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

Interpreting results from Rasch analysis 2. Advanced model applications and the data-model fit assessment

Purpose: The present paper presents developments and advanced practical applications of Rasch's theory and statistical analysis to construct questionnaires for measuring a person's traits. The flaws of questionnaires providing raw scores are well known. Scores only approximate objective, linear measures. The Rasch Analysis allows you to turn raw scores into measures with an error estimate, satisfying fundamental measurement axioms (e.g., unidimensionality, linearity, generalizability). A previous companion article illustrated the most frequent graphic and numeric representations of results obtained through Rasch Analysis. A more advanced description of the method is presented here.Conclusions: Measures obtained through Rasch Analysis may foster the advancement of the scientific assessment of behaviours, perceptions, skills, attitudes, and knowledge so frequently faced in Physical and Rehabilitation Medicine, not less than in social and educational sciences. Furthermore, suggestions are given on interpreting and managing the inevitable discrepancies between observed scores and ideal measures (data-model "misfit"). Finally, twelve practical take-home messages for appraising published results are provided.Implications for rehabilitationThe current work is the second of two papers addressed to rehabilitation clinicians looking for an in-depth introduction to the Rasch analysis.The first paper illustrates the most common results reported in published papers presenting the Rasch analysis of questionnaires.The present article illustrates more advanced applications of the Rasch analysis, also frequently found in publications.Twelve take-home messages are given for a critical appraisal of the results.

Impact of intracerebral hemorrhage and cerebral infarction on ADL and outcome in stroke patients: A retrospective cohort study

BACKGROUND

The impact of different stroke types on specific activities of daily living (ADL) is unclear.

OBJECTIVE

To investigate how differences between intracerebral hemorrhage (ICH) and cerebral infarction (CI) affect improvement of ADL in patients with stroke within a hospital by focusing on the sub-items of the Functional Independence Measure (FIM).

METHODS

Patients with first-stroke hemiplegia (n = 212) were divided into two groups: ICH (86 patients) and CI (126 patients). Primary assessments included 13 motor and 5 cognitive sub-items of the FIM assessed at admission and discharge. Between-group comparisons and multiple regression analyses were performed.

RESULTS

Upon admission, the ICH group exhibited significantly lower FIM scores than those of the CI group across various activities, including grooming, dressing (upper body and lower body), toileting, bed/chair transfer, toilet transfer, walking/wheelchair, and stairs. Age and FIM motor scores at admission influenced both groups' total FIM motor scores at discharge, whereas the duration from onset affected only the CI group.

CONCLUSION

Several individual FIM motor items were more adversely affected by ICH than by CI. Factors related to ADL at discharge may differ depending on stroke type. Recognizing these differences is vital for efficient rehabilitation practices and outcome prediction.

Assessing independence in mobility activities in trauma care: Validity and reliability of the Activity Independence Measure-Trauma (AIM-T) in humanitarian settings

The importance of measuring outcomes after injury beyond mortality and morbidity is increasingly recognized, though underreported in humanitarian settings. To address shortcomings of existing outcome measures in humanitarian settings, the Activity Independence Measure-Trauma (AIM-T) was developed, and is structured in three subscales (i.e., core, lower limb, and upper limb). This study aimed to assess the AIM-T construct validity (structural validity and hypothesis testing) and reliability (internal consistency, inter-rater reliability and measurement error) in four humanitarian settings (Burundi, Iraq, Cameroon and Central African Republic). Patients with acute injury (n = 195) were assessed using the AIM-T, the Barthel Index (BI), and two pain scores. Structural validity was assessed through confirmatory factor analysis. Hypotheses were tested regarding correlations with BI and pain scores using Pearson correlation coefficient (PCC) and differences in AIM-T scores between patients' subgroups, using standardized effect size Cohen's d (d). Internal consistency was assessed with Cronbach's alpha (α). AIM-T was reassessed by a second rater in 77 participants to test inter-rater reliability using intraclass correlation coefficient (ICC). The results showed that the AIM-T structure in three subscales had an acceptable fit. The AIM-T showed an inverse weak to moderate correlation with both pain scores (PCC<0.7, p≤0.05), positive strong correlation with BI (PCC≥0.7, p≤0.05), and differed between all subgroups (d≥0.5, p≤0.05). The inter-rater reliability in the (sub)scales was good to excellent (ICC 0.86-0.91) and the three subscales' internal consistency was adequate (α≥0.7). In conclusion, this study supports the AIM-T validity in measuring independence in mobility activities and its reliability in humanitarian settings, as well as it informs on its interpretability. Thus, the AIM-T could be a valuable measure to assess outcomes after injury in humanitarian settings.

Efficacy of a Training on Executive Functions in Potentiating Rehabilitation Effects in Stroke Patients

Cognitive impairment after a stroke has a direct impact on patients' disability. In particular, impairment of Executive Functions (EFs) interferes with re-adaptation to daily life. The aim of this study was to explore whether adding a computer-based training on EFs to an ordinary rehabilitation program, regardless of the specific brain damage and clinical impairment (motor, language, or cognitive), could improve rehabilitation outcomes in patients with stroke. An EF training was designed to have minimal motor and expressive language demands and to be applied to a wide range of clinical conditions. A total of 37 stroke patients were randomly assigned to two groups: a training group, which performed the EF training in addition to the ordinary rehabilitation program (treatment as usual), and a control group, which performed the ordinary rehabilitation exclusively. Both groups were assessed before and after the rehabilitation program on neuropsychological tests covering multiple cognitive domains, and on functional scales (Barthel index, Functional Independence Measure). The results showed that only patients who received the training improved their scores on the Attentional Matrices and Phonemic Fluency tests after the rehabilitation program. Moreover, they showed a greater functional improvement in the Barthel scale as well. These results suggest that combining an EF training with an ordinary rehabilitation program potentiates beneficial effects of the latter, especially in promoting independence in activities of daily living.

Item Difficulties of the FIM-Motor Subscale in Patients with Ischemic Stroke during Acute Care: An Ordinal Logistic Modeling Study

Objective:

The aim of the current study was to assess the item difficulties of the motor subscales of the Functional Independence Measure (FIM-motor) in patients with ischemic stroke during acute care.

