Wan-Hui Yu

Comparison of the Test-Retest Reliability of the Balance Computerized Adaptive Test and a Computerized Posturography Instrument in Patients With Stroke

OBJECTIVE To compare the test-retest reliabilities of the scores of the Balance Computerized Adaptive Test (CAT) and the Biodex Balance System in patients with stroke. DESIGN A repeated-measures design (at a 1-wk interval) was used to examine the test-retest reliabilities of the scores of the Balance CAT and the Biodex Balance System. SETTING One rehabilitation unit in a local hospital. PARTICIPANTS Patients (N=50) with stroke for more than 6 months and undergoing outpatient rehabilitation completed the Balance CAT and the eyes open (EO)/closed (EC) tests, but only 17 patients finished the Limit of Stability (LOS) test because they were unable to reach all the targets. INTERVENTIONS Not applicable. MAIN OUTCOME MEASURES The Balance CAT and 2 computerized tests of the Biodex Balance System, namely the EO/EC test and the LOS, were used to evaluate balance function. RESULTS The test-retest reliabilities of the scores of the Balance CAT (Pearson r=.92, minimal detectable change [MDC] percent=12.8%) was excellent. Those of the EO/EC and LOS tests were poor to good (Pearson r=.56-.85, MDC%=50.8%-126.9%). CONCLUSIONS The test-retest reliabilities of the scores of the Balance CAT were sufficient for assessing balance function in patients with stroke. Moreover, the test-retest reliabilities of the scores of the Balance CAT, one of the functional balance measures, were superior to those of the Biodex Balance System, 1 type of computerized posturography instrument. Therefore, the Balance CAT may be a more reliable measure for clinicians and researchers to use in assessing the balance function of patients with stroke for more than 6 months.

A comparison of responsiveness and predictive validity of two balance measures in patients with stroke

OBJECTIVE To compare the responsiveness and predictive validity of the Balance Computerized Adaptive Test (Balance CAT) and the Postural Assessment Scale for Stroke patients (PASS) in inpatients with stroke receiving rehabilitation. DESIGN A pre-post test design. SUBJECTS Eighty-five inpatients after stroke. METHODS Effect size d and Wilcoxon signed-rank test were used to assess the internal responsiveness of the Balance CAT and PASS. The changes in the Barthel Index (BI) and the mobility subscale of the Stroke Rehabilitation Assessment of Movement (MO-STREAM) scores were both chosen as the external criteria for examining external responsiveness. Moreover, to investigate the predictive validity, the admission scores of the two balance measures, and the discharge score of the BI/MO-STREAM, were examined by simple linear regression analysis. RESULTS Both the Balance CAT and PASS had high internal responsiveness (effect size d ≥ 0.87) and fair external responsiveness (r(2) ≥ 0.20). The predictive validities of both measures were sufficient (r(2) ≥ 0.33). The Balance CAT took approximately 3 items (min-max = 2-4) to complete. CONCLUSION The Balance CAT and PASS have sufficient responsiveness and predictive validity in inpatients with stroke receiving rehabilitation. The Balance CAT is more efficient to administer and is thus recommended over the PASS.

Responsiveness and Predictive Validity of the Hierarchical Balance Short Forms in People With Stroke

Background The lack of knowledge about the responsiveness and predictive validity of a set of Hierarchical Balance Short Forms (the HBSF) in people with stroke limits the utility of the HBSF in both clinical and research settings. Objective The purpose of this study was to investigate the responsiveness and predictive validity of the HBSF in people receiving inpatient rehabilitation after stroke. Design A prospective cohort study was conducted. Methods Sixty-six participants completed both the 6-item HBSF and the 12-item Postural Assessment Scale for Stroke (PASS) after admission to the rehabilitation ward and before hospital discharge. The standardized effect size (ES) and the standardized response mean (SRM) were used to investigate the internal responsiveness of the HBSF and the PASS. Changes in the Barthel Index and the mobility subscale of the Stroke Rehabilitation Assessment of Movement were used as the external criteria for examining external responsiveness. Moreover, the admission scores on the HBSF and the PASS and the discharge scores on the Barthel Index and mobility subscale of the Stroke Rehabilitation Assessment of Movement were analyzed to investigate the predictive validity of the 2 balance measures. Results The internal responsiveness of the HBSF was high (ES>0.9, SRM>1.6). The SRM of the HBSF was significantly larger than that of the PASS, whereas the ES of the HBSF was not significantly larger than that of the PASS. The external responsiveness and predictive validity of the HBSF were sufficient and similar to those of the PASS (external responsiveness: r≥.35; predictive validity: r≥.67). Limitations The convenience sampling of people receiving inpatient rehabilitation after stroke may limit the generalization of the results. Conclusions The HBSF has sufficient responsiveness and predictive validity in people receiving inpatient rehabilitation after stroke and is thus recommended for both clinicians and researchers.

