Yu Luen Chen

Neural network and fuzzy control in FES-assisted locomotion for the hemiplegic

This study is aimed at establishing a neural network and fuzzy feedback control FES system used for adjusting the optimum electrical stimulating current to control the motion of an ankle joint. The proposed method further improves the drop-foot problem existing in hemiplegia patients. The proposed system includes both hardware and software. The hardware system determines the patients ankle joint angle using a position sensor located in the patients affected side. This sensor stimulates the tibialis anterior with an electrical stimulator that induces the dorsiflexion action and achieves the ideal ankle joint trace motion. The software system estimates the stimulating current using a neural network. The fuzzy controller solves the nonlinear problem by compensating the motion trace errors between the neural network control and actual system. The control qualities of various controllers for four subjects were compared in the clinical test. It was found that both the root mean square error and the mean error were minimal when using the neural network and fuzzy controller. The drop-foot problem in hemiplegics locomotion was effectively improved by incorporating the neural network and fuzzy controller with the functional electrical simulator.

Patient-driven loop control for hand function restoration in a non-invasive functional electrical stimulation system.

Purpose. In this study, a patient-driven loop control in a non-invasive functional electrical stimulation (FES) system was designed to restore hand function of stroke patients with their residual capabilities. Method. With this patient-driven loop control, patients use the electromyographic (EMG) signals from their voluntary controlled muscles in affected limbs to adjust stimulus parameters of the system. A special designed FES system generated electrical stimuli to excite the paralyzed muscles through surface electrodes on the basis of the control command from the residual myoelectric signals. EMG signals were also served as the trigger and the adjustment of stimulus parameters and thereby adding versatility of the FES system. Four stroke patients were recruited in the experiment to validate our system. Results. The experimental results showed that hemiplegics could successfully control the system to restore their lost hand functions with the strategy of patient-driven loop control (the average estimated success rate was 77.5% with the tasks of cylindrical grasp and lateral pinch); and further, they would benefit by using the residual capabilities to regain their hand functions from the viewpoints of rehabilitation and psychology. Conclusion. According to the experiment results, this patient-driven loop control can be beneficial for hemiplegics to restore their hand functions such as cylindrical grasp and lateral pinch. The control strategy of this study has the potential to be employed not only in the FES system but also in other assistive devices.

The development of a knee locker with closed-loop functional electrical stimulation (FES) for hemiplegia in gait training

Purpose: A knee locker with closed-loop functional electrical stimulation (FES) system has beendeveloped to prevent the quadriceps weakness and the drop-foot of the hemiplegia during gait training. Method: The FES system is triggered by a footswitch on the heel of the disabled foot to stimulate the tibialis anterior muscle for dorsi-flexion and to turn-off the knee locker in the swing phase through the main controller. Besides, the footswitch on the heel of the affected-side can be used to stimulate the quadriceps and to turn-on the knee locker for quadriceps weakness in the stance phase. Results: It is revealed that the mean velocity, cadence, stride length, active ankle motion range, and functional ambulation category (FAC) have improved significantly from 0.15 ± 0.04 m sec − 1, 43.3 ± 15.4 steps min − 1, 0.36 ± 0.11 m, 15°, level 2 to 0.43 ± 0.21 m sec − 1, 69.4 ± 19.1 steps min − 1, 0.73 ± 0.17 m, 40°, level 4 respectively for the patient. A paired t-test indicated that differences in the electromyography (EMG) of the tibialis anterior and the quadriceps muscles between patients disabled (affected-side) foot and normal (unaffected-side) foot are not significant (p > 0.05) after 16 weeks of training. Conclusions: It is concluded that this new knee locker with closed-loop FES system is capable of providing the hemiplegia with restoration to regular walking after appropriate gait training.

