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.

SourceResearch connectionFrom yearThrough year

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

At least 541 records · Page 30Linked to original sources

PubMed1982

Vesicourethral electromyography: facts or artefacts.

A vesicourethral electromyographic study was carried out on 21 cats of both sexes with extracellular electrodes along with monitoring of contraction and relaxation of various parts of the bladder and urethra. No consistent electromyographic pattern of slow and fast waves was observed in the bladder and urethra either in any empty bladder or during filling and voiding phases. Most of the recorded waves were traced to a defined source of artefact. Twenty-two experiments were done with glass microelectrodes recording intracellularly in bladder strips of various animals bathed in normal and modified Krebs solutions. No spike activity was recorded during periods of contractions, whether spontaneous or electrically stimulated. Both in vivo and in vitro experiments suggest that the mechanism of excitation-contraction coupling of the bladder remains unidentified. The clinical application of bladder electromyography (EMG) has to be interpreted cautiously.

Action Potentials↗

PubMed1985

A comparative study of various electrodes in electromyography of the striated urethral and anal sphincter in children.

The series comprised 41 children aged 6 to 14 years consecutively referred with recurrent urinary tract infection and/or enuresis. Carbon dioxide cystometry was carried out in the supine and the erect position and combined with simultaneous electromyography (EMG). The external urethral sphincter was examined with a ring electrode mounted on a urethral catheter, while recordings from the striated anal sphincter were based on an anal plug electrode and perianal electrocardiographic (ECG) skin electrodes: 211 EMG and cystometric examinations were performed and all three methods gave satisfactory results. Correlation between them was good, as was reproducibility. Perianal surface ECG electrodes are recommended for the evaluation of functional disturbances of the external sphincter. They are painless, easy to use, and are well tolerated by the patient.

Adolescent↗

PubMed1992

Sphincter electromyography in patients after radical prostatectomy and cystoprostatectomy.

Urethral sphincter weakness may occur after major pelvic surgery and urinary incontinence, either temporary or permanent, may result. In order to determine whether the cavernous nerves described by Donker and Walsh carry fibres to the distal urethral sphincter as well as those supplying the corporal bodies, we have studied prospectively the sphincter electromyography in 2 groups of 10 patients: (1) those who had undergone nerve-sparing radical prostatectomy for prostatic carcinoma and (2) those who has undergone radical cystoprostatectomy for bladder carcinoma. This study group was compared with a control group of normal individuals. The results showed significant differences in duration of motor units between the control group and prostatectomy group and between the control group and cystectomy group but no significant difference between the 2 operated groups. There was no significant difference in amplitude of the motor units, the sacral reflex latencies or the pudendal somatosensory evoked potentials between all 3 groups. It was therefore concluded that division of the cavernous nerve of Walsh does not compromise distal urethral sphincter function. Furthermore, radical transabdominal lower urinary tract surgery may induce significant electromyographic changes in the external sphincter which may not be clinically evident. This may potentially affect continence later if second-stage urinary reconstructive surgery is undertaken.

Aged↗

PubMed1993

Electromyography of cavernous smooth muscle during flaccidity: evaluation of technique and normal values.

Objective evaluation of the penile innervation in impotent patients is mostly restricted to examination of the somatic pudendal pathways. These tests provide little information on the pelvic-cavernous autonomic innervation of the corporeal bodies. Electromyography of the flaccid penile smooth muscle is a reproducible and non-invasive method of evaluating these autonomic pathways and the status of intrinsic smooth muscle. Examination techniques and normal values have been studied in 15 young and potent volunteers. Recordings in 13 patients with neuropathology and 57 impotent patients are discussed.

Adult↗

PubMed1979

Gait electromyography in normal and spastic children, with special reference to quadriceps femoris and hamstring muscles.

Telemetered gait electromyography was used to investigate gait patterns and the phasic behavior of the quadriceps femoris and medial hamstring muscles in 26 normal children and 32 children with spastic cerebral palsy. The average child with spastic cerebral palsy was found to have a shorter stance phase than the normal, but the cadence, while more variable, was nearly the same as normal. The spastic muscles typically exhibited prolonged phasic activity or a dysphasic pattern. Most of the patients with spastic hamstrings also had spastic quadriceps, suggesting that over-weakening the hamstrings may produce an unwanted genu recurvatum or hyperextended knee gait. Care must be taken to balance hamstring spasticity with quadriceps spasticity. A final result with slight knee flexion is preferable to hyperextension.

