Appendix 6 on microfiche in end pocket / 256 leaves : ill., diagrs., graphs, photos ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Mechanical Engineering, 1978

Appendix 6 on microfiche in end pocket / 256 leaves : ill., diagrs., graphs, photos ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Mechanical Engineering, 1978

Swallowing difficulties after acute stroke are common. Clinical bedside assessments are used frequently to detect acute dysphagia. Published studies which have assessed the natural history of swallowing using bedside assessments have only observed swallowing for a short period of time. The purpose of this investigation was to monitor the natural progression of dysphagic symptoms in stroke over three month using a clinical assessment. 26 patients consecutively admitted to the regional public hospital were assessed using a clinical assessment consisting of cranial nerve exam, observation of oral intake, water swallow test and inhalation cough challenge. The assessment was implemented within 72 hours post admission and then after one week, three weeks and three months. For this exploratory study, descriptive statistics were used to explore the data set. The results confirm that dysphagia after stroke is common and that there are improvements within three months.

Diss. (sammanfattning) Stockholm : Karol. inst., 2001. / Härtill 6 uppsatser.

Thesis (Ph.D.) -- University of Adelaide, Department of Mechanical Engineering , 1978. / Appendix 6 on microfiche in end pocket.

Diss. (sammanfattning) Uppsala : Uppsala universitet, 2007. / Härtill fyra uppsatser.

Diss. (sammanfattning) Sundsvall : Mittuniversitetet.

<p>Stroke är en vanlig sjukdom som många drabbas av. Inom den prehospitala akutsjukvården möter ambulanssjuksköterskan patienter drabbade av stroke. Tiden är avgörande för den fortsatta vården och att patienten kommer till rätt vårdinstans direkt. Användningen av mätinstrumentet inom den prehospitala akutsjukvården ökar patientens möjligheter till rätt vård. <strong>Syfte:</strong> undersöka vilka mätinstrument och metoder som är lämpliga för att identifiera strokesymtom hos patienter i en prehospital akutfas. <strong>Metod: </strong>artikelsökningen genomfördes i databaserna ELIN, PubMed, Cinahl, EBSCO samt via American stroke associations hemsida och utfördes under perioden februari 2009 till september 2009. I studien inkluderades 15 vetenskapliga artiklar och dessa kvalitetsgranskades utifrån en granskningsmall för kvantitativa artiklar. Resultatet presenteras i form av kategorier. <strong>Resultat:</strong> användning av mätinstrument är bra för att identifiera stroke inom prehospital akutsjukvård. Mätinstrument ska vara lätta att förstå och inte vara tidskrävande. Vid användningen fås en snabbare identifiering av stroke och patienten kan få rätt vård utan extra tidsfördröjning vilket i sin tur leder till bättre livskvalitet och mindre lidande för patienterna. <strong>Slutsats:</strong> I studien framgår inte vilket mätinstrument som passar bäst inom den prehospitala akutsjukvården men att använda ett mätinstrument är att föredra. Beaktande bör tas att inget mätinstrument kan diagnostisera stroke utan mätinstrumenten identifierar symtomen.</p>

