• Proceedings of the KIEE Conference
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• 1992.07a
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• pp.468-472
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• 1992

In this paper, we classified electromyographic(EMG) signal for prothesis control using neural network. For this study fast Fourier transform(FFT) with ensemble averaged spectrum is applied to two-channeI EMG signal for biceps and triceps. We used the three layer network. And a cumulative back-propagation algorithm is used for classification of six arm functions, flexion and extension of elbow and pronation and supination of the forearm and abduction and adduction of wrist.

• Journal of Korean Neurosurgical Society
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• v.29 no.1
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• pp.101-107
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• 2000

Objectives : The evaluation of peripheral nerve injuries has traditionally relied on a clinical history, physical examination, and electrodiagnostic studies. The purpose of the present study was to examine serial magnetic resonance image(MRI) changes following acute muscle denervation under experimental conditions and to identify potential advantages and disadvantages of this use of MRI. Methods : An experimental transection of right sciatic nerve on Spargue-Dawley rats was performed. MRI was performed with T1-weighted spin-echo and STIR sequences. The imaging findings were compared with EMG in order to determine its sensitivity relative to this standard procedure. A simultaneous histopathological study provided information about the morphological basis of the imaging findings. Signal intensities were expressed as a ratio of abnormal to normal. Results : The signal intensity ratio of muscles with the STIR sequence was increased significantly at 2 weeks after sciatic nerve transection(p<0.05), although definite signal change was seen as early as 4 days postdenervation in one. EMG revealed significant denervation potential from 3 days after nerve transection. Diffuse cell atrophy was revealed hostologically at 2 weeks after transection, which was at the same time of significant signal change in MRI. Conclusion : MRI signal changes in denervated muscles secondary to nerve injury correlate with the degree of muscle atrophy on histologic examination. In addition to EMG, MRI can document the course of muscle atrophy and mesenchymal abnormalities in denervation. These results indicate that MRI can play a complementary role in the evaluation of patients with denervation.

• The Journal of Korean Physical Therapy
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• v.20 no.1
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• pp.11-16
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• 2008

Purpose: This study was undertaken to compare the signal characteristics of surface electromyography (EMG) between progressive resistive increase exercise (PRIE) and progressive resistive decrease exercise (PRDE). Methods: Forty healthy male subjects were randomly assigned to either the PRIE group or the PRDE group. Subjects participated in the PRIE and PRDE methods, with 10 RM for each subject. EMG activity was recorded from the rectus femoris muscle. Outcome data were collected for both groups pre-exercise, immediately post-exercise, then at 5 and 10 minutes post-exercise. Repeated measures 2-way ANOVA was used to determine the statistical difference of the root mean square (RMS) in EMG activity. Results: We showed that RMS values, when compared with pre-exercise, were decreased immediately after exercise and were increased at 5 and 10 minutes after exercise (p<0.05). The RMS values were not significantly different between the two groups (p>0.05). Conclusion: These results can indicate that both the PRIE and PRDE protocols will be improve strength with equivalent efficacy. Further studies are needed to address exercise duration, frequency of exercise sessions, and rest times than the PRIE and PRDE protocols with regard to the changes in strength improvement without a large amount of muscle fatigue.

• Proceedings of the KOSOMBE Conference
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• v.1993 no.11
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• pp.145-150
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• 1993

It is an important component of the diagnosis to research the morphological changes of EMG in pathological conditions. In order to provide an EMG signal resulting from a predetermined neuromuscular pathophysiology, we have initially developed a mathmatical model of electromyographic interference pattern(IP). It can be used to study the variation of the IP resulting from morphological and electrophysiological changes occurring in disease states, because the model computes the IP from the underlying fiber and muscle structure. We performed quantative analysis or the model output, focusing on IPs resulting from simulations of dystrophic fiber loss and the MU denervation and reinnervation typical of neuropathies. To discribe the characteristics of IPs associated with these pathologies, a set of frequency domain discriptors, activity, mobility, and complexity were used, as well as several measures of the spectral density function. These discriptors demonstrate distinct patterns of variation corresponding to morphological changes observed in disease states, and closely with results obtained from the classical method, turn/amp technique.

• Proceedings of the KIEE Conference
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• 1991.07a
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• pp.799-804
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• 1991

This paper is concerned with the artificial control of prosthetic devices using the electromyographic(EMG) activities of biceps and triceps in human subject during isometric contraction adjustments at the elbow. And it was analysised about recognition of EMG signals and dynamic characteristics at arm movements of human. For this study the error signal of autoregressive(AR) model were used to discriminate arm movement patterns of human. Interaction of dynamic characteristics (Position, Velocity, Acceleration) and EMG of biceps and triceps at arm movements of human was measured.

