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Comparison of evoked electromyography and mechanical activity during vecuronium-induced neuromuscular blockade.

The relationship of compound electromyography to mechanical myography was investigated in 20 patients given vecuronium in a dose of 0.1 mg kg-1. Mechanical response was affected less quickly and recovered faster than the electrical response. Although there was a good correlation between the two throughout the study, a shift towards mechanical responses was observed in all cases for the onset of blockade and recovery from blockade. Moreover, during recovery the mechanical responses became greater than the control value in all patients. This was also reflected in the statistically significant difference (P less than 0.05) of the regression lines relating tension and electromyography (TI as well as train-of-four ratio) between onset of, and recovery from, neuromuscular block.

Electromyography↗

Electromyography of anal sphincters after radical gynecological surgery.

In this study, the Authors report their own experience in electromyography of anal sphincters. The clinical evaluation concerns a clinical series of 14 patients suffering from carcinoma of the uterine cervix at SPS stage A and B, and undergoing a personalized radical hysterectomy during 1986. The protocol included a preoperative electromyographic and urodynamic evaluation and a post-operative re-evaluation 30-60 days after surgery. The pre-operative evaluation in both the urodynamic test and the electromyographic test showed bladder-urethral function in all the cases examined. The post-operative electromyographic evaluation was considered normal and did not show alterations in the sphincteral function in 9 cases (64.3%). In the remaining 5 cases (35.7%) the presence of sphincteral incoordination was shown. The analysis of the results shows that the use of electromyography, connected with the usual urodynamic study in gynaecological oncology, objectively recognises the sphincter-detrusorial situations characterized by dysuria and retention from a clinical-anamnestic point of view.

Adult↗

[The role of total colonic electromyography in children in case of chronic constipation. Preliminary study].

Since December 1987, the chirurgical pediatric team in Clermond-Ferrand performs total colonic electromyography in children. This examination is integrated into a diagnostic and therapeutic protocol for chronic constipation. We used an intraluminal probe supporting 10 groups of 3 ring electrodes. Inside the probe a lead pellet was placed opposite each electrode. The probe was inserted through the colon by colonoscopy into a starving child. The recording starts 24 hours later and is registered for 3 hours before and 3 hours after a meal. The aim of this work is to report the preliminary results of 6 electromyography in constipated children.

Adolescent↗

[Diagnostic and prognostic significance of electromyography in laryngeal movement disorders].

Electromyography of the larynx has been increasingly used during recent years in the diagnosis and differential diagnosis of laryngeal motility disorders. The method is routinely employed at the university ENT department in Göttingen. The qualitative experience gained with regard to the diagnostic and prognostic value of electromyography in the region of the larynx is described and compared with the results and experience reported so far in the literature.

Electrodes↗

Conduction velocity of peripheral nerves and electromyography in infants and children.

The methods used to measure the conduction velocity of peripheral motor nerves in arms and legs and of the distal part of sensory fibres in the hand are demonstrated. Normal values in infancy, childhood and adolescence are given and discussed in relation to the maturation of the peripheral nervous system. This maturation is further elucidated by a study of the conduction velocity of peripheral motor nerves in different groups of mentally retarded children. The normal values in different ages also serve as a reference with which to compare a value found in a child with a possibly impaired function of the peripheral nerves. Conduction velocity of peripheral nerves is normal in diseases affecting the anterior horn cells or the muscles. It is abnormally low in diseases primarily localized in the peripheral nerves. It is thus a diagnostic tool in establishing a diagnosis of polyneuropathy, a condition, which may be particularly hard to diagnose clinically in children because of the difficulties in performing a good sensory examination in young child. The clinical conditions, in which measuring of conduction velocity of peripheral nerves may be of great help, are discussed. The technique of performing electromyography is briefly reviewed. The findings in normal children of different ages are discussed in relation to the maturation of the neuromuscular system. Abnormalities typical of different diseases of the peripheral neurones and the muscles are described. Finally, the clinical conditions are discussed in which electromyography may be of diagnostic help.

