• Physical Therapy Korea
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• v.28 no.3
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• pp.186-193
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• 2021

Background: While the formal test has been used to provide a quantitative measurement of core stability, studies have reported inconsistent results regarding its test-retest and intraobserver reliabilities. Furthermore, the validity of the formal test has never been established. Objects: This study aimed to establish the concurrent validity and test-retest reliability of the formal test. Methods: Twenty-two young adults with and without core instability (23.1 ± 2.0 years) were recruited. Concurrent validity was determined by comparing the muscle thickness changes of the external oblique, internal oblique, and transverse abdominal muscle to changes in core stability pressure during the formal test using ultrasound (US) imaging and pressure biofeedback, respectively. For the test-retest reliability, muscle thickness and pressure changes were repeatedly measured approximately 24 hours apart. Electromyography (EMG) was used to monitor trunk muscle activity during the formal test. Results: The Pearson's correlation analysis showed an excellent correlation between transverse abdominal thickness and pressure biofeedback unit (PBU) pressure as well as internal oblique thickness and PBU pressure, ranging from r = 0.856-0.980, p < 0.05. The test-retest reliability was good, intraclass correlation coefficient (ICC1,2) = 0.876 for the core stability pressure measure and ICC1,2 = 0.939 to 0.989 for the abdominal muscle thickness measure. Conclusion: Our results provide clinical evidence that the formal test is valid and reliable, when concurrently incorporated into EMG and US measurements.

• Physical Therapy Korea
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• v.28 no.2
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• pp.123-131
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• 2021

Background: Only 2% of falls in older adults result in serious injuries (i.e., hip fracture). Therefore, it is important to differentiate injurious versus non-injurious falls, which is critical to develop effective interventions for injury prevention. Objects: The purpose of this study was to a. extract the best features of surface electromyography (sEMG) for classification of injurious falls, and b. find a best model provided by data mining techniques using the extracted features. Methods: Twenty young adults self-initiated falls and landed sideways. Falling trials were consisted of three initial fall directions (forward, sideways, or backward) and three knee positions at the time of hip impact (the impacting-side knee contacted the other knee ("knee together") or the mat ("knee on mat"), or neither the other knee nor the mat was contacted by the impacting-side knee ("free knee"). Falls involved "backward initial fall direction" or "free knee" were defined as "injurious falls" as suggested from previous studies. Nine features were extracted from sEMG signals of four hip muscles during a fall, including integral of absolute value (IAV), Wilson amplitude (WAMP), zero crossing (ZC), number of turns (NT), mean of amplitude (MA), root mean square (RMS), average amplitude change (AAC), difference absolute standard deviation value (DASDV). The decision tree and support vector machine (SVM) were used to classify the injurious falls. Results: For the initial fall direction, accuracy of the best model (SVM with a DASDV) was 48%. For the knee position, accuracy of the best model (SVM with an AAC) was 49%. Furthermore, there was no model that has sensitivity and specificity of 80% or greater. Conclusion: Our results suggest that the classification model built upon the sEMG features of the four hip muscles are not effective to classify injurious falls. Future studies should consider other data mining techniques with different muscles.

• PNF and Movement
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• v.20 no.1
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• pp.135-145
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• 2022

Purpose: The purpose of this study was to investigate the association between cognitive and motor inhibition by comparing muscle activity and ground reaction force during unplanned gait termination according to reaction time measured through the stop-signal task. Methods: Sixteen young adults performed a stop-signal task and an unplanned gait termination separately. The subjects were divided into fast and slow groups based on their stop-signal reaction time (SSRT), as measured by the stop-signal task. Electromyography (EMG) and ground reaction force (GRF) were compared between the groups during unplanned gait termination. The data for gait termination were divided into three phases (Phase 1 to 3). The Mann-Whitney U test was used to compare spatiotemporal gait parameters and EMG and GRF data between groups. Results: The slow group had significantly higher activity of the tibialis anterior in Phase 2 and Phase 3 than the fast group (p <0.05). In Phase 1, the fast group had significantly shorter time to peak amplitude (TPA) of the soleus than the slow group (p <0.05). In Phase 2, the TPA of the tibialis anterior was significantly lower in the fast group than the slow group (p <0.05). In Phase 3, there was no significant difference in the GRF between the two groups (p >0.05). There were no significant difference between the two groups in the spatiotemporal gait parameters (p >0.05). Conclusion: Compared to the slow group, the fast group with cognitive inhibition suppressed muscle activity for unplanned gait termination. The association between SSRT and unplanned gait termination shows that a participant's ability to suppress an incipient finger response is relevant to their ability to construct a corrective gait pattern in a choice-demanding environment.

