Luigi Tesio

Assessing and adjusting for cross-cultural validity of impairment and activity limitation scales through differential item functioning within the framework of the Rasch model the pro-esor project

IntroductionIn Europe it is common for outcome measures to be translated for use in other languages. This adaptation may be complicated by culturally specific approaches to certain tasks; for example, bathing. In this context the issue of cross-cultural validity becomes paramount. ObjectiveTo facilitate the pooling of data in international studies, a project set out to evaluate the cross-cultural validity of impairment and activity limitation measures used in rehabilitation from the perspective of the Rasch measurement model. MethodsCross-cultural validity is assessed through an analysis of Differential Item Functioning (DIF) within the context of additive conjoint measurement expressed through the Rasch model. Data from patients undergoing rehabilitation for stroke was provided from 62 centers across Europe. Two commonly used outcome measures, the Mini-Mental State Examination (MMSE) and the Functional Independence Measure (FIM) motor scale are used to illustrate the approach. ResultsPooled data from 3 countries for the MMSE were shown to fit the Rasch model with only 1 item displaying DIF by country. In contrast, many items from the FIM expressed DIF and misfit to the model. Consequently they were allowed to be unique across countries, so resolving the lack of fit to the model. ConclusionsWhere data are to be pooled for international studies, analysis of DIF by culture is essential. Where DIF is observed, adjustments can be made to allow for cultural differences in outcome measurement.

Trunk Control Test as an Early Predictor of Stroke Rehabilitation Outcome

BACKGROUND AND PURPOSE The aim of this study was to investigate the construct and predictive validity of the Trunk Control Test (TCT) in postacute stroke patients by comparing TCT scores at admission and discharge with the Functional Independence Measure (FIM) scores. METHODS Forty-nine patients participated in the study. The TCT examines four movements: rolling from a supine position to the weak side (T1) and to the strong side (T2), sitting up from a lying-down position (T3), and sitting balance (T4). The FIM is an 18-item scale (13 motor [motFIM] and 5 cognitive [cognFIM]) used to determine the level of dependence of patients in daily life. RESULTS Thirty-six patients (73%) increased their TCT overall score at discharge. The TCT item-total correlations were high, both at admission and discharge (P < .0001). The individual TCT items were intercorrelated. Furthermore, the homogeneity of the TCT was confirmed by a high Cronbachs index. High correlations were found between admission and discharge scores in the different tests (TCT, FIM, and motFIM; P < .0001) and between TCT at admission and FIM (P < .0001) and motFIM (P < .0001) at admission. TCT at admission alone explained 71% of the variance in motFIM at discharge. CONCLUSIONS The TCT showed a good sensitivity to change in assessing recovery of stroke patients. The high item-total correlation and Cronbachs alpha value of the TCT suggest that there is one homogeneous construct underlying the item list. The TCT construct validity was confirmed by the correlation between this test and the FIM scores. TCT at admission predicted motFIM at discharge even better than motFIM at admission alone. Possibly, the TCT captures basic motor skills that foreshadow the recovery of more complex behavioral skills described by the FIM.

The ABILHAND Questionnaire as a Measure of Manual Ability in Chronic Stroke Patients: Rasch-Based Validation and Relationship to Upper Limb Impairment

Background and Purpose— Chronic hemiparetic patients often retain the ability to manage activities requiring both hands, either through the use of the affected arm or compensation with the unaffected limb. A measure of this overall ability was developed by adapting and validating the ABILHAND questionnaire through the Rasch measurement model. ABILHAND measures the patient’s perceived difficulty in performing everyday manual activities. Methods— One hundred three chronic (>6 months) stroke outpatients (62% men; mean age, 63 years) were assessed (74 in Belgium, 29 in Italy). They lived at home and walked independently and were screened for the absence of major cognitive deficits (dementia, aphasia, hemineglect). The patients were administered the ABILHAND questionnaire, the Brunnström upper limb motricity test, the box-and-block manual dexterity test, the Semmes-Weinstein tactile sensation test, and the Geriatric Depression Scale. The brain lesion type and site were recorded. ABILHAND results were analyzed with the use of Winsteps Rasch software. Results— The Rasch refinement of ABILHAND led to a change from the original unimanual and bimanual 56-item, 4-level scale to a bimanual 23-item, 3-level scale. The resulting ability scale had sufficient sensitivity to be clinically useful. Rasch reliability was 0.90, and the item-difficulty hierarchy was stable across demographic and clinical subgroups. Grip strength, motricity, dexterity, and depression were significantly correlated with the ABILHAND measures. Conclusions— The ABILHAND questionnaire results in a valid person-centered measure of manual ability in everyday activities. The stability of the item-difficulty hierarchy across different patient classes further supports the clinical application of the scale.

