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Biomedical subjects

David Thompson

Publications and source records attributed to David Thompson.

51 records · Page 3Linked to original sources
PubMed2003

Modifying dyspepsia management in primary care: a cluster randomised controlled trial of educational outreach compared with passive guideline dissemination.

BACKGROUND: Quality improvement initiatives in health services rely upon the effective introduction of clinical practice guidelines. However, even well constructed guidelines have little effect unless supported by dissemination and implementation strategies. AIM: To test the effectiveness of 'educational outreach' as a strategy for facilitating the uptake of dyspepsia management guidelines in primary care. DESIGN OF STUDY: A pragmatic, cluster-randomised controlled trial of guideline introduction, comparing educational outreach with postal guideline dissemination alone. SETTING: One-hundred and fourteen general practices (233 general practitioners) in the Salford and Trafford Health authority catchment area in the northwest of England. METHOD: All practices received guidelines by post in July 1997. The intervention group practices began to receive educational outreach three months later. This consisted of practice-based seminars with hospital specialists at which guideline recommendations were appraised, and implementation plans formulated. Seminars were followed up with 'reinforcement' visits after a further 12 weeks. Outcome measures were: (a) the appropriateness of referral for; and (b) findings at, open access upper gastrointestinal endoscopy; (c) costs of GP prescriptions for acid-suppressing drugs, and (d) the use of laboratory-based serological tests for Helicobacter pylori. Data were collected for seven months before and/or after the intervention and analysed by intention-to-treat. RESULTS: (a) The proportion of appropriate referrals was higher in the intervention group in the six-month post-intervention period (practice medians: control = 50.0%, intervention = 63.9%, P < 0.05); (b) the proportion of major findings at endoscopy did not alter significantly; (c) there was a greater rise in overall expenditure on acid-suppressing drugs in the intervention as compared with the control group (+8% versus +2%, P = 0.005); and (d) the median testing rate per practice for H pylori in the post-intervention period was significantly greater in the intervention group (four versus O, P < 0.001). CONCLUSION: This study suggests that educational outreach may be more effective than passive guideline dissemination in changing clinical behaviour. It also demonstrates that unpredictable and unanticipated outcomes may emerge.

Algorithms↗
PubMed2002

Driving plasticity in human adult motor cortex is associated with improved motor function after brain injury.

Changes in somatosensory input can remodel human cortical motor organization, yet the input characteristics that promote reorganization and their functional significance have not been explored. Here we show with transcranial magnetic stimulation that sensory-driven reorganization of human motor cortex is highly dependent upon the frequency, intensity, and duration of stimulus applied. Those patterns of input associated with enhanced excitability (5 Hz, 75% maximal tolerated intensity for 10 min) induce stronger cortical activation to fMRI. When applied to acutely dysphagic stroke patients, swallowing corticobulbar excitability is increased mainly in the undamaged hemisphere, being strongly correlated with an improvement in swallowing function. Thus, input to the human adult brain can be programmed to promote beneficial changes in neuroplasticity and function after cerebral injury.

Adult↗
PubMed2002

Outcomes and costs of acute treatment of traumatic brain injury.

BACKGROUND: Although there are nearly a quarter of a million hospitalizations for traumatic brain injury (TBI) in the United States each year, data on the outcomes and costs of TBI treatment in the acute-care setting are limited. METHODS: Using a large, geographically diverse, multihospital database, we examined inpatient records for persons aged 16 years or older who were hospitalized for TBI between January 1, 1997, and June 30, 1999. Patients were stratified by TBI severity using an adaptation of the Abbreviated Injury Scale for administrative data (ICD/AIS), as follows: 2 = "moderate"; 3 = "serious"; 4 = "severe"; and 5 = "critical." Patient characteristics, patterns of treatment, and outcomes and costs were examined by injury severity and mechanism of injury. RESULTS: Of 8,717 study subjects identified, 12.5% had moderate, 44.8% had serious, 29.6% had severe, and 13.2% had critical TBI. Falls were the most common reported cause of injury (40.8%), followed by motor vehicle crashes (39.3%), blows to the head (11.3%), and gunshot wounds (2.4%). Average length of stay in hospital ranged from 6.7 days for moderate TBI to 17.5 days for critical TBI. The overall rate of death in hospital was relatively low among patients with moderate (1.3%), serious (5.7%), and severe (8.7%) TBIs, but much higher among the most critically injured patients (52.0%). Costs of hospitalization averaged 8,189 dollars for moderate, 14,603 dollars for serious, 16,788 dollars for severe, and 33,537 dollars for critical TBI. Costs also varied by injury type, averaging 20,084 dollars for gunshot wounds, 20,522 dollars for motor vehicle crashes, 15,860 dollars for falls, and 19,949 dollars for blows to the head. CONCLUSION: The economic burden of TBI in the acute-care setting is substantial; treatment outcomes and costs vary considerably by TBI severity and mechanism of injury.