Adolescent↗

A method of percutaneous laryngeal electromyography.

A method of percutaneous laryngeal electromyography is described. The technique is simple, safe and it allows a sampling of muscles within the superior laryngeal and recurrent laryngeal territories. The procedure can be performed on an out-patient basis in a conventional electromyography laboratory, and complications have not been encountered.

Action Potentials↗

[Correlations among clinical, caudographic, electromyographic examinations and surgical findings in lumbosacral disc herniations: value of electromyography].

The Authors examined 50 patients affected by lumboischialgy deriving from disk herniation and on the basis of the surgical results determined the degree of reliability of the clinical examination the caudography and the electromyography. The electromyography resulted the most trustworthy test of the three demonstrating a degree of accuracy equal to 85% against that of 80% of the caudography and of 67.5% of the clinical examination. Moreover a statistical elaboration of data is carried out.

Adult↗

[Computerized axial tomography and electromyography in vertebral and spinal cord pathology].

Fifty patients with lumbar spinal disease, 47 of them with disk herniation, were studied preoperatively using both electromyography and computerized tomography (CT), in order to verify the mutual diagnostic significance and accuracy of these techniques. Electromyographic studies provided correct informations regarding the level of the lesion in 41 patients with 1 mistaken level and 8 false negatives, without indicating the nature of involved pathologies. The specific nature of the lesions was correctly indicated by CT studies in 43 patients with 4 incorrect diagnoses and 3 false negatives, without defining the functional loss produced by the lesions. Using electromyography and CT together, first electromyographic studies to establish the spinal level to investigate principally with CT, the diagnostic accuracy can improve because of the decrease of the false negatives.

Adult↗

Application of electromyography in ergonomics: new vistas.

The application of electromyography in analysis of muscle strain in working situations is far from straight-forward. Muscle force, for instance, is not directly accessible using electromyography. New insight in electrophysiological phenomena of human muscle provides however a firm basis for analysis of localized muscle fatigue at work. Such applications entail information at the muscle fiber membrane level.

Electromyography↗

Functional evaluation of the pes anserinus transfer by electromyography and gait analysis.

The effectiveness of the pes anserinus transfer, proposed by Slocum and Larson to control anteromedial rotatory instability of the knee, depends on the pes anserinus muscles contracting at times when the instability threatens the patient's function. To examine the activity of the transferred pes anserinus muscles, quantitated dynamic electromyography, isometric testing of muscle strength, and gait-analysis techniques were employed. Seven normal subjects and nine patients who had undergone pes anserinus transfer for anteromedial rotatory instability were tested. In contrast to the normal subjects, who demonstrated pes anserinus muscle activity primarily during swing phase, the patients displayed conspicuous activity of the semitendinosus, gracilis, and sartorius tendons during stance phase. Quantitated electromyography indicated that the pes anserinus muscles worked harder in the patients than in the normal subjects, and more effort was required from the muscles of patients with poor results than from those of patients with good results. All of the patients also demonstrated reduction of single-limb support time, as well as a shorter stride length and reduced gait velocity. We concluded that the pes anserinus transfer is kinetically sound. Since instability of the knee is a functional defect that is present during stance, the finding of marked activity of the pes anserinus muscles during stance phase in the patients but not in the normal subjects suggests that these muscles were being used to control the instability.

Adolescent↗

[Electroneurography of the laryngeal nerves in the awake patient using electromyography of the larynx under zoom-endoscopic-control (author's transl)].

Electromyography of the larynx in the awake patient using zoom-endoscopy provides an earlier diagnosis of recurrent laryngeal nerve diseases by recording action potentials of the posterior cricoarytenoid muscle. Not in every case the type of nerve lesion (neurapraxy, neurotmesis, axonotmesis) could be determined by the EMG alone. Therefore, neurography of the laryngeal nerves was investigated. With respect to the mixed innervation of the larynx by both the more sensible superior and the motoric inferior laryngeal nerve a reflex arc can be examined. The upper laryngeal nerve was stimulated transcutaneously. The afferent reflex arc leads to the ganglions of the vagus nerve and its central nuclei, its efferent motor neurons conduct reflex activity via the recurrent and upper laryngeal nerves back to the larynx. The reflex potentials can be measured out of the various larynx muscles by electromyography under endoscopic control. The importance of this method is demonstrated in cases of vocal cord palsies.

