Minimal detectable change for spatial and temporal measurements of gait after incomplete spinal cord injury

Gait deviations in individuals after incomplete spinal cord injury (ISCI) that are quantified using spatiotemporal (ST) parameters are often targeted during therapeutic interventions. The purpose of our study was to establish reliability and responsiveness of ST parameters of gait after ISCI using an instrumented walkway (GaitMat II).

Sixteen individuals with ISCI participated in the study. Each subject completed at least 2 walking trials at self-selected (SS) walking speed. Intraclass correlation coefficients model 2, 1 (ICC2,1) with 95% confidence intervals (CIs), standard error of measurement (SEM), SEM percent change (SEM%), the minimal detectable change (MDC), and the MDC percent change (MDC%) were determined for 8 ST parameters including step length, single limb support, and double limb support time for the more and less impaired limb, cadence, and speed.

Excellent test-retest agreement (0.84-0.99) was observed in all ST parameters. SEM% ranged from 8% to 29%, while MDC% ranged from 21% (cadence) to 80% (double limb support time). MDC% values were relatively higher (5-12 MDC%) for the more versus less impaired limb.

SEM% results indicate that small to moderate changes were needed to indicate a real change in walking performance. Differences in MDC% values between limbs indicated that variability in parameters might be sensitive to level of motor impairment.

In individuals with ISCI, different gait, balance, or strength training programs can be compared and contrasted based on a quantifiable and meaningful change in the ST parameter of interest.