Walking index for spinal cord injury version 2 (WISCI-II) with repeatability of the 10-m walk time: Inter- and intrarater reliabilities.

Objective: To demonstrate the inter-/intrarater reliability of the Walking Index for Spinal Cord Injury version 2 scale and the repeatability of the time to walk 10 m in chronic subjects. Design: In this reliability study, 26 subjects from the United States and Italy with spinal cord injury/disorder were tested by two blinded raters on two separate days to determine self-selected and maximum Walking Index for Spinal Cord Injury levels and the time to complete a 10-m walk. Subjects were progressed from self-selected to maximum Walking Index for Spinal Cord Injury incrementally until they failed the higher level. Intraclass correlations were calculated for Walking Index for Spinal Cord Injury levels and repeatability coefficients for the 10-m time. Results: Twenty-two of 26 subjects showed increases of one to eight levels from self-selected to maximum Walking Index for Spinal Cord Injury, whereas 10-m walking time remained relatively unchanged (n = 15) or increased markedly (n = 7). Inter- and intrarater reliabilities were 1.00 for the self-selected Walking Index for Spinal Cord Injury level. Intrarater reliability for the maximum level was 1.0; interrater reliability was 0.98. Repeatability coefficients for time to walk 10 m were smaller (better) at self-selected than at maximum Walking Index for Spinal Cord Injury and on the same day than on different days. On same-day assessments, repeatability coefficients were 18%-20% of 10-m walk time, excluding subjects with discrepant Walking Index for Spinal Cord Injury levels (n = 2). For different-day assessments, repeatability coefficients were 27%-35% of 10-m walk time. Conclusions: The determination of both self-selected and maximum Walking Index for Spinal Cord Injury levels is highly reliable, whereas 10-m walking time is more variable. Walking "profiles" of speed at self-selected and maximum Walking Index for Spinal Cord Injury may better characterize walking ability than a single Walking Index for Spinal Cord Injury level.