Methods:

FIM scores were assessed for each patient on admission to, and discharge from, acute care. The relationship between individual FIM-motor items (target variables) and the total FIM-motor score (explanatory variable) was assessed by ordinal logistic modeling. The total FIM-motor scores that corresponded to a 50% probability of independence level 5 (supervision or setup) for each FIM-motor item were assessed.

Results:

A total of 250 patients (155 men, 95 women) were included in the analytical database. The median age was 74 (interquartile range [IQR], 66–81) years and the median length of hospital stay was 14 (IQR, 10–24) days. Ordinal logistic modeling was successfully performed for all 13 FIM-motor items. The total FIM-motor scores that corresponded to a 50% probability of independence level 5 for individual FIM-motor items were as follows: eating, 34.1; bowel management, 42.2; bladder management, 43.4; grooming, 51.0; toileting, 62.0; dressing the lower body, 64.5; transfer to bed/chair/wheelchair, 65.5; transfer to toilet, 65.9; bathing, 70.3; dressing the upper body, 73.6; locomotion, 74.2; transfer to tub/shower, 80.0; and stair climbing, 89.2.

Conclusions:

These results revealed that eating, grooming, and bowel and bladder management were relatively easy, whereas gait-related items such as locomotion and stair climbing were difficult. Items such as transfer to bed/chair/wheelchair and toileting had intermediate difficulty. These results should facilitate efficient rehabilitative treatments during acute care.

Applicability of International Classification of Functioning, Disability and Health-based participation measures in stroke survivors in Africa: a systematic review

To appraise available International Classification of Functioning, Disability and Health (ICF)-based tools for the measurement of participation after stroke and to examine their applicability in the African sociocultural context. Pubmed/Medline, Science Direct, Cochrane Library, and Hinari databases were systematically searched. The literature search was limited to studies published in the English or French language from January 2001 up to May 2019. Two reviewers independently screened all identified studies and selected eligible articles. Disagreements about inclusion or exclusion of studies were resolved by consensus. Two reviewers independently extracted the psychometric properties of each instrument using the Consensus-based Standard for the Selection of Health Measurement Instruments checklist and examined the methodological quality of each selected study using the MacDermid checklist. A total of 1030 articles were systematically reviewed for relevance, yielding 22 studies that met inclusion criteria. These studies were related to nine participation tools. The MacDermid scores ranged from 13 to 21 out of 24. The number of investigated psychometric properties and the number of ICF participation domains covered by each tool varied among studies. This systematic review revealed nine ICF-based tools for the measurement of participation after stroke. We examined the content of these tools and provided valuable information that can be used to guide researchers in Africa in their selection of the most appropriate tool for the measurement of participation after stroke.

What matters to patients with stroke in India and why: a qualitative study

PURPOSE

To gain insight into the preferred outcomes of patients with stroke living in India and develop a conceptual framework of participation in daily activities based on patient perspectives informed by the International Classification of Functioning, Disability, and Health.

METHODS

This study took a phenomenological approach. A purposive sample of 30 patients with stroke and diverse socio-demographic and disease related characteristics participated in semi-structured interviews. Interviews consisted of open-ended questions about their post stroke rehabilitation goals. Data were analyzed using content analysis.

RESULTS

Patients expressed preference for outcomes such as the use of eastern toilets, squatting and sitting on the floor, eating with the right hand, taking a "bucket bath," walking for long distances (1-2 km) and the use of public transportation. Patients attributed their outcome preferences to contextual factors such as the physical environment (natural and built environment), family structure and living conditions, cultural values, norms and practices. Based on the outcomes identified by the patients, we developed the conceptual framework of participation in daily activities relevant to Indian context consisting of Mobility, Self-care, Domestic Life, and Social participation domains informed by the International Classification of Functioning, Disability, and Health.

CONCLUSIONS

Outcome preferences of patients with stroke are not universal. The conceptual framework including its domains and contents developed in this study can be a useful guide to clinicians and researchers in choosing what to measure within Indian as well as other similar sociocultural contexts.Implications for rehabilitationPost-stroke functional outcome measurement is meaningful only when it is conceptualized within the context in which the personal, social, and cultural values of patients are well-recognized.There are notable differences in the type of activities constituting daily activities and how they were performed in India compared to a western cultural context.Patients' daily functioning is characterized by the differences in personal preferences, cultural norms and practices, family and living arrangements, lifestyle, and characteristics of natural and built environment and the available public infrastructure.Differentiating activities patients cannot do from the "no need to do" or "don't want to do" should be viewed as a critical aspect of patient reported outcome measurement.

Rasch Analysis of the Edmonton Symptom Assessment System

CONTEXT

The Edmonton Symptom Assessment System (ESAS) is a widely used multisymptom assessment tool in cancer and palliative care settings, but its psychometric properties have not been widely tested using modern psychometric methods such as Rasch analysis.

OBJECTIVES

To apply Rasch analysis to the ESAS in a community palliative care setting and determine its suitability for assessing symptom burden in this group.

METHODS

ESAS data collected from 229 patients enrolled in a community hospice service were evaluated using a partial credit Rasch model with RUMM2030 software (RUMM Laboratory Pty, Ltd., Duncraig, WA). Where disordered thresholds were discovered, item rescoring was undertaken. Rasch model fit and differential item functioning were evaluated after each iterative phase.

RESULTS

Uniform rescoring was necessary for all 12 items to display ordered thresholds. The best model fit was achieved after item rescoring and combining three pairs of locally dependent items into three superitems (χ² = 29.56 [27]; P = 0.33) that permitted ordinal-to-interval conversion.

CONCLUSION

The ESAS satisfied unidimensional Rasch model expectations in a 12-item format after minor modifications. This included uniform rescoring of the disordered response categories and creating superitems to improve model fit and clinical utility. The accuracy of the ESAS scores can be improved by using ordinal-to-interval conversion tables published in the article.

The Rest of the Story: A Qualitative Study of Complementing Standardized Assessment Data with Informal Interviews with Older Patients and Families

BACKGROUND

While standardized health assessments capture valuable information on patients' demographic and diagnostic characteristics, health conditions, and physical and mental functioning, they may not capture information of most relevance to individual patients and their families. Given that patients and their informal caregivers are the experts on that patient's unique context, it is important to ensure they are able to convey all relevant personal information to formal healthcare providers so that high-quality, patient-centered care may be delivered. This study aims to identify information that older patients and families consider important but that might not be included in standardized assessments.

