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Response Variability (response + variability)
Selected AbstractsTrust in the Medical Profession: Conceptual and Measurement IssuesHEALTH SERVICES RESEARCH, Issue 5 2002Mark A Hall Objective. To develop and test a multi-item measure for general trust in physicians, in contrast with trust in a specific physician. Data Sources. Random national telephone survey of 502 adult subjects with a regular physician and source of payment. Study Design. Based on a multidimensional conceptual model, a large pool of candidate items was generated, tested, and revised using focus groups, expert reviewers, and pilot testing. The scale was analyzed for its factor structure, internal consistency, construct validity, and other psychometric properties. Principal Findings. The resulting 11-item scale measuring trust in physicians generally is consistent with most aspects of the conceptual model except that it does not include the dimension of confidentiality. This scale has a single-factor structure, good internal consistency (alpha=.89), and good response variability (range=11,54; mean=33.5; SD=6.9). This scale is related to satisfaction with care, trust in one's physician, following doctors' recommendations, having no prior disputes with physicians, not having sought second opinions, and not having changed doctors. No association was found with race/ethnicity. While general trust and interpersonal trust are qualitatively similar, they are only moderately correlated with each other and general trust is substantially lower. Conclusions. Emerging research on patients' trust has focused on interpersonal trust in a specific, known physician. Trust in physicians in general is also important and differs significantly from interpersonal physician trust. General physician trust potentially has a strong influence on important behaviors and attitudes, and on the formation of interpersonal physician trust. [source] Development of a Scale to Measure Patients' Trust in Health InsurersHEALTH SERVICES RESEARCH, Issue 1 2002Article first published online: 18 MAR 200 Objective.,To develop a scale to measure patients' trust in health insurers, including public and private insurers and both indemnity and managed care. A scale was developed based on our conceptual model of insurer trust. The scale was analyzed for its factor structure, internal consistency, construct validity, and other psychometric properties. Data Sources/Study Setting.,The scale was developed and validated on a random national sample (n=410) of subjects with any type of insurance and further validated and used in a regional random sample of members of an HMO in North Carolina (n=1152). Study Design.,Factor analysis was used to uncover the underlying dimensions of the scale. Internal consistency was assessed by Cronbach's alpha. Construct validity was established by Pearson or Spearman correlations and t tests. Data Collection.,Data were collected via telephone interviews. Principal Findings.,The 11-item scale has good internal consistency (alpha=0.92/0.89) and response variability (range=11,55, M=36.5/37.0, SD=7.8/7.0). Insurer trust is a unidimensional construct and is related to trust in physicians, satisfaction with care and with insurer, having enough choice in selecting health insurer, no prior disputes with health insurer, type of insurer, and desire to remain with insurer. Conclusions.,Trust in health insurers can be validly and reliably measured. Additional studies are required to learn more about what factors affect insurer trust and whether differences and changes in insurer trust affect actual behaviors and other outcomes of interest. [source] Cognitive effects of a Ginkgo biloba/vinpocetine compound in normal adults: systematic assessment of perception, attention and memoryHUMAN PSYCHOPHARMACOLOGY: CLINICAL AND EXPERIMENTAL, Issue 5 2001John Polich Abstract A computerized test battery was used in a double-blind design to assess the cognitive effects of a nutrient compound containing Ginkgo biloba in 24 normal adults. Ten tasks (perceptual, attention and short-term memory) were presented in a standardized manner designed to maximize performance, with substantial pre-test practice employed to minimize response variability. Subjects were given either placebo or Ginkgo biloba extract capsules to consume for 14 days, after which they performed all tasks twice. They then received the other condition, and after 14 days completed the final test session. Response time and error rate stabilized after pre-test practice. A ,working memory capacity' paradigm demonstrated a reliable 50,ms response time decrease between the placebo and Ginkgo biloba testing, suggesting that Ginkgo biloba speeds short-term working memory processing in normal adults. Copyright © 2001 John Wiley & Sons, Ltd. [source] Robust control of depth of anesthesiaINTERNATIONAL JOURNAL OF ADAPTIVE CONTROL AND SIGNAL PROCESSING, Issue 5 2009Guy A. Dumont Abstract This paper presents a systematic procedure to design both robust PID controllers and robust controllers based on fractional calculus (based on Commande Robuste d'Ordre Non Entier, or CRONE methodology) to regulate the hypnotic state of anesthesia with the intravenous administration of propofol. The objective of