Temporal differences in relative phasing of gait initiation and first step length in patients with cervical and lumbosacral spinal cord injuries

Study design: Comparison group design. Objective: To compare the temporal distance factors during gait initiation between patients with incomplete cervical spinal cord injury, incomplete lumbosacral spinal lesion, and unimpaired control adults. Setting: Human performance and movement analysis laboratory, Taiwan. Participants: Five patients with an incomplete cervical spinal cord injury (Group 1), five patients with an incomplete lumbosacral spinal lesion (Group 2) and nine unimpaired control adults ( Group 3). Methods: Subjects underwent a three-dimensional gait analysis. The total gait initiation period, reaction time, each relative phasing of gait initiation and the length of the first step were identified by using the kinematic measurement system. Main outcome measures: The total gait initiation period (start of the auditory cue for gait initiation to heel-strike of the first swing leg); each relative phasing of gait initiation indicated that the duration of the preparatory phase ( start of auditory cue for gait initiation to heel-off of the first swing leg), the duration of the push-up phase (heel-off to toe-off of the first swing leg), and the duration of the single-stance phase (toe-off to heel-strike of the first swing leg) established by the total gait initiation period; and the length of the first step. Results: The gait initiation period was greater in Groups 1 and 2 than that of Group 3 (P<0.05). Each relative phasing including the duration of the preparatory phase, the push-up phase, and the swing phase relative to the total gait initiation period, did not differ among Groups 1-3 (P > 0.05). The length of the first step, measured while the nonpreferred leg stepped first in Groups 1 and 2, was shorter than that of Group 3 (P < 0.05). Conclusions: Patients with incomplete cervical spinal cord injuries or lumbosacral spinal lesions took more time in gait initiation than unimpaired control adults. The first step length also reduced in these patients while the nonpreferred leg stepped first, as compared to unimpaired control adults. The data indicated that centrally programmed gait initiation might be preserved in ASIA-D spinal patients who, in this study, executed gait initiation with varying temporal distance strategies to compensate for peripheral impairments, as compared to unimpaired control adults.