• Science of Emotion and Sensibility
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• v.26 no.4
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• pp.41-50
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• 2023

This study aims to develop electromyography (EMG) textile electrodes and assess their performance and signal stability by examining variations in layer count and fabric types. We fabricated the electrodes through layering and pressing techniques, focusing on configurations with different layer counts (Layer-0, Layer-1, and Layer-2). Our findings indicate that layer presence significantly influences muscle activation measurements, with enhanced performance correlated with increased layer numbers. Subsequently, we created electrodes from five distinct fabrics (neoprene, spandex cushion, 100% polyester, nylon spandex, and cotton canvas), each maintaining a Layer-2 structure. In performance tests, nylon spandex fabric, particularly heavier variants, outperformed others, while the spandex cushion electrodes showed superior stability in muscle activation signal acquisition. This research elucidates the connection between electrode performance and factors like layer number and electrode-skin contact area. It suggests a novel approach to electrode design, focusing on layer properties and targeted pressure application on specific sensor areas, rather than uniformly increasing sleeve pressure.

• Journal of Acupuncture Research
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• v.41 no.1
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• pp.53-62
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• 2024

Background: The aim of this study is to determine the correlation between clinical assessment scales, self-assessment scales, and surface electromyography (SEMG) for facial nerve palsy. Methods: This study assessed 32 cases of facial nerve palsy on the first visit, 11 cases on the second visit, and 9 cases on the third visit to the Korean medicine hospital, university. This study was conducted from October 22, 2022, to December 22, 2022. The patients were evaluated using SEMG, clinical assessment scales, and self-assessment scales 3 times. The House-Brackmann grading systems (HBGS), Yanagihara unweighted grading system (Y-score), facial disability index, numerous rating scale, and accompanying symptoms of facial nerve palsy were used for assessment. Moreover, statistical correlation was analyzed using Pearson correlation. Results: On Visit 1, Significant correlations were observed between the results of SEMG and other clinical assessment scales as well as between SEMG-F (frontalis) and different parts of the Y-score. On Visit 2, significant correlations were observed between the results of SEMG and HBGS as well as between SEMG-F and the detailed parts of the Y-score. On Visit 3, significant correlations were observed only between SEMG-F and the detailed parts of the Y-score. A significant correlation was also observed between the changes in the clinical assessment scales on Visits 1 and 3 and between the changes in SEMG-F and those in the patient self-assessment scales. Conclusion: These findings suggest that SEMG can be used to evaluate facial nerve palsy in conjunction with the use of other clinical assessment scales.

• Journal of Acupuncture Research
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• v.31 no.2
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• pp.51-63
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• 2014

Background or Objectives : The purpose of this study is to measure surface Electromyography(sEMG) of facial muscles in normal person and to find method for standardizing of sEMG's value. Methods : We measured 3points on face, frontalis muscle($GB_{14}$), zygomaticus muscle($SI_{18}$), orbicularis oris muscle($LI_{19}$) of 40 normal person by sEMG. 40 normal person consist with two groups, each 20 male, 20 female. Average age of subject was $26.50{\pm}4.79$. SEMG instrument QEMG-4 XL was used. After training exercise of facial muscles, sEMG's root mean square value was measured once. Results : 1. In whole experimental group, frontalis muscle's both side average was $78.36{\pm}40.87$, zygomaticus muscle's both side average was $84.70{\pm}49.81$, orbicularis oris's both side average was $104.83{\pm}38.81$. 2. Left side of Frontalis muscle, both side of zygomaticus muscle are high marked in male than female in statistically. 3. In whole experimental group, average of ratio comparing smaller value with bigger value in difference between left side and right side was $19.60{\pm}12.88$ %. 4. Average of asymmetry index(AI) was $11.46{\pm}8.36$ %. orbicularis oris muscle's average of AI had least difference was $8.95{\pm}7.50$ %. zygomaticus muscle's average of AI had most difference was $13.95{\pm}8.90$ %. Conclusions : The result of this study could provide useful information of field of sEMG is used in oriental medicine treatment of facial muscles. To assess efficacy of treatment in facial muscles, we need to standardize facial muscle's sEMG values by using AI, ratio comparing values and etc.

