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At least 1,549 records · Page 86Linked to original sources
PubMed2005

Cricopharyngeal muscle electromyography in laryngopharyngeal reflux.

OBJECTIVES/HYPOTHESIS: The objective was to determine whether laryngopharyngeal reflux was associated with an electrophysiological abnormality of the main part of the upper esophageal sphincter, namely, the cricopharyngeal muscle, which could be related to laryngopharyngeal reflux symptoms. STUDY DESIGN: A prospective study of 20 patients with symptoms of laryngopharyngeal reflux. METHODS: The diagnosis was based on clinical, laryngoscopic, and ambulatory 24-hour pH monitoring findings. Double-probe pH monitoring was performed with placement of the distal and proximal probes 5 cm above the proximal border of the lower esophageal sphincter and 15 cm proximal to the distal probe, in or just beneath the upper esophageal sphincter. Electromyographic recordings were obtained simultaneously on submental and cricopharyngeal muscles during water swallowing. The peak of the submental electromyographic amplitude and its duration was measured using bipolar surface electrodes placed under the chin. The electromyographic features of the cricopharyngeal muscle were investigated by means of concentric needle electrodes inserted percutaneously both in 20 normal subjects and in 20 patients with laryngopharyngeal reflux. RESULTS: All electrophysiological parameters were normal in all of the patients. The durations of foreburst revealed significant correlation with the number of reflux episodes and acid exposure time (P = .026 and P = .044, respectively). CONCLUSION: The duration of the foreburst correlating with acid exposure time and number of reflux episodes suggested that foreburst duration was extended because of the irritation caused by the acid reflux.

Adult↗
PubMed2006

Cervical paraspinal electromyography: normal values in 100 control subjects.

The normal electromyographic values and the significance of spontaneous activity, when examining the cervical paraspinal muscles, has been studied rarely, and there are very few studies concerning this issue. To obtain muscle unit potential (MUP) reference values for cervical paraspinal muscles, we examined 100 volunteers. Spontaneous activity and the analysis of 20 MUPs in every individual were checked by the automated MUP analysis program. In those individuals ages 20 to 40 years, no spontaneous activity was observed, and in the ones ages 40 to 60 years and 60 years or older, fibrillations and/or positive sharp waves were seen in 8% and 92%, respectively. MUP values were found to be close to those of upper limb muscles. Age has no significant effect on MUP values, except for mean amplitude that was increased in individuals ages 60 to 80 years.Our findings suggest that fibrillations and positive sharp waves do not have much electrodiagnostic value in the study of cervical paraspinal muscles of middle-aged and elderly subjects, when it is an isolated finding, and there is a need for an extended electromyographic examination, including other muscles, to exclude radiculopathy. Automated MUP analysis is easily performed, and our results may serve as reference values.

Action Potentials↗
PubMed1992

A comparative study of simultaneous vibromyography and electromyography with active human quadriceps.

Vibromyographic (VMG) signals, which are low-frequency vibration signals generated during muscle contraction, were studied in comparison with electromyographic (EMG) signals recorded simultaneously during isometric contraction of the human quadriceps muscles. The comparison was accomplished by evaluating the averaged root mean squared (rms) value, mean frequency (MF), and peak frequency (PF) of the VMG and EMG signals for four muscle contraction levels at joint angles of 30 degrees, 60 degrees, and 90 degrees. The four contraction levels, namely 20, 40, 60, and 80% of maximum voluntary contraction (MVC), were estimated and controlled by the torque readings of a Cybex II dynamometer. It was found that the VMG and EMG under the same conditions on the same muscle group are in general equally sensitive to the levels of muscle contraction. Results show that the rms value of the VMG signal increases linearly, in a manner similar to the EMG rms/%MVC relationship, with increasing muscle contraction levels. Furthermore, the study indicates that the averaged MF (6-24 Hz) and PF (9-19 Hz) of the VMG signals are much lower than the MF (75-109 Hz) and PF (40-80 Hz) of the EMG signals. The slopes of MF/%MVC curves for the VMG and EMG are approximately the same for 60 degrees and 90 degrees joint angles (approximately 3.1 Hz per 20% MVC for VMG and approximately 2.6 Hz per 20% MVC for EMG).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

A practical electrode-array myoprocessor for surface electromyography.

