A two-degree-of-freedom motor-powered gait orthosis for spinal cord injury patients

Abstract

A number of orthoses have been developed to restore stance and walking in paraplegic subjects. Compliance, however, has been limited, mainly owing to walking effort. Use of the forces produced by actuators is an effective way to solve the problem of the considerable effort required for orthotic gait, namely high muscular effort and high energy expenditure. The purpose of the present study was to investigate the effects of assistance by external actuators on the orthotic gait of spinal cord injury (SCI) patients. Two kinds of linear actuator were developed by using direct current (d.c.) motors for assisting the knee and hip joint of a gait orthosis. They were mounted on the knee and hip joint of a commercial advanced reciprocating gait orthosis (ARGO), and a new two-degree-of-freedom externally powered gait orthosis was thus developed. The orthosis was assessed through inter-subject experiments on five male adult complete SCI patients. Owing to the short training period available for the assisted gait, simultaneous operation of both joint actuators was not conducted: either the knee actuation or the hip actuation was executed only. Thus, the knee actuator and the hip actuator were assessed with a T12 subject and with subjects for T5, T8, T11, and T12 respectively. The motions of the gaits, assisted by the linear actuators, were measured by a Vicon 370 system, and the general gait parameters and compensatory motions were evaluated. Results demonstrated that (a) all subjects could walk without falling, assisted either by the knee or the hip actuator; (b) both the knee and hip joint actuator increased the gait speed and the step length; (c) the knee flexion produced by the orthosis improved the dynamic cosmesis of walking; and (d) lateral compensatory motions as well as vertical ones tended to decrease when the hip joint was assisted, which could contribute to a reduction in walking effort.

The influence of orthosis options on walking parameters in spinal cord-injured patients: a literature review

“…21 In using powered hip joint, the mean of walking speed was announced 0.40 m per second compared with 0.16 m per second in using orthosis without hip actuator. 30 It shows that adding FES to mechanical orthosis reduced heart rate and improved walking speed during ambulation, 19,28 but using MLO increased the PCI ( as the energy consumption predicator) compared with IRGO (155 beats per min, 164 beats per min). 16 In wearing new reciprocating MLO, the PCI was reduced in four SCI patients.…”

“…53,57 The evidence to date suggests that powered orthoses have the capability to improve specific gait parameters when compared with non-powered mechanical orthoses such as the IRGO, 11,54,58-60 a conventional HKAFO 60 and the ARGO. 30,61 Walking with the IRGO was considered as the higher levels of walking parameters between the RGOs in the SCI patients. The means of speed of walking were reported 0.17, 0.19, 0.22, 0.25 and 0.34 m per second.…”

“…In addition, an increase in temporal spatial parameters (speed of walking, cadence, step length) was reported with powered knee joints or unlock able knee joint compared with a mechanical orthosis (for example, IRGO, ARGO) in SCI patients. [30][31][32] In the modified knee joint category in using mechanical linked knee ankle joints, the value of the speed of walking reported 0.14 m per second. 29 Using powered knee joint associated with ARGO, IRGO had significant influence.…”

“…Five studies investigated the role of knee joint options on gait parameters and compensatory trunk motion. [28][29][30][31][32] These studies had a low level of evidence according to the PEDro score (2/10). In an identifying paper, it has been shown that adding FES to knee extensor (quadriceps) muscles with the RGO system reduces heart rate and energy expend.…”

Effect of Dynamic Knee Motion on Paralyzed Lower Limb Muscle Activityduring Orthotic Gait: A Test for the Effectiveness of the Motor-Assisted Knee Motion Device

“…In the previous study, we evaluated it from the viewpoint of the gait kinematics [12], and suggested that the knee dynamic motions were suitably accomplished with maintaining the ordinary gait speed. In the present study, we aimed to examine the effect of an additional dynamic knee motion on the muscle activities in the paralyzed lower limb during orthotic gait.…”