| Stroke is one of the main causes of paralysis in the elderly.At present,countries are facing the problem of an increase in the number of paralysis with the increase of the incidence of stroke.Rehabilitation training with functional electrical stimulation equipment can effectively alleviate the degree of paralysis.Current studies have shown that functional electrical stimulation plays an active role in the rehabilitation of paralysis and has been widely used in rehabilitation training of paralysis.However,the rehabilitation training based on functional electrical stimulation equipment is a passive rehabilitation training method.The limbs of paralysis can only be passively trained under electrical stimulation.Research shows that this method cannot excavate the recovery ability of patients well,and the rehabilitation effect needs to be improved.The emerging BCI system can control specific rehabilitation equipment through EEG signals,which can be actively controlled by subjects.Therefore,a functional electrical stimulation system based on brain-computer interface is proposed to carry out active rehabilitation training,which provides a new idea for the rehabilitation of paralysis.In this paper,a combined system of brain-computer interface and functional electrical stimulation of lower limbs is designed.This paper realizes the combined system from two parts: the algorithm design of processing EEG signal,and the software and hardware design of the joint system.Then the paper designs experiments to verify the system.At first,EEG signal processing is divided into motor imagery EEG signal processing and steady-state visual evoked potential EEG signal processing.A new method for processing motion imagination EEG signals is proposed in the designing algorithm part.This method extracts EEG features based on multiple empirical mode decomposition,optimizes feature dimension based on common spatial pattern and chooses appropriate features based on sequential floating forward selection.Meanwhile,canonical correlation analysis is used to analyze steady-state visual evoked potential EEG signals.Secondly,the hardware design of the combined system completes the selection of functional electrical stimulation equipment,and uses infrared coding to realize the communication between electrical stimulation equipment and computer.And,the combined system software design completes the GUI design of the combined system.Subjects complete the follow-up rehabilitation action through this GUI when using the system.Finally,the off-line experiment and the on-line experiment are designed.The shared database on the Internet is used in off-line experiment.The off-line experiment paradigm is designed by ourselves to verify the EEG signal processing algorithm proposed in this paper.In online experiment,the experimental flow is designed and the effectiveness of the brain-computer interface and functional electrical stimulation system of lower limbs is verified.Through the design of the above two parts,this paper intends to build a combined system of brain-computer interface and functional electrical stimulation of lower limbs.Through this system,the subjects can control the switch of the stimulation device at will by watching stroboflash,and the subjects can imagine the ipsilateral movement according to the direction displayed by the system interface to control the stimulation device for rehabilitation training of ankle function.At the same time,the system can automatically match the most suitable electrical stimulation parameters according to the sex and age of the subjects.The experimental data show that the classification accuracy of the proposed EEG signal processing algorithm can reach 85.36% when processing the off-line motor imagery EEG data,which is higher than other EEG processing algorithms.Moreover,after verification the combined system of brain-computer interface and functional electrical stimulation of lower limbs designed in this paper can restore the lower limb function of subjects. |
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