Development and Validation of the Function In Sitting Test (FIST) in Adults with Acute Stroke
Background and Purpose: Current studies indicate that sitting balance ability is a substantial predictor of functional recovery after stroke. No gold standard for sitting balance assessment currently exists for adults post stroke. Commonly used balance measures also do not isolate sitting balance abilities. The Function In Sitting Test (FIST), a functional, performance-based test, was developed, pilot tested, and analyzed to establish a reliable and valid shorter test.
Methods: The original FIST was constructed after interviews with 15 physical therapists and review of existing balance measures. Surveys of 12 physical therapists with expertise in measurement construction, balance assessment, and/or research examined the individual FIST items and scoring scale. Thirty-one adults diagnosed with stroke in the prior 3 months pilot tested the FIST.
Results: An 83.3% return rate of expert panel surveys and weighted rank analysis reduced the number of FIST items from 26 to 17 items. Item Response Theory (IRT) analysis reduced the FIST by 3 additional items after pilot testing in adults post stroke. Person separation index of 0.978 and coefficient alpha of 0.98 indicated high internal consistency of the FIST. IRT analysis demonstrated content validity and construct validity. Concurrent validity is high via correlations to modified Rankin Scale and static and dynamic balance grades.
Discussion and Conclusions: The FIST, a 14 item, function-based tool for the assessment of seated postural control, is reliable and valid in adults post acute stroke. Intra/inter-tester reliability and evaluative validity studies are recommended, followed by validation studies in other populations with sitting balance dysfunction.