Infrared-based communication augmentation system for people with multiple disabilities

Purpose: This study describes an eyeglass-type infrared-based communication board for the nonspeaking with quadriplegia. Method: This system is composed of four major components: a headset, an infrared transmitting module, an infrared receiving/signal-processing module, and a main controller, the Intel-8951 microprocessor. This design concept was based on the use of an infrared remote module fastened to the eyeglasses which could allow the convenient control of the input motion on the keys of a communication board, which are all modified with infrared receiving/signal-processing modules. For system evaluation, 12 subjects (all men, 21 – 45 years old, six normal subjects as the control group and six nonspeaking with quadriplegia as the experimental group) were recruited. Results: The average accuracy of the control group and the experimental group were 93.1 ± 4.3% and 89.7 ± 5.5%, respectively. The average time cost of the control group and the experimental group were 78.3 ± 8.7 s and 89.9 ± 10.2 s, respectively. An independent t-test revealed that the differences in the average accuracy and the average time cost of the control group and the experimental group were not significant (p > 0.05). Conclusions: The increase of opportunity to communicate using the infrared-based communication board would help people with multiple disabilities to socialize actively.

Application of RFID technology—upper extremity rehabilitation training

[Purpose] Upper extremity rehabilitation after an injury is very important. This study proposes radio frequency identification (RFID) technology to improve and enhance the effectiveness of the upper extremity rehabilitation. [Subjects and Methods] People use their upper extremities to conduct daily activities. When recovering from injuries, many patients neglect the importance of rehabilitation, which results in degraded function. This study recorded the training process using the traditional rehabilitation hand gliding cart with a RFID reader, RFID tags in the panel, and a servo host computer. [Results] Clinical evidence, time taken to achieve a full score, counts of missing the specified spots, and Brunnstrom stage of aided recovery, the proximal part of the upper extremity show that the RFID-based upper extremity training significantly and reduce negative impacts of the disability in daily life and activities. [Conclusion] This study combined a hand-gliding cart with an RFID reader, and when patients moved the cart, the movement could be observed via the activated RFID tags. The training data was collected and quantified for a better understanding of the recovery status of the patients. Each of the participating patients made progress as expected.

Application of the blobo bluetooth ball in wrist rehabilitation training

[Purpose] The introduction of emerging technologies such as the wireless Blobo bluetooth ball with multimedia features can enhance wrist physical therapy training, making it more fun and enhancing its effects. [Methods] Wrist injuries caused by fatigue at work, improper exercise, and other conditions are very common. Therefore, the reconstruction of wrist joint function is an important issue. The efficacy of a newly developed integrated wrist joint rehabilitation game using a Blobo bluetooth ball with C# software installed was tested in wrist rehabilitation (Flexion, Extension, Ulnar Deviation, Radial Deviation). [Results] Eight subjects with normal wrist function participated in a test of the system’s stability and repeatability. After performing the Blobo bluetooth ball wrist physical therapy training, eight patients with wrist dysfunction experienced approximately 10° improvements in range of motion (ROM) of flexion extension, and ulnar deviation and about 6° ROM improvement in radial deviation. The subjects showed progress in important indicators of wrist function. [Conclusion] This study used the Blobo bluetooth ball in wrist physical therapy training and the preliminary results were encouraging. In the future, more diverse wrist or limb rehabilitation games should be developed to meet the needs of physical therapy training.

Low-cost computer mouse for the elderly or disabled in Taiwan

BACKGROUND A mouse is an important communication interface between a human and a computer, but it is still difficult to use for the elderly or disabled. OBJECTIVE To develop a low-cost computer mouse auxiliary tool. METHODS The principal structure of the low-cost mouse auxiliary tool is the IR (infrared ray) array module and the Wii icon sensor module, which combine with reflective tape and the SQL Server database. RESULTS This has several benefits including cheap hardware cost, fluent control, prompt response, adaptive adjustment and portability. Also, it carries the game module with the function of training and evaluation; to the trainee, it is really helpful to upgrade the sensitivity of consciousness/sense and the centralization of attention. The intervention phase/maintenance phase, with regard to clicking accuracy and use of time, p value (p< 0.05) reach the level of significance. CONCLUSIONS The development of the low cost adaptive computer mouse auxiliary tool was completed during the study and was also verified as having the characteristics of low cost, easy operation and the adaptability. To patients with physical disabilities, if they have independent control action parts of their limbs, the mouse auxiliary tool is suitable for them to use, i.e. the user only needs to paste the reflective tape by the independent control action parts of the body to operate the mouse auxiliary tool.