• Journal of Acupuncture Research
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• v.33 no.2
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• pp.51-60
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• 2016

Objectives : Although integrative Korean medical treatments have been suggested to be effective for treating Bell's palsy, the effect of Korean medical treatment according to when treatment was started is unknown in the clinical field. Therefore, this study was conducted to determine the results of treating Bell's palsy according to different starting points of integrative Korean medical treatments. Methods : We screened patients who visited the Facial Palsy Center at Kyung Hee University Hospital for Korean and Western combined medical treatment from March 2011 to February 2016. A total of 821 out of 2086 patients were studied, including their basic characteristics and results of an electromyography. Patients who started Korean medical treatment within 3 days of onset were placed in group A, within 9 days of onset in group B, and patients who started treatment after 10 days of onset were placed in group C. We tried to compare the level of facial nerve damage by electromyography between groups. Results : The patients in group C had the highest axonal loss rates in all branches(frontal, oculi, nasal, oris). The post hoc analyses revealed the difference of axonal loss rates between group A and B was not statistically significant. Only group C showed statistically higher axonal loss rates in all branches. Conclusion : The study results showed that the patients who had delayed Korean medical treatments had a higher level of facial nerve damage by electromyography. According to the results of this study, early application of integrative Korean medical treatment is suggested.

• Journal of the Korean Academy of Clinical Electrophysiology
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• v.5 no.2
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• pp.61-72
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• 2007

INTRODUCTION: Local heat and cold application has been frequently used as means of muscle relaxation and blood circulation or reinforcing muscle strength, relaxing muscle tension in clinical situation. In particular, it has been known that long-term heat and cold application for relaxing muscle tension inhibits muscle spasticity or tension. But, it has been rarely reported that what influences of heat and cold application on activation of muscle action potential. Therefore, this study aims to analyze surface temperature and electromyography activities according to the heat and cold application. METHODE: Subjects of this research were 10 normal men and women (5 men, 5 women). Hot pack and cold pack was applied to vastus medialis muscle of thigh and rectus femoris muscle for 20 min. Surface temperature of vastus medialis muscle and rectus femoris muscle was measured, knee joint of subjects was in $45^{\circ}$ flexion, sitting on a chair, maximal isometric contraction was induced, surface electromyography (sEMG) signals were collected and root mean square (RMS) and median frequency (MOF) were analyzed. All measurements were conducted before and immediately after experiment, 10 min., 20 min. and 30 min. after experiment. Data were analyzed with SPSS 12.0 program, comparison of changes in superficial temperature and sEMG signals through repeated measurement was conducted with repeated measures ANOVA and significance level $\alpha$ was 0.05. RESULTS: Changes of surface temperature of vastus medialis muscle according to cold application were radically decreased immediately after application, but it was recovered after 30 min. of application and it showed significant difference (F4. 36=72.216, P<0.001). Surface temperature of rectus femoris also showed radical decrease immediately after application, but it was recovered after 30 min. of application and showed significant difference (F4. 36=88.930, P<0.001). Changes of surface temperature of vastus medialis muscle according to heat application were radically increased immediately after application, but it was recovered after 30 min. of application and it showed significant difference (F4. 36=27.267, P<0.001). Surface temperature of rectus femoris also showed radical decrease immediately after application, but it was recovered after 30 min. of application and showed significant difference (F4. 36=19.774, P<0.001). Changes of sEMG by heat and cold application were no statistical difference. Surface temperature of skeletal muscle after heat and cold application showed significant change for 30 min., but it was found that increase or decrease of surface temperature had not great influence on sEMG activities.

