Joll’s triangle & Superior thyroid pole vessel dissection. Using 2.0 mA current to stimulate the Joll’s triangle along the superior thyroid pole vessel for preliminary EBSLN location. Observing the tremble of CTM for identifying EBSLN. When the EMG signal captured, which defined as S1. Then dissecting the superior thyroid pole vessel and prevent EBSLN injury.

ASVIDE ◽  
2021 ◽  
Vol 8 ◽  
pp. 292-292
Author(s):  
Yishen Zhao ◽  
Zihan Zhao ◽  
Daqi Zhang ◽  
Yujia Han ◽  
Gianlorenzo Dionigi ◽  
...  
Keyword(s):  
Emg Signal ◽  
Vessel Dissection

Amplitude cancellation reduces the size of motor unit potentials averaged from the surface EMG

2006 ◽  
Vol 100 (6) ◽  
pp. 1928-1937 ◽  
Author(s):  
Kevin G. Keenan ◽  
Dario Farina ◽  
Roberto Merletti ◽  
Roger M. Enoka
Keyword(s):  
Motor Unit ◽  
Conduction Velocity ◽  
Motor Units ◽  
Surface Emg ◽  
Excitation Level ◽  
Bipolar Electrode ◽  
Emg Signal ◽  
Motor Unit Synchronization ◽  
Rate Coding ◽  
Simulated Surface

The purpose of the study was to evaluate the influence of selected physiological parameters on amplitude cancellation in the simulated surface electromyogram (EMG) and the consequences for spike-triggered averages of motor unit potentials derived from the interference and rectified EMG signals. The surface EMG was simulated from prescribed recruitment and rate coding characteristics of a motor unit population. The potentials of the motor units were detected on the skin over a hand muscle with a bipolar electrode configuration. Averages derived from the EMG signal were generated using the discharge times for each of the 24 motor units with lowest recruitment thresholds from a population of 120 across three conditions: 1) excitation level; 2) motor unit conduction velocity; and 3) motor unit synchronization. The area of the surface-detected potential was compared with potentials averaged from the interference, rectified, and no-cancellation EMGs. The no-cancellation EMG comprised motor unit potentials that were rectified before they were summed, thereby preventing cancellation between the opposite phases of the potentials. The percent decrease in area of potentials extracted from the rectified EMG was linearly related to the amount of amplitude cancellation in the interference EMG signal, with the amount of cancellation influenced by variation in excitation level and motor unit conduction velocity. Motor unit synchronization increased potentials derived from both the rectified and interference EMG signals, although cancellation limited the increase in area for both potentials. These findings document the influence of amplitude cancellation on motor unit potentials averaged from the surface EMG and the consequences for using the procedure to characterize motor unit properties.

scholarly journals Specific modulation of corticomuscular coherence during submaximal voluntary isometric, shortening and lengthening contractions

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Dorian Glories ◽  
Mathias Soulhol ◽  
David Amarantini ◽  
Julien Duclay
Keyword(s):  
H Reflex ◽  
Medial Gastrocnemius ◽  
Emg Activity ◽  
Beta Band ◽  
Lengthening Contractions ◽  
Time Frequency ◽  
Corticomuscular Coherence ◽  
Emg Signal ◽  
Voluntary Contractions ◽  
Spinal Excitability

AbstractDuring voluntary contractions, corticomuscular coherence (CMC) is thought to reflect a mutual interaction between cortical and muscle oscillatory activities, respectively measured by electroencephalography (EEG) and electromyography (EMG). However, it remains unclear whether CMC modulation would depend on the contribution of neural mechanisms acting at the spinal level. To this purpose, modulations of CMC were compared during submaximal isometric, shortening and lengthening contractions of the soleus (SOL) and the medial gastrocnemius (MG) with a concurrent analysis of changes in spinal excitability that may be reduced during lengthening contractions. Submaximal contractions intensity was set at 50% of the maximal SOL EMG activity. CMC was computed in the time–frequency domain between the Cz EEG electrode signal and the unrectified SOL or MG EMG signal. Spinal excitability was quantified through normalized Hoffmann (H) reflex amplitude. The results indicate that beta-band CMC and normalized H-reflex were significantly lower in SOL during lengthening compared with isometric contractions, but were similar in MG for all three muscle contraction types. Collectively, these results highlight an effect of contraction type on beta-band CMC, although it may differ between agonist synergist muscles. These novel findings also provide new evidence that beta-band CMC modulation may involve spinal regulatory mechanisms.

