Validity and responsiveness of the Standing and Walking Assessment Tool for sub-acute traumatic spinal cord injury

Abstract

Study design: This is a retrospective longitudinal study.

Objective: The Standing and Walking Assessment Tool (SWAT) combines stages of standing and walking recovery (SWAT stages) with established measures (Berg Balance Scale (BBS), 10-m walk test (10MWT), 6-min walk test (6MWT), and modified Timed Up-and-Go (mTUG)). We evaluated the SWAT's validity (known-groups and convergent) and responsiveness among inpatients with sub-acute, traumatic spinal cord injury (SCI).

Setting: Ten Canadian rehabilitation hospitals.

Methods: Upon admission, SWAT stage and core measures (BBS, 10MWT, 6MWT, and mTUG), International Standards for Neurological Classification of SCI sensory and motor scores, and Spinal Cord Independence Measure III (SCIM) were collected from 618 adults with SCI. Known-groups validity was evaluated by comparing SWAT stage distributions across American Spinal Injury Association Impairment Scale (AIS) classification. Convergent validity was evaluated by correlating SWAT stages with scores on other measures using Spearman's rho. The SWAT (stage and core measures) was re-administered at discharge. To evaluate responsiveness, SWAT stages at admission and discharge were compared. The standardized response mean (SRM) was used to evaluate the responsiveness of core SWAT measures.

Results: The SWAT stage distribution of participants with AIS D injuries differed from those of participants with AIS A-C injuries (p ≤ 0.002). SWAT stages correlated strongly with BBS and motor scores (ρ = 0.778-0.836), and moderately with SCIM, mTUG, 10MWT, 6MWT, and sensory scores (ρ = 0.409-0.692). Discharge SWAT stage was greater than the admission stage (p < 0.0001). The BBS was the most responsive core SWAT measure (SRM = 1.26).

Conclusions: The SWAT is a valid and responsive approach to the measurement of standing and walking ability during sub-acute SCI.