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Patient-driven loop control for ambulation function restoration in a non-invasive functional electrical stimulation system
Type
article
Resource
Disability and Rehabilitation. 2010 May; 32(1): 65-71
Date Issued
2010-05
Author(s)
Chen WL, Chen SC, Chen CC, Chou CH, Shih YY, Chen YL, Kuo TS.
Subjects
學科：復健學科
期刊論文
Abstract
Purpose. In this study, a patient-driven loop control in a non-invasive functional electrical stimulation (FES) system was
designed to restore ambulation function of patients with stroke with their residual capabilities.
Method. With this patient-driven loop control, patients use the electromyographic (EMG) signals from their voluntary
controlled muscles in affected extremity to adjust stimulus parameters of the system. A special designed FES system
generated electrical stimuli to excite the paralysed muscles through surface electrodes on the basis of the control command
from the residual myoelectric signals. The EMG signals were also served as the trigger and the adjustment of stimulus
parameters and thereby adding versatility of the FES system. One patient with hemiplegia was recruited to conduct clinical
evaluation and treated by using the new closed-loop FES system.
Results. The experimental results showed that hemiplegic could successfully control the system to restore their lost
ambulation functions with the strategy of patient-driven loop control. It is revealed that the mean velocity, cadence, stride
length, active ankle motion range and functional ambulation category have improved significantly from 0.22+0.17 m/s,
37.3+15.5 steps/min, 0.32+0.11 m, 108, level 2 to 0.46+0.23 m/s, 58.2+19.1 steps/min, 0.73+0.22 m, 358, level 4
respectively for the patient. A paired t-test indicated that differences in the EMG of the tibialis anterior and the
gastrocnemius muscles between patient’s disabled (affected-side) foot and normal (unaffected-side) foot are not significant
(p 4 0.05) after 12 weeks of training.
Conclusions. According to the experiment results, this patient-driven loop control can be beneficial for patient with
hemiplegia to restore their ambulation functions such as dorsi-flexion and plantar-flexion. The control strategy of this study
has the potential to be employed not only in the FES system but also in other assistive devices.
designed to restore ambulation function of patients with stroke with their residual capabilities.
Method. With this patient-driven loop control, patients use the electromyographic (EMG) signals from their voluntary
controlled muscles in affected extremity to adjust stimulus parameters of the system. A special designed FES system
generated electrical stimuli to excite the paralysed muscles through surface electrodes on the basis of the control command
from the residual myoelectric signals. The EMG signals were also served as the trigger and the adjustment of stimulus
parameters and thereby adding versatility of the FES system. One patient with hemiplegia was recruited to conduct clinical
evaluation and treated by using the new closed-loop FES system.
Results. The experimental results showed that hemiplegic could successfully control the system to restore their lost
ambulation functions with the strategy of patient-driven loop control. It is revealed that the mean velocity, cadence, stride
length, active ankle motion range and functional ambulation category have improved significantly from 0.22+0.17 m/s,
37.3+15.5 steps/min, 0.32+0.11 m, 108, level 2 to 0.46+0.23 m/s, 58.2+19.1 steps/min, 0.73+0.22 m, 358, level 4
respectively for the patient. A paired t-test indicated that differences in the EMG of the tibialis anterior and the
gastrocnemius muscles between patient’s disabled (affected-side) foot and normal (unaffected-side) foot are not significant
(p 4 0.05) after 12 weeks of training.
Conclusions. According to the experiment results, this patient-driven loop control can be beneficial for patient with
hemiplegia to restore their ambulation functions such as dorsi-flexion and plantar-flexion. The control strategy of this study
has the potential to be employed not only in the FES system but also in other assistive devices.
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