Feasibility, stability and validity of the four square step test in typically developed children and children with brain damage

Purpose: To assess feasibility, test–retest reliability and validity of the Four Square Step Test (FSST) in typically developed children (TD), and children with cerebral palsy (CP) and acquired brain injury (ABI). Methods: 30 TD children, 20 with CP and 12 with ABI participated in the study. The FSST while sitting and standing, the Timed Up and Go (TUG) and the balance subtest of the Bruininks-Oseretsky Test (BOT-2) were assessed. Each child attempted the FSST twice within 1 week. The scores for the FSST were assigned according to the original test: two successes in four trials, and according to a more lenient test, one success in four trials. Results: The original form of the FSST is not feasible for children with CP or ABI. In TD children the lenient version is feasible (93%) and has moderate stability (Interclass correlation, ICC = 0.723), with a significant, positive correlation with the TUG (r_s = 0.56). In children with CP the lenient test is feasible (80%), stable (r_s = 0.83) and negatively correlates with the BOT-2 (r_s=-0.69). In children with ABI the test is less feasible (67%) and neither stable nor valid. Conclusions: The lenient form of the FSST is feasible, reliable and valid in TD children and children with CP.