Adolescent↗
PubMed2002

Psychological disorder and severity of inflammatory bowel disease predict health-related quality of life in ulcerative colitis and Crohn's disease.

OBJECTIVE: The determinants of health-related quality of life in inflammatory bowel disease are not completely understood. The present study aimed to assess two factors in patients with inflammatory bowel disease: a) whether health-related quality of life is independently associated with both bowel disease severity and psychological disorder, and b) whether Crohn's disease is associated with more marked psychological disorder than ulcerative colitis. METHODS: 116/170 (68%) consecutive patients with inflammatory bowel disease attending a GI clinic (37 patients with ulcerative colitis, 75 patients with Crohn's disease, and four unspecified) completed the following self-report questionnaires: demographic details, a modified disease activity index, a total severity measure, the Hospital Anxiety and Depression Scale, and the Short Form-36. RESULTS: Thirty patients (25.9%) scored 11 or more on either the depression or anxiety subscales of the Hospital Anxiety and Depression Scale indicating probable psychological disorder; 55% (47.4%) scored over 8 indicating possible psychological disorder. Stepwise multiple regression analyses showed that both psychological symptoms and disease severity or activity contributed independently to impaired health-related quality of life. After severity of disease was taken into account, there were no significant differences between Crohn's disease and ulcerative colitis in terms of depression scores and health-related quality of life. CONCLUSIONS: The presence of psychological disorder in inflammatory bowel disease contributes to poor health-related quality of life, regardless of the severity of the condition. Detection and treatment of psychological disorder in inflammatory bowel disease carries the potential to improve health-related quality of life for these patients.

Adult↗
PubMedDate not supplied

The clinical effectiveness of a multisensory therapy on clients with developmental disability.

Many clients in Hong Kong with developmental disabilities stay in mental hospitals because of mental disorders and behavioural problems. There is a need to identify strategies that promote psychological well-being and reduce problem behaviours in this group of clients. This study evaluates the impact of multisensory therapy on participants' emotional state, level of relaxation, challenging behaviour, stereotypic self-stimulating behaviour (SSB) and adaptive behaviour (AB). Using an experimental design, 89 participants were recruited from a developmental disability unit in a hospital in Hong Kong and randomly assigned to either an experimental (n = 48) or a control group (n = 41). Multisensory therapy sessions (n = 36) were conducted with experimental group and activity sessions (n = 36) were conducted with controls for 12 weeks. Multisensory therapy promoted participants' positive emotions and relaxation. However, there was no evidence that multisensory therapy was superior to activity therapy in reducing aggressive behaviour and stereotypic self-stimulating behaviour or promoting adaptive behaviour. The key variables that influence clients' behaviours in the multisensory therapy may be related to the relationship with the carer, constant environment, relaxation and freedom from demands rather than sensory input. Multisensory therapy could be used to provide leisure and promote psychological well-being, rather than for reducing problem behaviour.

Activities of Daily Living↗
PubMedDate not supplied

Toward a pharmacoeconomic model of neuropathic pain.

