Massimo Penta

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.

ABILHAND-Kids A measure of manual ability in children with cerebral palsy

Objective: To develop a clinical tool for measuring manual ability (ABILHAND-Kids) in children with cerebral palsy (CP) using the Rasch measurement model. Methods: The authors developed a 74-item questionnaire based on existing scales and experts’ advice. The questionnaire was submitted to 113 children with CP (59% boys; mean age, 10 years) without major intellectual deficits (IQ > 60) and to their parents, and resubmitted to both groups after 1 month. The children’s and parents’ responses were analyzed separately with the WINSTEPS Rasch software to select items presenting an ordered rating scale, sharing the same discrimination, and fitting a unidimensional scale. Results: The final ABILHAND-Kids scale consisted of 21 mostly bimanual items rated by the parents. The parents reported a finer perception of their children’s ability than the children themselves, leading to a wider range of measurement, a higher reliability (R = 0.94), and a good reproducibility over time (R = 0.91). The item difficulty hierarchy was consistent between the parents and the experts. The ABILHAND-kids measures are significantly related to school education, type of CP, and gross motor function. Conclusions: ABILHAND-Kids is a functional scale specifically developed to measure manual ability in children with CP providing guidelines for goal setting in treatment planning. Its range and measurement precision are appropriate for clinical practice.

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.

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.

Hand impairments and their relationship with manual ability in children with cerebral palsy.

OBJECTIVE To study hand impairments and their relationship with manual ability in children with cerebral palsy. DESIGN Cross-sectional survey. PATIENTS A total of 101 children with cerebral palsy (mean age 10 years, age range 6-15 years) were assessed. METHODS Three motor and 3 sensory impairments were measured on both hands. Motor impairments included grip strength (Jamar dynamometer), gross manual dexterity(Box and Block Test) and fine finger dexterity (Purdue Peg-board Test). Sensory impairments included tactile pressure detection (Semmes-Weinstein aesthesiometer), stereognosis(Manual Form Perception Test) and proprioception (passive mobilization of the metacarpophalangeal joints). Manual ability was measured with the ABILHAND-Kids questionnaire. The relationship between hand impairments and manual ability was studied through correlation coefficients and a multiple linear forward stepwise regression analysis. RESULTS Motor impairments were markedly more prevalent than sensory ones. Gross manual dexterity on the dominant hand and grip strength on the non-dominant hand were the best independent predictors of the childrens manual ability,predicting 58% of its variance. CONCLUSION Hand impairments and manual ability are not related in a predictable straightforward relationship. It is important that, besides hand impairments, manual ability is also measured and treated, as it is not simply the integration of hand functions in daily activities.

Cross-cultural validity of functional independence measure items in stroke: A study using Rasch analysis

OBJECTIVE To analyse cross-cultural validity of the Functional Independence Measure (FIM) in patients with stroke using the Rasch model. SETTINGS Thirty-one rehabilitation facilities within 6 different countries in Europe. PARTICIPANTS A total of 2546 in-patients at admission, median age 63 years. METHODS Data from the FIM were evaluated with the Rasch model, using the Rasch analysis package RUMM2020. A detailed analysis of scoring functions of the 7 categories of the FIM items was undertaken prior to testing fit to the model. Categories were re-scored where necessary. Analysis of Differential Item Functioning was undertaken in pooled data for each of the FIM motor and social-cognitive scales, respectively. RESULTS Disordered thresholds were found on most items when using 7 categories. Fit to the Rasch model varied between countries. Differential Item Functioning was found by country for most items. Adequate fit to the Rasch model was achieved when items were treated as unique for each country and after a few country-specific items were removed. CONCLUSION Clinical collected data from FIM for patients with stroke cannot be pooled in its raw form, or compared across countries. Comparisons can be made after adjusting for country-specific Differential Item Functioning, though the adjustments for Differential Item Functioning and rating scales may not generalize to other samples.