• Journal of Biomedical Engineering Research
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• v.32 no.3
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• pp.191-197
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• 2011

Lifting chair is a typical assistive product to aid for standing up and sitting down for persons with disability. It is particularly useful for the elderly persons whose muscular system is weakened by degenerative joint disease. This paper describes biomechanical assessments of lifting chair with hip-up function. In experiments we measured 3D motion and electromyographic(EMG) signal on the femoral muscle when subject performs the standing motion on the predetermined seat height. Based on assessment of the standing motion, we select the hip-up angle as 15 degrees to cover the relative femoral angle when EMG peak value is appeared. Using an implemented prototype lifting chair with hip-up function we perform standing experiments with five subjects. The experimental results show that the lifting and hip-up functions are effective to assist for standing up motion with less muscle force.

• Journal of the Korean Society of Physical Medicine
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• v.6 no.3
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• pp.323-330
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• 2011

Purpose : The purpose of this study was to examine the effects of using a pressure bio-feedback unit (PBFU) and a pelvic belt (PB) on the electromyographic (EMG) signal amplitude of the gluteus medius (Gmed) and the quadratus lumborum (QL) during hip abduction exercise when lying on the side. Methods : Twenty able-bodied volunteers (10 male, 10 female) were recruited for this study. The EMG signal amplitude was randomly measured during hip abduction with preferred hip abduction (PHA), with PBFU, and with PB. The surface EMG signal was recorded from the Gmed and the QL. Data were analyzed using a one-way repeated ANOVA. Results : Muscle activity of Gmed was significantly higher in PBFU and in PB than in PHA (p<.05). There were no significant difference between PBFU and PB(p>.05). Muscle activity of the QL was significantly lower in PB than in PHA(p<.05). The Gmed/QL muscle activity ratio was also significantly higher in PBFU and in PB than in PHA(p<.05), with no significant difference between PBFU and PB (p>.05). Conclusion : Based on these findings, using a PBFU and a PB is an effective method to disassociate QL use from Gmed use during hip abduction exercises when lying on the side.

• Journal of Korean Institute of Industrial Engineers
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• v.25 no.3
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• pp.330-335
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• 1999

The goal of the study is to determine the most sensitive parameter to represent the degree of muscle force and fatigue. Various numerical parameters such as the first coefficient of Autoregressive (AR) Model, Root Mean Square (RMS), Zero Crossing Rate (ZCR), Mean Power Frequency (MPF), Median Frequency (MF) were tested in this study. Ten healthy male subjects participated in the experiment. They were asked to extend their trunk by using the right and left erector spinae muscles during a sustained isometric contraction for twenty seconds. The force levels were 15%, 30%, 45%, 60%, and 75% of Maximal Voluntary Contraction (MVC), and the order of trials was randomized. The results showed that RMS was the best parameter to measure the force level of the muscle, and that the first coefficient of AR model was relatively sensitive parameter for the fatigue measurement at less than 60% MVC condition. At the 75% MVC, however, both MPF and the first coefficient of AR Model showed the best performance in quantification of muscle fatigue. Therefore, the sensitivity of measurement can be improved by properly selecting the parameter based upon the level of force during a sustained isometric condition.

• Journal of Korean Institute of Industrial Engineers
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• v.24 no.2
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• pp.297-309
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• 1998

Numerical parameters have been developed to diagnose L4/L5 disc patients during repetitive flexions and extensions. Electromyography(EMG) has been used to define the muscle excitation and movement cycle in this study. Twenty healthy subjects and twenty L4/L5 disc patients were recruited for the experiment. The subjective pain levels of patients were recorded as $3.7{\pm}1.6$ according to visual analogue scale where 10 was the maximum pain level. Variance ratio of motion cycle was suggested as a new parameter to examine the consistency of the trunk movement. The results indicated that the temporal EMG pattern such as peak time difference between Quadriceps and Hamstrings, the duration of coexcitation between Erector spinae and Rectus abdominis muscle pairs showed a statistically significant difference between healthy subjects and patients. Variance ratio of External oblique and Internal oblique also showed a statistically significant difference. It is expected that those results could be used for diagnosis by building a database for various back pain patients and healthy subjects. This method can eventually help physicians for early diagnosis and prevention of low back disorders.

• Journal of Institute of Control, Robotics and Systems
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• v.17 no.12
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• pp.1248-1255
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• 2011

In daily life, another major role of human hand is a communicative function using hand gestures besides grasp function. Therefore, if amputees can express their intention by the prosthetic hand, they can much actively participate in social activities. Thus, this paper propose myoelectric multi-function prosthetic hand which can express 6 useful hand gestures such as Rock, Scissors, Paper, Indexing, Ok and Thumb-up. It was designed as under-actuated structure to minimize volume and weight of the prosthetic hand. Moreover, in order to effectively control various hand gestures by only two EMG sensors, we propose a control strategy that the signal type are expanded as "Strong" and "Light", and hand gestures are hierarchically classified for the intuitive control. Finally, we prove the validity of the developed prosthetic hand with the experiment.