the controllers is to provide an adequate drug administration regimen for propofol to avoid under or over dosing of the patients. The controllers are designed to compensate for the patients inherent drug,response variability (uncertainty), to achieve good output disturbance rejection, and to attain good set point response. The performance of the controllers is assessed by calculating typical time domain measures and using the median PE, median absolute PE, divergence, and wobble. Copyright © 2008 John Wiley & Sons, Ltd. [source] The functional neuroanatomy of geriatric depressionINTERNATIONAL JOURNAL OF GERIATRIC PSYCHIATRY, Issue 8 2009Gwenn S. Smith Abstract Objective Positron Emission Tomography (PET) studies of cerebral glucose metabolism have demonstrated sensitivity in evaluating the functional neuroanatomy of treatment response variability in depression, as well as in the early detection of functional changes associated with incipient cognitive decline. The evaluation of cerebral glucose metabolism in late life depression may have implications for understanding treatment response variability, as well as evaluating the neurobiological basis of depression in late life as a risk factor for dementia. Methods Sixteen patients with geriatric depression and 13 comparison subjects underwent resting PET studies of cerebral glucose metabolism, as well as magnetic resonance (MR) imaging scans to evaluate brain structure. Results Cerebral glucose metabolism was elevated in geriatric depressed patients relative to comparison subjects in anterior (right and left superior frontal gyrus) and posterior (precuneus, inferior parietal lobule) cortical regions. Cerebral atrophy (increased cerebrospinal fluid [CSF] and decreased grey and white matter volumes) were observed in some of these regions, as well. Regional cerebral metabolism was positively correlated with severity of depression and anxiety symptoms. Conclusions In contrast to decreased metabolism observed in normal aging and neurodegenerative conditions such as Alzheimer's disease, cortical glucose metabolism was increased in geriatric depressed patients relative to demographically matched controls, particularly in brain regions in which cerebral atrophy was observed, which may represent a compensatory response. Copyright © 2009 John Wiley & Sons, Ltd. [source] Regional variability of climate,growth relationships in Pinus cembra high elevation forests in the AlpsJOURNAL OF ECOLOGY, Issue 5 2007MARCO CARRER Summary 1The tree-ring growth response of stone pine (Pinus cembra L.) to climatic variability was studied in the Alps. The aims were (i) to assess tree-ring growth patterns at different spatial-temporal scales; (ii) to identify the climate parameters that explain most of the variability in radial growth at different time domains; and (iii) to study past and current trends in radial growth and climate,growth relationships at different locations. 2High- and low-frequency stone pine chronologies were compiled for 30 treeline sites on the French and Italian Alps. We used gridded climate data computed from 200 years of instrumental records from an extensive Alpine network. Climate,growth relationships were computed with bootstrap correlation functions and their stationarity and consistency over time assessed with moving correlation. 3No spatial patterns were detected in stone pine chronology statistics despite the regional clustering observed in tree-ring series and climate responses. This can be attributed to (i) local weather variability; (ii) different biophysical conditions caused by soil moisture, solar radiation, snowmelt dynamics and growing season length; and (iii) forest stand history and age structure, the expression of long-term land use and disturbances. 4The exceptionally long-term climate records allowed significant stone pine growth response changes to be assessed at both annual and decadal time scales. Winter conditions and spring,summer temperatures mainly affected the growing season length, in addition to site carbon and water balance. Most of these limiting factors varied spatially and temporally along the latitudinal and longitudinal gradients in response to the corresponding changes in local conditions. 5Our results show evidence of a clear response variability of Pinus cembra to climate limiting factors, at both spatial and temporal scale. Such knowledge extended to other species and regions will provide better estimates of the effect of climate variability on species distribution and dynamics within global change scenarios and more accurate past climate reconstruction and forest ecosystem modelling. [source] Preoperative Functional Assessment of Auditory Cortex in Adult Cochlear Implant Users,,THE LARYNGOSCOPE, Issue 1 2001Peter S. Roland MD Abstract Objectives To e-plore functional neuroanatomical responses to auditory stimulation before and after implantation. Study Design A prospective study of three cochlear implant candidates (pure-tone averages of 90 dB HL or greater bilaterally and hearing in noise test [HINT] performances of <40%) in which regional cerebral blood flow (rCBF) was assessed using single photon emission computed tomography (SPECT). Methods Candidates watched a 15-minute videotaped story under four conditions: audio presented