Action Potentials↗

Use of electromyography in a cow with esophageal paralysis.

Electromyography of the esophageal musculature of a cow that had been regurgitating and losing weight after correction of an esophageal obstruction was suggestive of unilateral denervation. Radiography before and after oral administration of barium sulfate revealed a dilated terminal portion of the thoracic esophagus, suggestive of a focal motility problem. Electromyography was performed on the esophageal musculature by positioning the electrode through the rumen fistula and into the thoracic esophagus and by positioning the electrode percutaneously with the aid of a tube placed in the cervical esophagus. Numerous fibrillation potentials and sharp epsilon-positive waves were detected in the muscles of the left side of the distal portions of the cervical and thoracic esophagus. During hospitalization, the cow was given alfalfa pellets, ground corn, and sodium bicarbonate through the rumen fistula 3 times each day for several weeks to maintain body weight.

Animals↗

[Radical prostatectomy: usefulness of selective electromyography of the periurethral sphincter in the assessment of urinary continence].

The exact mechanisms of urinary continence in patients submitted to radical prostatectomy remain unknown. The aim of our study was to evaluate these mechanisms of continence through a complete urodynamic study, with a special emphasis on selective electromyography of the periurethral aphincter. Of a total of 10 consecutive patients who underwent radical prostatectomy between 1990-1993, a complete clinical control of urinary continence was demonstrated in 7 patients. The complete urodynamic work-up and particularly selective electromyography of the periurethral sphincter permitted evaluating the distal sphincteric mechanism and the degree of functional capacity. All of the cases showed loss of motor units, diminished electromyographic sphincter activity and incomplete lesion of the inferior motor neuron. The present study analyzed the pathophysiological, clinical and urodynamic aspects of these patients.

Aged↗

[Electromyographic findings in muscles around the osteoarthritic knee: integrated electromyography and frequency analysis].

An evaluation of the muscular functions of the vastus medialis, vastus lateralis, rectus femoris, medial hamstring, and of the lateral hamstring was performed using electromyography in 33 knees of 26 female patients with osteoarthritis (OA group) and in 25 knees of 19 healthy female volunteers (control group). During standing on both feet, all muscles in the OA group showed higher IEMG (integrated electromyography) and higher LMR (IEMG of vastus lateralis/IEMG of vastus medialis ratio in the quadriceps; and lateral hamstring/medial hamstring ratio in the hamstrings) than the control group. These augmentary muscular activities ameliorated the varus deformity caused by the osteoarthritis. During maximum isometric voluntary contraction, the OA group showed lower extension and flexion torque of the knees and also lower IEMG than to the control group, while the IEMG of vastus lateralis was not lower. These findings indicated decreased muscular activities in the osteoarthritic knee, and that the activity of the quadriceps was maintained mainly by the vastus lateralis under such conditions. Frequency analysis of the myoelectric signal during maximum isometric voluntary contraction revealed a single peak of low frequency in the power spectrum density function of the quadriceps and double peaks of low and of high frequency in the hamstring. In the OA group, the peak height of the low frequency component was increased in the quadriceps and decreased in the hamstring. We concluded that the duration of the motor unit action potentials was affected in the osteoarthritic knee.

Aged↗

[Surface electromyography in the diagnosis of lateral dominance in children: psychomotor features].

Surface electromyography was used to verify the lateral dominance in 100 six to fourteen years old normal children. Electromyographic records were obtained during verbal stimulation. Dexterity was found in 90, sinistrallity in 3 and indefinite dominance in 7 patients. Comparing with results from clinical examination, the electromyography seems more accurate and easy to perform. The responses obtained after verbal stimulations were attributed to a psychomotor phenomenon. Mechanisms involved in the production of muscle contractions after verbal stimulation, were not proved. Pharmacologic action of cathecolamines on the central motor neural subsystems is advanced.

