Biomedical subjects

Sara Ahmed

Publications and source records attributed to Sara Ahmed.

7 recordsLinked to original sources

PubMed2005

The structural equation modeling technique did not show a response shift, contrary to the results of the then test and the individualized approaches.

BACKGROUND AND OBJECTIVE: Persons experiencing changes in their physical health may change their values and rerate the importance of basic elements of health-related quality of life (HRQL), a process known as response shift. Developing an estimator of HRQL that differentiates between objective change and response shift is essential for the interpretation of the results. The purpose of the present article was to contrast three methodologic approaches for evaluating response shift to develop a proposed set of HRQL measurement recommendations under circumstances where response shift is expected to occur. METHODS: The three approaches compared were a structural equation modeling (SEM) technique, the then test, and an individualized approach. The data collection procedures for these methods were incorporated into a poststroke randomized controlled trial. RESULTS: The SEM did not show a response shift, contrary to the results of the then test and the individualized approaches. We discuss factors that effect the selection of a methodologic approach including feasibility, subjects' memory and more advanced cognitive tasks, and whether response shift was evaluated at the group or individual level. CONCLUSION: The evaluation of response shift is an integral part of HRQL evaluations, and further comparisons between methodologic approaches are needed.

Activities of Daily Living↗

PubMed2005

Change in quality of life of people with stroke over time: true change or response shift?

UNLABELLED: In many studies, assessments of change in self-report measures such as health-related quality of life must account for potential response shift, including reconceptualization and changes in internal standards of measurement. OBJECTIVE: The objective of our study was to compare healthy controls and individuals with stroke on the extent to which changes in internal standards and reconceptualization of health related quality of life (HRQL) occurs over the first 6 months post-stroke. METHODS: Confirmatory factor analysis was used to assess invariance of the SF-36 measurement model over time among 238 individuals with stroke and 392 controls, separately. This procedure assessed changes over time in the factor loadings, variances, and covariances of responses, and compared the extent of change between individuals with stroke and those in the control group. In addition a multisample comparison was made between individuals with stroke and members of the control group at the first evaluation in order to assess invariance of the SF-36 measurement model between the groups. The controls were considered to be a 'proxy' for the stroke cohort prior to the stroke. RESULTS: We found no evidence of reconceptualization and changes in internal standards over time when the groups were assessed separately. There was a significant difference in the factor covariances (reconceptualization) between the two groups at the time of the first evaluation. However, measurement error was also significant for this comparison. CONCLUSION: This study indicates that the improvement in HRQL over time is real rather than a result of reconceptualization or a recalibration. If response shift does occur with stroke it is likely to be mediated by the event itself and not the recovery process.

Activities of Daily Living↗

PubMed2005

Using the Patient Generated Index to evaluate response shift post-stroke.

BACKGROUND: Individualized measures allow for the assessment of health-related quality of life (HRQL) based on areas that are relevant to the person and may prove to be useful for evaluating response shift (reconceptualization of HRQL and change in values). OBJECTIVE: The objective of this study was to assess reconceptualization of HRQL and change of individual values among persons with stroke during the first six months of recovery. METHODS: The data collection for this study was incorporated into a randomized trial of acute post-stroke care. Individualized HRQL was evaluated at 6 and 24 weeks post-stroke using the Patient Generated Index (PGI). At 24 weeks a semi-structured interview was administered to assess whether verbalizations given by subjects indicated that they had experienced a response shift. RESULTS: Ninety two subjects (61%) had complete PGI information at the 6- and 24-week evaluations, and of these, 46 completed the semi-structured interview. Between the 6- and 24-week evaluations, the domains selected were: the same for 10 (11%) subjects, reduced for 27 (29%), expanded for 11 (12%), and completely different for 44 (48%) subjects. Twenty eight percent (n = 13) of subjects recovering from stroke experienced a response shift as evidenced by the semi-structured interviews. CONCLUSION: The PGI provides valuable information regarding changes in person's conceptualization of HRQL and values, but the feasibility of using an individualized measure during the first six months post-stroke is limited by the added complexity of completing and interpreting such a measure.

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PubMed2004

Incorporating the International Classification of Functioning, Disability, and Health (ICF) into an electronic health record to create indicators of function: proof of concept using the SF-12.

