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 325 records · Page 18Linked to original sources
PubMed1994

Improved method for needle electromyography of the urethral sphincter in women.

Needle electromyography (EMG) of the urethral sphincter using the periurethral approach is a procedure which most women find painful and their discomfort can restrict the usefulness of the test. A new technique has been devised using a transvaginal approach. The patient lies in the left lateral position and using a Sims speculum the posterior vaginal wall is retracted. The urethral sphincter can be easily seen and palpated, assisting correct electrode placement. This new technique is much less uncomfortable and highly satisfactory EMG recordings are obtained.

Electromyography↗
PubMed1995

Transrectal ultrasound guided needle electromyography of the urethral sphincter in males.

Needle electromyography (EMG) of the urethral sphincter in males is commonly performed using a transperineal approach. The technique involves transcutaneous insertion of an EMG needle into the sphincter guided by the investigator's finger placed in the rectum. We describe a new method of needle placement into the urethral sphincter in males using transrectal ultrasound (TRUS). With the patient in the left lateral position, the apex of the prostate gland is identified in the longitudinal plane. Using the TRUS biopsy channel, a specially designed long EMG needle is inserted into the sphincter commencing approximately 1.5-2 cm distal to the prostatic apex in an oblique fashion. This method allows precise identification of the site for needle insertion, reducing blind attempts at localization. The transrectal route is much less uncomfortable to patients, potentially improving patient compliance and overall effectiveness of the technique.

Electromyography↗
PubMed2006

Comparison of pelvic floor muscle training, electromyography biofeedback, and neuromuscular electrical stimulation for bladder dysfunction in people with multiple sclerosis: a randomized pilot study.

AIM: Bladder dysfunction affects up to 90% of the multiple sclerosis (MS) population. Interventions such as Pelvic Floor Training and Advice (PFTA), Electromyography (EMG) Biofeedback, and Neuromuscular Electrical Stimulation (NMES) have received limited research attention within this population. This study aimed to determine the effectiveness of a combined programme of PFTA, EMG Biofeedback, and NMES for bladder dysfunction in MS. METHODS: Females (n = 30) who fulfilled strict inclusion/exclusion criteria were recruited. Outcome measures (weeks 0, 9, 16, and 24) included: 3-day Voiding Diary; 24 hr Pad-Test; Uroflowmetry; Pelvic Floor Muscle Assessment; Incontinence Impact Questionnaire (IIQ); Urogenital Distress Inventory (UDI); King's Health Questionnaire (KHQ), and the Multiple Sclerosis Quality of Life-54 Instrument (MSQoL-54). Following baseline (week 0) assessment, participants were randomly allocated, under double blind conditions, to one of the three groups: Group 1 (PFTA); Group 2 (PFTA and EMG Biofeedback); and Group 3 (PFTA, EMG Biofeedback, and NMES). Treatment was for 9 weeks. RESULTS: Baseline severity (measured by number of leaks and pad weight) showed some variation between groups, although not statistically significant (P > 0.05); with the caveat that this baseline imbalance makes interpretation difficult, a picture emerges that at week 9, Group 3 demonstrated superior benefit as measured by the number of leaks and pad test than Group 2, with Group 1 showing less improvement when compared to week 0; this was statistically significant between Groups 1 and 3 for number of leaks (P = 0.014) and pad tests (P = 0.001), and Groups 1 and 2 for pad tests (P = 0.001). A similar pattern was evident for all other outcome measures. CONCLUSION: Results suggest that these treatments, used in combination, may reduce urinary symptoms in MS. Further research will establish the effectiveness of these interventions.

Adult↗
PubMed1999

Recording of swallowing events using electromyography as a non-invasive measurement of salivation.

The present study examined whether the measurement of swallowing activity by electromyography (EMG) provides a sensitive and valid method for the assessment of the amount of saliva secreted. Thirteen subjects tasted lemon juice and water, and smelled lasagna and hay, while the amount of saliva, measured with the aid of cotton dental rolls, was compared with the number of peaks in the EMG activity of the musculus digastricus. Swallowing indeed differentiated between the stimuli and the correlation between the number of swallows and the amount of saliva was significant. The present data suggest that monitoring the swallowing movement using EMG might be a sensitive, valid and reliable method for the measurement of salivary flow. The use is recommended for the measurement of salivation when a simple and non-invasive method is needed.