Acoustic Stimulation↗

[Surface electromyography during experimental stress as a tool in the diagnosis of tension headache: results in 100 cases].

We report the use of surface scalp and neck electromyography during experimental stress state in a series of 100 out-patients suffering from chronic tension headache. Results revealed a 24% to 32% of diagnostic errors in the diagnostic obtained by routine anamnestic procedures and following the criteria recommended by the Headache Classification Committee of the International Headache Society (1988). The electromyography with stress is proposed as a new diagnostic criterion for tension headache.

Adolescent↗

Is quantitative electromyography reliable?

The reliability of quantitative electromyography (EMG) of the masticatory muscles was investigated in 14 subjects without any signs or symptoms of temporomandibular disorders. Integrated EMG activity from the anterior temporalis and masseter muscles was recorded bilaterally by means of bipolar surface electrodes during chewing and biting activities. In the first experiment, the influence of electrode relocation was investigated. No influence of electrode relocation on the recorded EMG signal could be detected. In a second experiment, three sessions of EMG recordings during five different chewing and biting activities were performed in the morning (I); 1 hour later without intermediate removal of the electrodes (II); and in the afternoon, using new electrodes (III). The method errors for different time intervals (I-II and I-III errors) for each muscle and each function were calculated. Depending on the time interval between the EMG recordings, the muscles considered, and the function performed, the individual errors ranged from 5% to 63%. The method error increased significantly (P < .05 to P < .01) with the time interval between recordings. The error for the masseter (mean 27.2%) was higher than for the temporalis (mean 20.0%). The largest function error was found during maximal biting in intercuspal position (mean 23.1%). Based on the findings, quantitative electromyography of the masticatory muscles seems to have a limited value in diagnostics and in the evaluation of individual treatment results.

Adolescent↗

[Magnesium balance in patients with spasmophilia. Relation to results of electromyography].

BACKGROUND: The pathophysiological basis of spasmophilia is frequently magnesium deficiency and the therapeutic administration of magnesium salts has usually a favourable effect. However the parameters of magnesium balance are not always consistent with the results of electromyography. The objective of the present work was to test and interpret the relationship of results of these two basic diagnostic procedures indicated when spasmophilia is suspected. METHODS AND RESULTS: Thirty-three subjects (9 men and 24 women) with suspected spasmophilia were examined by non-invasive electromyography, using the technique of surface electrodes. All subjects had concurrently biochemical examinations: serum calcium and ionized calcium, serum magnesium (S-mg), magnesium in erythrocytes (ery-Mg) and magnesium in the blood haemolysate (H-Mg). In 29 patients and oral magnesium loading test was made with evaluation of the urinary Mg excretion after a constant Mg load (U-Mg). Statistical evaluation of the investigated parameters of the magnesium balance revealed a highly significant relationship between ery-Mg and U-Mg and H-Mg and ery-Mg (p < 0.005). A less close relationship was found between H-Mg and S-Mg (p < 0.05). Total and ionized calcium was in all examined subjects within the range of the arbitrary normal range. The EMG finding was positive (the finding of two and more multiplets in the ischaemic and hyperventilation test resp.) in 30 instances, i.e. in 91% of the examined subjects. In 72% there was agreement of the positivity of the EMG and magnesium deficiency (i.e. reduced values of ery-Mg and U-Mg), positivity of EMG combined with normal parameters of the Mg balance was recorded in 18%. In 6.1% of the examined subjects magnesium deficiency was confirmed combined with a normal EMG finding. CONCLUSIONS: Concurrent positivity of EMG and magnesium deficiency in 72% justifies the therapeutic administration of magnesium. In patients with a normal magnesium deficiency and positive EMG another cause of spasmophilia must be taken into consideration, incl. technical errors of interpretation of EMG results. A negative EMG associated with magnesium deficiency can suggest the central form of tetany, where magnesium treatment is also unequivocally indicated.

Adolescent↗