• Journal of Acupuncture Research
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• v.32 no.3
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• pp.53-60
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• 2015

Purpose : This study aimed to prove that surface electromyography(SEMG) can be used to identify the degree of symptoms of diseases in the upper extremities; it also aimed to confirm various potential therapeutic effects through an inquiry into the value measured by the SEMG on certain acupuncture points in the upper extremities. Methods : Fifty healthy people received instructions for the method of exercise: wrist flexion, extension and hand grasping. Disposable electrodes were attached to acupuncture points of Susamni($LI_{10}$), Naegwan($PC_6$), Oegwan($TE_5$) and below Sohae($HT_3$) two cun on both sides in flexion, extension and grasping to measure the SEMG values. The research results were analyzed using SPSS statistics Ver. 22.0(IBM, USA). Results : The average value was highest on Naegwan($PC_6$) in grasping, and the average SEMG value was higher in the order of grasping, extension and flexion. The asymmetry index of each point was Susamni($LI_{10}$) $16.26{\pm}13.59%$, Oegwan($TE_5$) $20.38{\pm}15.59%$, below Sohae($HT_3$) two cun $20.89{\pm}16.77%$, Naegwan($PC_6$) $22.49{\pm}14.91%$ in wrist extension, Susamni($LI_{10}$) $25.99{\pm}21.44%$, Oegwan($TE_5$) $21.15{\pm}15.94%$, below Sohae($HT_3$) two cun $19.62{\pm}15.46%$, Naegwan($PC_6$) $19.93{\pm}16.85%$ in wrist flexion, Susamni($LI_{10}$) $16.60{\pm}12.21%$, Oegwan($TE_5$) $10.94{\pm}8.29%$, below Sohae($HT_3$) two cun $15.20{\pm}12.60%$, Naegwan($PC_6$) $11.68{\pm}7.77%$ in grasping. Conclusions : In this study, to identify the degree of symptoms of diseases in the upper extremities and confirm therapeutic effects, it is necessary to analyze the calculated percentage and compare the SEMG measurement of special points with those of other points, and with the asymmetry index.

• Journal of Acupuncture Research
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• v.33 no.4
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• pp.93-100
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• 2016

Objectives : To find an acupuncture point where more exact Surface Electromyography(SEMG) measurement can be drown, through the study of measurement of orbicularis oris. Methods : Of healthy people from 19 to 40 years of age, who did not fall under exclusion criteria (22 males and 22 females), were selected as subjects, after relaxation for 10 minutes, and they were told how to pronounce 'O' and 'U' with their lips puckered. The SEMG figures were measured with attaching disposable electrode on acupuncture point of right-and-left Hwaryo(LI19) and 1 cun away from Seungjang(CV24) on both sides when the subjects pronounced 'O' and 'U'. Results : The average value was highest on left 1 cun away from Seungjang(CV24) in pronouncing 'O' and 'U', and the average SEMG value was higher in the order of right 1 cun away from Seungjang(CV24), right Hwaryo(LI19), left Hwaryo(LI19). Average of the lower orbicularis oris is statistically higher than that of the upper orbicularis oris, which has significant meaning. However, there was no significant difference when compared by pronunciation. Average of percentage mark of differences of right-and-left measured value of each pronunciation and each acupuncture point : Pronounced 'O' and the upper part of orbicularis oris: $16.76{\pm}11.29%$, pronounced 'O' and the lower part of orbicularis oris: $22.41{\pm}12.92%$, pronounced 'U' and the upper part of orbicularis oris: $17.10{\pm}9.89%$, pronounced 'U' and the lower part of orbicularis oris : $19.20{\pm}10.82%$. Conclusion : The difference of pronunciation will not affect the results in SEMG measurement. In addition, the average of the lower orbicularis oris is statistically and significantly higher than that of the upper orbicularis oris.