Effects of continuous passive motion on reversing the adapted spinal circuit in humans with chronic spinal cord injury

Objective: To investigate the possibility of restoring the adapted spinal circuit after spinal cord injury (SCI) by means of long-term continuous passive motion (CPM) of the ankle joint. Design: Randomized controlled trial with repeated measures. Setting: Research laboratory in a general hospital. Participants: Individuals with motor complete SCI (N=14) were recruited from a community. Intervention: CPM of the ankle joint for 1 hour a day, 5 days a week for 4 weeks. Main Outcome Measures: Modified Ashworth Scale (MAS) scores for evaluation of spasticity and postactivation depression (PAD) were documented prior to and after intervention. Results: MAS scores improved after 4 weeks of CPM intervention, indicating a reduction in spasticity of the ankle joint. PAD was restored after 4 weeks of training. Conclusions: Passive motion of the ankle joint alone was sufficient in reversing the adapted spinal circuit, and therefore indicates that spasticity after SCI could possibly be managed by CPM intervention. The results of this study support the use of the passive mode of robot-assisted therapy for humans with complete SCI who cannot exercise actively.