Adult↗
PubMed1995

Single fiber electromyography in studies of neuromuscular function.

Single-fiber electromyography (SFEMG) allows precise study of the microphysiology of the human motor unit under normal conditions. The physiological parameters that can be quantified include impulse transmission along the intramuscular axon collaterals, pre- and post synaptic events at the neuromuscular junction, and muscle fiber membrane properties. This chapter illustrates some of the advantages of SFEMG in studies of neuromuscular fatigue in normal muscle, as well as in disorders of neuromuscular transmission, and conditions associated with disturbed muscle fiber depolarization-repolarization.

Animals↗
PubMed1995

Estimation of dynamic joint torques and trajectory formation from surface electromyography signals using a neural network model.

In this study, human arm movement was reconstructed from electromyography (EMG) signals using a forward dynamics model acquired by an artificial neural network within a modular architecture. Dynamic joint torques at the elbow and shoulder were estimated for movements in the horizontal plane from the surface EMG signals of 10 flexor and extensor muscles. Using only the initial conditions of the arm and the EMG time course as input, the network reliably reconstructed a variety of movement trajectories. The results demonstrate that posture maintenance and multijoint movements, entailing complex via-point specification and co-contraction of muscles, can be accurately computed from multiple surface EMG signals. In addition to the model's empirical uses, such as calculation of arm stiffness during motion, it allows evaluation of hypothesized computational mechanisms of the central nervous system such as virtual trajectory control and optimal trajectory planning.

Arm↗
PubMed1993

Amplitude and frequency measures of surface electromyography during dual task elbow torque production.

Studies of motor unit recruitment thresholds have demonstrated the existence of task-specific motor units within the muscles controlling the elbow. Two degree-of-freedom (df) task specificity was investigated at higher levels of elbow torque using the amplitude and frequency characteristics of surface electromyography (EMG). Flexion and supination torque data were collected together with EMG from electrode pairs on the brachioradialis (BRAD), biceps brachii short head, and medial and lateral aspects of biceps brachii long head, while subjects (n = 14) performed the following four combinations of isometric tasks: (1) maximum voluntary contraction (MVC) flexion (F) and (2) MVC supination (S), each with a targeted torque of zero in the second df; (3) MVC flexion with targeted MVC supination (FS); and (4) MVC supination with targeted MVC flexion (SF). Median power frequency (MEDF) and root mean square (RMS) amplitude under steady-state torque conditions were calculated and analyzed using ANCOVA models with planned contrasts (alpha = 0.05). A significant main effect for task was found in RMS, but not in MEDF. Contrasts showed a significant increase in RMS response in the dual MVC tasks (FS and SF) over the single MVC tasks of F and S. The lack of frequency changes with alterations in RMS data indicates that the underlying recruitment/rate coding scheme in use for dual-df tasks may be different than in single-df tasks, and provides possible support for the notion of motor unit task groups. Task-by-site interactions were found for both MEDF and RMS, and illustrated that the three biceps sites differed from BRAD in their responses to the F versus S tasks.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Effects of psychophysiological stress on trapezius muscles blood flow and electromyography during static load.

Mental stress was induced by the Stroop colour word task (CW task) and the effects on the microcirculation and electromyography (EMG) in the upper portion of the trapezius muscle were studied during a series of fatiguing, standardized static contractions. A lowered blood flow of the skin recorded continuously by laser-Doppler flowmetry (LDF) was used as a stress indicator in addition to an elevated heart rate. Muscle blood flow was recorded continuously by LDF using a single optical fibre placed inside the muscle, and related to surface EMG. A group of 20 healthy women of different ages was examined. Recordings were made during a 50-min period in the following sequence: a 10-min series of alternating 1-min periods of rest and stepwise increased contraction induced by keeping the arms straight and elevated at 30, 60, 90 and 135 degrees with a 1-kg load carried in each hand; a 10-min recovery period without load; a repeated contraction series with simultaneous performance of the CW task; a second 10-min recovery period, and a second contraction series without CW task. Signal processing was done on line by computer. The LDF and root mean square (rms)-EMG values were calculated, as well as the EMG mean power frequency (MPF) for fatigue. The CW-task added to the contraction series caused an increase in the heart rate accompanied by a decrease in the blood flow to the skin and a 30% increase in the blood flow in the exercising muscle. Both returned to normal during the subsequent recovery period and showed normal levels during the final contraction series without CW. The rms-EMG showed a 20% increase that persisted during the final contraction series performed without CW. There was no influence on MPF. This CW has previously been shown to evoke an increased secretion of adrenaline from the adrenal medullae to the blood. The increased blood flow in the exercising muscle would therefore appear to have been caused by beta-adrenoceptor vasodilatation, and the fall in the blood flow in the skin by alpha-adrenoceptor vasoconstriction. The findings may have implications for work situations characterized by repetitive static loads to the shoulder muscles and psychological stress.