Development of digitized apparatus for upper limb rehabilitation training

BACKGROUND People use upper limbs to conduct daily activities. When recovering from injuries, many patients neglect the importance of rehabilitation, which results in degraded function. OBJECTIVE Rehabilitation after treatment of an injury is very important. This study proposes to improve and enhance the effectiveness of rehabilitation practice. METHODS A patient record of the training process using the traditional rehabilitation hand gliding cart is produced by using a magnetic sensing element in the panel, a servo host computer, and other devices. RESULTS Clinical evidence shows that the training aids help significantly with the rehabilitation of patients with impaired upper limb function and reduce negative impacts from the disability in daily life and activities. CONCLUSIONS This study has combined the gliding cart with reed switches, such that when the patient moves the cart, the movement tracks can be observed via the activated reed switches. The training data are collected and quantified for a better understanding of the recovery status of the patients. Each of the participating patients makes progress as expected.

Relevance of nerve conduction velocity in the assessment of balance performance in older adults with diabetes mellitus

Abstract Purpose This study investigated the relationship between peripheral nerve conduction velocity (NCV) and balance performance in older adults with diabetes. Methods Twenty older adults with diabetes were recruited to evaluate the NCV of their lower limbs and balance performance. The balance assessments comprised the timed up and go (TUG) test, Berg balance scale (BBS), unipedal stance test (UST), multidirectional reach test (MDRT), maximum step length (MSL) test and quiet standing with eyes open and closed. The relationship between NCV and balance performance was evaluated by Pearson’s correlation coefficients, and the balance performances of the diabetic patients with and without peripheral neuropathy were compared by using Mann–Whitney U tests. Results The NCV in the lower limbs exhibited a moderate to strong correlation with most of the balance tests including the TUG (r = −0.435 to −0.520, p < 0.05), BBS (r = 0.406–0.554, p < 0.05), UST (r = 0.409–0.647, p < 0.05) and MSL (r = 0.399–0.585, P < 0.05). In addition, patients with diabetic peripheral neuropathy had a poorer TUG (p < 0.05), BBS (p < 0.01), UST (p < 0.05) and MSL performance (p < 0.05) compared with those without peripheral neuropathy (p < 0.05). Conclusion Our findings revealed that a decline in peripheral nerve conduction in the lower limb is not only an indication of nerve dysfunction, but may also be related to the impairment of balance performance in patients with diabetes. Implications for Rehabilitation Nerve conduction velocity in the lower limbs of diabetic older adults showed moderate to strong correlations with most of the results of balance tests, which are commonly used in clinics. Decline in nerve conduction velocity of the lower limbs may be related to the impairment of balance control in patients with diabetes. Diabetic older adults with peripheral neuropathy exhibited greater postural instability than those without peripheral neuropathy.

Football APP based on smart phone with FES in drop foot rehabilitation

BACKGROUND Long-term, sustained progress is necessary in drop foot rehabilitation. The necessary inconvenient body training movements, the return trips to the hospital and repetitive boring training using functional electrical stimulation (FES) often results in the patient suspending their training. The patients drop foot rehabilitation will not progress if training is suspended. OBJECTIVE A fast spread, highly portable drop foot rehabilitation training device based on the smart phone is presented. This device is combined with a self-made football APP and feedback controlled FES. The drop foot patient can easily engage in long term rehabilitation training that is more convenient and interesting. METHODS An interactive game is established on the smart phone with the Android system using the originally built-in wireless communications. The ankle angle information is detected by an external portable device as the game input signal. The electrical stimulation command to the external device is supplemented with FES stimulation for inadequate ankle efforts. RESULTS After six-weeks training using six cases, the results indicated that this training device showed significant performance improvement (p< 0.05) in the patients ankle dorsiflexion strength, ankle dorsiflexion angle, control timing and Timed Up and Go. CONCLUSIONS Preliminary results show that this training device provides significant positive help to drop foot patients. Moreover, this device is based on existing and universally popular mobile processing, which can be rapidly promoted. The responses of clinical cases also show this system is easy to operate, convenient and entertaining. All of these features can improve the patients willingness to engage in long term rehabilitation.