Adolescent↗

PubMed1989

Surface electromyography of pelvic floor muscles in healthy children. Methodological study.

Pelvic floor muscle activity was recorded in ten healthy children, aged six to ten years, by using surface electromyography and a polygraph writer. The electromyograms were recorded simultaneously from four electrode pairs on the perineum and three electrode pairs on adjacent muscle groups, i.e. hip and abdominis muscles. The children performed ten different manoeuvres. Necessary prerequisites for this investigatory method include good electrode application, adequate instruction of the child and the child's adjustment to the method. Using the described procedure, it was possible to record pelvic floor muscle activity without any appreciably detectable electrical influence from adjacent muscles. The method sometimes allows selective recording of electromyographic activity between the ventral urogenital and the dorsal anal regions. Therefore both anal and urethral electrode pairs should be used to achieve functional information about the pelvic floor muscles. The envisaged method should be useful as a tool for assessment of pelvic floor muscle exercises in children with voiding disorders.

Child↗

PubMed1997

Depression of neuromuscular transmission in methylmercury-poisoned rats: a glass microelectrode and single fiber electromyography study.

Changes in neuromuscular transmission were examined in methylmercury (MeHg)-poisoned rats, given a total oral dose of 60 mg CH3HgCl at 5 mg/kg/day. A microelectrode study was done on the 21st day. The mean quantal content and mean values of the immediately available pool of ACh in the MeHg-poisoned rats were reduced as compared to those in the control rats, but the mean values for the release probability of ACh did not differ significantly. Stimulation single fiber electromyography (SFEMG) was done on the biceps femoris muscle at 1, 5, 10 and 20 Hz on the 28th day. Both a significant and consistent increase in jitter were found at increasing stimulation rates in the MeHg-poisoned rats. The SFEMG findings suggest presynaptic involvement due to accelerated depletion of ACh. We confirmed that neuromuscular transmission is depressed in MeHg-poisoned rats in vivo and in vitro.

Animals↗

PubMed2006

A reproducibility study of corpus cavernosum electromyography in young healthy volunteers under controlled conditions.

INTRODUCTION: Although the corpus cavernosum electromyography (CC-EMG) has been studied already for 16 years, doubts regarding its reproducibility have remained. AIM: To assess the reproducibility of CC-EMG under controlled conditions and the influence of confounding factors. METHODS: Three CC-EMG recording sessions were performed in 13 healthy young men under the same conditions. Furthermore, the effects of potentially confounding factors, such as intake of caffeine, alcohol and smoking, and sexual activity, were investigated in the same population. Using auto- and cross-correlation techniques, CC-potentials were characterized with parameters amplitude (A), duration (D), dominant frequency (DF), maximum cross-correlation coefficient of longitudinal and bilateral CC-potential pairs (Rmax-lon. and Rmax-bi.), and propagation velocity (PV ). MAIN OUTCOME MEASURES: Comparison of CC-EMG parameters A, D, DF, Rmax-lon., and Rmax-bi. between three recording sessions and assessment of the impact of confounding factors on these parameters. RESULTS: DF, D, A, and Rmax-lon. showed significant correlations among three sessions; PV showed significant correlations between two sessions performed within the same day but not between those performed on different days; Rmax-bi. did not show significant correlations between any two sessions. Intake of caffeine, alcohol, and smoking did not affect CC-potentials, while the recordings shortly after ejaculation showed more irregular oscillations and less CC-potentials with smaller A. CONCLUSIONS: CC-potential parameters DF, D, A, and Rmax-lon. have been demonstrated to be reproducible. The results provide a basis for the clinical and scientific application of CC-EMG. CC-potentials are not sensitive to confounding factors such as intake of caffeine, alcohol, and smoking, while measurements shortly after ejaculation should be avoided.

Adult↗

PubMed1991

Electromyography and morphology during regeneration of muscle injury in rats.