OBJECTIVE: The purpose of this proof-of-concept study was to assess the feasibility of using a generic health measure to create coded functional status indicators and compare the characterization of a stroke population using coded functional indicators and using health-related quality-of-life summary measures alone. DESIGN: Multiple raters assigned International Classification of Functioning, Disability, and Health (ICF) codes to the items of the 12-Item Short Form Health Survey (SF-12). Data for comparing the information from the SF-12 and from ICF codes were derived from the Montreal Stroke Cohort Study that was set up to examine the long-term impact of stroke. Available for analysis were data from 604 persons with stroke, average age 69 years, and 488 controls, average age 62 years. MEASUREMENT: The SF-12 provides two summary scores, one for physical health and one for mental health. Domains of the ICF are coded to three digits, before the decimal; specific categorizations of impairments, activity limitations, and participation restrictions are coded to four digits before the decimal. RESULTS: Persons with stroke scored, on average, approximately 10 points lower than controls on physical and mental health. The ICF coding indicated that this was attributed, not surprisingly, to greater difficulty in doing moderate activities including housework, climbing stairs, and working and was not attributed to differences in pain. Differences in mental health were attributed most strongly to greater fatigue (impairment in energy), but all areas of mental health were affected to some degree. CONCLUSION: The ICF coding provided enhanced functional status information in a format compatible with the structure of administrative health databases.

Activities of Daily Living↗

PubMed2004

Response shift influenced estimates of change in health-related quality of life poststroke.

OBJECTIVE: The interpretability of changes in perceived health status over time is threatened if people experience a response shift. This study assessed whether the recovery process following stroke altered individuals' perceptions of past health status and the impact that change in internal standards (response shift) had on ratings over time. We hypothesized that individuals with stroke would experience changes in internal standards, not experienced by the control group. Two other hypotheses related to objective criterion measures also were tested. STUDY DESIGN AND SETTING: Individuals were recruited through a randomized trial of acute poststroke care. Health status was evaluated at baseline (within the first week poststroke), 6 and 24 weeks later using the EQ VAS. At 6 and 24 weeks, subjects were asked to retrospectively re-evaluate their health status for the preceding evaluation using the then test technique. RESULTS: The pattern of mean scores was indicative of changes in internal standards among individuals with stroke but not for the control group. Memory had an impact on estimates of response shift. Hypotheses related to the objective criterion measures were not supported. CONCLUSION: The results suggest that there was a change in internal standards, and that measures of improvement in health status are different based on prospective as compared to retrospective ratings. Further understanding of the impact of recall on the assessment of response shift using the then test is needed to validate the use of this technique.

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PubMed2003

The Stroke Rehabilitation Assessment of Movement (STREAM): a comparison with other measures used to evaluate effects of stroke and rehabilitation.

BACKGROUND AND PURPOSE: The Stroke Rehabilitation Assessment of Movement (STREAM) is a relatively new measure of voluntary movement and basic mobility. The main objectives of this study were: (1) to examine the relationship of the STREAM to other measures of impairment and disability and (2) to compare its usefulness for evaluating effects of stroke and rehabilitation and for assessing change over time with that of other measures of impairment and disability. SUBJECTS AND METHODS: The performance of 63 patients with acute stroke on the STREAM and other measures of impairment and disability was evaluated during the first week after stroke and 4 weeks and 3 months later. RESULTS: Scores on the STREAM were associated with scores on the Box and Block test, Balance Scale, Barthel Index, gait speed, and the Timed "Up Go" Test (with Pearson correlation coefficients ranging from .57 to .80) and were associated with categories of the Barthel Index and Balance Scale. The STREAM's ability to predict discharge destination from the acute care hospital, as well as to predict gait speed and Barthel Index scores at 3 months poststroke, was comparable to that of other commonly used measures. Standardized response mean estimates provided supporting evidence for the ability of the STREAM to reflect change over time. DISCUSSION AND CONCLUSION: The results obtained with the STREAM, as compared with other measures of impairment and disability in people with stroke, suggest that it may be useful in clinical practice and research.

Adult↗

PubMedDate not supplied

Upper-limb function and recovery in the acute phase poststroke.

This study evaluates stroke patients with upper-limb (UL) motor deficits using measures of impairment and "activity limitation" to quantify recovery of UL function poststroke and to identify predictors of UL function and predictors of UL recovery following stroke. The study also compares the recovery of UL function with that of the lower limb (LL). Measures of impairment and "activity limitation" of the UL and LL improved over the first 5 weeks. The Box and Block Test performance improved the most over 5 weeks (standardized response mean [SRM] = 1.34), followed closely by the 5-meter walk test (SRM = 0.97). Performances on measures of UL "activity limitation" measured at 1 week poststroke were the most important predictors of UL function 5 weeks poststroke. The results of this study do not support the belief that recovery of LL function is faster than that of UL.

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