METHODS

Transcripts were analyzed from 29 interviews relating to eight patients with hip fractures from three sites (large urban, smaller urban, rural) in two provinces in Canada. These interviews were conducted as part of a larger ethnographic study. Each transcript was analyzed by two researchers using content analysis. Results were reviewed in two focus group interviews with older adults and family caregivers. Identified themes were compared with items from two standardized assessments used in healthcare settings.

RESULTS

Three broad themes emerged from the qualitative analysis that were not covered in the standardized assessments: informal caregiver and family considerations, insider healthcare knowledge, and patients' healthcare attitudes and experiences. The importance of these themes was confirmed through focus group interviews. Focus group participants also emphasized the importance of conducting assessments in a patient-centered way and the importance of open-ended questions.

CONCLUSIONS

A less structured interview approach may yield information that would otherwise be missed in standardized assessments. Combining both sources could yield better-informed healthcare planning and quality-improvement efforts.

Identification of the components associated with functioning using the international classification of functioning, disability and health comprehensive core set for stroke in Indian stroke survivors

OBJECTIVES

Rehabilitation interventions are expected to ensure best possible recovery and minimize functional disability in stroke survivors. However, not many studies have investigated patterns of recovery and outcomes after stroke in low-income countries. The objective of this study is to identify the biological, psychological, and social components associated with functioning over time in Indian stroke patients using the International Classification of Functioning, Disability and Health (ICF)-based tools and the Functional Independence Measure (FIM).

METHODS

The functioning profile of stroke survivors who received a standard multi-disciplinary rehabilitation was prospectively assessed using the ICF and the FIM at admission (baseline), at 12 & 24 weeks. Descriptive analyses were performed to identify changes in the frequencies of ICF categories and qualifiers from admission to follow-up.

RESULTS

One hundred and twenty-seven participants (mean age of 56 years) with mean FIM score 68 at baseline participated and completed the study. The mean FIM score at follow-up was 108. The numbers and frequency of ICF categories for activities and participation reduced after rehabilitation. More numbers of environmental factors were identified as barriers at follow-up (15 out of 33) compared to baseline. Within the components of Activities and Participation, significant improvement in functioning was found in 43 out of 51 categories.

CONCLUSION

The results show a reduction in frequencies in ICF activities and participation categories corresponding to basic activities of daily living. Categories corresponding to employment and social integration showed little or no improvement.

Cultural adaptation and validation of Stroke Impact Scale 3.0 version in Uganda: A small-scale study

BACKGROUND

Knowledge is scarce about the impact of stroke in Uganda, and culturally adapted, psychometrically tested patient-reported outcome measures are lacking. The Stroke Impact Scale 3.0 is recommended, but it has not been culturally adapted and validated in Uganda.

OBJECTIVE

To culturally adapt and determine the psychometric properties of the Stroke Impact Scale 3.0 in the Ugandan context on a small scale.

METHOD

The Stroke Impact Scale 3.0 was culturally adapted to form Stroke Impact Scale 3.0 Uganda (in English) by involving 25 participants in three different expert committees. Subsequently, Stroke Impact Scale 3.0 Uganda from English to Luganda language was done in accordance with guidelines. The first language in Uganda is English and Luganda is the main spoken language in Kampala city and its surroundings. Translation of Stroke Impact Scale 3.0 Uganda (both in English and Luganda) was then tested psychometrically by applying a Rasch model on data collected from 95 participants with stroke.

RESULTS

Overall, 10 of 59 (17%) items in the eight domains of the Stroke Impact Scale 3.0 were culturally adapted. The majority were 6 of 10 items in the domain Activities of Daily Living, 2 of 9 items in the domain Mobility, and 2 of 5 items in the domain Hand function. Only in two domains, all items demonstrated acceptable goodness of fit to the Rasch model. There were also more than 5% person misfits in the domains Participation and Emotion, while the Communication, Mobility, and Hand function domains had the lowest proportions of person misfits. The reliability coefficient was equal or larger than 0.90 in all domains except the Emotion domain, which was below the set criterion of 0.80 (0.75).

CONCLUSION

The cultural adaptation and translation of Stroke Impact Scale 3.0 Uganda provides initial evidence of validity of the Stroke Impact Scale 3.0 when used in this context. The results provide support for several aspects of validity and precision but also point out issues for further adaptation and improvement of the Stroke Impact Scale.

Mirror therapy in unilateral neglect after stroke (MUST trial): a randomized controlled trial

OBJECTIVE

We explored the effectiveness of mirror therapy (MT) in the treatment of unilateral neglect in stroke patients.

METHODS

This is an open, blinded endpoint, randomized controlled trial carried out from January 2011 to August 2013. We included stroke patients with thalamic and parietal lobe lesions with unilateral neglect 48 hours after stroke. Patients were randomized to the MT group or the control group (sham MT), and both the groups received limb activation. Patients received treatment for 1-2 hours a day 5 days a week for 4 weeks. The primary outcome was unilateral neglect assessed by a blinded assessor using the star cancellation test, the line bisection test, and a picture identification task at 1, 3, and 6 months. This study was registered at http://clinicaltrials.gov (NCT 01735877).

RESULTS

Forty-eight patients were randomized to MT (n = 27) or the control group (n = 21). Improvement in scores on the star cancellation test over 6 months was greater in the MT group (mean difference 23, 95% confidence interval [CI] 19-28; p < 0.0001). Similarly, improvement in the MT group was observed in the scores on the picture identification task (mean difference 3.2, 95% CI 2.4-4.0; p < 0.0001) and line bisection test (mean difference 8.6, 95% CI 2.7-14.6; p = 0.006).

CONCLUSIONS

In patients with stroke, MT is a simple treatment that improves unilateral neglect.

CLASSIFICATION OF EVIDENCE

This study provides Class I evidence that for patients with neglect from thalamic and parietal lobe strokes, MT improves neglect.

