Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “ELECTROMYOGRAPHY”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,333 records · Page 74Linked to original sources
PubMed1975

Single fibre electromyography in various processes affecting the anterior horn cell.

SFEMG recordings were carried out in patients with amyotrophic lateral sclerosis, progressive muscular atrophy, familial spinal muscular atrophy and syringomyelia. The fibre density was increased in all conditions, especially in progressive muscular atrophy indicating marked collateral sprouting. The duration of the action potential was increased indicating a mixture of hypertrophic and atrophic fibres and slowly conducting newly formed nerve sprouts. The action potentials were unstable with varying degree of impulse blocking especially in the more progressive cases (ALS), representing recent re-innervation. The SFEMG method is used to characterize the functional status of the motor unit and helps in diagnosis and in predicting prognosis. In addition, SFEMG recordings reveal abnormalities in clinically and electromyographically normal muscles.

Action Potentials↗
PubMed1979

Quantitative electromyography using automatic analysis. A comparative study with a fixed fraction of a subject's maximum effort and two levels of thresholds for analysis.

Quantitative electromyographic (QEMG) data recorded with two levels of threshold for the apparatus are compared. Using a fixed fraction of a subject's maximum effort the data are shown to be independent of sex, age and the strength of the muscles. The diagnostic yield of such a method is shown to be better with 50 muV threshold for analysis than with 100 muV, in cases of muscle disorders such as Duchenne muscular dystrophy and polymyositis. However, in cases of neurogenic lesions due to anterior horn cell disease the diagnostic yield remains the same with both thresholds.

Adolescent↗
PubMed1980

Quantitative electromyography using automatic analysis--diagnostic utility of turns per unit amplitude.

Quantitative electromyographic (QEMG) data from 3 muscles recorded with a 50-micronV threshold for the turns and amplitude measurements are presented. Using turns per unit amplitude as the index, consistent and comparable readings were recorded from abductor digiti minimi, biceps brachii and vastus medialis in normal subjects, namely 1.132 +/- 0.08 (31 subjects), 1.059 +/- 0.122 (31 subjects) and 1.007 +/- 0.088 (11 subjects), respectively. It is shown here that the diagnostic yield increases when all 3 values, namely, turns/s, average amplitude and turns/unit amplitude are considered in conjunction rather than considering the first 2 alone.

Adult↗
PubMed1982

Quantitative electromyography in babies and young children with no evidence of neuromuscular disease.

A technique of quantitative EMG suitable for use in babies and young children is described. No specific level of force is required and portions of EMG as short as 100 ms are suitable for analysis. A specially modified Medelec APA6 action potential analyser converted the EMG into two pulse trains representing amplitude pulses and turns pulses with a display on the CRT screen. The ratio of the mean amplitude/turns per second was determined for between 15 and 20 different portions of EMG to produce a Mean Ratio of mean amplitude/turns per second. Ninety-seven children were investigated for neuromuscular disease. Twenty-two had a primary muscle disease, 21 a neurogenic process and 25 no neuromuscular disease. This last group was called the Apparent control group. The problem of obtaining control values is discussed. A 5-year follow-up study found no change in the clinical diagnosis of the patients in the 3 groups. Numerical limits for the Mean Ratio of mean amplitude/turns per second for the Apparent control group are defined.

Adolescent↗
PubMed1991

Electromyography of some respiratory muscles in the horse.

To investigate activity in respiratory muscles, insulated wire electrodes were used to record electromyographic activity in the costal diaphragm and in the intercostal, serratus ventralis, internal abdominal oblique, transversalis and rectus abdominis muscles in conscious horses and in the same animals when anaesthetised. Electromyographic activity was related to respiratory phases as recorded by a stethograph around the chest wall. The costal diaphragm showed tonic and inspiratory activity in both conscious and anaesthetised animals. The principal muscle actively involved in expiration was the transversalis muscle. Intercostal muscle activity, and any increased activity in the second part of either inspiration or expiration recorded in the conscious animal, was absent under anaesthesia. The very marked tonic activity found in the serratus ventralis muscle in standing horses disappeared during anaesthesia. It was concluded that any stabilisation of the chest wall contributed by activity in the serratus ventralis and intercostal muscles in conscious, standing horses is greatly reduced during anaesthesia.

