The added value of an actuated ankle-foot orthosis to restore normal gait function in patients with spinal cord injury: a systematic review.

Objective: To provide an overview of robot-assisted rehabilitation devices developed for actuation of the ankle-foot complex and their ability to influence the attributes of normal gait in patients with spinal cord injury.

Methods: A search was conducted in MEDLINE, Web of Knowledge, National Academic Research and Collaborations Information System, and Physiotherapy Evidence Data-base (1985-2011), using, "ankle", "foot", "robotics", "orthotics" and "spinal cord injury" as most relevant keywords. Article inclusion was performed in 3 stages; at the level of: (i) title, (ii) abstract and (iii) full text.

Results: The actuated ankle-foot orthoses currently available are characterized by several combinations of an actuator and a control mechanism. Both the actuator and the control strategy substantially influence human-machine interaction and therefore the potential of the device to assist in modifying locomotor function and potentially modify the underlying motor control mechanisms.

Conclusion: Due to small sample sizes, limited studies in patients with spinal cord injury, and limitations in study design, it is difficult to draw firm conclusions on the effect of different types of actuated ankle-foot orthoses. Based on the limited data available, pneumatic artificial muscles in combination with proportional myoelectric control are suggested to have the potential to meet most of the preconditions to restore the attributes of normal gait and therefore facilitate neuroplasticity.