Development and Rasch Validation of an Observational Assessment Tool of Upper Limb Functional Impairment in Stroke Survivors: Functional Assessment Test for Upper Limb

Objective: To develop and validate a quick observational clinical tool, the Functional ASsessment Test for Upper Limb (FAST-UL), for the evaluation of upper limb impairment in goal-directed functional-oriented motor tasks after stroke. Design: Observational, cross-sectional, psychometric study. Setting: Inpatient and outpatient rehabilitation clinic. Participants: A total of 188 post-stroke survivors (mean age 65.2±17.7 years, 61% men, 48% with ischemic stroke and 66% in the sub-acute phase; N=188). Interventions: Not applicable. Main outcome measures: Principal component analysis and Rasch analysis through a Partial Credit Model were used to assess the structure and psychometric properties of the 5 items of the FAST-UL (Hand to Mouth [HtM], Reach to Target, Prono-Supination, Grasp and Release, and Pinch and Release [PaR]). Results: The Cronbach's α equal to 0.96 was indicative of an acceptable internal consistency; the reliability, as measured through the Person Separation Reliability equal to 0.87, was good. The FAST-UL tool was unidimensional. All the FAST-UL items were found to fit well the Rasch measurement model. The easiest to perform FAST-UL item was the HtM movement while the most difficult was the PaR movement. Conclusions: The FAST-UL is a quick, easy-to-administer observational assessment tool of upper limb motor impairment in post-stroke survivors with good item-level psychometric properties.