Examining unidimensionality and improving reliability for the eight subscales of the SF-36 in opioid-dependent patients using Rasch analysis

PurposeThe Medical Outcome Study Short Form 36 (SF-36) is one of the most commonly used questionnaires for monitoring the Health-Related Quality of Life (HRQOL) of opioid-dependent patients. However, the unidimensionality and reliability of the SF-36 have not been verified in opioid-dependent patients. The aim of this study was to examine the unidimensionality and to improve the test reliability of the SF-36 for use in opioid-dependent patients.MethodsA total of 583 opioid-dependent patients were recruited in the study. Unidimensionality was examined by conducting unidimensional Rasch analysis. Item fit statistics and principle component analysis were used to check the item-model fit in each of the eight subscales of the SF-36. Reliability was evaluated by applying both unidimensional and multidimensional Rasch analyses.ResultsAfter three misfitting items were excluded, the remaining items of each subscale in the SF-36 represented a single construct. The test reliabilities (0.80–0.87) yielded by the multidimensional approach were much higher than those (0.68–0.82) produced by the unidimensional approach.ConclusionThe remaining 32 items of the SF-36 are appropriate for evaluating the HRQOL in opioid-dependent patients in terms of unidimensionality. Additionally, the test scores produced by the multidimensional approach were more accurate than those obtained by the unidimensional approach.

Test-retest reliability and responsiveness of the Barthel Index-based Supplementary Scales in patients with stroke.

BACKGROUND A lack of evidence on the test-retest reliability and responsiveness limits the utility of the BI-based Supplementary Scales (BI-SS) in both clinical and research settings. AIM To examine the test-retest reliability and responsiveness of the BI-based Supplementary Scales (BI-SS) in patients with stroke. DESIGN A repeated-assessments design (1 week apart) was used to examine the test-retest reliability of the BI-SS. For the responsiveness study, the participants were assessed with the BI-SS and BI (treated as an external criterion) at admission to and discharge from rehabilitation wards. SETTING Seven outpatient rehabilitation units and one inpatient rehabilitation unit. POPULATION Outpatients with chronic stroke. METHODS Eighty-four outpatients with chronic stroke participated in the test-retest reliability study. Fifty-seven inpatients completed baseline and follow-up assessments in the responsiveness study. RESULTS For the test-retest reliability study, the values of the intra-class correlation coefficient and the overall percentage of minimal detectable change for the Ability Scale and Self-perceived Difficulty Scale were 0.97, 12.8%, and 0.78, 35.8%, respectively. For the responsiveness study, the standardized effect size and standardized response mean (representing internal responsiveness) of the Ability Scale and Self-perceived Difficulty Scale were 1.17 and 1.56, and 0.78 and 0.89, respectively. Regarding external responsiveness, the change in score of the Ability Scale had significant and moderate association with that of the BI (r=0.61, P<0.001). The change in score of the Self-perceived Difficulty Scale had non-significant and weak association with that of the BI (r=0.23, P=0.080). CONCLUSIONS The Ability Scale of the BI-SS has satisfactory test-retest reliability and sufficient responsiveness for patients with stroke. However, the Self-perceived Difficulty Scale of the BI-SS has substantial random measurement error and insufficient external responsiveness, which may affect its utility in clinical settings. CLINICAL REHABILITATION IMPACT The findings of this study provide empirical evidence of psychometric properties of the BI-SS for assessing ability and self-perceived difficulty of ADL in patients with stroke.

Obstacle crossing in 7-9-year-old children with Down syndrome.

This study aimed to investigate obstacle crossing in 7-9-year-old children with Down syndrome (DS). Fifteen children with DS, age- and gender-matched with 15 typically developing (TD) children, were recruited to walk and cross obstacles with heights of 10%, 20% and 30% of their leg lengths. End-point and kinematic variables of obstacle crossing were obtained using a three-dimensional motion analysis system. The results showed that children with DS tend to adopt a lower speed and larger step width when they perceive instability. Moreover, unlike TD children, children with DS adopt a pelvic strategy (i.e., greater pelvic leading-side listing and forward rotation) to achieve a higher leading toe clearance with a longer step length, presumably for safety reasons. This pelvic strategy increased the frontal plane motion of the whole leg and trunk, and thus possibly stability, during obstacle crossing. However, this strategy may be inefficient. Trailing toe clearance did not differ significantly between two groups. The results of this study suggest that children with DS tend to use inefficient and conservative strategies for obstacle crossing. Knowledge of both end-point and kinematic control of obstacle crossing in children with DS is useful for understanding the mechanisms of obstacle-related falls. Moreover, obstacle crossing can be used as a task-oriented rehabilitation program for children with DS.