Neurophysiological and Behavioral Effects of tDCS Combined With Constraint-Induced Movement Therapy in Poststroke Patients

Background. Recovery of motor function after stroke may depend on a balance of activity in the neural network involving the affected and the unaffected motor cortices. Objective. To assess whether transcranial direct current stimulation (tDCS) can increase the training-induced recovery of motor functions. Methods. In an exploratory study, 14 patients with chronic stroke and mean Fugl-Meyer Upper Extremity Motor Assessment of 29 (range = 8-50) entered a double-blind sham-controlled study, aimed to investigate neurophysiological and behavioral effects of bihemispheric tDCS (cathodal stimulation of the unaffected motor cortex and anodal stimulation of the affected motor cortex), combined with constraint-induced movement therapy (CIMT). Results. Patients in both groups demonstrated gains on primary outcome measures, that is, Jebsen Taylor Hand Function Test, Handgrip Strength, Motor Activity Log Scale, and Fugl-Meyer Motor Score. Gains were larger in the active tDCS group. Neurophysiological measurements showed a reduction in transcallosal inhibition from the intact to the affected hemisphere and increased corticospinal excitability in the affected hemisphere only in the active tDCS/CIMT group. Such neurophysiological changes correlated with the magnitude of the behavioral gains. Both groups showed a reduction in corticospinal excitability of the unaffected hemisphere. Conclusions. CIMT alone appears effective in modulating local excitability but not in removing the imbalance in transcallosal inhibition. Bihemispheric tDCS may achieve this goal and foster greater functional recovery.

A multicenter international study on the spinal cord independence measure, version III: Rasch psychometric validation

Background:A third version of the Spinal Cord Independence Measure (SCIM III), made up of three subscales, was formulated following comments by experts from several countries and Rasch analysis performed on the previous version.Objective:To examine the validity, reliability, and usefulness of SCIM III using Rasch analysis.Design:Multicenter cohort study.Setting:Thirteen spinal cord units in six countries from North America, Europe, and the Middle-East.Subjects:425 patients with spinal cord lesions (SCL).Interventions:SCIM III assessments by professional staff members. Rasch analysis of admission scores.Main outcome measures:SCIM III subscale match between the distribution of item difficulty grades and the patient ability measurements; reliability of patient ability measures; fit of data to Rasch model requirements; unidimensionality of each subscale; hierarchical ordering of categories within items; differential item functioning across classes of patients and across countries.Results:Results supported the compatibility of the SCIM subscales with the stringent Rasch requirements. Average infit mean-square indices were 0.79–1.06; statistically distinct strata of abilities were 3 to 4; most thresholds between adjacent categories were properly ordered; item hierarchy was stable across most of the clinical subgroups and across countries. In a few items, however, misfit or category threshold disordering were found.Conclusions:The scores of each SCIM III subscale appear as a reliable and useful quantitative representation of a specific construct of independence after SCL. This justifies the use of SCIM in clinical research, including cross-cultural trials. The results also suggest that there is merit in further refining the scale.

The use of outcome measures in physical medicine and rehabilitation within Europe.

The aim of the study was to survey the use of outcome measures in rehabilitation within Europe. It was envisaged that this would provide the basis for further studies on the cross-cultural validity of outcome measures. A postal questionnaire was distributed in November 1998 to 866 units providing rehabilitation. In total, 418 questionnaires were returned, corresponding to a response rate of 48%. These 418 centres treated an estimated 113,000 patients annually, undertaking 360,000 assessments. The survey focused on nine diagnostic groups: hip and knee replacement, low back pain, lower limb amputees, multiple sclerosis, neuromuscular disorders, rheumatoid arthritis, spinal cord lesions, stroke and traumatic brain injury. It identified a relatively small number of dominant outcome assessments for each diagnostic group and some variation in the preference for measures across regions. A large number of measures, however, are being used in one or a small number of locations and with relatively few patients. For rehabilitation of orthopaedic patients the majority of assessments undertaken are at the impairment level. For patients with neurological disorders the emphasis is mostly upon measures of disability.