Healing of the partially ruptured rat gastrocnemius muscle was studied correlating electromyographical findings with morphological changes. Fibrillation potentials and positive sharp waves were seen both proximal and distal to the injury 7 days after the injury and disappeared in the proximal part by day 14 and in the distal part by day 21. Late components of motor action potential were observed from day 14 onwards. Denervation was mainly myogenic, i.e. caused either by rupture of myofibres, whence the abjunctional stump lost its contact with the neuromuscular junction on the adjunctional stump, or by necrosis of the segment of the ruptured myofibre lying underneath the neuromuscular junction. Lesser extent of denervation was neurogenic, i.e. caused by damage to intramuscular nerve fibres. The reinnervation occurs either by regeneration of the necrotized myofibres, by regeneration of the severed nerves, or by collateral innervation of new neuromuscular junctions in the abjunctional stumps. The present study indicates that electromyography may be useful in the diagnosis and follow-up of skeletal muscle injuries.

Animals↗

PubMed2006

The influence of the leaf gauge and anterior jig on jaw muscle electromyography and condylar head displacement: a pilot study.

BACKGROUND: A leaf gauge and an anterior jig may be used to assist the recording of a reproducible jaw position for restorative and prosthodontic treatment. This study investigated possible condylar displacement using an opto-electronic jaw-tracking device and a leaf gauge or anterior jig. The effect of a leaf gauge and anterior jig on jaw muscle electromyography was also examined. METHODS: Five healthy adults without symptoms of temporomandibular disorders were selected. Condylar displacement during clenching were recorded simultaneously with electromyographic activity of superior and inferior heads of the lateral pterygoid, anterior and posterior temporalis, masseter, and suprahyoid muscles. Subjects were trained to bite at maximum and half-maximum bite-force using an anterior jig incorporating a force transducer. RESULTS: No consistent condylar displacement was observed in x, y and z axes between different bite-forces although there was a trend towards superior displacement. Comparison of maximum intercuspal clench and maximum clench on a leaf gauge and an anterior jig produced significant decrease in anterior temporalis activity (p < 0.05), whilst an anterior jig with maximum clench significantly decreased posterior temporalis muscle activity. CONCLUSION: Within the limits of this pilot study, no consistent change in condylar position was identified with these appliances.

Adult↗

PubMedDate not supplied

Evaluation of jitter by stimulated single-fiber electromyography in normal dogs.

Single-fiber electromyography (SFEMG), a technique used to investigate neuromuscular transmission, has been described previously in the pelvic limb of dogs. Because preferential involvement of isolated muscle groups can occur in disorders of neuromuscular transmission, SFEMG was done in the peroneus longus (PL), extensor carpi radialis (ECR), and orbicularis oculi (OO) muscles of 10 adult, clinically normal dogs. Jitter was calculated as the mean absolute value of the consecutive differences in latency of 50 single muscle fiber action potentials after stimulation of intramuscular nerve bundles at the level of the motor point in at least 20 muscle fibers per muscle. Bilateral recordings were performed in 3 dogs. Mean jitter values were determined for each muscle, and differences among muscle groups and among dogs were compared. The upper limits of mean consecutive difference (mean plus 3 standard deviations) for the PL, ECR, and OO muscles were 21.94, 22.53, and 23.39 micros, respectively, and the upper limit of mean consecutive difference for individual muscle fibers in the respective fiber pools was 28.62, 36.39, and 35.68 micros. Jitter values for the ECR and OO were significantly higher than the jitter value for the PL muscle (P < .05). Significant differences among muscles or dogs or between sides were not observed for the ECR. Significant differences among dogs were observed for OO jitter values and were attributed to extremely low jitter values in 1 dog. Significant differences were demonstrated between sides for the PL and were attributed to small sample size. Results of this study provide normative data that can be used in the application of the stimulated SFEMG technique to dogs with suspected disorders of neuromuscular transmission.

Action Potentials↗

PubMed1986

Small intestinal motility and transit by electromyography and radiology in the fasted and fed pig.

