Activity-based therapy for recovery of walking in chronic spinal cord injury: results from a secondary analysis to determine responsiveness to therapy.

OBJECTIVE To gain insight into who is likely to benefit from activity-based therapy (ABT), as assessed by secondary analysis of data obtained from a clinical trial. DESIGN Secondary analysis of results from a randomized controlled trial with delayed treatment design. SETTING Outpatient program in a private, nonprofit rehabilitation hospital. PARTICIPANTS Volunteer sample of adults (N=38; 27 men; 11 women; age, 22-63y) with chronic (≥12mo postinjury), motor-incomplete (American Spinal Injury Association [ASIA] Impairment Scale [AIS] grade C or D) spinal cord injury (SCI). INTERVENTIONS A total of 9h/wk of ABT for 24 weeks including developmental sequencing; resistance training; repetitive, patterned motor activity; and task-specific locomotor training. Algorithms were used to guide group allocation, functional electrical stimulation utilization, and locomotor training progression. MAIN OUTCOME MEASURES Walking speed and endurance (10-meter walk test and 6-minute walk test) and functional ambulation (timed Up and Go test). RESULTS This secondary analysis identified likely responders to ABT on the basis of injury characteristics: AIS classification, time since injury, and initial walking ability. Training effects were the most clinically significant in AIS grade D participants with injuries <3 years in duration. This information, along with information about preliminary responsiveness to therapy (gains after 12wk), can help predict the degree of recovery likely from participation in an ABT program. CONCLUSIONS ABT has the potential to promote neurologic recovery and enhance walking ability in individuals with chronic, motor-incomplete SCI. However, not everyone with goals of walking recovery will benefit. Individuals with SCI should be advised of the time, effort, and resources required to undertake ABT. Practitioners are encouraged to use the findings from this trial to assist prospective participants in establishing realistic expectations for recovery.