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Asymmetry of weight-bearing and impaired ability to maintain centre of pressure in midline contribute to an increased fall risk during sit-to-stand in people with stroke. The main objective of this thesis was to investigate the effect of constraint-induced movement strategies on affected limb weight-bearing and measures of balance in people with stroke. Four studies were conducted to achieve this objective. Study one and two investigated the methodology for describing sit-to-stand performance in people with stroke and reliability of measures of sit-to-stand performance. Findings from study one demonstrated that methods for describing sit-to-stand performance in healthy adults are not feasible in people with stroke and established a method for describing sit-to-stand performance in subsequent studies. Findings from the second study demonstrated within and between day reliability of temporal, weight-bearing and displacement measures of sit-to-stand performance in both groups. The third study of this thesis described impairments of sit-to-stand performance in people with stroke when compared with healthy age and sex matched adults. The findings confirmed results from previous studies and further described sit-to-stand performance by demonstrating a shift in the frontal plane centre of pressure and centre of mass position toward the unaffected limb at seat-off in people with stroke. The final study investigated the effect of three constraint-induced movement strategies on sit-to-stand performance in people with stroke. The results demonstrated increased affected limb weight-bearing and a shift of the centre of pressure and centre of mass toward midline with all of the strategies. Only two of the strategies altered centre of pressure and centre of mass displacement in the sagittal plane. Findings from this body of research provide new information regarding the methodology of describing sit-to-stand performance in people with stroke and the reliability of measures of sit-to-stand performance. The results also provide an advanced understanding of sit-to-stand performance in people with stroke and the effect of constraint-induced movement strategies on sit-to-stand performance. Additional research using constraint-induced movement strategies in a randomized controlled trial will inform clinical practice and may reduce the fall risk in people with stroke. / Thesis (Ph.D, Rehabilitation Science) -- Queen's University, 2013-07-24 13:30:53.585

Thesis (M.Sc.(Physiotherapy)--University of the Witwatersrand, 2015. / Background Despite it being used clinically, there is limited, inconclusive literature available on shoulder strapping techniques for patients with stroke. Of the published techniques, circumferential strapping seems to show the most positive results. However, in South Africa, variations of a longitudinal technique are applied most often. This study aimed to establish if longitudinal or circumferential strapping techniques would have an impact on a patient's upper limb tone, subluxation, motor function or pain, post stroke and how they compared to each other. Participants This study recruited 56 participants within two weeks of having a stroke, presenting with upper limb involvement (hemiplegia). Participants were excluded if they had receptive aphasia and/or were medically unstable. Method The study was a longitudinal randomised controlled trial comprising of three groups: a control, longitudinal strapping and circumferential strapping groups. Patients with stroke who met the inclusion criteria were assessed at baseline, week one, week two and week six post baseline assessments. The participants were assessed for shoulder subluxation (finger width measurement system), shoulder pain (Ritchie Articular Index), upper limb motor function (upper limb subscales six, seven and eight of the Motor Assessment Scale) and muscle tone (Modified Ashworth Scale). The intervention groups were strapped for two weeks. The sample size for the study was originally calculated at 15 participants however we felt that this should be larger and thus using the central limit theorem a minimum of 30 participants per group was calculated. Demographic data were analysed using descriptive statistics and are presented in tables using frequencies and percentages for the following variables: age, gender and side of stroke. The two-sample test of proportions was used to determine differences among the groups over the study period. The overall within group effect was tested using the Cochran's Q test. The generalized estimated equations were was used to determine the overall effects of the intervention overtime adjusting for groups as well as using population levels. Ethical approval was granted by the Human Research Ethics Committee at the University of the Witwatersrand and informed consent was obtained from all participants prior to the study. Results The total number of participants recruited into the study over three years was 56. The number of participants in the control, circumferential and longitudinal groups was 19, 15 and 22 respectively. Data showed that the study participants were generally young with a mean age of 49.4 (± 13.8) years. There were more females (51.8%) than males and the majority ofthe study sample (60.7%) had a right cerebrovascular accident. Longitudinal strapping decreased shoulder subluxation and pain, but not tone, however, across all of the outcome measures the changes did not reach statistical significance. Circumferential strapping had no significant effect on any of the outcomes compared to the control group, however, it prevented the shoulder pain from worsening, but it had no positive effect on shoulder subluxation post stroke. Improvement in upper limb motor function was observed for all three groups with only a significant improvement in upper arm function being observed for the circumferential group. Conclusion and implications Overall, the study showed positive trends in changes in the shoulder post stroke but no significant differences were found between the groups in any of the outcomes, even when both intervention groups were combined and analysed against the control participants. Looking at the trends, however, the longitudinal technique, with its positive effect on shoulder subluxation and pain, would appear to be the preferred method of the two. Although the study produced overall results that did not have statistical significance one cannot discredit the use of the strapping. Even if strapping had purely a placebo effect it would still serve a purpose by creating awareness in the patient, caregivers and medical personal and thus ensure more cautious handling of the affected upper limb. Thus, when rehabilitating the shoulder post stroke, there appears to be enough clinical evidence to suggest that strapping, more precisely longitudinal strapping, of the hemiplegic shoulder may be used.