The pattern of small intestinal digesta transit was studied in six young pigs (20-30 kg) by simultaneous electromyography and radiology. Pigs showed migrating myoelectric complexes (m.m.c.s) in the small intestine both when fasted and after feeding. The m.m.c.s were modified by feeding; quiescence was much reduced in duration and irregular spiking activity (i.s.a.) was prolonged; m.m.c.s were not disrupted and phases of regular spiking activity (r.s.a.) were still seen after feeding. The r.s.a. phase could be recognized on the screen and in spot films from both fasting and fed pigs as a band of intense rhythmic contractions pinching off the intestine and propelling all intestinal contents ahead of it. The r.s.a. moved caudad clearing the small intestine of digesta and leaving an empty quiescent intestine behind it. It was particularly characteristic in the fasted pig where it was usually associated with the progression of a gas bubble. The pattern of m.m.c.s in both fasted and fed animals along with the intermittent nature of stomach emptying, divided digesta into batches which progressed through the small intestine. Each batch--propelled by a m.m.c.--normally took 180-190 min to pass through the small intestine. M.m.c.s had a cycle length of 70-115 min in different parts of the small intestine. Usually two or three m.m.c.s and batches of intestinal contents were present in the small intestine at any one time. 22-33% of the m.m.c.s faded out in the proximal ileum. Batches of digesta propelled by these m.m.c.s had transit times increased by one m.m.c. duration and fused with the subsequent batch. Sometimes new m.m.c.s were generated in the terminal ileum. Two patterns of transport into the large intestine were seen. Usually digesta was transported by peristaltic rushes starting 100-200 cm from the ileo-caecal junction. The rush then continued through 1-1 1/2 turns of the spiral colon; occasionally the terminal ileum emptied by slow peristalsis. In this case there was no colonic rush and digesta went into the caecum.

Action Potentials↗

PubMed1984

Use of electromyography to study leg muscle activity in patients with arthritis and in normal subjects during rising from a chair.

A previous study indicated the need for patients with arthritis to have an armchair from which it is easy to rise. To determine criteria for such a chair a greater understanding of the rising activity and the objective assessment of chair design is required. The major muscle groups of the leg were monitored by electromyography (EMG) in normal subjects and for patients with arthritis during rising from a chair. The effects on EMG patterns of changes of seat height, foot position, and the use of armrests were studied. This paper outlines the practical difficulties that must be borne in mind when designing an EMG study on arthritic and elderly subjects. The results did not illustrate any differences in the pattern of muscle activity between arthritic and normal subjects, nor did they show any differences caused by changing the variables of chair design.

Arthritis↗

PubMed2006

Effect of lower limb massage on electromyography and force production of the knee extensors.

OBJECTIVE: To evaluate the effect of massage on force production and neuromuscular recruitment. METHODS: Ten healthy male subjects performed isokinetic concentric contractions on the knee extensors at speeds of 60, 120, 180, and 240 degrees /s. These contractions were performed before and after a 30 minute intervention of either rest in the supine position or lower limb massage. Electromyography (EMG) and force data were captured during the contractions. RESULTS: The change in isokinetic mean force due to the intervention showed a significant decrease (p<0.05) at 60 degrees /s and a trend for a decrease (p = 0.08) at 120 degrees /s as a result of massage compared with passive rest. However, there were no corresponding differences in any of the EMG data. A reduction in force production was shown at 60 degrees /s with no corresponding alteration in neuromuscular activity. CONCLUSIONS: The results suggests that motor unit recruitment and muscle fibre conduction velocity are not responsible for the observed reductions in force. Although experimental confirmation is necessary, a possible explanation is that massage induced force loss by influencing "muscle architecture". However, it is possible that the differences were only found at 60 degrees /s because it was the first contraction after massage. Therefore muscle tension and architecture after massage and the duration of any massage effect need to be examined.

Adult↗

PubMed1999

Analysis of the aerobic-anaerobic transition in elite cyclists during incremental exercise with the use of electromyography.

OBJECTIVES: To investigate the validity and reliability of surface electromyography (EMG) as a new non-invasive determinant of the metabolic response to incremental exercise in elite cyclists. The relation between EMG activity and other more conventional methods for analysing the aerobic-anaerobic transition such as blood lactate measurements (lactate threshold (LT) and onset of blood lactate accumulation (OBLA)) and ventilatory parameters (ventilatory thresholds 1 and 2 (VT1 and VT2)) was studied. METHODS: Twenty eight elite road cyclists (age 24 (4) years; VO2MAX 69.9 (6.4) ml/kg/min; values mean (SD)) were selected as subjects. Each of them performed a ramp protocol (starting at 0 W, with increases of 5 W every 12 seconds) on a cycle ergometer (validity study). In addition, 15 of them performed the same test twice (reliability study). During the tests, data on gas exchange and blood lactate levels were collected to determine VT1, VT2, LT, and OBLA. The root mean squares of EMG signals (rms-EMG) were recorded from both the vastus lateralis and the rectus femoris at each intensity using surface electrodes. RESULTS: A two threshold response was detected in the rms-EMG recordings from both muscles in 90% of subjects, with two breakpoints, EMGT1 and EMGT2, at around 60-70% and 80-90% of VO2MAX respectively. The results of the reliability study showed no significant differences (p > 0.05) between mean values of EMGT1 and EMGT2 obtained in both tests. Furthermore, no significant differences (p > 0.05) existed between mean values of EMGT1, in the vastus lateralis and rectus femoris, and VT1 and LT (62.8 (14.5) and 69.0 (6.2) and 64.6 (6.4) and 68.7 (8.2)% of VO2MAX respectively), or between mean values of EMGT2, in the vastus lateralis and rectus femoris, and VT2 and OBLA (86.9 (9.0) and 88.0 (6.2) and 84.6 (6.5) and 87.7 (6.4)% of VO2MAX respectively). CONCLUSION: rms-EMG may be a useful complementary non-invasive method for analysing the aerobic-anaerobic transition (ventilatory and lactate thresholds) in elite cyclists.