BACKGROUND: Pharmacoeconomic analysis is increasingly being used to assist decision makers in getting the biggest "bang for the buck" within cost-constrained health care budgets. The tools and techniques of this science, however, have scarcely been applied to neuropathic pain. OBJECTIVE: To describe the basic principles of pharmacoeconomic analysis and set forth a preliminary pharmacoeconomic model of neuropathic pain. KEY FINDINGS: Applying the tools and techniques of pharmacoeconomic analysis to neuropathic pain yields several insights. First, because pain treatment predominantly benefits quality of life, the results of a pharmacoeconomic analysis of neuropathic pain treatment should be expressed in terms of the cost per quality-adjusted life-year (QALY)-gained metric. Second, because pain can fluctuate, a state-transition modeling approach should be used in constructing the pharmacoeconomic model to account for changes in pain status over time, particularly as relates to the effects of treatment. Finally, assessment of typical practice patterns in neuropathic pain suggests that the pharmacoeconomic model should account for multiple rounds of treatment (i.e., first-line therapy, second-line therapy, and so on), primary care to specialty care referral patterns, and differences in costs and outcomes between primary care physicians and pain specialists. CONCLUSIONS: Pharmacoeconomic analysis of neuropathic pain treatments can play an influential role in formulary committee deliberations, treatment algorithms, and decision making in the clinical setting. By describing the fundamental concepts and key challenges in this field, it is hoped that this article will represent a useful first step toward a pharmacoeconomic model of neuropathic pain.

Economics, Pharmaceutical↗
PubMedDate not supplied

Spatial domain wavelet design for feature preservation in computational data sets.

High-fidelity wavelet transforms can facilitate visualization and analysis of large scientific data sets. However, it is important that salient characteristics of the original features be preserved under the transformation. We present a set of filter design axioms in the spatial domain which ensure that certain feature characteristics are preserved from scale to scale and that the resulting filters correspond to wavelet transforms admitting in-place implementation. We demonstrate how the axioms can be used to design linear feature-preserving filters that are optimal in the sense that they are closest in L2 to the ideal low pass filter. We are particularly interested in linear wavelet transforms for large data sets generated by computational fluid dynamics simulations. Our effort is different from classical filter design approaches which focus solely on performance in the frequency domain. Results are included that demonstrate the feature-preservation characteristics of our filters.

Algorithms↗
PubMedDate not supplied

Vortex visualization for practical engineering applications.

In order to understand complex vortical flows in large data sets, we must be able to detect and visualize vortices in an automated fashion. In this paper, we present a feature-based vortex detection and visualization technique that is appropriate for large computational fluid dynamics data sets computed on unstructured meshes. In particular, we focus on the application of this technique to visualization of the flow over a serrated wing and the flow field around a spinning missile with dithering canards. We have developed a core line extraction technique based on the observation that vortex cores coincide with local extrema in certain scalar fields. We also have developed a novel technique to handle complex vortex topology that is based on k-means clustering. These techniques facilitate visualization of vortices in simulation data that may not be optimally resolved or sampled. Results are included that highlight the strengths and weaknesses of our approach. We conclude by describing how our approach can be improved to enhance robustness and expand its range of applicability.

Journal Article↗
PubMedDate not supplied

Methods and framework for visualizing higher-order finite elements.

The finite element method is an important, widely used numerical technique for solving partial differential equations. This technique utilizes basis functions for approximating the geometry and the variation of the solution field over finite regions, or elements, of the domain. These basis functions are generally formed by combinations of polynomials. In the past, the polynomial order of the basis has been low-typically of linear and quadratic order. However, in recent years so-called p and hp methods have been developed, which may elevate the order of the basis to arbitrary levels with the aim of accelerating the convergence of the numerical solution. The increasing complexity of numerical basis functions poses a significant challenge to visualization systems. In the past, such systems have been loosely coupled to simulation packages, exchanging data via file transfer, and internally reimplementing the basis functions in order to perform interpolation and implement visualization algorithms. However, as the basis functions become more complex and, in some cases, proprietary in nature, it becomes increasingly difficult if not impossible to reimplement them within the visualization system. Further, most visualization systems typically process linear primitives, in part to take advantage of graphics hardware and, in part, due to the inherent simplicity of the resulting algorithms. Thus, visualization of higher-order finite elements requires tessellating the basis to produce data compatible with existing visualization systems. In this paper, we describe adaptive methods that automatically tessellate complex finite element basis functions using a flexible and extensible software framework. These methods employ a recursive, edge-based subdivision algorithm driven by a set of error metrics including geometric error, solution error, and error in image space. Further, we describe advanced pretessellation techniques that guarantees capture of the critical points of the polynomial basis. The framework has been designed using the adaptor design pattern, meaning that the visualization system need not reimplement basis functions, rather it communicates with the simulation package via simple programmatic queries. We demonstrate our method on several examples, and have implemented the framework in the open-source visualization system VTK.