Differences in muscular activation and fatigue for intermittent and constant load

2005 ◽  
Vol 5 (1) ◽  
pp. 43-56
Author(s):  
Danuta Roman-Liu ◽  
Krzysztof Kȩdzior
Keyword(s):  
External Force ◽  
Upper Limb ◽  
Muscle Activation ◽  
Regression Line ◽  
Constant Load ◽  
Median Frequency ◽  
Experimental Conditions ◽  
Emg Signal ◽  
Limb Posture ◽  
Muscular Activation

The aim of this study was to compare the influence of constant or intermittent load on muscle activation and fatigue. The analysis and assessment of muscular activation and fatigue was based on surface EMG measurements from eight muscles (seven muscles of the right upper limb and trapezius muscle). Two EMG signal parameters were analyzed for each of the experimental conditions distinguished by the value of the external force and the character of the load – constant or intermittent. The amplitude related to its maximum (AMP) and the slope of the regression line between time and median frequency (SMF) were the EMG parameters that were analyzed. The results showed that constant load caused higher muscular fatigue than intermittent load despite the lower value of the external force and lower muscle activation. Results suggest that additional external force might influence muscle activation and fatigue more than upper limb posture. The results of the study support the thesis that all biomechanical factors which influence upper limb load and fatigue (upper limb posture, external force and time sequences) should be considered when work stands and work processes are designed. They also indicate that constant load should be especially avoided.

Staged angioplasty: A sensible approach to prevent hyperperfusion syndrome after carotid artery stenting? A meta-analysis

2021 ◽  
pp. 159101992110183
Author(s):  
Bingyang Zhao ◽  
Xinzhao Jiang ◽  
Pei Wang ◽  
Zhongyu Zhao ◽  
Jing Mang ◽  
...  
Keyword(s):  
Carotid Artery ◽  
Carotid Artery Stenting ◽  
Meta Analysis ◽  
Random Effect ◽  
Thromboembolic Events ◽  
Current Recommendation ◽  
Hyperperfusion Syndrome ◽  
Asian Populations ◽  
Significant Difference ◽  
Vessel Dissection

Objective To investigate whether staged angioplasty (SAP) is a safe and effective treatment to prevent hyperperfusion syndrome after carotid artery stenting (CAS). Methods A systematic literature search was performed according to established criteria to identify eligible articles published before October 2020. Pooled dichotomous data were presented as odds ratios (OR) and corresponding 95% confidence intervals (CI) using random-effect models. The efficacy endpoints were hyperperfusion syndrome (HPS), hyperperfusion phenomenon (HPP), and intracerebral hemorrhage (ICH). The safety endpoint was post-procedural thromboembolic events. The feasibility of the procedure was assessed by device-related adverse events (vessel dissection and failed angioplasty) in SAP. Results Ten studies (1030 participants) were eligible. SAP was superior to regular CAS in preventing HPS (OR = 0.35, 95% CI 0.14–0.86, P = 0.02). There was no significant difference in the rate of thromboembolic events between the SAP group and the regular CAS group. The rates of vessel dissection and failed angioplasty with the use of a 3.0-mm-diameter balloon were 5.4% and 0.4%, respectively. Conclusion SAP may reduce the incidence of post-CAS HPS without increasing procedure-related complications. A 3.0-mm-diameter balloon used in SAP may be appropriate for Asian populations. However, the confounded study design and confused definitions of reporting items hinder the current recommendation of SAP in clinical use.

Rectification is required to extract oscillatory envelope modulation from surface electromyographic signals

2014 ◽  
Vol 112 (7) ◽  
pp. 1685-1691 ◽  
Author(s):  
Christopher J. Dakin ◽  
Brian H. Dalton ◽  
Billy L. Luu ◽  
Jean-Sébastien Blouin
Keyword(s):  
Motor Unit ◽  
Stimulus Frequency ◽  
Motor Units ◽  
Surface Emg ◽  
Medial Gastrocnemius ◽  
Single Motor Unit ◽  
Single Motor ◽  
Single Motor Units ◽  
Emg Signal ◽  
Envelope Modulation

Rectification of surface electromyographic (EMG) recordings prior to their correlation with other signals is a widely used form of preprocessing. Recently this practice has come into question, elevating the subject of EMG rectification to a topic of much debate. Proponents for rectifying suggest it accentuates the EMG spike timing information, whereas opponents indicate it is unnecessary and its nonlinear distortion of data is potentially destructive. Here we examine the necessity of rectification on the extraction of muscle responses, but for the first time using a known oscillatory input to the muscle in the form of electrical vestibular stimulation. Participants were exposed to sinusoidal vestibular stimuli while surface and intramuscular EMG were recorded from the left medial gastrocnemius. We compared the unrectified and rectified surface EMG to single motor units to determine which method best identified stimulus-EMG coherence and phase at the single-motor unit level. Surface EMG modulation at the stimulus frequency was obvious in the unrectified surface EMG. However, this modulation was not identified by the fast Fourier transform, and therefore stimulus coherence with the unrectified EMG signal failed to capture this covariance. Both the rectified surface EMG and single motor units displayed significant coherence over the entire stimulus bandwidth (1–20 Hz). Furthermore, the stimulus-phase relationship for the rectified EMG and motor units shared a moderate correlation ( r = 0.56). These data indicate that rectification of surface EMG is a necessary step to extract EMG envelope modulation due to motor unit entrainment to a known stimulus.

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