Abdominal Muscles↗
PubMed1985

The effect of rebreathing CO2 on ventilation and diaphragmatic electromyography in newborn infants.

We tested the hypothesis of whether the reduced ventilatory response to CO2 in preterm as compared to term infants is related to primary central unresponsiveness, or to mechanical impairment of the respiratory pump. Eleven preterm (n = 19; gestational age 32 +/- 0.4 wk) and 14 term (n = 24; GA 40 +/- 0.3 wk) infants were studied. Minute integrated diaphragmatic activity EMGDi X f), and mean inspiratory diaphragmatic activity (EMGDi/TI), were used as indices of central output. After 3 min breathing 21% O2 (control), infants rebreathed from a bag containing 5% CO2 in 40% O2 for 2 to 3 minutes. We measured VE, VT, f, VT/TI. Sleep states were monitored. Preterm infants had a decreased ventilatory response to CO2 both in quiet sleep (QS) (0.0379 +/- 0.067 vs 0.505 +/- 0.032 L . (min . kg . kPa PACO2)-1; P less than 0.04) and in active sleep (AS) (0.210 +/- 0.032 vs 0.331 +/- 0.048 L . (min . kg . kPa PACO2)-1; P less than 0.04). The decrease in response primarily was a function of a lack of increase in tidal volume with CO2 in QS and a lack of increase in f in AS. Parallel to these changes there were significant correlations between the increases in EMGDi X f and VE with inhaled CO2 (r = 0.75; P less than 0.001); VT and EMGDi (r = 0.63; P less than 0.01); and between the increases in EMGDi/TI and VT/TI with inhaled CO2 (r = 0.64; P less than 0.001). The results suggest that ventilatory response to CO2 is (1) correlated highly with diaphragmatic indices of central output; (2) less in active than in quiet sleep; (3) less in preterm than in term infants. We conclude that despite their increased chest wall compliance, preterm infant respond less to CO2 because of central unresponsiveness.

Carbon Dioxide↗
PubMed1979

Cystometry and periurethral striated muscle electromyography using cold and room temperature fluid.

In evlauating patients with neurologic lesions of the spinal cord and voiding abnormalities, it would appear from this study that distention is a more physiologic stimulus to bladder contraction than relatively smaller amounts of cold fluid. While the ice water test has speed and simplicity to recommend it, it should not be used as a sole means in determining whether or not a detrusor reflex is present. It may not uncover those patients with detrusor hyperreflexia or may fail to reveal a detrusor reflex. If iced contrast medium is to be used for voiding cystography, the volumes should approximate those used for regular cystometry.

Electromyography↗
PubMed1979

Anal stimulating electrodes in electromyography.

The Continaid pelvic floor stimulating electrode is useful in reception of electromyographic signals, a use for which the device was not originally conceived. I believe there is money to be saved and some clinical problems can be avoided when this plug is substituted for some others now in clinical use.

Anal Canal↗
PubMed1988

Surface electrodes in perineal electromyography.

In 40 elderly male patients undergoing multiple urodynamic evaluations, surface electrodes were used for recording electromyographic (EMG) activity of pelvic sphincter muscles; placement site was the external anal sphincter. The measured wave form was displayed as an analog plot. Different types of surface electrodes were evaluated in selected patients. The EMG wave form measurements varied with the type of surface electrode used and placement of the electrode. Surface electrodes for external anal sphincter EMG resulting in optimum signal response require a small metallic recording surface with an adhesive that will secure the electrode to the skin, proper anatomic placement of the electrode, appropriate preparation of the skin surface at the site of application of the electrode, and capabilities for oscilloscope monitoring of the sphincter EMG signal wave form. If properly used, surface electrodes result in a signal amplitude and frequency that approach the quality of concentric needle electrodes.

Aged↗
PubMed1992

Simultaneous electromyography and 31P nuclear magnetic resonance spectroscopy--with application to muscle fatigue.