Following sudden failure of the Na+/K+ATPase pump, the acute neuronal swelling and dendritic damage that occurs within minutes of stroke onset are consequences of anoxic depolarization (AD). The AD front in our protocol is imaged as an increase in tissue light transmittance (LT) propagating across gray matter of the hippocampal slice preparation. Under current clamp in the single neuron, AD is recorded as a sharp depolarization within 6 min of O2/glucose deprivation (OGD). Simultaneous imaging and current clamp recordings show that the increased LT front and sudden depolarization are coincident. AD onset in CA1 hippocampal neurons is delayed in slices pretreated with 10 μM dibucaine (dib), a local anaesthetic understood to block voltage-gated sodium channels, and 10 to 100 µM carbetapentane (CP), a sigma1 receptor agonist. We examined if changes to single cell excitability could explain how dibucaine and CP work to inhibit AD. Pretreatment of slices with dibucaine for 30 min had no effect upon resting membrane potential, or whole cell input resistance (n=11). However dib pretreatment consistently raised spike threshold, decreased AP frequency and increased the fast afterhyperpolarization (fAHP). Orthodromic and antidromic APs were also eliminated within 15 min. Intracellular dibucaine application in addition to similar effects upon intrinsic electophysiological properties reduced the peak potential of the fast AD while extending the time until the persistent depolarization of AD reached zero. In contrast, 30 -100 μM CP had no effect upon orthodromic or antidromic responses, probably because unlike dibucaine it did not markedly raise spike threshold. Also unlike dibucaine, the fAHP was eliminated while the slow AHP was accentuated, resulting in a lowering of the AP frequency during steady depolarization. Both drugs appear to inhibit AD onset by reducing cortical excitability at the level of the single pyramidal neuron, but through strikingly different mechanisms. Our simultaneous imaging and single cell recording under current clamp allowed for further examination of potential cell recovery after AD in CA1 neurons and astrocytes, as well as confirmation of AD generation in the CA3 region. Indirect evidence for a more robust AD generation and propagation was evident in the transverse slices of dorsal hippocampal CA3 region compared to coronal slices. AD in astrocytes was lower in amplitude and more prolonged, as well as often displaying recovery to near resting potential. This supported our previous imaging experiments showing that astrocytes quickly recover their volume post-AD. / Thesis (Master, Neuroscience Studies) -- Queen's University, 2008-09-25 15:44:07.114

