CI = 1.1-1.8), respectively). These comparisons persisted after adjusting for risk factors. Manuscript 2. Methods: We used marginal structural models with inverse probability weighting to adjust for selection bias in the SHSS, applied to the analysis of prevalent hypertension and covert VBI as measured by white matter hyperintensities. Predicted probabilities of survival from 1988-2010 and participation of survivors were estimated and inverted to create weights, and stabilized using conventional methods to reflect the distribution of hypertension in cohort participants. In addition, we computed novel stabilized weights that account for each person’s probability of meeting the inclusion criterion of remaining stroke-free up to their SHSS exam. These weights allowed us to avoid over-correcting for attrition of individuals who would have subsequently gone on to experience clinical stroke. We applied these weights to estimate the prevalence difference (PD) for the association of hypertension with a binary indicator of abnormal VBI, as well as the mean difference (MD) for a continuous variable reflecting the ratio of white matter/total intracranial volume; the ratio estimates were multiplied by 1000 to simplify presentation of results. Hypertension was evaluated as both a cross-sectional risk factor and accounting for longitudinal trends in prevalence since baseline. Results: In the cross-sectional analysis, hypertension was associated with higher prevalence of abnormal VBI in unweighted models (PD = 7.9% (95% CI = -2, 17)). The point estimate increased 13% after selection weighting (PD = 8.9% (95% CI = 0, 18)). Prevalent hypertension was likewise associated with a higher proportion of white matter volume compared to the total intracranial volume in unweighted models (MD = 0.8 (95% CI = -0.4, 2.0)) and after selection weighting (MD = 0.9 (95% CI = -0.3, 2.1)). Adjusting weights to account for the stroke-free inclusion criterion did not change results compared to the conventional stabilized estimates. In the analysis treating hypertension as a longitudinal exposure, prevalent hypertension at all three study exams was associated with higher prevalence of abnormal VBI (PD = 8.0% (95% CI = -6, 22)) and higher ratio of white matter/total intracranial volume (MD = 1.7 (95% CI = 0.0, 3.4)) compared to not having hypertension at any exam. Selection weighting had no appreciable impact on point estimates in the longitudinal analysis. Manuscript 3. Methods: We used Mathematica software with constrained optimization to identify bounds for the risk difference (RD) when conditioning on event-free survival to some minimum age or time since exposure. Bounds were identified assuming only causative exposure effects in the target population, and allowing for exposure to prevent disease in some individuals so long as the causative effects were proportionally greater in the overall population. We applied these bounds to the analysis of post-stroke survival from Manuscript 1, with follow-up time divided into 0-30 days, 31-180 days, and 181-365 days after the stroke event. Results: The RD attenuated across follow-up periods for American Indians vs. Blacks (0-30 days: RD = 14% (95% CI = 6, 23); 31-180 days: RD = -1% (95% CI = -7, 4); 181-365 days: RD = -3% (95% CI = -7, 2)) and Whites (0-30 days: RD = 12% (95% CI = 3, 21); 31-180 days: RD = 1% (95% CI = -5, 6); 181-365 days: RD = -2% (95% CI = -6, 3)). With assumptions of only causative exposure effects, bounds on the the conditional risk difference for American Indians vs. Blacks were 0-16% for 0-30 days post-stroke event, and 1-13% for 181-365 days post-stroke. For American Indians vs. Whites the bounds were 0-14% for 0-30 days post stroke, and 0-13% for 31-180 days post-stroke. Allowing for preventive effects that were equal to or less than causative effects yielded bounds that were too wide for meaningful interpretation (all lower bounds = 0; all upper bounds ≥ 30). Conclusions. We found that American Indians in the SHS had lower stroke risk than Blacks, but not than Whites, in ARIC after adjusting for risk factors that included prevalent diabetes. These findings suggest that diabetes may be a factor behind stroke disparities in some American Indian communities. American Indians had higher post-stroke mortality than Blacks and Whites especially in the first 30 days after stroke onset, but cumulative risk comparisons and analyses using bounds for conditional effects were consistent with elevated risk persisting for at least 1 year. Among long-term survivors of the SHS who participated in the SHSS assessment of covert VBI, selection bias may be of concern for some analyses. Although adjusting selection weights for the stroke-free inclusion criterion did not change results in this example, other studies with inclusion criteria that result in excluding larger proportions of the study population may wish to include sensitivity analyses with similar adjustments.
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    Stroke or TIA prevention in the setting of new onset atrial fibrillation.
    (2010-07-29) Surowiecka, Maria
    Atrial fibrillation is an irregular heartbeat that can lead to blood clots in the heart. These clots can dislodge and travel to the brain, resulting in stroke and possible death. This pamphlet describes how patients with atrial fibrillation, especially those with a prior history of stroke or mini-stroke (TIA), should be on anticoagulation medication with warfarin to prevent clot formation.