Assessing locomotion ability in West African stroke patients: validation of ABILOCO-Benin scale

OBJECTIVE

To calibrate and validate the Benin version of ABILOCO, a Rasch-built scale developed to assess locomotion ability in stroke patients.

DESIGN

Prospective study and questionnaire development.

SETTING

Rehabilitation centers.

PARTICIPANTS

Stroke patients (N=230; mean age ± SD, 51.1±11.6 y; 64.3% men).

INTERVENTION

Not applicable.

MAIN OUTCOME MEASURES

Participants completed a preliminary list of 36 items including the 13 items of ABILOCO. Items were scored as "impossible," "difficult," or "easy." The mobility subdomain of FIM (FIM-mobility), the Functional Ambulation Classification (FAC), the 6-minute walk test (6MWT), and the 10-meter walk test (10MWT) were used to evaluate and elucidate the validity of the ABILOCO-Benin scale.

RESULTS

Successive Rasch analyses led to the selection of 15 items that define a unidimensional, invariant, and linear measure of locomotion ability in stroke patients. This modified version of the ABILOCO scale, named ABILOCO-Benin, showed an excellent internal consistency, with a Person Separation Index of .93, and excellent test-retest reliability with high intraclass correlation coefficients of .95 (P<.001) for item difficulty and .93 (P<.001) for subject measures. It also presented good construct validity compared with FAC, FIM-mobility, 6MWT, and 10MWT (r≥.75, P<.001).

CONCLUSIONS

ABILOCO-Benin presents good psychometric properties. It allows valid, reliable, and objective measurements of locomotion ability in stroke patients.

One-year follow-up of Chinese people with spinal cord injury: a preliminary study

BACKGROUND

A tertiary spinal cord injury (SCI) center was established in the northern region of Hong Kong, China and a multidisciplinary SCI rehabilitation program was developed to reintegrate patients into the community.

OBJECTIVE

To investigate functional outcomes for Chinese people with SCI across a 1-year period.

DESIGN

Longitudinal prospective design.

METHODS

Thirty community-dwelling participants with traumatic SCI were recruited. Functional status was measured using functional independence measure (FIM) on admission, upon discharge, 1-month, 3-month, 6-month, and 1-year post-discharge. Information on use of assistive devices and life role were also obtained.

RESULTS

Twenty-three (76.67%) participants were men. Seventeen participants (10 with tetraplegia and 7 with paraplegia) were classified ASIA A, B, or C; 13 (7 with tetraplegia and 6 with paraplegia) were classified as ASIA D. Significant differences in FIM motor scores were only found between the tetraplegia group and three other diagnostic groups using Bonferroni post-hoc tests of repeated measure ANOVA (analysis of variance) (P < 0.05). Longitudinally, contrast tests of repeated measure ANOVA showed significant differences during the hospitalization period for all diagnostic groups. People in the ASIA D group showed significant functional improvement even after 1-year post-discharge (P < 0.05). At 1-year post-discharge, only two participants were engaged in either remunerative employment or academic pursuit.

CONCLUSION

Despite functional status improvement, few people with traumatic SCI were re-engaged in productive life role 1 year after discharge. Studies with longer follow-up would be beneficial.

Detection of activity limitations in older adults with MCI or Alzheimer's disease through evaluation of perceived difficulty in use of everyday technology: a replication study

OBJECTIVES AND METHODS

Earlier research indicates that the ability to use everyday technology (ET) may be sensitive to subtle functional change. People with mild cognitive impairment (MCI) have been identified as significantly more disabled in ET use compared to controls, albeit less disabled than people with dementia. The aim of this study was to investigate the replicability of these findings using an improved version of the Everyday Technology Use Questionnaire (ETUQ) to compare perceptions of relevance and difficulty in ET use in participants with MCI or Alzheimer's disease (AD) and controls. Additional aims were to explore the validity of ETUQ, and the relationships between perceived difficulty in ET use and cognitive status, mood state, and involvement in everyday life activities. In total, 118 participants were included, 37 with AD, 37 with MCI, and 44 controls.

RESULTS

Analyses confirmed that the rating scale of the ETUQ functioned well. The three groups overlapped but differed significantly in their perceptions of ETs relevance (p < 0.05) as well as of difficulties in ET use (p < 0.001). Moderate correlations were also found between ETUQ measures and cognitive status, mood, and involvement in activities, the strongest being that between ETUQ measures and involvement in activities (r = 0.563).

CONCLUSION

Taken together, the findings underscore the plausibility of disability already in people with MCI, as the use of ET strongly correlates to involvement in activities. It is therefore important that professionals who meet older adults with cognitive impairment take this aspect of function into account in assessments and targeted interventions.

The impact of cataract, cataract types, and cataract grades on vision-specific functioning using Rasch analysis

PURPOSE

To determine the impact of cataracts and their types and grades on vision-specific functioning.

DESIGN

Prospective population-based cross-sectional study.

METHODS

The Singapore Indian Eye Study examined 3400 of 4497 (75.6% response rate) ethnic Indians 40 years of age and older living in Singapore. Three thousand one hundred sixty-eight (93.2%) fulfilled inclusion criteria with complete information for final analysis. Cataracts were assessed on slit-lamp examination and were graded according to the Lens Opacity Classification System III. Vision-specific functioning scores were explored with the Visual Function scale, validated using Rasch analysis.

RESULTS

Two hundred sixty-nine (8.5%) and 740 (23.4%) of the study participants had unilateral and bilateral cataracts, respectively, and 329 (10.4%), 800 (25.2%), and 128 (4.1%) participants had nuclear, cortical, and posterior subcapsular (PSC) cataracts, respectively. In multivariate linear regression models, the presence of bilateral rather than unilateral cataract (β = -0.12; 95% confidence interval, -0.20 to 0.00) was associated independently with poorer vision-specific functioning, even after adjusting for undercorrected refractive error (β = -0.11; 95% confidence interval, -0.21 to 0.00). Bilateral nuclear, cortical, and PSC cataracts also were associated with poorer vision-specific functioning (β = -0.31, -0.15, and -1.15, respectively), with combinations of them having even greater impact. Significantly poorer vision-specific functioning occurred at Lens Opacity Classification System grades 4 (nuclear opalescence), 5 (nuclear color), 3 (cortical), and 1 (PSC) or higher.