Adult↗
PubMed1996

Evaluating the maneuverability of a control stick using electromyography.

This paper proposes maneuverability indexes for a control stick that are based on considerations of muscle characteristics. The indexes are defined on the basis of muscle forces: stiffness of the musculoskeletal system and torque for accelerating the stick. Measuring muscle forces with electromyography, we examine the effectiveness of the proposed indexes experimentally. In a slow tracking operation, the index based on stiffness conforms to the subjective evaluation, but the index based on the torque is inadequate as an index of maneuverability; we therefore use the index based on stiffness as the maneuverability index. In experiments on a step operation, we divided the operation into two phases: moving and holding. The index in the holding operation is in good agreement with the subjective evaluation. In both tracking and step operations the characteristics of the index are appropriate whether or not the controlled object has a first-order lag element. As a result, it is shown that the index can indicate the maneuverability in the low-frequency tracking operation of the stick.

Arm↗
PubMed1994

Comparative study of evoked electromyography and facial nerve latency test in the prognosis of idiopathic facial nerve palsy in childhood.

We report our results from the application of evoked electromyography (EEMG) and facial nerve latency testing (FNLT) in 30 children aged 4-14 years with idiopathic facial palsy. Our aim was to define the value of these tests as prognostic tools in Bell's palsy. From the EEMG results we ascertained that, when the amplitude of the compound muscle action potential varied between 51% and 95% of the normal value, the neuronal damage is slight (neurapraxia). When the percentage value of muscle response decreases, the prognosis is worse. The results of the FNLT showed that, when the latency is within normal limits, the damage to the nerve is slight (neurapraxia). If the latency is prolonged, the prognosis is worse. Evaluation of our results and comparison with the index of facial nerve functional recovery showed that those two tests have a high percentage of correctness (100% for the EEMG and 96.7% for the FNLT) and a low percentage of error. We conclude that these tests are excellent for predicting the outcome of facial nerve palsy in childhood and we suggest that young patents undergo both so that the determination of the lesion may be as correct as possible.

Adolescent↗
PubMed1986

Some remarks on computer-aided clinical electromyography based on experience with the Polish ANOPS minicomputer.

The author evaluates the application of the Polish minicomputer Analyser of Noise of Periodic Signals (ANOPS) in practical electromyography (EMG) and compares the diagnostic yield of ANOPS with that of manual quantitative EMG. The advantages of ANOPS--at least in the past--include speed, large samples, new data, reduced examiner bias, quantified evaluation of maximal effort record and online recording. The most important limitations of ANOPS are absence of complex potentials due to distortion of signals, loss of phase evaluation, and lack of comparability of amplitude with other methods. ANOPS is compared with other automated methods applied to evaluation of interference pattern and parameters of single motor unit potentials (MUPs). Most of the latter are based on pattern recognition. ANOPS does not meet all of the criteria which an automatic method should meet to be accepted in EMG practice. The most important problem is the distortion of properties of the EMG signal. Further search for computer-aided EMG methods and their careful testing in practice are necessary.

Computers↗
PubMed1989

Measurement of tendon reflexes by surface electromyography in normal subjects.