Background: Blood pressure is one of the most important modifiable risk factors for stroke. Although the influence of an individual’s average blood pressure (BP) on their overall stroke risk is well established, visit-to-visit blood pressure variability (BPV) - variation in blood pressure from one clinic visit to the next - may be an independent risk factor for stroke. The influence of BPV on stroke risk in the general population is not fully understood, nor is it known whether associations with BPV vary by pathological stroke type. Very large prospective studies, including exposure measurements of BP and BPV as well as accurate identification, confirmation and sub-classification of large numbers of stroke cases during follow-up, are needed to test the associations between BP parameters, stroke and its main pathological types. UK Biobank (UKB) is a very large prospective cohort study of ~500,000 middle aged adults recruited from England, Scotland, and Wales between 2006 and 2010. Participants completed a detailed baseline assessment at recruitment (which included self-report of prior stroke and BP measurement). Follow up for health-related outcomes (including new occurrences of stroke) in UKB relies on linkages to routine coded datasets for hospital admissions, death registrations and primary care data. Coded primary care data could also be used to capture novel exposures, like blood pressure variability (BPV). In this thesis, I aimed to investigate how large prospective epidemiological studies such as UK Biobank might be used to investigate the influence of BP, and in particular BPV, on stroke and its types and subtypes. I did this through advancing understanding of the identification and characterisation of stroke cases in large prospective studies, and of obtaining measures of BPV from linked primary care data. Specifically, I aimed: (1) to evaluate the accuracy of patient self-report of stroke, the accuracy of routinely available coded healthcare data for stroke, and the reliability and feasibility of ischaemic stroke classification systems for large epidemiological studies such as UKB; (2) to identify prevalent and early incident stroke cases in UKB using multiple overlapping sources of coded data, and determine the proportions of cases classified into main pathological types of stroke; (3) to explore the feasibility of using coded primary care data to obtain measures of BPV in UKB. Methods: (1) I performed a series of systematic reviews of published data on (i) the accuracy of patient self-report of stroke, (ii) the accuracy for stroke and its main pathological types (ischaemic stroke, intracerebral haemorrhage, subarachnoid haemorrhage) of International Classification of Diseases (ICD) coded hospital admissions and death certificates, and Read coded primary care records, and 3) the inter-rater reliability of ischaemic stroke classification systems. (2) Informed by this work I identified prevalent and early incident stroke cases in UKB using linked coded hospital and death registration data as well as self-report data. In a sub cohort of participants, I was able to assess the additional role in case identification of linked coded primary care data. I compared the numbers of potential stroke cases ascertained by multiple overlapping combinations of these data and examined the proportions classified into the main pathological stroke types. (3) Finally, I analysed data from about 10,000 Welsh UKB participants with linked coded primary care data to identify those in whom visit-to-visit BPV could be measured using coded systolic blood pressure values (BP). I explored the association between frequency of visits with coded BP values and: participant characteristics; time between visits; mean BPV; standard deviation of BPV (SD BPV). I also calculated within-individual agreement between coded BP and UKB baseline assessment BP. Results: (1) From my systematic reviews I found that self-report accuracy was strongly influenced by characteristics of the study population. In populations with low stroke prevalence up to 75% of self-reported strokes were false positives. ICD codes for cerebrovascular diseases had a broad range of accuracy for stroke and its main pathological types, but appropriately selected, ‘stroke specific’ ICD codes were consistently >70% accurate when compared to an independent reference standard for stroke. Few studies assessed the accuracy of either primary care data or combinations of data sources for stroke. The overall inter-observer reliability of ischaemic stroke classification systems ranged from moderate to almost perfect. Study characteristics other than classification system accounted for much of the variation in reliability. Additional features which enhanced reliability included use of clear rules, data abstraction protocols, computerised assignment, and reduced number of subtype categories. (2) The prevalence of stroke in UK Biobank based on linked ICD coded hospital admissions data and participant self-report was ~1.7%. The majority of these prevalent stroke cases were of ‘unspecified’ stroke type. Incident strokes captured by ICD codes were mostly hospital admitted cases, but a smaller additional proportion were fatal cases not detected in hospital admissions data. The majority (~89%) of ICD coded incident strokes were a specified pathological type. In the sub-cohort of UKB participants with additional primary care data linkage ~20% of potential incident stroke cases were detected by coded primary care data alone. (3) Among Welsh UKB participants with linked primary care data, around two thirds had sufficient coded data to estimate visit-to-visit BPV any time before recruitment, and just under half had sufficient coded data to estimate BPV during the 5 years before recruitment. Selecting participants with more visits reduced generalizability, but there was good variability in BPV amongst those selected (standard deviation in BPV range ~5mmHg to ~7mmHg), and reasonable agreement between coded BP and BP recorded at the UKB baseline assessment (intra class correlation coefficient 0.53, 95% CI 0.52 to 0.55). Conclusions: This work will inform the approaches to stroke outcomes ascertainment and the measurement of a novel exposure, blood pressure variability, in UK Biobank. This will enable future exploration of the associations between blood pressure parameters, stroke, and its main types and sub-types in UK Biobank. Investigating these associations will improve our understanding of causal pathways for the different pathological types and sub-types of stroke and underpin increasingly targeted strategies to modify BP for stroke prevention.

Among patients presenting acutely with ischaemic stroke who are being considered for intravenous thrombolysis, prompt brain imaging is used to exclude contraindications to treatment (chiefly haemorrhagic stroke or other conditions mimicking stroke) rather than to identify which patients are more or less likely to benefit from thrombolysis. For example, it is unclear whether the presence or absence of arterial obstruction on imaging should be used to guide thrombolysis treatment decisions. In this thesis I explore methods of imaging arterial patency among patients presenting acutely with ischaemic stroke and look for associations between these early imaging findings, response to intravenous thrombolysis and functional outcome six-months after stroke onset. I primarily use data from the Third International Stroke Trial (IST-3), the largest ever randomised-controlled trial testing the use of intravenous alteplase for the acute treatment of ischaemic stroke. I begin by summarising the main features of stroke, covering techniques for imaging the brain and for imaging arterial patency, and post-stroke outcomes. Next I describe two literature reviews which I compiled to increase my understanding of the topic with particular reference to imaging arterial patency. This is followed by a summary of IST-3. Then I describe the general methods I used to address my thesis aims exploring relationships between imaging characteristics of arterial patency, treatment with intravenous alteplase and functional outcome after ischaemic stroke. Specifically, I investigated the following imaging features: - The hyperattenuating artery sign (HAS), which is a non-contrast enhanced CT finding thought to be indicative of acute arterial obstruction by thrombus or embolus - Arterial patency or obstruction as demonstrated using contrast enhanced CT and MR angiographic imaging. In addition to providing better characterisation of the HAS and a better understanding of how angiography helps to assess ischaemic stroke patients, I found that arterial obstruction (however this is identified on imaging) is associated with more severe stroke at baseline and worse functional outcome six months after stroke. I also prove that intravenous alteplase is effective in the presence of arterial obstruction, counter to a widely held concern that it may not be effective in this context. Most of my work has been published in peer reviewed journals. My work should give front line clinicians greater confidence to use intravenous alteplase for the treatment of ischaemic stroke associated with arterial obstruction on imaging, but more work is needed to better understand the implications of apparently normal arterial patency on imaging among patients with ischaemic stroke.