Development of a Tablet-based symbol digit modalities test for reliably assessing information processing speed in patients with stroke.

Abstract Purpose: To develop a Tablet-based Symbol Digit Modalities Test (T-SDMT) and to examine the test–retest reliability and concurrent validity of the T-SDMT in patients with stroke. Methods: The study had two phases. In the first phase, six experts, nine college students and five outpatients participated in the development and testing of the T-SDMT. In the second phase, 52 outpatients were evaluated twice (2 weeks apart) with the T-SDMT and SDMT to examine the test–retest reliability and concurrent validity of the T-SDMT. Results: The T-SDMT was developed via expert input and college student/patient feedback. Regarding test–retest reliability, the practise effects of the T-SDMT and SDMT were both trivial (d=0.12) but significant (p≦0.015). The improvement in the T-SDMT (4.7%) was smaller than that in the SDMT (5.6%). The minimal detectable changes (MDC%) of the T-SDMT and SDMT were 6.7 (22.8%) and 10.3 (32.8%), respectively. The T-SDMT and SDMT were highly correlated with each other at the two time points (Pearson’s r=0.90–0.91). Conclusions: The T-SDMT demonstrated good concurrent validity with the SDMT. Because the T-SDMT had a smaller practise effect and less random measurement error (superior test–retest reliability), it is recommended over the SDMT for assessing information processing speed in patients with stroke. Implications for Rehabilitation The Symbol Digit Modalities Test (SDMT), a common measure of information processing speed, showed a substantial practise effect and considerable random measurement error in patients with stroke. The Tablet-based SDMT (T-SDMT) has been developed to reduce the practise effect and random measurement error of the SDMT in patients with stroke. The T-SDMT had smaller practise effect and random measurement error than the SDMT, which can provide more reliable assessments of information processing speed.

A comparison between the original and Tablet-based Symbol Digit Modalities Test in patients with schizophrenia: Test-retest agreement, random measurement error, practice effect, and ecological validity

We aimed to compare the test-retest agreement, random measurement error, practice effect, and ecological validity of the original and Tablet-based Symbol Digit Modalities Test (T-SDMT) over five serial assessments, and to examine the concurrent validity of the T-SDMT in patients with schizophrenia. Sixty patients with chronic schizophrenia completed five serial assessments (one week apart) of the SDMT and T-SDMT and one assessment of the Activities of Daily Living Rating Scale III at the first time point. Both measures showed high test-retest agreement, similar levels of random measurement error over five serial assessments. Moreover, the practice effects of the two measures did not reach a plateau phase after five serial assessments in young and middle-aged participants. Nevertheless, only the practice effect of the T-SDMT became trivial after the first assessment. Like the SDMT, the T-SDMT had good ecological validity. The T-SDMT also had good concurrent validity with the SDMT. In addition, only the T-SDMT had discriminative validity to discriminate processing speed in young and middle-aged participants. Compared to the SDMT, the T-SDMT had overall slightly better psychometric properties, so it can be an alternative measure to the SDMT for assessing processing speed in patients with schizophrenia.

Interrater and Intrarater Reliability of the Balance Computerized Adaptive Test in Patients With Stroke

OBJECTIVE To examine the interrater and intrarater reliability of the Balance Computerized Adaptive Test (Balance CAT) in patients with chronic stroke having a wide range of balance functions. DESIGN Repeated assessments design (1wk apart). SETTING Seven teaching hospitals. PARTICIPANTS A pooled sample (N=102) including 2 independent groups of outpatients (n=50 for the interrater reliability study; n=52 for the intrarater reliability study) with chronic stroke. INTERVENTIONS Not applicable. MAIN OUTCOME MEASURES Balance CAT. RESULTS For the interrater reliability study, the values of intraclass correlation coefficient, minimal detectable change (MDC), and percentage of MDC (MDC%) for the Balance CAT were .84, 1.90, and 31.0%, respectively. For the intrarater reliability study, the values of intraclass correlation coefficient, MDC, and MDC% ranged from .89 to .91, from 1.14 to 1.26, and from 17.1% to 18.6%, respectively. CONCLUSIONS The Balance CAT showed sufficient intrarater reliability in patients with chronic stroke having balance functions ranging from sitting with support to independent walking. Although the Balance CAT may have good interrater reliability, we found substantial random measurement error between different raters. Accordingly, if the Balance CAT is used as an outcome measure in clinical or research settings, same raters are suggested over different time points to ensure reliable assessments.