Development of an applied cognition scale to measure rehabilitation outcomes

Objective: To examine the structure and content coverage of an item pool of new items based on the Activity categories from the International Classification of Functioning, Disability and Health and items from existing instruments to measure the applied cognition dimension of function. Design: Prospective study. Setting: Four postacute care rehabilitation settings (inpatient, transitional care, home care, outpatient) in an urban-suburban area of northeast United States. Participants: Convenience sample of 477 patients (mean age, 62.7y) receiving rehabilitation services for neurologic, orthopedic, or complex medical conditions. Interventions: Not applicable. Main Outcome Measures: Participants were administered applied cognition items from the new Activity Measure for Post-Acute Care, the Medical Outcomes Study 8-Item Short-Form Health Survey, and an additional setting-specific measure: the FIM instrument (inpatient rehabilitation); the Minimum Data Set (skilled nursing facility); the Minimum Data Set-Post Acute Care (postacute settings); or the Outcome Assessment and Information Set (home care). Rasch (partial-credit model) analyses were conducted to examine item fit, item coverage, scale unidimensionality, and category difficulty estimates. Results: The majority of items (46/59) could be located along a single continuum. Relatively few people were performing at the lower end of the difficulty scale, and about 25% were at ceiling. Conclusions: The proposed definition of applied cognition dimension provides a useful guide for item development to measure this dimension. Further work is needed to determine how best to measure function in this domain for people at the upper and lower ends of the continuum.