2006 Fiscal Year Final Research Report Summary
Neural rehabilitation effect of an exoskeleton robot on the gait function of SCI patients
| Project/Area Number |
16500336
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Rehabilitation science/Welfare engineering
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| Research Institution | Ochanomizu University |
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Principal Investigator |
OHTA Yuji Ochanomizu University, Faculty of Human Life and Environmental Sciences, Associate Professor, 生活科学部, 助教授 (50203807)
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| Co-Investigator(Kenkyū-buntansha) |
NAKAZAWA Kimitaka National Rehabilitation Center for Persons with Disabilities, Research Institute, Department of Rehabilitation for Movement Functions, Chief, 運動機能障害研究部, 室長 (90360677)
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| Project Period (FY) |
2004 – 2006
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| Keywords | spinal cord injury / central pattern generator / treadmill / exoskeleton gait robot / disturbance device for ankle joint / stretch reflex / Gait model |
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| Research Abstract |
The results of the present research are summarized as follows :
(1)Orthotic gait in paraplegic persons is a "stiff-leg" gait, which is a gait with the knee locked in full extension position. We developed a motor-assisted knee motion device with used a pair of linear electric actuators attached to the knee and hip joint of a conventional reciprocal gait orthosis (Advanced Reciprocating Gait Orthosis : ARGO). To examine the effectiveness of the knee motion, we evaluated the lower limb muscle electromyography (EMG) activities during orthotic gait with and without knee motions. Six motor complete spinal cord injured persons participated, and the subjects were asked to walk on the treadmill with two orthosis improved ARGO and normal ARGO. The results demonstrated that the magnitude of the EMG activity in the medial head of the gastrocnemius and the rectus femoris muscles was significantly increased by the accomplished dynamic knee motion. These changes might attribute to the occurrence of th
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e additional afferent neural inputs with the knee motions. The present results suggest that the knee dynamic motion by generating powered device have a potential to activate the neuromuscular function in the paralyzed lower limb.
(2)The purpose of this study was to investigate the effects of hip proprioceptors on soleus stretch reflex excitability in standing humans. A custom-made device to stretch the ankle extensors was mounted on the lower leg portion of a gait orthosis and was used to elicit stretch reflex responses during standing. Six subjects with motor complete spinal cord injury (SCI) and six spinal intact subjects were placed in the orthosis, and stretch reflex responses were elicited when static and/or dynamic hip joint angle changes were imposed. We found that static hip extension significantly enhanced the stretch reflex responses as compared to the neutral position and the hip flexion position only in the SCI group. The EMG magnitude induced by hip extension was 142 ± 16.6%reater than that induced by the neutral position. When the leg was dynamically swung, the reflex responses also changed with the phase of the hip angle in the SCI group; in particular, the reflex amplitude was enhanced with hip extension and in the transition phase from flexion to extension. Although the magnitude of the changes was less than in the SCI group, a similar type of modulation was found in the Normal group. Given the fact that the persons with SCI had lost the neural connection between higher nervous center and the paralyzed lower limb muscles, the mechanism underlying the present results can be attributed to the peripheral afferent input due to the hip angle changes. We concluded that hip mediated afferent input has a significant influence on the excitability modulation of the coleus stretch reflex pathway: Such neural modulation may play a role in the mechanism responsible for the phase-dependent modulation of the stretch reflex during walking.
(3)Due to long term physical inactivity on wheelchairs, people with motor paralysis in their lower legs are always at risk for developing secondary diseases around the paralysis area. For example muscle atrophy, loss of bone mineral density, and hypo-circulation. These diseases occur easily, but are difficult to cure. Daily stretching exercises are generally considered as the most effective measure for prevention. Often the patients don't exercise due to a lack of willpower. We developed an everyday rehabilitation device for individuals with motor disorders. Its aim is to prevent secondary disease by stretching the ankle joints passively. A pair of linear actuators were mounted under the seat of a wheelchair and connected to each footrest. By installing this device into the wheelchair, the patients have no need to transfer to another machine, which would encourage them to use the device more frequently: The device has two different exercise modes a rhythmical planter/dorsiflexion movement and a stretch mode. In the former mode, the neutral position was set at 105 degrees. The range of the rotation angle was between +/6 degrees and +/-12 degrees. The flapping frequency was set at 0.7 Hz based on the normal gait. In this study, we investigated the physiological effect of the former mode at the motion range of +/12 degrees. 12 spinal cord injury persons participated in the experiment, and EMG and blood flow in the paralyzed muscles were recorded during 10 minutes of passive ankle motion. As a result, we found that the passive ankle motion could induce rhythmical muscular activity and enhance the blood flow in the calf muscles. These results suggested that this device might be effective for the prevention of secondary disease, or the facilitation of neuromuscular function and the peripheral circulation in paralyzed lower limbs. Less
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Research Products
(5 results)