Stroke is a leading cause of disability in Canada. To maximize a patient's chance of returning to their pre-stroke state, rehabilitation programs must be tailored to their specific brain impairments. Unfortunately, assessment of post-stroke impairments is largely based on the perceptual decisions of a clinician. To ensure inter-rater reliability, many current assessment tools use coarse, ordinal scales resulting in floor and ceiling effects. The purpose of this thesis was to use robotic technology coupled with a visually guided reaching task to develop a reliable and sensitive tool for assessing upper limb motor function after stroke. Robotic devices have contributed greatly to our under- standing of motor function because of their ability to objectively, repeatedly, and reliably measure behavior. Visually guided reaching is an ideal task for assessing up- per limb motor function because it requires a broad range of sensorimotor functions as well as healthy functioning of a diverse neural network. Control and stroke subjects performed an unassisted visually guided reaching task with each arm using the KINARM robot. Sensorimotor functions were assessed using a broad range of parameters derived from the kinematics of movement. In our first study we examined the reaching performance of subjects with subacute stroke and reliably found impairments in both their affected and unaffected arms. We also found performance asymmetries between the affected and unaffected arms that were present even when both arms demonstrated normal reaching behaviour independently. In our second study we examined changes in reaching performance that occur over the first six months following stroke. We found that with time reaching performance improved with both arms, but performance asymmetries persisted throughout the first six months after stroke. In our final study we examined reaching performance of healthy adults between the ages of 20 and 84 years of age. We found linear declines with age across most of our movement parameters, but interlimb asymmetries to be stable across adulthood. To generate age-specific performance curves descriptive statistics were tabulated for each parameter. The results of this thesis demonstrate that a visually guided reaching task can provide reliable and sensitive information about a subject's sensorimotor impairments following stroke. / Thesis (Ph.D, Neuroscience Studies) -- Queen's University, 2011-04-21 15:16:11.342

Stroke is the third most common cause of death in the developed world.  Stroke results from cerebral ischaemia and leads to neuro-glial cell death.  Cell death is induced by a cascade of events and potently stimulates a potentially deleterious inflammatory response.  The inflammation is driven by cytokine release; one of the major cytokines involved being interleukin-1.  IL-1<span lang=EN-US style='font-family:Symbol'>b, which is implicated in ischaemic brain damage, is converted from its inactive form by caspase-1. In this study the IL-1 pathway in ischaemic brain damage was manipulated with the endogenous IL-1 antagonist, IL-1 receptor antagonist (IL-1ra) and with the caspase-1 inhibitor RU36384.  As a preliminary step the induction of transient cerebral ischaemia with the filament technique of middle cerebral artery occlusion (tMCAo) in rats was characterised, and found to be reproducible.  Administration of IL-1ra (10<span lang=EN-US style='font-family:Symbol'>mg) into the lateral cerebral ventricle (icv) at ischaemia and reperfusion resulted in a 43% reduction in total lesion volume.  This effect was also obtained by administering (20<span lang=EN-US style='font-family:Symbol'>mg) at later time points out to 3h after the initiation of ischaemia (41% reduction).  After independently confirming the effects of RU36384 on IL-1<span lang=EN-US style='font-family:Symbol'>b processing <i>in vitro.  </i>RU36384 was administered to rats icv after tMCAo and reduced ischaemic lesion volume when compared to control in a dose dependent fashion.  Administration of 5<i>, </i>10, 20 and 40<span lang=EN-US style='font-family:Symbol'>mg at ischaemia and reperfusion resulted in reductions of 37%, 46%, 65%<i> </i>and 40% respectively.  This effect was sustained out to 3h after the initiation of ischaemia but lost by 6h.  Administration of RU36384 did not alter cardiorespiratory variables or core body temperature when compared to control animals. These data implicate IL-1 as an important mediator of cell death after cerebral ischaemia and indicate that its therapeutic manipulation may have a role in the clinical arena.

Patients with conditions involving physical disability vary considerably in the course of their recovery. Initial severity as judged by clinical examination is the usual baseline for predicting eventual outcome but considerable variability has been observed in the process of recovery in patients with conditions of similar initial severity. Recognizing the many potential influences on the process of recovery, medical, personal, environmental and social, this study investigated psychological factors as predictors of different aspects of recovery. The hypotheses tested were that cognitions, such as the patients' perceptions of their condition and its implications for them, their perceptions about their control over their own recovery, the attributions made about their condition and events in their recovery, the ways in which they coped with the problems imposed by their condition and their emotional responses, would be more reliable predictors of different aspects of recovery from physical disability than initial clinical severity. Physical disability was conceptualized at two levels, as restriction in the performance of movements and restriction in the performance of functions and activities. The investigation was undertaken in four stages. Early exploratory work of the first two stages studied over 100 patients with physical disability during the process of their recovery, by observation, semi-structured interviews and videorecording. In the third stage methods of measurement of clinical indices of the selected conditions were developed and tested with the study population. Psychometric methods were also tested and where necessary developed. In the fourth stage hypotheses about the relationships between clinical indices and psychological factors were tested with 40 subjects with physical disability, 20 with stroke, 20 with a wrist fracture. There was considerable support for the overall hypothesis that psychological factors would be reliable predictors of different aspects of recovery. Initial clinical severity was a poor predictor of outcome in terms of performance of movements and functions, and individual perceptions of severity of condition showed little relationship to objective measurements of severity. Perceptions of personal control over recovery were associated with more effective recovery in terms of performance, and general level of raised emotional response with some less effective levels of performance. These results need to be re-examined using larger groups of subjects, and including those with other conditions involving physical disability to find if results can be generalized. The results provide information about factors influencing the process of recovery from conditions involving physical disability.