Cross-cultural validity of FIM in spinal cord injury

Objective:To analyse cross-culture validity of the Functional Independence Measure (FIM™) in patients with a spinal cord injury using a modern psychometric approach.Settings:A total of 19 rehabilitation facilities from four countries in Europe.Participants:A total of 647 patients at admission, median age 46 years, 69% male.Methods:Data from the FIM™, collected on inpatient admission, was fitted to the Rasch model. A detailed analysis of scoring functions of the seven categories of the FIM™ items was undertaken before to testing fit to the model. Categories were rescored where necessary. Fit to the model was assessed initially within country, and then in the pooled data. Analysis of differential item functioning (DIF) was undertaken in the pooled data for each of the FIM™ motor and social cognitive scales, respectively. Final fit to the model was tested for breach of local independence by principle components analysis (PCA).Results:The present scoring system for the FIM™ motor and cognitive scales, that is a seven category scale, was found to be invalid, necessitating extensive rescoring. Following this, DIF was found in a number of items within the motor scale, requiring a complex solution of splitting items by country to allow for the valid pooling of data. Five country-specific items could not be retained within this solution. The FIM cognitive scale fitted the Rasch model after rescoring, but there was a substantial ceiling effect.Conclusions:Data from the FIM™ motor scale for patients with spinal cord injury should not be pooled in its raw form, or compared from country to country. Only after fit to the Rasch model and necessary adjustments could such a comparison be made, but with a loss of clinical important items. The FIM cognitive scale works well following rescoring, and data may be pooled, but many patients were at the maximum score.

Validation of the ABILHAND questionnaire as a measure of manual ability in patients with rheumatoid arthritis

Objective: Hand and upper limb involvement is common in patients with rheumatoid arthritis (RA). However, its impact on manual activities of daily life has not been fully evaluated. A measure of manual ability was developed, through the Rasch measurement model, by adapting and validating the ABILHAND questionnaire, which measures the patient’s perceived difficulty in performing everyday manual activities. Methods: 112 patients with RA were evaluated. The following tests were performed: the ABILHAND questionnaire, the Health Assessment Questionnaire (HAQ), the Jamar grip and key pinch strength tests, the Box and Block dexterity test and the Purdue pegboard dexterity test. In total, 35 patients were reassessed to determine the test–retest reliability of the ABILHAND, and 6 patients were studied before and after therapy with tumour necrosis factor (TNF) blockers to address sensitivity to change. Results: The Rasch refinement of the ABILHAND led to a selection of 27 items rated on a 3-point scale. The resulting ability scale was targeted to the ability of the patients. The item-difficulty hierarchy was stable across demographic and clinical subgroups and over time. Grip and key pinch strength and manual and digital dexterity on both hands were significantly, though moderately, correlated with the ABILHAND measures. Manual ability was also significantly related to the number of affected hands, disease duration, tender and swollen joint counts on upper limbs, disease activity and the HAQ. Sensitivity to change was demonstrated in patients treated with TNF blockers, commensurate with their clinical improvement. Conclusion: The ABILHAND questionnaire is a clinically valid person-centred measure of manual ability that could be useful in longitudinal RA studies.

Rasch-built measure of pleasant touch through active fingertip exploration.

Background: Evidence suggests that somatic sensation has a modality for pleasant touch. Objective: To investigate pleasant touch at the fingertip level (i.e., glabrous skin site) through the elaboration of a linear unidimensional scale that measures (i) various materials according to the level of pleasantness they elicit through active fingertip explorations and (ii) subjects according to their pleasantness leniency levels. Subjects: We enrolled 198 healthy subjects without any neurological disease. Methods: Blindfolded subjects actively explored 48 materials with their index fingertips and reported the perceived pleasantness of each on a 4-level scale. The fingertip moisture levels on each subject were measured before the experimental session. Data were analyzed using the Rasch model. Results: We elaborated unidimensional linear scale that included 37 materials according to their pleasantness of touch. The pleasantness level of 21 materials was perceived differently, depending on the fingertip moisture levels of the subjects. Conclusion: Based on our findings, we formulated a Pleasant Touch Scale. Fingertip moisture levels appeared to be a major factor for (un)pleasant feelings during active exploration.

Outcome evaluation of the hand and wrist according to the International Classification of Functioning, Disability, and Health

This article is a brief review of the outcome evaluation of the hand and wrist according to the International Classification of Functioning, Disability, and Health. Several tools currently exist to quantify outcome in hand surgery at the impairment level (eg, mobility, hand strength, cutaneous sensation, dexterity). According to the World Health Organizations paradigm, however, activity limitations and participation restrictions are also clinically relevant. The authors have recently built a measure of an upper limb-impaired individuals ability to manage manual activities in daily life. Participation and quality of life are difficult outcomes to measure because they are multidimensional and depend on such factors as functional abilities, general physical health, financial security, and stability of the social and familial environment.