monaurally in the right and left ears (aided), audio presented binaurally (aided), and visual-only presentation of the story. Five minutes into each story, 20 to 25 mCi of technetium 99m (99mTc) hexamethyl-propyleneamine-oxime (HMPAO) (Ceratec; Nycomed Amersham, Princeton, NJ, U.S.A.) was injected over a 30-second period to ensure that subjects were unaware of tracer administration. Subjects were scanned for 20 minutes using a PRISM 3000 gamma camera (Picker International, Cleveland, OH, U.S.A.). Data were normalized and co-registered, and subtraction images were compiled. Subtraction images contrasted activation patterns generated under the visual-only control condition to the auditory activation states acquired monaurally and binaurally. Results Right and left ear monaural stimulation in normal hearing subjects resulted in significant bilateral activation of Brodmann areas 41, 42, 21, 22, and 38. Although substantial intersubject response variability was noted, subjects generally failed to bilaterally activate these areas under monaural hearing aid presentations; however, bilateral activation of areas 41 and 22 was noted under binaural presentations. Conclusions Despite relatively similar hearing losses in each ear, significant differences in preoperative auditory corte- activation were observed between ears. These data suggest that functional brain imaging provides a useful tool for e-ploring the responsiveness of the auditory corte- in cochlear implant candidates. [source] Reliability reconsidered: Cronbach's alpha and paediatric assessment in occupational therapyAUSTRALIAN OCCUPATIONAL THERAPY JOURNAL, Issue 3 2009Georgia Spiliotopoulou Background/aim:,Using reliable outcome measures is a necessity for the occupational therapy profession in enabling valid assessments of clients. Although Cronbach's alpha is the most widely applied index of internal consistency reliability, there are misconceptions about its use and interpretation. This paper aims to guide assessment developers in paediatric occupational therapy, as well as practitioners who are evaluating outcome measures in using and interpreting the Cronbach's alpha estimates appropriately. This will enable them to decide on the tools' clinical value and incorporate them into their practice with children. Method:,Previously published papers reporting on internal consistency issues of outcome measures in paediatric occupational therapy were searched through the Allied and Complementary Medicine database. These papers were used as a basis to discuss possible reasons for reporting of low internal consistency. Results:,The analysis demonstrates that Cronbach's alpha reports are not always interpreted in a sound way. The paper emphasises that one should be cautious about judging estimates of internal consistency. Low size of the coefficient alpha might not always indicate problems with the construction of the tool; whereas large sizes do not always suggest adequate reliability. Instead, these reports might be related to the data characteristics of the construct. Conclusion:,In judging an outcome measure's internal consistency, researchers and practitioners in occupational therapy should report and consider the nature of data, the scale's length and width, the linearity and the normality of response distribution, the central response tendency, the sample response variability and the sample size. [source] Antiplatelet drug response variability and the role of platelet function testing: A practical guide for interventional cardiologists,CATHETERIZATION AND CARDIOVASCULAR INTERVENTIONS, Issue 1 2009Dominick J. Angiolillo MD Abstract Antiplatelet therapy is the cornerstone of treatment for patients with acute coronary syndrome and is also of particular importance in those who undergo percutaneous coronary intervention with stent implantation. Dual antiplatelet therapy with aspirin and clopidogrel is associated with improvement in long-term clinical outcomes in such patients and is presently the antiplatelet therapy of choice for secondary prevention of thrombotic events. However, a significant number of patients experience recurrent events despite antiplatelet therapy. Although poor patient compliance can account for some of these events, particularly in those patients who receive a drug-eluting stent, increasing evidence indicates that there is variability in response to antiplatelet therapy and patients who have higher levels of platelet reactivity are at increased risk for recurrent ischemic events. However, the lack of a consistent definition of inadequate platelet response, as well as the lack of a standardized measurement technique, has made it difficult to define how to treat these patients. To translate findings associated with variability in platelet response into improved patient care, it is necessary to gain a better understanding of what variable platelet response is, how it is measured, who it should be measured in, and what its clinical relevance is. The objective of this review is to evaluate the data regarding interindividual response variability to antiplatelet therapy with the aim of providing practical considerations and where possible, recommendations, regarding this topic for interventional cardiologists. © 2008 Wiley-Liss, Inc. [source] | ||||||||||