A simple method for measuring the tendon reflexes was developed. A manually operated, electronic reflex hammer was applied that enabled measurement of the strength of tendon taps. Reflex responses were recorded by surface electromyography. Stimulus-response relations and latencies of tendon reflexes in the biceps, triceps, quadriceps and triceps surae were examined in 40 healthy subjects. A characteristic relation between stimulus strength and response amplitude was found which could be described by an empirical function. Latencies of both arm and leg reflexes were linearly related to the height of the subjects. Variations of reflex amplitudes within and between subjects were comparable with previous results obtained with more complicated techniques. Although repeatability of measurement of the amplitude is limited by the variability of reflexes, significant agreement was found between repeated measurements. Most reflex amplitudes were diminished during repeated examination after a short interval. Both measurement and clinical examination showed the frequent occurrence of left-right asymmetry of reflex amplitudes. These left-right differences were reproducible to a significant degree on repeated measurements after more than 2 years.

Adult↗
PubMed1989

Complete bilateral internal ophthalmoplegia as sole clinical sign of botulism: confirmation of diagnosis by single fibre electromyography.

A case of complete bilateral internal ophthalmoplegia as the sole clinical sign of botulism is reported. Diagnosis was immediately confirmed by single-fibre electromyography (SFEMG), which revealed abnormally high blocking (14.3%), contrasting with moderately increased jitter (mean consecutive difference in the extensor digitorum communis muscle, 43.9 microseconds). After giving equine botulinum antitoxin and simultaneous forced emptying of the bowels, ocular symptoms completely disappeared within 2 days. Six days, 5 weeks and 6 months after the first SFEMG study, the jitter was still abnormal, even becoming more so with time. Blocking, however, was only rarely observed in the follow-up studies. It is concluded that SFEMG may serve as a useful and sensitive method for the rapid diagnosis of botulinum intoxication, even in cases where no clinical signs of general muscular weakness are apparent.

Adult↗
PubMed1994

Fatigue and recovery of phosphorus metabolites and pH during stimulation of rat skeletal muscle: an evoked electromyography and in vivo 31P-nuclear magnetic resonance spectroscopy study.

31P-nuclear magnetic resonance spectroscopy and evoked electromyography were applied to rat skeletal muscle to examine the mechanism of muscle fatigue and the recovery of muscle phosphorus metabolites and pH during fatigue. When the sciatic nerve was electrically stimulated at 1 Hz, the contraction force of the gastrocnemius muscle decreased gradually to 46% of the maximal force, accompanied by a decrease in phosphocreatine (PCr) and a corresponding increase in inorganic phosphate (P(i)) and diprotonated inorganic phosphate (H2PO4-). Neither the amplitudes of compound muscle action potentials (CMAP) nor muscle pH changed significantly. At 10-Hz stimulation, contraction force rapidly decreased to 26% of maximal force, accompanied by a decrease in PCr and increases in P(i) and H2PO4-. Muscle pH decreased for a few minutes, then gradually recovered during continued stimulation. The amplitude of the CMAP also decreased for a few minutes and then reached steady values. At 100-Hz stimulation, the contraction force decreased to 6% of the maximal force and there was a decrease in the amplitude of the CMAP. However, the changes in the phosphorus metabolites and pH were transient and recovered to the control value during the stimulation. These results indicated that fatigue at 1 and 100-Hz stimulation was mainly caused by the change in phosphorus metabolite concentrations and electrical failure, respectively, and that fatigue at 10-Hz stimulation might have been due to both of these factors. These results also indicated that electrical failure might have been the cause of the recovery of the phosphorus metabolites and pH during 100-Hz stimulation and of pH during 10-Hz stimulation.

Action Potentials↗
PubMed1995

Microcirculation in the upper trapezius muscle during sustained shoulder load in healthy women--an endurance study using percutaneous laser-Doppler flowmetry and surface electromyography.

