Zonghao Huang

A novel functional electrical stimulation-control system for restoring motor function of post-stroke hemiplegic patients

Hemiparesis is one of the most common consequences of stroke. Advanced rehabilitation techniques are essential for restoring motor function in hemiplegic patients. Functional electrical stimulation applied to the affected limb based on myoelectric signal from the unaffected limb is a promising therapy for hemiplegia. In this study, we developed a prototype system for evaluating this novel functional electrical stimulation-control strategy. Based on surface electromyography and a vector machine model, a self-administered, multi-movement, force-modulation functional electrical stimulation-prototype system for hemiplegia was implemented. This paper discusses the hardware design, the algorithm of the system, and key points of the self-oscillation-prone system. The experimental results demonstrate the feasibility of the prototype system for further clinical trials, which is being conducted to evaluate the efficacy of the proposed rehabilitation technique.

Signal Regeneration and Function Rebuilding Using Microelectronic Neural Bridge between Two Far-Separated Nervous Systems

This paper reviews at first the features of the present information techniques including the telephone, the television, the computer, and the body sensor network briefly. Then, the concept and the construction of microelectronic neural bridges (MENB) are discussed. A special animal experiment in which the signal regeneration and the function rebuilding were realized by using a MENB between two far-separated nervous systems is demonstrated. The applications of presented concept are prospected.

A wireless wearable surface functional electrical stimulator

ABSTRACT In this paper, a wireless wearable functional electrical stimulator controlled by Android phone with real-time-varying stimulation parameters for multichannel surface functional electrical stimulation application has been developed. It can help post-stroke patients using more conveniently. This study focuses on the prototype design, including the specific wristband concept, circuits and stimulation pulse-generation algorithm. A novel stimulator circuit with a driving stage using a complementary current source technique is proposed to achieve a high-voltage compliance, a large output impedance and an accurate linear voltage-to-current conversion. The size of the prototype has been significantly decreased to 17 × 7.5 × 1 cm3. The performance of the prototype has been tested with a loaded resistor and wrist extension/flexion movement of three hemiplegic patients. According to the experiments, the stimulator can generate four-channel charge-balanced biphasic stimulation with a voltage amplitude up to 60 V, and the pulse frequency and width can be adjusted in real time with a range of 100–600 μs and 20–80 Hz, respectively.

Design of a Pulse-Triggered Four-Channel Functional Electrical Stimulator Using Complementary Current Source and Time Division Multiplexing Output Method

In this paper, a four-channel pulse-triggered functional electrical stimulator using complementary current source and time division output method is proposed for the research and application of functional electrical stimulation (FES). The high-voltage compliance and output impedance is increased by adopting the complementary current source, which can also realize the linear voltage-to-current conversion and high channel isolation. A high-voltage analog switch chip MAX14803, combined with a FIFO queue algorithm in the microprocessor, is used to setup the H-bridge and multiplexers for the four-channel time division multiplexing output. With this method, the size and cost of the key components are reduced greatly. The stimulating core circuit area is 30×50 mm2. According to the experiments, the stimulator can achieve the four-channel charge-balanced biphasic stimulation with a current range between 0 and 60 mA and a single-phase pulse amplitude up to 60 V.

Neural signal sensing, transmission and functional regeneration on different toads’ bodies

The presence of neural signals is the most important feature of animals’ life. Monitoring, analysis and regeneration of neural signals are important for the rehabilitation of paralyzed patients. In this paper, the neural signal regeneration between the proximal and the distal end of an injured nerve is introduced. In the experiment a microelectronic module is used as a channel bridge. The regeneration of nerve signals is realized from one toad’s sciatic nerve to another’s. Corresponding neural signals and EMG were recorded and analyzed. It will be a reference to further study on the neural signals and the relationship between a neural signal and the muscle locomotion.

System design for remote motor function restoration based on 3G wireless mobile technology

Repair of injured spinal cords by regeneration therapy remains an elusive goal. In this paper, a system aiming at remote motor function restoration with 3G technology has been presented. This system contains three principle sub-systems: neural signal detecting, communication, and functional electrical stimulation. Functions of each sub-system have been introduced. At the end of this paper, electrical test result of the system has been given, which is qualified for the further animal experiments.

Surface myoelectric signals decoding using the continuous wavelet transform singularity detection

Electromyographic (EMG) signals are the resultant of electrical activity of muscle fibers during a muscle contraction, whose pattern can provide a significant reference of a motor rehabilitation system. The EMG decoding method using “refractory period” and “threshold” is appropriate for real-time processing system due to its low algorithm complexity and the good fidelity of time domain information. In this paper, the distribution of intervals between continuous wavelet transform modulus maxima was analyzed to provide a reasonable determination of the “refractory period”. In addition, the source signals were decoded according to the “refractory period”. Promising results are demonstrated.

The Principle of the Micro-Electronic Neural Bridge and a Prototype System Design

The micro-electronic neural bridge (MENB) aims to rebuild lost motor function of paralyzed humans by routing movement-related signals from the brain, around the damage part in the spinal cord, to the external effectors. This study focused on the prototype system design of the MENB, including the principle of the MENB, the neural signal detecting circuit and the functional electrical stimulation (FES) circuit design, and the spike detecting and sorting algorithm. In this study, we developed a novel improved amplitude threshold spike detecting method based on variable forward difference threshold for both training and bridging phase. The discrete wavelet transform (DWT), a new level feature coefficient selection method based on Lilliefors test, and the k-means clustering method based on Mahalanobis distance were used for spike sorting. A real-time online spike detecting and sorting algorithm based on DWT and Euclidean distance was also implemented for the bridging phase. Tested by the data sets available at Caltech, in the training phase, the average sensitivity, specificity, and clustering accuracies are 99.43%, 97.83%, and 95.45%, respectively. Validated by the three-fold cross-validation method, the average sensitivity, specificity, and classification accuracy are 99.43%, 97.70%, and 96.46%, respectively.

Electromyography signal bridge and motor function rebuilding of paralyzed limbs based on principles of communication of body-sensor network

In this presentation the motor function rebuilding of paralyzed limbs of hemiplegic patients after stroke and paraplegic patients due to spinal cord injury is concerned. Novel biomedical methods and traditional physical methods for the rehabilitation of two kinds of paralyses are reviewed. The core part is to discuss the electromyography signal bridge and the rebuilding of limb functions based on principles of communication of body sensor network and functional electrical stimulation. For the communication part, a ZigBee system and a super-regenerative system are incorporated. The construction of the whole bio-electronic system, the animal experiments, and the preliminary experiments on healthy subjects and paralyzed patients will be demonstrated.

Neural signal regeneration and motor function rebuilding of paralyzed limbs based on principles of communication incorporated with microwave transmission system

In this presentation the motor function rebuilding of paralyzed limbs of the paraplegic patients caused by spinal cord injury and the hemiplegic patients after stroke and SCI is concerned. The biomedical methods and the traditional physical methods for the rehabilitation of two kinds of paralyses are reviewed. The core part is to discuss the neural and muscular signal regeneration and the limb function rebuilding based on the principles of communication and functional electrical stimulation - a novel concept developed by the speakers. For the communication, a microwave transmission system is incorporated. The construction of the whole bio-electronic system, the animal experiments, and the elementary experiments on healthy and paralyzed patients will be demonstrated.