Necessary and sufficient causes of participation post-stroke: practical and philosophical perspectives.

INTRODUCTION: Participation, a construct within the disability/functioning framework, is evaluated on a person's involvement in life situations including family, community, work, social, and civic life. In the context of recovering from a major health event, participation is a treatment goal and it is known to correlate with the quality of life. OBJECTIVE: The purpose of this study is to track the dynamics of participation post-stroke in relationship to the dynamics of walking capacity, social support, and mood. METHODS: An inception cohort was followed over the first post-stroke year. Group-based trajectory analysis, a form of latent class analysis, was used to identify distinctive groups of individuals with similar trajectories. Dual trajectories were used to estimate concordance between participation trajectory and trajectories for each of the three constructs under study. RESULTS: From the sample of 102 persons (mean age 70), four trajectories of participation were identified, two of which were qualified as excellent and very good, and two qualified as fair and poor. All those with excellent walking showed excellent participation. However, people with excellent (and very good) community participation had a range of walking capacities. Most (82%) people with normal mood showed excellent participation. People with good mood but not meeting norms for age showed the complete range of participation trajectories from excellent to poor. The higher proportion of people with excellent or good social support (57%) showed excellent participation. CONCLUSION: Two treatable component causes of participation, walking capacity and mood, were identified; of these, only excellent walking capacity could be considered a sufficient cause.

Development and initial psychometric evaluation of the Stroke Arm Ladder: a measure of upper extremity function post stroke.

OBJECTIVE: To develop an adaptive measure, the Stroke Arm Ladder, to parsimoniously quantify upper extremity function post stroke. SETTING: Various studies conducted in Montreal and elsewhere in Canada. SUBJECTS: A total of 4058 persons with stroke who participated in various studies were assessed on different occasions post stroke. Assessments spanned from 3 days to 1 year post stroke. MAIN MEASURES: A calibrated bank containing 49 items from tests and indices designed to assess global motor recovery of the upper extremity, upper extremity function and activities involving the upper extremity was used. Data including all testing occasions were analysed to test whether they adhered to the expectations of the Rasch partial credit model and whether item hierarchy remained stable across testing occasions. RESULTS: Fifteen items did not meet the requirements of the Rasch model and were deleted. An adaptive measure of upper extremity function, the Stroke Arm Ladder, containing 34 items was created. The easiest item was partially executing the bilateral task of tying a scarf around one's neck, while the hardest item was being able to transfer more than 60 blocks on the Box and Block Test. The items' difficulty thresholds cover a wide range of difficulty levels from -7.4 to 6.2 and the global fit statistics (χ(2): 331; probability: 0.18), confirmed content validity. CONCLUSION: The Stroke Arm Ladder demonstrates adequate initial psychometric properties. Further testing of the measure in its adaptive format is necessary before it can be used clinically.

Development and initial psychometric evaluation of an item bank created to measure upper extremity function in persons with stroke.

OBJECTIVE: To create and illustrate the development of a method to parsimoniously and hierarchically assess upper extremity function in persons after stroke. DESIGN: Data were analyzed using Rasch analysis. SETTING: Re-analysis of data from 8 studies involving persons after stroke. SUBJECTS: Over 4000 patients with stroke who participated in various studies in Montreal and elsewhere in Canada. METHODS: Data comprised 17 tests or indices of upper extremity function and health-related quality of life, for a total of 99 items related to upper extremity function. Tests and indices included, among others, the Box and Block Test, the Nine-Hole Peg Test and the Stroke Impact Scale. Data were collected at various times post-stroke from 3 days to 1 year. RESULTS: Once the data fit the model, a bank of items measuring upper extremity function with persons and items organized hierarchically by difficulty and ability in log units was produced. CONCLUSION: This bank forms the basis for eventual computer adaptive testing. The calibration of the items should be tested further psychometrically, as should the interpretation of the metric arising from using the item calibration to measure the upper extremity of individuals.

A measure of physical functioning to define stroke recovery at 3 months: preliminary results.