A new myoprocessor is described which produces a relatively smooth and accurate measure of a muscle's electrical activity during both slow and rapid movements. This is achieved partly by spatial averaging of weakly correlated EMG signals from electrodes distributed over the surface of the muscle.

Electromyography↗
PubMed1994

NNERVE: neural network extraction of repetitive vectors for electromyography--Part I: Algorithm.

Artificial neural network (ANN) based signal processing methods have been shown to have significant robustness in processing complex, degraded, noisy, and unstable signals. A novel approach to automated electromyogram (EMG) signal decomposition, using an ANN processing architecture, is presented in this paper. Due to the lack of a priori knowledge of motor unit action potential (MUAP) morphology, the EMG decomposition must be performed in an unsupervised manner. An ANN classifier, consisting of a multilayer perceptron neural network and employing a novel unsupervised training strategy, is proposed. The ANN learns repetitive appearances of MUAP waveforms from their suspected occurrences in a filtered EMG signal in an autoassociative learning task. The same training waveforms are fed into the trained ANN and the output of the ANN is fed back to its input, giving rise to a dynamic retrieval net classifier. For each waveform in the data, the network discovers a feature vector associated with that waveform. For each waveform, classification is achieved by comparing its feature vector with those of the other waveforms. Firing information of each MUAP is further used to refine the classification results of the ANN classifier. Then, individual MUAP waveform shapes are derived and their firing tables are created.

Algorithms↗
PubMed1996

A dynamic neural network identification of electromyography and arm trajectory relationship during complex movements.

We propose a new approach based on dynamic recurrent neural networks (DRNN) to identify, in human, the relationship between the muscle electromyographic (EMG) activity and the arm kinematics during the drawing of the figure eight using an extended arm. After learning, the DRNN simulations showed the efficiency of the model. We demonstrated its generalization ability to draw unlearned movements. We developed a test of its physiological plausibility by computing the error velocity vectors when small artificial lesions in the EMG signals were created. These lesion experiments demonstrated that the DRNN has identified the preferential direction of the physiological action of the studied muscles. The network also identified neural constraints such as the covariation between geometrical and kinematics parameters of the movement. This suggests that the information of raw EMG signals is largely representative of the kinematics stored in the central motor pattern. Moreover, the DRNN approach will allow one to dissociate the feedforward command (central motor pattern) and the feedback effects from muscles, skin and joints.

Adult↗
PubMed2005

Application of a neuro-fuzzy network for gait event detection using electromyography in the child with cerebral palsy.

An adaptive neuro-fuzzy inference system (ANFIS) with a supervisory control system (SCS) was used to predict the occurrence of gait events using the electromyographic (EMG) activity of lower extremity muscles in the child with cerebral palsy (CP). This is anticipated to form the basis of a control algorithm for the application of electrical stimulation (ES) to leg or ankle muscles in an attempt to improve walking ability. Either surface or percutaneous intramuscular electrodes were used to record the muscle activity from the quadriceps muscles, with concurrent recording of the gait cycle performed using a VICON motion analysis system for validation of the ANFIS with SCS. Using one EMG signal and its derivative from each leg as its inputs, the ANFIS with SCS was able to predict all gait events in seven out of the eight children, with an average absolute time differential between the VICON recording and the ANFIS prediction of less than 30 ms. Overall accuracy in predicting gait events ranged from 98.6% to 95.3% (root mean-squared error between 0.7 and 1.5). Application of the ANFIS with the SCS to the prediction of gait events using EMG data collected two months after the initial data demonstrated comparable results, with no significant differences between gait event detection times. The accuracy rate and robustness of the ANFIS with SCS with two EMG signals suggests its applicability to ES control.

Adolescent↗
PubMed1984

Electromyography in anaesthesia. A comparison between two methods.

Two instruments measuring evoked compound muscle action potentials (EMG) produced by train of four stimulation of the ulnar nerve were compared. The neuromuscular transmission section of a Datex Anaesthesia and Brain Monitor (ABM), which utilises an integration technique to measure the EMG, and the Medelec MS6 , by which amplitude of the EMG was recorded and measured were attached to the same electrodes placed over adductor pollicis. Eight patients scheduled for surgery requiring non-depolarising neuromuscular blockade were studied. The changes in neuromuscular transmission measured by the two methods correlated well, with no statistically significant difference in results. The ABM provides a simple and accurate automatic measurement of evoked EMG for use in the study of neuromuscular transmission.

Action Potentials↗