CONCLUSIONS

People with bilateral but not unilateral cataracts experience difficulty with performing vision-specific daily activities independent of refractive error, with PSC cataracts and cataract combinations having the greatest impact. Cataract types cause poorer vision-specific functioning beginning at different severity grades.

Underestimating physical function gains: comparing FIM motor subscale and interRAI post acute care activities of daily living scale

OBJECTIVE

To investigate the construct validity of the activities of daily living (ADLs) sections of 2 major systems developed to measure functional ability in rehabilitation settings. Health assessment systems can inform care planning as well as policy decision-making on service effectiveness. Frailty, comorbidity, and heterogeneity make it difficult to accurately measure health outcomes for older adults. Objective investigation of the value of geriatric rehabilitation services requires assessment systems that are comprehensive, reliable, valid, and sensitive to clinically relevant changes in older patients.

DESIGN

Trained health care workers assessed patients with both tools at admission and discharge. We used Rasch analysis to compare the instruments' dimensionality, item difficulty, item fit, differential item function, and number of response options.

SETTING

Musculoskeletal and geriatric rehabilitation units in 2 Ontario hospitals.

PARTICIPANTS

Older adults receiving rehabilitation (N=209; mean age ± SD, 78.5±9.3; 67% women).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

FIM and the interRAI Post Acute Care Assessment (interRAI PAC).

RESULTS

For both the FIM motor and the interRAI PAC ADLs items, the difficulty level of the items was much lower than the participant's level of ability, resulting in a large ceiling effect. Also, on both scales, less actual change in functional ability was required to move between the midlevel response options.

CONCLUSIONS

Both scales have limited ability to discriminate between subjects with higher functional ability, which indicates that they may underestimate the effectiveness of inpatient rehabilitation for this group of patients when used alone.

ACTIVLIM-Stroke: A Crosscultural Rasch-Built Scale of Activity Limitations in Patients With Stroke

Background and Purpose—

This study describes the development of a Rasch-built scale measuring activity limitations in stroke patients, named ACTIVLIM-Stroke.

Method—

This new Rasch-built measure was constructed based on stroke patients' perceptions of difficulty in performing daily activities. Patients were recruited from inpatient and outpatient rehabilitation departments in Belgium and Benin. A 73-item questionnaire was completed by 204 participants. A random subsample of 83 subjects was given the questionnaire a second time. Data were analyzed using RUMM2030 software.

Results—

After successive Rasch analyses, the ACTIVLIM-Stroke questionnaire, a unidimensional and linear 20-item measure of activity limitations, was constructed. All 20 items fulfilled Rasch requirements (overall and individual item fit, category discrimination, invariance, local response independence, and nonredundancy in item difficulty). This simple patient-based scale encompasses a large range of activities related to self-care, transfer, mobility, manual ability, and balance. The ACTIVLIM-Stroke questionnaire exhibited high internal validity, excellent internal consistency, and good crosscultural validity. The test–retest reliability of item difficulty hierarchy (intraclass correlation coefficient=0.99) and patient location (intraclass correlation coefficient=0.92) were both excellent. Furthermore, it showed good external construct validity using correlations with the Functional Independence Measure motor and the Barthel Index and a higher discriminating capacity than either of these widely used indices.

Conclusions—

The ACTIVLIM-Stroke questionnaire has good psychometric qualities and provides accurate measures of activity limitations in patients with stroke. It is recommended for evaluating clinical and research interventions in patients with stroke, because it provides a higher discrimination and might be more sensitive to change.

Measuring functioning in people with fibromyalgia (FM) based on the international classification of functioning, disability and health (ICF)--a psychometric analysis

OBJECTIVES

Instruments to assess functioning in patients with FM vary considerably in their content and are often symptom-specific. This study aimed to examine whether it is feasible to construct a psychometric-sound clinical instrument to measure functioning in FM based on the Brief ICF-Core-Set for chronic widespread pain (CWP).

METHODS

Two hundred and fifty six people with FM completed the Brief ICF-Core-Set. The Rasch model was used for analysis. Once ordering of response options of ICF categories was ensured, the following properties were studied: fit of the ICF categories to the Rasch model, the targeting between ICF categories and a person's abilities, unidimensionality, and reliability.

RESULTS

Six ICF categories were rescored due to disordered thresholds. Five ICF categories were removed due to high model-misfit and differential item functioning (DIF) for gender. Scores from 46 participants were excluded due to extreme scores. The ICF categories included display consistency with an underlying unidimensional construct, are free of DIF for age, disease duration and gender, display excellent overall reliability, and cover a range of functioning difficulties.

CONCLUSIONS

This study illustrates that it is possible to measure functioning as a unidimensional construct based on selected ICF categories from the components body functions, as well as activities and participation of the Brief ICF-Core-Set for CWP in patients with FM.

The response scale for the intellectual disability module of the WHOQOL: 5-point or 3-point?

OBJECTIVE

To deal with the question of whether a 5-point response Likert scale should be changed to a 3-point scale when used in the field testing of people with intellectual disabilities (IDs), which was raised after the pilot study of World Health Organization Quality of Life (WHOQOL)-DIS, a module being developed with the World Health Organization measure of quality of life for disabilities.

METHODS

Three possible ways were used to generate hypothetical data by merging a 5-point scale into a 3-point scale. The analyses were based on both item response theory and classical measurement theory. The partial credit model for polytomous response was performed for item evaluation; the confirmatory factor analysis was used to check construct validity, the Cronbach's alpha for domain reliability, and correlation analyses for the relationship between the 5-point scale and the generated 3-point scale.

RESULTS

Most items with a 5-point response scale had disordered response options and/or unequal-length intervals between successive response options; these deficiencies were removed or improved without decline of validity and reliability in the hypothetical data of 3-point scales.

CONCLUSION

Instead of the 5-point scale, a 3-point scale could be used for IDs in the field test of developing the module WHOQOL-DIS.

Investigating the internal validity of the Trunk Impairment Scale (TIS) using Rasch analysis: the TIS 2.0

PURPOSE

To examine the internal validity of the static sitting balance, dynamic sitting balance, and coordination subscales of the Trunk Impairment Scale (TIS), a reliable and valid scale measuring trunk performance and sitting balance in people after stroke.

