Review of hybrid exoskeletons to restore gait following spinal cord injury.
Spinal cord injury (SCI) can lead to the complete loss of voluntary control of the leg muscles. This article looks at the hybrid gait restoration options which exist.
1: Hybrid exoskeleton controlled by joint brakes Functional electrical stimulation (FES) powers gait.
- Variable Hip Constraint Mechanism Hip flexion is coupled with extension on the opposite side, while knee & ankle are locked. Side-to-side movements are needed to walk.
- Controlled-Brake Orthosis Lightweight orthosis using magnetic brakes to control the knee and hip,. Elastic actuators drive ankle dorsiflexion. Limited lateral movement is also provided. FES on the quadriceps and peroneal nerve gives variable stimulation.
- Spring-Brake Orthosis After toeing-off a spring releases energy, creating knee flexion and using gravity for hip flexion. Knee extension in swing is a result of stimulation of quads., whilst energy is returned to spring. A proportion-integral-device allows maximum limb acceleration in minimum time, reducing muscle fatigue.
- Joint-Coupled Orthosis Elastic-energy storage concept across hip & knee. Friction brakes release after toe off, allowing stance control. FES allows full knee extension on swing. Studies show this delays muscle fatigue onset, but not yet tested on persons suffering from SCI.
- Energy-Storing Orthosis Energy is stored from stimulation using pneumatic circuitry. Then, knee locks and energy releases into hip, allowing extension. A spring brake gives stance support. > From: del-Ama et al., J Rehabil Res Dev 49 (2012) 497-514 . All rights reserved to Springer-Verlag.
The free full text article can be read here.
>> Stay tuned for the second part of this summary by Miranda that will be posted september 16! <<