Table 3.

Lower limb function neuroprostheses: walking with greater lower limb impairment

Function	Name	Target population	Number of channels	Orthosis use	Surface/implanted/percutaneous	FDA/CE approval	Control interface
Walking	Hybrid FES system developed by Andrews et al. [14]	SCI		AFO, spinal brace	Surface		Sensors on the handles of crutches, a spinal brace, or on the ankle–foot portion of the AFO Goniometers and FRS’s used by a state machine to determine the gait phase and time the stimulation
	Hybrid Assistive System [15]	SCI	6	Unilateral actuated orthosis	Surface		Switches, force transduces under the toe and heel, and potentiometers to measure knee and vertical shank displacement. All sensors used to define stimulation phase.
	Reciprocating gait orthosis (RGO) [28]	SCI	4	HKAFO	Surface		Push buttons placed on the handles of a walker
	Case Western Reserve University/Department of Veteran Affairs (CWRU-VA) Neuroprosthesis for Standing [17]	SCI	16	AFO	Implanted		Push buttons
	Parastep [29]	SCI	6		Surface	FDA	Push buttons placed on the handles of a walker
	COMPEX Motion FES system for walking [30]	SCI	4		Surface		Push button

SCI spinal cord injury, AFO ankle–foot orthosis, HKAFO hip–knee–ankle–foot orthosis, FDA Federal Drug Administration, FSR force-sensitive resistor