ABILHAND: A Rasch-built measure of manual ability

OBJECTIVE To apply the Rasch measurement model to the development of a clinical tool for measuring manual (dis)ability (ABILHAND). DESIGN Manual ability was evaluated in terms of the difficulty perceived by a hand-impaired patient on 57 representative unimanual or bimanual activities. SETTING A clinical laboratory. PATIENTS Eighteen rheumatoid arthritis patients (14 women, 4 men) were interviewed after wrist arthrodesis (10 right, 4 left, and 4 both wrists). Their ages ranged from 38 to 77 years, time since diagnosis ranged from 7 to 41 years, and time since surgery ranged from 0.5 to 17 years. MAIN OUTCOME MEASURE ABILHAND, administered at a mean duration of 7 years after arthrodesis. RESULTS Forty-six of the 57 items define a common, single manual ability continuum with widespread measurement range and regular item distribution. Items relating to feeding, grooming, and dressing upper body worked consistently with their counterparts in other disability scales. More difficult items extend the measurement range beyond that of most existing manual ability scales. CONCLUSION Even in a small sample of patients, using the Rasch methodology enabled the investigators to produce a useful scale of manual (dis)ability and to define manual ability as a unique construct, at least in patients with rheumatoid arthritis.

Reliability of four simple, quantitative tests of balance and mobility in healthy elderly females

Four common tests of balance and mobility were administered to 45 healthy women, aged 55–71 years: Sharpened Romberg (also defined as tandem stance), eyes open and closed; One-Legged Stance Test, eyes open and closed; Functional Reach; and Sit-To-Stand test. Two independent observers scored the tests, which were performed on two successive days. Inter-rater (IRR) and test-retest reliability (TRR) were good. Across the six different tests, Intraclass Correlation Coefficients ranged from 0.95 to 0.99 for scoring consistency between raters, and from 0.73 to 0.93 within raters. This is in line with previous findings based on similar subjects and similar, though not identical, testing procedures. Intercorrelations between the scores were moderate: r coefficients ranged 0.40–0.66. The results suggest that this simple test battery provides reliable scores, and that the different tests relate to a homogeneous construct, while not being redundant. It thus seems worthwhile to further investigate whether they represent and measure a unidimensional domain, rather than conceptually different dimensions, in view of achieving a unique measure of balance performance.

Depression is the main determinant of quality of life in multiple sclerosis: A classification-regression (CART) study

Purpose. Quality of life in multiple sclerosis has been often measured through the SF-36 questionnaire. In this study, validation of the SF-36 summary scores, its ‘physical’ component, and its ‘mental’ component was attempted by exploring the joint predictive power of disability (EDSS score), of anxiety and depression (HADS-A and -D scores, respectively), and of disease duration, progression type, age, gender and marital status. Method. The sample consisted of 75 patients suffering from multiple sclerosis admitted to an inpatient rehabilitation unit. The interplay between potential predictors was assessed through a particular regression model (classification and regression tree, CART). Two main advantages of this technique are its robustness with respect to distributional assumptions (rarely met by scores coming in from questionnaires) and its sensitivity to high-order interactions, between independent variables, difficult to detect through conventional multiple regression. Results. Predictive variables for physical component of the SF-36 were EDSS and HADS-D (36.8% variance explanation). The only predictive variable for mental component of SF-36 was HADS-D (39.1% variance explanation). Conclusion. Results confirm previous findings showing that in patients with multiple sclerosis quality of life is heavily determined by persons mood, whatever his/her neurological or functional severity. The usefulness and validity of the SF-36 as an index representative of quality of life is debatable, as long as depression explains much of its variance. Further refinement of quality of life definition and measurement is worth further psychometric and statistical research.

Rehabilitating patients with left spatial neglect by prism exposure during a visuomotor activity

OBJECTIVE Adaptation to prisms displacing the visual scene rightward is a therapeutic tool for left unilateral spatial neglect (USN). We aimed at comparing the effects of the classic adaptation procedure (repeated pointing toward visual targets, control treatment, C), with those of a novel adaptation method, involving ecological visuomotor activities (experimental treatment, E). METHOD In 10 right-brain-damaged USN patients, each treatment was given for 1 week, with a crossover design, for a total of 20 sessions, twice per day. USN was assessed by cancellation, reading, and drawing tasks, and by a standardized scale. Neurological severity was assessed by the National Institutes of Health (NIH) stroke scale (Brott et al., 1989), disability by the Functional Independence Measure (FIM) scale. RESULTS The 2-week treatments (EC, CE) were equally effective, improving both USN, confirming previous reports (Frassinetti, Angeli, Meneghello, Avanzi, & Làdavas, 2002) and, importantly, disability. The improvement was independent of baseline performance, duration of disease, and neurological severity. Recovery took place after the first week, continued in the second week, and was stable at the follow-up of 3 months. The improvement of USN, measured by cancellation performance, and, in part, that of disability, measured through the FIM scale, were mediated by the size of the leftward aftereffects, suggesting a causal relationship between prism exposure and recovery. The E protocol was better tolerated. CONCLUSIONS Daily life visuomotor activities, associated with prism exposure, are a useful tool for rehabilitating USN patients. This new treatment may widen the compliance with prism exposure treatments and their feasibility within home-based programs.