METHOD

A total of 162 people after stroke were included in the study. Participants were recruited from an acute unit and in- and out- patient rehabilitation setting. To examine internal validity of the subscales of the TIS, we conducted a Rasch analysis by means of the Partial Credit Model. For each subscale, we examined whether the distribution of scores fitted the theoretical Rasch model.

RESULTS

The first item of the static sitting balance subscale had to be removed since it had a large ceiling effect. The remaining static sitting balance subscale did not fit the Rasch model (Chi-square = 7.03, p < 0.0001 with Bonferroni adjusted p-level = 0.01). Both the dynamic sitting balance (Chi-square = 42.65, p = 0.0052 with Bonferroni adjusted p-level = 0.005) and coordination subscales (Chi-square = 7.87, p = 0.4461 with Bonferroni adjusted p-level = 0.01) fitted the Rasch model.

CONCLUSIONS

Internal validity of the dynamic sitting balance and coordination subscales was confirmed. Based on our results, we present the TIS, version 2.0 (TIS 2.0).

Psychometric properties of the Fatigue Severity Scale: Rasch analyses of responses in a Norwegian and a Swedish MS cohort

Background: Rigorous testing of the original Fatigue Severity Scale (FSS—9) with modern psychometric methods is warranted.

Objective: To determine the psychometric properties of the FSS—9 in multiple sclerosis (MS): internal scale validity; person response validity; unidimensionality; uniform differential item functioning; temporal stability of response patterns; and ability to separate people into distinct groups of fatigue.

Methods: Rasch analyses were conducted on data from a Norwegian and a Swedish MS cohort followed for two years.

Results: Item estimations in the FSS—9 did not differ between sex or levels of education but between the cohorts with regard to disability, disease course and time for evaluation, however, items 1 and 2 demonstrated unacceptable high outfit mean-square values in both cohorts. In an FSS—7 item version, items 3 and 4 in the Norwegian and 4 in the Swedish cohort demonstrated unacceptable goodness of fit but high separation indexes. In the FSS—7, the first unidimensional factor explained 87.5% (Norwegian cohort) and 86.4% (Swedish cohort) of the total variation.

Conclusions: In MS, the FSS—7 demonstrates better psychometric properties than the FSS—9; items 1 and 2 neither empirically nor conceptually fit with the other seven items.

Application of Rasch analysis to examine psychometric aspects of the activities-specific balance confidence scale when used in a new cultural context

Arnadottir SA, Lundin-Olsson L, Gunnarsdottir ED, Fisher AG. Application of Rasch analysis to examine psychometric aspects of the Activities-Specific Balance Confidence Scale when used in a new cultural context.

OBJECTIVE

To investigate by using Rasch analysis the psychometric properties of the Activities-Specific Balance Confidence (ABC) Scale when applied in a new Icelandic context.

DESIGN

Cross-sectional, population-based, random selection from the Icelandic National Registry.

SETTING

Community-based.

PARTICIPANTS

Icelanders (N=183), 65 to 88 years old, and 48% women.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURE

ABC, an instrument used to evaluate how confident older people are in maintaining balance and remaining steady when moving through the environment. An Icelandic translation of the ABC (ABC-ICE) scale was evaluated by implementing Rasch rating scale analysis to transform ordinal ABC-ICE scores into interval measures and evaluating aspects of validity and reliability of the scale.

RESULTS

Participants were not able to differentiate reliably between the 11 rating scale categories of the ABC-ICE. Additionally, 3 items failed to show acceptable goodness of fit to the ABC-ICE rating scale model. By collapsing categories and creating a new 5-category scale, only 1 item misfit. Removing that item resulted in a modified version of ABC-ICE with 5 categories and 15 items. Both item goodness-of-fit statistics and principal components analysis supported unidimensionality of the modified ABC-ICE. The ABC-ICE measures reliably separated the sample into at least 4 statistically distinct strata of balance confidence. Finally, the hierarchical order of item difficulties was consistent with theoretic expectations, and the items were reasonably well targeted to the balance confidence of the persons tested.

CONCLUSIONS

Rasch analysis indicated a need to modify the ABC-ICE to improve its psychometric properties. Further studies are needed to determine if similar analyses of other versions of the ABC, including the original one, will yield similar results.

Impact of diabetic retinopathy on vision-specific function

OBJECTIVE

To assess the influence of the spectrum of diabetic retinopathy (DR) on vision-specific function in an Asian population.

DESIGN

Population-based cross-sectional study.

PARTICIPANTS

Persons aged 40 to 80 years of Malay ethnicity in Singapore.

METHODS

The Singapore Malay Eye Study was a population-based, cross-sectional study of 3280 Asian Malays (78.7% response rate). Five end points were considered: (1) any DR, (2) macular edema (ME), (3) clinically significant macular edema (CSME), (4) vision-threatening DR (VTDR), and (5) DR severity levels ranging from none to proliferative diabetic retinopathy (PDR). Vision function was assessed using the Vision-Specific Functioning Scale validated using Rasch analysis.

MAIN OUTCOME MEASURES

Vision-specific functioning score.

RESULTS

Of 357 diabetic participants in the study, 23.2% had any DR, 5.6% had ME, 5.0% had CSME, 10.6% had VTDR, and 6.2% had PDR. In linear regression models adjusting for age, gender, stroke, diabetic risk factors, and socioeconomic factors, poorer vision-specific function was associated independently with any DR (beta, -0.21; P<0.05), ME (beta, -0.48; P<0.05), CSME (beta, -0.42; P<0.05), VTDR (beta, -0.64; P<0.05), and PDR (beta, -0.92; P<0.001). When controlling further for presenting visual acuity, VTDR (beta, -0.37; P = 0.01) and PDR (beta, -0.61; P = 0.002) were the only 2 DR categories independently associated with poorer vision-specific function and PDR. Persons with VTDR and PDR were 6 to 12 times more likely to report lower participation in daily living activities than those without these DR levels.

CONCLUSIONS

People with VTDR and PDR have substantial difficulty undertaking vision-specific daily activities. These findings reinforce the importance of preventative efforts targeted at the earliest DR stages to prevent progression to later stages of DR.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found after the references.