Microcirculation in the upper portion of the trapezius muscle was measured percutaneously in a group of 16 healthy women of different ages by continuous laser-Doppler flowmetry (LDF) in relation to electromyography (EMG) during an endurance test. During the measurements the subject kept her arms straight and elevated at 45 degrees in the scapular plane and held a 1-kg load in each hand as long as possible. This was followed by rest with the arms hanging and carrying no load. The 10-min recording period comprised 1-min initial rest followed by the endurance test and then recovery. Signal processing was done by computer on line. The LDF and root-mean-square (rms) EMG signals were normalized. Spectrum analyses of EMG mean power frequency (MPF) were performed. The amount of load produced was on average 2,267 (SD 939) N.m.s, i.e. shoulder torque x time expressed as Newton meter seconds, and the endurance time was 4.3 (SD 1.20) min. The rms-EMG as well as the LDF increased significantly during endurance, both when related to endurance time and to amount of load. The MPF showed no significant changes. The mean total increase in muscle blood flow was 175% of that recorded in the initial rest period. The average increase per each 10 s of contraction was 2.9%. Maximum was reached during the 1st min of recovery followed by a fall to the base level that was reached within 77 s on average. The amount of load produced and the blood flow increase was smaller than that found in a separate study of men, indicating a lower functional capacity.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1996

Automatic decomposition electromyography in idiopathic inflammatory myopathies.

Automatic decomposition electromyography (ADEMG) is a commercially available software package with installed reference values that enables the objective measurement of motor unit action potentials (MUAPs). To assess the diagnostic yield of this package in idiopathic inflammatory myopathies (IIM) we performed bicepts brachii ADEMG in 17 patients with polymyositis, dermatomyositis and inclusion body myositis. Results were compared with those in 12 controls, and with the results of conventional EMG of the biceps and other muscles. Decreased mean values for MUAP duration occurred significantly more frequently in IIM patients than in controls; other MUAP characteristics did not differ. In IIM patients, decreased mean amplitude and increased mean number of turns occurred significantly less frequently on ADEMG than did corresponding abnormalities on conventional biceps EMG. Decreased mean values for duration and amplitude, and increased mean values for number of turns were seen significantly less often on ADEMG than corresponding abnormalities on conventional EMG of four different, individually chosen muscles. Overall evaluation of ADEMG resulted in a diagnosis of "possible myopathy" in 1 and "probable myopathy" in 8 patients, whereas overall evaluation of conventional EMG led to a diagnosis "suggestive of IIM" in 13 patients. We conclude that, although measurement of mean MUAP duration might be valuable in IIM diagnosis, our results do not favour the use of biceps brachii ADEMG and the installed reference values for the diagnosis of IIM. We suggest modifications to improve ADEMG's applicability.

Adult↗
PubMed1990

Prolonged anorectal manometry and external anal sphincter electromyography in ambulant human subjects.

We have developed a method for prolonged combined anorectal manometry and electromyography (EMG) of the external anal sphincter in ambulant subjects. Fourteen healthy volunteers were studied for a total of 284 hr (mean of 20.3 hr/subject). Anorectal manometry was performed using a probe with twin pressure sensors. EMG was recorded by one indifferent and two differential silver-silver chloride surface electrodes positioned 0.5-0.75 cm from the anus on either side. The sampling reflex occurred frequently and was significantly (P less than 0.001) more common during wakefulness than during sleep and also following meals than during fasting (P less than 0.01). The passage of flatus was associated with transient relaxation of the anal canal in 19% of episodes. In contrast, there was a contractile episode with no preceding relaxation in 75% of episodes. The anal sphincter had significantly (P less than 0.05) more action potentials (APs) during the day (12.8 +/- 3.2 APs/10 min) than at night (1.6 +/- 1.3 APs/10 min). During micturition, anal canal pressure rose (mean 15 mm Hg) in association with powerful external anal sphincter contractions. Our data show that, normally, contractile activity both in the anal canal and external anal sphincter maintains fecal continence during micturition and the passage of flatus. The technique should lead to a better understanding of the normal mechanisms of fecal continence during waking and sleep and of the pathophysiology of disorders of anorectal function.

Action Potentials↗
PubMed1985

Electromyography for the investigation and early diagnosis of scoliosis.

A clinically normal 5 year old child with a family history of scoliosis was studied. Electromyography of the thoracic and lumbar erector spinae muscles and roentgenography of the spine were both done on two separate occasions, six months apart. On the first electromyographic investigation, moderate predominance of activity was found over the left thoracic erector spinae muscles. At that time, spinal roentgenography showed normal results, whereas six months later left thoracolumbar scoliosis was evident. It was concluded that electromyographic investigation is useful for the early diagnosis of scoliosis in school-age children.

Child, Preschool↗