Mobility activities measurement for outpatient rehabilitation settings.

OBJECTIVE: To investigate the factor structure and scale properties of items underlying the mobility activities subdomains of the International Classification of Functioning, Disability and Health (ICF).

DESIGN: A cross-sectional self-report-based psychometric study.

SETTING: Outpatient rehabilitation settings (N=3) in 3 urban areas of Spain.

PARTICIPANTS: Convenience sample of 615 patients with musculoskeletal conditions (mean age, 38.1y) participating in an active physiotherapy program.

INTERVENTIONS: Not applicable.

MAIN OUTCOMES MEASURES: A 22-item Mobility Activities Measure by using a self-report questionnaire that assessed whether patients had limitations on daily activities across major ICF categories of mobility subdomains. Factor analysis, tests of item scaling, internal consistency reliability analysis, Rasch item response theory modeling, and modified parallel analysis were used.

RESULTS: Initial exploratory factor analysis results for each ICF subdomain produced a total of 5 distinct and interpretable factors or dimensions: changing and maintaining body position involving sitting and/or lying; changing and maintaining body position involving standing up; carrying, moving, and handling objects using the hand and shoulder; carrying, moving, and handling objects using the hand and/or forearm; and walking and moving. Dimensionality of these 5 factors was verified by using confirmatory factor analyses and scaling assumptions were met for each dimension. Rasch scaling and modified parallel analysis supported the unidimensionality.

CONCLUSIONS: The Mobility Activities Measure is a promising new self-report measure of mobility activities as defined by the ICF. Information about Mobility Activities Measure items and dimensions from this study will be useful in the future operationalization and implementation of ICF.