Comparing the functional independence measure and the interRAI/MDS for use in the functional assessment of older adults: a review of the literature

BACKGROUND

The rehabilitation of older persons is often complicated by increased frailty and medical complexity - these in turn present challenges for the development of health information systems. Objective investigation and comparison of the effectiveness of geriatric rehabilitation services requires information systems that are comprehensive, reliable, valid, and sensitive to clinically relevant changes in older persons. The Functional Independence Measure is widely used in rehabilitation settings - in Canada this is used as the central component of the National Rehabilitation Reporting System of the Canadian Institute of Health Information. An alternative system has been developed by the interRAI consortium. We conducted a literature review to compare the development and measurement properties of these two systems.

METHODS

English language literature published between 1983 (initial development of the FIM) and 2008 was searched using Medline and CINAHL databases, and the reference lists of retrieved articles. Relevant articles were summarized and charted using the criteria proposed by Streiner. Additionally, attention was paid to the ability of the two systems to address issues particularly relevant to older rehabilitation clients, such as medical complexity, comorbidity, and responsiveness to small but clinically meaningful improvements.

RESULTS

In total, 66 articles were found that met the inclusion criteria. The majority of FIM articles studied inpatient rehabilitation settings; while the majority of interRAI/MDS articles focused on nursing home settings. There is evidence supporting the reliability of both instruments. There were few articles that investigated the construct validity of the interRAI/MDS.

CONCLUSION

Additional psychometric research is needed on both the FIM and MDS, especially with regard to their use in different settings and with different client groups.

Differential item functioning was negligible in an adaptive test of functional status for patients with knee impairments who spoke English or Hebrew

OBJECTIVE

We examined the presence and impact of differential item functioning (DIF) in a set of knee-specific functional status (FS) items administered using computerized adaptive testing (CAT) among English (United States) and Hebrew (Israel) speaking patients receiving therapy for knee impairments. DIF occurs in an item if probabilities of endorsing responses differ across groups after controlling for the FS measured.

METHODS

We analyzed data from 28,320 patients (14,160 U.S., 14,160 Israel) who completed the knee-specific CAT. Items were assessed for DIF by gender, age, symptom acuity, surgical history, exercise history, and language spoken using a hybrid technique that combines multiple ordinal logistic regression and item response theory FS estimates.

RESULTS

Several items had non-uniform DIF for covariates including language, but unadjusted and DIF-adjusted functional status estimates were in strong concordance [ICC(2,1) values >/=0.97], and differences between unadjusted and adjusted FS scores represented <0.4% of the unadjusted FS standard deviation.

CONCLUSIONS

Statistically significant DIF was identified in some items but represented negligible clinical impact. Results suggested no need to adjust items for DIF when assessing FS outcomes across groups of patients with knee impairments who answer the knee CAT items in English in the United States or Hebrew in Israel. These findings suggest negligible differences in cultural perceptions between English and Hebrew wording of these knee-specific CAT FS items.

Adjusting expectations after spinal cord injury across global settings: A commentary

PURPOSE

The objective of this paper is to stimulate thought and discussion as to how best to set rehabilitation goals to maximize activities and participation of persons with spinal cord injury, across global settings where circumstances and environments may be widely different.

METHOD

A review of literature and commentary are presented. Three points are articulated: (1) rehabilitation professionals need to understand factors that impact upon activities and participation, and need measurement tools that report these factors, in order to better appreciate outcomes in different settings, (2) rehabilitation professionals generally set goals with patients, but current measures of activities and participation do not indicate when or why maximal achievable function is sometimes not chosen, and (3) we need to develop realistic expectations for activities and participation after SCI in settings where current standard outcome chart targets are not feasible, due to socio-economic circumstances.

CONCLUSIONS

A standardized approach to reporting measures of activities and participation, along with factors that influence these scores, is required for purposes of comparing rehabilitation outcomes in settings of differing socio-economic environments. In regards to spinal cord injury rehabilitation, an accepted standard of setting achievable rehabilitation goals is required for each level of complete spinal cord injury that could apply in various global settings.

Cross-cultural validation of the Pediatric Evaluation of Disability Inventory (PEDI) norms in a randomized Norwegian population

The Pediatric Evaluation of Disability Inventory (PEDI) is one of the most commonly used assessments for children with a disability. Normative data from the US are used to determine whether a deficit or delay exists with regard to functional skill development. The purpose of this study was to analyse the cross-cultural validity of the PEDI American normative data for a general Norwegian population. A random selection of 174 typically developed Norwegian children between 1.0 and 5.9 years participated. The results for capability and caregiver assistance in the domains of self-care, mobility, and social function ranged from a mean of 38.0-46.8 against an expected 50. The Norwegian sample scored significantly lower than the US reference values for functional skills and caregiver assistance, and the results had less fit, especially for self-care. For mobility and social function, the magnitudes of the differences were smaller than self-care. Specific items deviated, suggesting necessary adjustments for the applicability of the norm-referenced scores of the PEDI in the Norwegian culture. The result of this research confirms other findings of cultural influence of the age norms in PEDI. Even though interpretations of the normative score results must be made with some caution, the option of using the scaled scores of PEDI is useful and recommended to describe and measure abilities and to evaluate change. This finding highlights the importance of cultural validation of norm-referenced tests.

Rasch analysis of the Locomotor Capabilities Index-5 in people with lower limb amputation

The aim of this study was to perform a Rasch analysis on the 5-level ordinal scale version of the Locomotor Capabilities Index (LCI-5), in order to investigate rating scale quality and conduct reliability and validity assessments. A questionnaire was mailed to 144 subjects who had undergone lower limb amputation (LLA) in the previous five years and completed a rehabilitation and prosthetic training programme. A total of 123 persons (85%) responded to the questionnaire, a self-report assessment of prosthetic capability and performance which included the LCI-5, the Mobility Section of the Prosthesis Evaluation Questionnaire (PEQ-MS) and other variables associated to prosthetic wear and use. Following Rasch analysis and expert review, the LCI-5 response categories level 1 ('yes, if someone helps me') and 2 ('yes, if someone is near me') were combined into a single category and 4 items were deleted (due to misfitting). The remaining 10 items fitted the Rasch model (LCI10-4) and demonstrated good reliability (person separation reliability = 0.94, item separation reliability = 0.98) and internal construct validity. Moreover, the good correlation with the PEQ-MS (r(s) = 0.77) and with prosthetic wear and use (r(s) range 0.34 - 0.51) supported the convergent validity of the scale. In conclusion, Rasch analysis provided the rationale for improving the measurement qualities of the LCI-5, refining its rating scale (through category diagnostics), identifying those items most useful for measuring the intended construct (as per the indexes of unidimensionality and internal construct validity) and showing that one can place high confidence in the consistency of both the person-ability and item-difficulty estimates obtained (reliability).