OBJECTIVE: To develop a physical functioning measure through Rasch analysis conceptualized using the International Classification of Functioning, Disability and Health (ICF). DESIGN: Observational cohort study. SETTING: Acute-hospital and community-based study. PARTICIPANTS: Subjects (N=235) hospitalized with postacute stroke and reassessed in the community at 3-months (mean age, 71.6+/-12.9 y). INTERVENTIONS: None. MAIN OUTCOME MEASURES: Functional assessments 3 months poststroke included self-report and observational indices and tests commonly used to evaluate stroke survivors. Sociodemographic information was also collected. Rasch analysis assisted in combining the items across ICF components to develop the measure. Items were retained based on fit to the model and relationship to the construct; reliability and validity were assessed. RESULTS: The best 44 items formed the Physical Functioning Measure at 3 months (F3m) measure of functioning evaluating limb movement, balance, activities of daily living, and participation. All Rasch model assumptions were met. Both item and person reliably (.96) indicated a stable hierarchy, while precision varied from .51 to 1.2 logits. Early evidence for construct validity is adequate. CONCLUSIONS: The F3m combines patient reported and observed ratings of performance items into a single measure quantifying functioning with good preliminary psychometric properties that with further testing can assist in directing and evaluating interventions and recovery.

A measure of early physical functioning (EPF) post-stroke.

OBJECTIVE: To develop a comprehensive measure of Early Physical Functioning (EPF) post-stroke quantified through Rasch analysis and conceptualized using the International Classification of Functioning Disability and Health (ICF). DESIGN: An observational cohort study. SUBJECTS: A cohort of 262 subjects (mean age 71.6 (standard deviation 12.5) years) hospitalized post-acute stroke. METHODS: Functional assessments were made within 3 days of stroke with items from valid and reliable indices commonly utilized to evaluate stroke survivors. Information on important variables was also collected. Principal component and Rasch analysis confirmed the factor structure, and dimensionality of the measure. Rasch analysis combined items across ICF components to develop the measure. Items were deleted iteratively, those retained fit the model and were related to the construct; reliability and validity were assessed. RESULTS: A 38-item unidimensional measure of the EPF met all Rasch model requirements. The item difficulty matched the person ability (mean person measure: -0.31; standard error 0.37 logits), reliability of the person-item-hierarchy was excellent at 0.97. Initial validity was adequate. CONCLUSION: The 38-item EPF measure was developed. It expands the range of assessment post acute stroke; it covers a broad spectrum of difficulty with good initial psychometric properties that, once revalidated, can assist in planning and evaluating early interventions.

Effort-limited treadmill walk test: reliability and validity in subjects with postpolio syndrome.

OBJECTIVE: To determine the reliability and construct validity of an effort-limited treadmill walk test to measure functional ability in subjects with postpolio syndrome in an outpatient postpolio clinic. DESIGN: Functioning and distance walked on a treadmill to a Borg "hard" effort level were measured three times, a week apart, by two blinded raters in 15 subjects with postpolio syndrome, aged 37-67 yrs, with new weakness, fatigue, and pain but with no other cause of symptomatology or condition-limiting walking. One rater tested them twice. Fatigue activity level, mobility, and health-related quality of life (Medical Outcome Study Short Form Health Survey [SF-36]) defined functioning. Generalizability correlation coefficients determined intrarater, test-retest and interrater reliability. The correlations relating the distance walked and functioning determined construct validity. RESULTS: Reliability for generalizability correlation coefficients were: intrarater, 0.91; test-retest, 0.85; and interrater, 0.58. Interrater reliability improved to 0.91 with adherence to a standardized protocol. Validity was established with correlations between the distance walked and SF-36 physical component score (0.66), physical role (0.60), bodily pain (0.60), and vitality (0.55). CONCLUSIONS: The treadmill walk test provides a reproducible and valid measure of ability in persons with postpolio syndrome with a single rater, but a standardized protocol is essential for reliability.