Automatic decomposition of pediatric high density surface EMG:A pilot study

This pilot study presents a novel application of high density surface electromyography(EMG)decomposition in pediatric patients,with a view toward promoting its potential clinical application for examination of pediatricneuromuscular diseases.Automatic progressive FastICA peel-off(APFP)framework was used to decompose high density surface EMG signals recorded from the first dorsal interosseous and abductor pollicis brevis muscles ofchildren with spinal muscular atrophy.The performance of the decomposition with reduced EMG recordingchannels was also investigated.In total 131 motor units were extracted from 15 trials of 64-channel(8×8)surface EMG.The decomposition yield reduced to 102 motor units when 36-channel(6×6)was used,amongwhich 84 motor units were common ones with an average matching rate of(95.68±5.26)%.The decompositionyield further reduced to 65 motor units when only 16-channel(4×4)was used,among which 57 were common ones with an average matching rate of(95.99±4.56)%.These results indicate that using the APFP frameworksingle motor unit activity can be reliably and automatically extracted from pediatric surface EMG signals recordedby an electrode array,which can facilitate potential clinical application of surface EMG as an alternative or supplement to invasive needle EMG for examination of neuromuscular diseases in children.

FastICA Peel-off for ECG Interference Removal from Surface EMG

Multi-channel recording of surface electromyographyic (EMG) signals is very likely to be contaminat-ed by electrocardiographic (ECG) interference, specifically when the surface electrode is placed on mus-cles close to the heart.

Improved Long Short-term Memory Network for Gesture Recognition

Surface EMG contains a lot of physiological information reflecting the intention of human movement.Gesture recognition by surface EMG has been widely concerned in the field of human-computer interaction and rehabilitation.At present,most studies on gesture recognition based on surface EMG signal are obtained by discrete separation method,ignoring continuous natural motion.A gesture recognition method of surface EMG based on improved long short-term memory network is proposed.sEMG sensors are rationally arranged according to physiological structure and muscle function.In this paper,the finger curvature is used to describe the gesture state,and the gesture at every moment can be represented by the set of different finger curvature,so as to realize continuous gesture recognition.Finally,the proposed gesture recognition model is tested on Ninapro(a large gesture recognition database).The results show that the proposed method can effectively improve the representation mining ability of surface EMG signal,and provide reference for deep learning modeling of human gesture recognition.

Downhill running impairs peripheral but not central neuromuscular indices in elbow flexor muscles

The purpose of this study was to examine the effects of a 1-h downhill running exercise on the elbow flexor muscles’neuromuscular functions.Seventeen adults(Control[CON]:n=9;Experimental[EXP]:n=8)completed this study.The CON rested for 30 min while the EXP performed the downhill running.Before,10 min,24 h,and 48 h after the interventions,dependent variables(knee extensor muscle soreness,elbow flexion and knee extension isometric strength,elbow flexion resting twitch and voluntary activation[VA],and the biceps surface electromyography[EMG]amplitude)were measured.Knee extensor muscle soreness was significantly greater in the EXP than the CON group following the intervention throughout the entire 48 h.This was accompanied by the greater decline in the knee extension strength in the EXP than the CON(mean±SD:-6.9±3.4%vs.1.0±3.2%,p=0.044).The elbow flexion strength,VA,and EMG amplitude were not affected by the exercise.However,the decline of the elbow flexion resting twitch was greater in the EXP than the CON(±19.6±6.3%vs.8.7±5.9%,p=0.003).Therefore,the downhill running impaired the remote elbow flexor muscles at a peripheral level.

Effects of Shoe Heel Height on Loading and Muscle Activity for Trans-Tibial Amputees During Standing

This study accesses the effects of shoe heel heights on loading, muscle activity, and plantar foot pressure of trans-tibial amputees during standing. Five male subjects with unilateral trans-tibial amputation volunteered to participate in this study. Three pairs of shoes with zero, 20 mm, and 40 mm heel heights were used. The loading line of the prosthetic side, the plantar foot pressure, and the surface electromyography （EMG） of 10 muscles were simultaneously recorded. With increasing shoe heel heights during standing, the loading line of the prosthetic side shifted from the anterior to the posterior side of the knee center, the peak pressure was increased in the medial forefoot region, and the peak pressure was reduced in the heel region. The EMG of the medial and lateral gastrocnemius of the sound leg almost doubled and that of the rectus fomris, vastus lateralis, and vastus medialis of the prosthetic side increased to different extents with in- creasing heel heights from zero to 40 mm. These results show a high correlation with human physical be- havior. Changing of the heel heights for trans-tibial amputees during standing actually had similar effects to altering the prosthetic sagittal alignment. The results suggest that an alignment change is necessary to accommodate heel height changes and that prosthesis users should be cautious when choosing shoes.