Bakgrund: De patienter som insjuknat i stroke löper stor risk att drabbas av sekundär depression, vilket kan leda till högre mortalitet. Syfte: Syftet är att belysa situationen med fokus på indikationer och symtom hos patienter som har drabbats av sekundär depression efter stroke i Europa. Metod: En systematisk litteraturstudie med en analys inspirerad av innehållsanalys. Analysen av 10 kvantitativa, en kvalitativ och en mixed-method artikel utgör underlag för resultatet. Resultat: Följande kategorier arbetades fram: kroppslig svaghet, könsskillnader, tidsaspekt och känslor. Ett skiftande och ofta motsägelsefullt resultat framträdde. Konklusion: De resultat som har gjorts i denna litteraturstudie bör användas med försiktighet, då forskning som analyserats bestod av mindre observationsstudier som har lågt bevisvärde. Några indikationer som framkom i studien som kan vara av värde i sjuksköterskans möte med strokepatienter för att urskilja patienter i riskzonen för sekundär depression efter stroke.

The strokes are an important cause of death for all the people, not only for the aged population. Sooner a stroke is discovered better chances are for the patient to minimize the damage or even to survive it. The complexity of strokes reveals clearly the importance of early stroke predetection which are not only helping the doctors but they could literally save lives. Algorithms for predetection of stroke are diverse, however they are little explored. This thesis is mainly centered on predetection of stroke, based on the inversion of T waves in electrocardiograms. Two models were proposed in this thesis to help providing efficient predetection of stroke for people suffering of myocardium diseases and myocardial ischemia. The algorithms were tested on data from four electrocardiograms given by a library and five electrocardiograms from five different patients. Filters for noisy signals are also provided in this thesis. These algorithms can be used as a tool by nurses and doctors but they do not represent a fully automated detection of stroke.

Background 200 million patients undergo noncardiac surgery every year. Overt stroke after noncardiac surgery is not common, but has a substantial impact on duration and quality of life. Covert stroke in the nonsurgical setting is much more common than overt stroke, and associated with an increased risk of cognitive decline and dementia. Little is known about covert stroke after noncardiac, noncarotid artery surgery. Methods We undertook a prospective cohort pilot study to inform the incidence of covert stroke after noncardiac, noncarotid artery surgery, and to determine the feasibility of a full prospective cohort study to characterize the epidemiology of perioperative covert stroke. Patients underwent a brain MRI study between postoperative days 3-10, and were followed up at 30 days after surgery. Results of the pilot study We enrolled a total of 100 patients from 6 centres in 4 countries, demonstrating excellent recruitment and no loss to follow-up at 30 days after surgery. The incidence of perioperative covert stroke was 10.0% (10/100 patients, 95% confidence interval 5.5% to 17.4%). Full study protocol We describe a proposal for a prospective cohort study of 1,500 patients. An MRI study of the brain will be performed between postoperative days 2 and 9. The primary outcome is cognitive function, measured 1 year after surgery using the Montreal Cognitive Assessment tool. We will perform multivariable logistic regression analysis where the dependent variable is the change in cognitive function 1 year after surgery, and the independent variables are incidence of perioperative covert stroke and other risk factors for cognitive decline. Conclusions This international multicentre pilot study suggests that 1 in 10 patients ≥65 years of age experiences a perioperative covert stroke. The proposed protocol describes a larger study which will determine the impact of perioperative covert stroke on patient-important outcomes. / Thesis / Master of Science (MSc) / This thesis describes a program of research to investigate silent stroke after surgery.