Are Standard Instruments Valid for the Assessment of Quality of Life and Symptoms in Glaucoma?

PURPOSE

To determine if the impact of Visual Impairment Instrument (IVI) and Glaucoma Symptom Scale (GSS) are valid instruments to assess participation in daily living and ophthalmic complaints, respectively, in a glaucoma population.

METHODS

Patients with glaucoma were recruited from private and public clinics and completed the IVI and GSS questionnaires. The two scales were assessed for fit to the Rasch model. Unidimensionality, individual item and person fit to the model, response category performance (how respondents differentiate between the response options), differential item functioning (how subgroups, despite equal levels of the underlying trait, respond differently to an individual item), and targeting of items to patients (good spread of items across the full range of patients' scores) were assessed.

RESULTS

One hundred seventy-five participants (mean age = 71 year) were recruited. The majority (65%) had primary open angle glaucoma and good presenting visual acuity >or=6/9 in the better eye (87%). Only one-third of the participants had severe visual field loss in both eyes. Disordered thresholds were evident across all GSS items, indicating that the categories were difficult to discriminate and required category collapsing (5 to 3 categories). There was no evidence of person and item misfit, differential item functioning, and multidimensionality. However, both scales displayed ineffective person-item targeting as a large number of participants demonstrated little difficulty with the most difficult items.

CONCLUSIONS

Because of unsatisfactory targeting, The IVI and GSS are suboptimal scales to assess patients with glaucoma but relatively good vision. It is likely that items could be added to optimize the performance of both instruments. There may however be a need to develop a glaucoma-specific instrument to assess Quality of Life in this population.

Cross-diagnostic validity in a generic instrument: an example from the Functional Independence Measure in Scandinavia

Background

To analyse the cross-diagnostic validity of the Functional Independence Measure (FIM™) motor items in patients with spinal cord injury, stroke and traumatic brain injury and the comparability of summed scores between these diagnoses.

Methods

Data from 471 patients on FIM™ motor items at admission (stroke 157, spinal cord injury 157 and traumatic brain injury 157), age range 11–90 years and 70 % male in nine rehabilitation facilities in Scandinavia, were fitted to the Rasch model. A detailed analysis of scoring functions of the seven categories of the FIM™ motor items was made prior to testing fit to the model. Categories were re-scored where necessary. Fit to the model was assessed initially within diagnosis and then in the pooled data. Analysis of Differential Item Functioning (DIF) was undertaken in the pooled data for the FIM™ motor scale. Comparability of sum scores between diagnoses was tested by Test Equating.

Results

The present seven category scoring system for the FIM™ motor items was found to be invalid, necessitating extensive rescoring. Despite rescoring, the item-trait interaction fit statistic was significant and two individual items showed misfit to the model, Eating and Bladder management. DIF was also found for Spinal Cord Injury, compared with the other two diagnoses. After adjustment, it was possible to make appropriate comparisons of sum scores between the three diagnoses.

Conclusion

The seven-category response function is a problem for the FIM™ instrument, and a reduction of responses might increase the validity of the instrument. Likewise, the removal of items that do not fit the underlying trait would improve the validity of the scale in these groups. Cross-diagnostic DIF is also a problem but for clinical use sum scores on group data in a generic instrument such as the FIM™ can be compared with appropriate adjustments. Thus, when planning interventions (group or individual), developing rehabilitation programs or comparing patient achievements in individual items, cross-diagnostic DIF must be taken into account.

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.

Psychometric properties of the Mini-Mental State Examination in patients with acquired brain injury in Turkey

OBJECTIVE

To evaluate the psychometric properties of Mini-Mental State Examination (MMSE) in patients with acquired brain injury in Turkey.

METHODS

A total of 207 patients with acquired brain injury were assessed. Reliability was tested by internal consistency and the person separation index; internal construct validity by Rasch analysis; external construct validity by correlation with cognitive disability; and cross-cultural validity by differential item functioning analysis compared with Italian MMSE data.

RESULTS

Reliability was adequate with a Cronbach's alpha of 0.75 and person separation index of 0.76. After collapsing some categories, and adjustment for differential item functioning, internal construct validity was supported by fit of the data to Rasch model. Differential item functioning for culture was found in 2 items and after adjustment, data could be pooled between Turkey and Italy. External construct validity was supported by expected associations.

CONCLUSION

The Turkish version of the Mini-Mental State Examination can be used as a cognitive screening tool in acquired brain injury. Cross-cultural validity between Italy and Turkey is supported, given appropriate adjustment for differential item functioning. However, shortfalls in reliability at the individual level, as well as the presence of differential item functioning suggest that a better instrument should be developed to screen for cognitive deficits following acquired brain injury.

Scoring alternatives for FIM in neurological disorders applying Rasch analysis

OBJECTIVE

The Functional Independence Measure (FIM) is an internationally widely used outcome measure. The aim of this study was to evaluate the structural properties of FIM using the Rasch model, with regard to scoring within rehabilitation centres in Scandinavia.

MATERIALS AND METHODS

FIM data from 1660 patients with stroke, traumatic brain injury and spinal cord injury were analysed. The best models with respect to person separation were determined, together with person reliability, item separation, disordered categories, distance of more than 1.4 logits between categories and item fit to the model.

RESULTS

Analysis showed disordering using seven categories in all three diagnoses. After collapsing of categories a four-category scale was the best solution.

CONCLUSIONS

Decreasing the categories from seven to four may be one way of dealing with problems of disordered thresholds. Further studies are also needed in order to try the suggested scale in clinical settings and to compare it with the original FIM scale.