The electromyogram (EMG) is often used to study human muscle fatigue, but the changes in the electromyographic signals during muscle contraction are not well understood in relation to muscle metabolism. The 31P NMR spectroscopy is a semi-quantitative non-invasive method for studying the metabolic changes in human muscle. The aim of this study was to develop a method by which EMG and NMR spectroscopy measurements could be performed simultaneously. All measurements were performed in a whole body 1.5 Tesla NMR scanner. A calf muscle ergometer, designed for use in a whole body NMR scanner, was used. The subject had the left foot strapped to the ergometer. The anterior tibial EMG was recorded by bipolar surface electrodes. A surface coil was strapped to the anterior tibial muscle next to the EMG electrodes. Simultaneous measurements of surface EMG and surface coil 31P NMR spectroscopy were performed in the scanner during an isometric submaximal voluntary contraction until exhaustion, in 6 normal volunteers. Concentrations of phosphocreatine (PCr), inorganic phosphate (P(i)) and pH were analysed together with root mean square (RMS) and median frequency of the EMG. The fatiguing contractions (endured 5-13 min) produced a rapid decline in PCr and pH accompanied by a rapid rise in P(i). The RMS was approximately constant until the normalized PCr concentration declined below 0.6-0.7 and the pH declined below 6.75-6.85; exceeding these metabolic limits was associated with a rapidly increasing RMS value (2-3 times the previous level by exhaustion). The median frequency declined linearly with time and was found to be highly linearly correlated with the pH value (r = 0.82).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

Neuromuscular effects of chronic exposure to fenthion in dogs and predictive value of electromyography.

Chronic exposure to organophosphates (OP) can result in nonspecific neurologic signs in both man and animals. Improved methods are needed to predict toxicity and to better characterize neuromuscular effects. In this study, dogs were exposed to an OP (fenthion) by weekly dermal application of a 20% solution at a dosage of 44 mg/kg. This dosage does not produce signs of acute OP toxicity in dogs, although plasma cholinesterase (ChE) levels are significantly decreased. Electromyograms (EMG) were used to monitor motor unit potential (MUP) activity at minimal and submaximal contractile effort in four different muscles. At 1-month intervals, muscle biopsies were obtained and plasma ChE levels were determined. At 3 months, hyperreflexia and/or mild proprioceptive deficits were observed. The dosage was reduced to 22 mg/kg for the remaining 3 months of the study. At the end of this 6-month study, nerve and muscle biopsies were obtained. Mean plasma ChE levels were decreased (preexposure value of 1775 IU/liter to low of 310 IU/liter) and correlated with duration of exposure and change in dosage level. Fourier analysis of EMG indicated some increase in higher frequency components of the power spectrum with time, and analysis of individual MUPs revealed a significant (p less than 0.05) increase in the product of the amplitude times the duration of the potentials in all muscles examined. Biopsy results were supportive of EMG findings of altered neuromuscular function and loss of small motor units. The EMG changes were most consistent in the gastrocnemius muscle and were detected prior to development of clinical signs. These results indicate that EMG can be useful in monitoring OP exposure and predicting toxicity.

Animals↗
PubMed1980

Relationships between facial electromyography and subjective experience during affective imagery.

Sixty subjects were exposed for 40 s each to 48 imagery situations designed to reflect happy, sad, angry and fearful conditions. Facial electromyographic (EMG) activity from zygomatic, corrugator, masseter and lateral frontalis muscle regions was recorded, and experienced emotion was measured on a scale tapping these four emotions. Results showed that: (1) zygomatic activity reliably differentiated happy imagery, corrugator activity reliably differentiated sad imagery, but masseter activity did not differentiate angry imagery and lateral frontalis activity did not differentiate fearful imagery; (2) different intensities of specific emotional imagery situations evoked the expected differential patterns of self-report and EMG; (3) higher correlations between self-report and EMG for 'present', rather than 'future' ratings of experienced emotion emerged for positive affect only; and (4) the use of a standardized imagery scale, rather than the self-generated, personally-relevant affective situations used in previous studies, allowed for more sensitive measurement of the relationship between facial muscle activity and subjective experience of emotion during affective imagery.

Adolescent↗