commercially available. The Parastep's digital design allows a considerable reduction in rate of patient-fatigue by drastically reducing of stimulation pulse-width (100–140 microseconds) and pulse-rate (12–24 per sec.), to result, in walking times of 20–60 minutes and average walking distances of 450 meters per walk, for adequately trained thoracic-level complete paraplegics patients who complete training that includes daily treadmill sessions, with some patients exceeding one mile per walk. Also, Parestep-based walking was reported to result in several medical and psychological benefits, including restoration of near-normal blood flow to lower extremities and holding of bone density decline. Walking performance with the Parastep system greatly depends on rigorous upper body conditioning-training and on a completing 3–5 months of a daily one–two-hour training program which includes 30 of more minutes of treadmill training. An alternative approach to the above techniques is the FES system for walking developed using the Compex Motion neuroprosthesis, by Popovic et al. . Compex Motion neuroprosthesis for walking is an eight to sixteen channel surface FES system used to restore voluntary walking in stroke and spinal cord injury individuals. This system does not apply peroneal nerve stimulation to enable locomotion. Instead, it activates all relevant lower limb muscles in a sequence similar to the one that brain uses to enable locomotion. The hybrid assistive systems (HAS) and the RGO walking neuroprostheses are devices that also apply active and passive braces, respectively. The braces were introduced to provide additional stability during standing and walking. A major limitation of neuroprostheses for walking that are based on surface stimulation is that the hip flexors cannot be stimulated directly. Therefore, hip flexion during walking must come from voluntary effort, which is often absent in paraplegia, or from the flexor withdrawal reflex. Implanted systems have the advantage of being able to stimulate the hip flexors, and therefore, to provide better muscle selectivity and potentially better gait patterns. Hybrid systems with exoskeleton have been also proposed to solve this problem. These technologies have been found to be successful and promising, but at the present time these FES systems are mostly used for exercise purposes and seldom as an alternative to wheelchair mobility. Stroke and upper limb recovery In the acute stage of stroke recovery, the use of cyclic electrical stimulation has been seen to increase the isometric strength of wrist extensors. In order to increase strength of wrist extensors, there must be a degree of motor