Adult↗

PubMed2005

When is Onuf's nucleus involved in multiple system atrophy? A sphincter electromyography study.

BACKGROUND: External anal sphincter (EAS) electromyography (EMG) abnormalities can distinguish multiple system atrophy (MSA) from Parkinson's disease in the first five years after disease onset. However, the prevalence of the abnormalities in the early stages of MSA is unknown. OBJECTIVES: To present EAS-EMG data in the various stages of MSA. METHODS: 84 patients with "probable" MSA were recruited (42 men, 42 women; mean age 62 years (range 47 to 78); mean disease duration 3.2 years (0.5 to 8.0; <1 year in 25%); 50 cerebellar form (MSA-C), 34 parkinsonian form (MSA-P)). EAS motor unit potential (MUP) analysis and EMG cystometry were carried out in all patients. RESULTS: The overall prevalence of neurogenic change of the EAS MUP was 62%-52% in the first year after disease onset, increasing to 83% by the fifth year (p<0.05); it also increased with severity of gait disturbance (p<0.05), storage and voiding disorders, and detrusor sphincter dyssynergy (NS). The neurogenic change was not correlated with sex, age, MSA-P/C, postural hypotension, constipation, erectile dysfunction in men, underactive or acontractile detrusor, or detrusor overactivity. In 17 incontinent patients without detrusor overactivity or low compliance, urinary incontinence was more severe in those with neurogenic change than in those without (p<0.05). CONCLUSIONS: Involvement of Onuf's nucleus in MSA is time dependent. Before the fifth year of illness, the prevalence of neurogenic change does not seem to be high, so a negative result cannot exclude the diagnosis of MSA.

Aged↗

PubMed1970

Observations on muscle pain in man, with particular reference to pain during needle electromyography.

Muscle pain receptors have been studied in man. During the advance of an EMG needle pain is most regularly experienced as the muscle fascia is pierced. Further advancing the needle is usually quite painless. However, there are scantily distributed points within the muscle (`pain spots') which may give rise to pain if encountered by the advancing needle. The nature of the responsible receptors is obscure but it is likely that pain may sometimes be caused by activation of nerve fibres (presumably from these receptors) coursing through the muscle rather than by activation of the receptors themselves. Intramuscular bleeding is unlikely to contribute often to the pain of needle electromyography. Mechanically sensitive `pain spots' are more painful than other areas when stimulated electrically or injected with hypertonic (6%) saline. This suggests a common receptor. The high electrical threshold and relative invulnerability to pressure of afferent fibres from these receptors suggest that they are mainly of small diameter. These findings are discussed in relation to experimental work on pressure-pain receptors in animals.

Electric Stimulation↗

PubMed1976

Electromyography in nutritional osteomalacic myopathy.

Electromyographic studies in 15 women with nutritional osteomalacia and proximal muscle weakness showed brief duration motor unit action potentials of normal amplitude and increased proportion of polyphasic motor unit potentials in the majority of them. By employing quantitative methods of electromyography, more positive results were obtained, thus reducing the sampling data. The histology showed non-specific muscle fibre atrophy without degenerative changes and the clinical and electromyographic examinations together showed clear evidence of a myopathy, suggesting a reversible transient block of the muscle fibres. Contrary to a recent suggestion, the nature of muscular change in osteomalacia remains the same regardless of its cause being nutritional or otherwise.

Action Potentials↗