Algorithms↗
PubMedDate not supplied

Collection of health-economic data alongside clinical trials: is there a future for piggyback evaluations?

OBJECTIVE: The objective of this article is to discuss issues surrounding the conduct of "piggyback evaluations," in which health-economic data are collected within an otherwise typical clinical trial. METHODS: We review the methodologic literature on piggyback economic evaluations, as well as selected empiric studies. We summarize the challenges encountered in the conduct of these studies, alternative ways of addressing these challenges, and their future role in pharmacoeconomic research. RESULTS: Piggyback evaluations have certain advantages over other types of pharmacoeconomic studies. An economic evaluation can benefit from the experimental design that maximizes the trial's internal validity, and it is often more practical to collect economic data alongside a trial rather than to fund a stand-alone economic study. However, piggyback evaluations are subject to problems deriving from the competing nature of clinical versus economic study objectives, which can give rise to tension in such fundamental aspects of study design as the selection of study subjects and sites; the extent of protocol-mandated health-care services; and the determination of sample size, length of follow-up, and the study comparator(s). Many solutions have been put forth in the literature to address these challenges. CONCLUSIONS: Piggyback evaluations can be an appropriate means to measure the economic impact of medical interventions, provided that the methodologic challenges are acknowledged and addressed within the context of each individual study. As long as a desire for patient-level data from clinical trials exists, there will be a need for piggyback economic evaluations in the future.

Clinical Protocols↗
PubMedDate not supplied

Field demonstration of the combined effects of absorption and evapotranspiration on septic system drainfield capacity.

Drainfields for disposal of septic tank effluents are typically designed by considering the loss of water by either upward evapotranspiration into the atmosphere or lateral and downward absorption into the adjacent soil. While this approach is appropriate for evapotranspiration systems, absorption systems allow water loss by both mechanisms. It was proposed that, in areas where high evapotranspiration rates coincide with permeable soils, drainfield sizes could be substantially reduced by accounting for both mechanisms. A two-year field demonstration was conducted to determine appropriate design criteria for areas typical of the Texas High Plains. The study consisted of evaluating the long-term acceptance rates for three different drainfield configurations: evapotranspiration only, absorption only, and combined conditions. A second field demonstration repeated the experiments for additional observation of the combined evapotranspiration and absorption and achieved similar results as the first study. The field tests indicated that the current design loading criteria may be increased by at least a factor of two for the Texas High Plains region and other Texas areas with similar soil composition and evapotranspiration rates, while still retaining a factor of safety of two.

Absorption↗
PubMedDate not supplied

Environmental effects on the assessment of people with dementia: a pilot study.

OBJECTIVE: The purpose of this pilot study was to use a standardized assessment of independent living skills to explore the effects of environment on functional performance of individuals with dementia. METHODS: Twelve participants (6 males, 6 females), diagnosed with dementia, were given the Structured Assessment of Independent Living Skills (SAILS), a standardized assessment of functional motor, cognitive, instrumental, and social performance. Participants were assessed in their homes, in an adult day-services facility they regularly attended, and in an occupational therapy clinic. RESULTS: Data were analyzed using repeated measures analysis of variance (ANOVA). There was no evidence of a learning effect from repeated assessments. Participants' performances did not differ among the home, clinic, and adult day-services settings on the total SAILS score (F = 1.22; df = 2,20; p = 0.3176), nor on three of its subscales: cognitive score (F = 0.80; df = 2,20; p = 0.4648), instrumental activities (F = 1.37; df = 2,20; p = 0.2777), and social interaction (F = 0.34; df = 2,20; p = 0.7147). However, participants' performance on the SAILS motor score was significantly higher in the home than in the clinic (t = 2.925, df = 11, p = 0.0138). CONCLUSION. Participants' motor performance was significantly better at home than in an unfamiliar environment. Effects of environment on motor performance, and absence of effects on cognitive, instrumental, and social performances, can be explained through ecological theory. These results suggest that the ability to adapt movement to an unfamiliar environment may decline with the onset and progression of dementia.

Activities of Daily Living↗