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PubMed1984

A comparison of concentric needle electromyography, quantitative EMG and single fibre EMG in the diagnosis of neuromuscular diseases.

Conventional concentric needle electromyography, quantitative electromyography using automatic analysis (Quant-EMG) and single fibre electromyography (SFEMG) were compared in the right biceps muscle of 10 patients with anterior horn cell disease and 20 patients with primary muscle disease. Abnormalities were demonstrable by all 3 techniques in the majority of cases irrespective of whether the biceps was weak. SFEMG was found to be more sensitive than Quant-EMG in neurogenic cases and it also provided an indication of disease activity. In cases of myopathy Quant-EMG was of more diagnostic help and was easier to perform than SFEMG. Large amplitude potentials found in some cases of myopathy were associated with increase in the mean amplitude on Quant-EMG and these probably emanate from hypertrophied muscle fibres.

Adult↗
PubMed1978

Rest vertical dimension determined by electromyography with biofeedback as compared to conventional methods.

This study was undertaken to determine if electromyography with biofeedback can be utilized to produce a more reliable determination of rest vertical dimension than conventional methods such as phonetics and swallowing. It was found that: 1. Electromyography with biofeedback appeared to produce a more consistently reliable determination of rest vertical dimension than conventional methods when used with edentulous subjects. 2. Determinations of rest vertical dimension by individual dentists using phonetics and swallowing had wide variations in two of the five patients in a range of up to 6 mm. An error of this magnitude could easily cause an intrusion upon the interocclusal distance and resultant failure of treatment. Since this study was limited to five patients, a more expanded study is necessary to determine the validity of electromyography vs. conventional methods for determining rest vertical dimension. Both methods have questionable aspects in relation to the time of day, patient's understanding of each technique, and past dental history. However, the most critical problem of the electromyographic technique is the feasibility of its use in a private practice in light of the excessive cost of the required equipment.

Biofeedback, Psychology↗
PubMed2005

Assessment of skeletal muscle fatigue in men with coronary artery disease using surface electromyography during isometric contraction of quadriceps muscles.

OBJECTIVE: To evaluate whether using surface electromyography to assess skeletal muscle fatigue during an isometric exercise has the potential to be clinically useful in patients with coronary artery disease (CAD). DESIGN: Double sample comparative study. SETTING: Cardiac rehabilitation service in France. PARTICIPANTS: Sixteen men with documented CAD and 9 age-matched healthy men. INTERVENTIONS: Assessment of quadriceps skeletal muscle fatigue on an isokinetic apparatus with surface electromyography measurements and a symptom-limited exercise test in a laboratory. MAIN OUTCOME MEASURES: The maximal voluntary isometric force (MVIF) of the quadriceps was quantified as a measure of muscle strength and isometric endurance was defined as the time required to sustain a contraction at 50% of MVIF until exhaustion. Surface electromyography signals were recorded from the vastus lateralis, rectus femoris, and vastus medialis during isometric endurance. The root mean square (RMS) and the median frequency (MF) were directly calculated on a computer and then normalized (as a percentage of the initial value). RESULTS: Muscle strength did not differ significantly between the patients with CAD and the healthy subjects (229+/-21N/m vs 228+/-52N/m), but isometric endurance was reduced (64+/-17s vs 90+/-7s, P <.01). The RMS values showed a significantly higher increase in the healthy subjects versus the patients with CAD for the vastus lateralis and vastus medialis ( P <.001). The MF values were significantly lower for the vastus lateralis, rectus femoris ( P <.01), and vastus medialis ( P <.05) in patients with CAD compared with the healthy subjects. CONCLUSIONS: Skeletal muscle fatigue occurs sooner in men with CAD relative to matched healthy men, despite similar muscle strength. This finding may be the result of an abnormality of skeletal muscle function and may play an important role in measuring functional capacity. In addition, it may be a useful tool to assess the efficacy of cardiac rehabilitation interventions.

Coronary Artery Disease↗
PubMed1983

Neurogenic detrusor areflexia: correlation of perineal electromyography and bethanechol chloride supersensitivity testing.

We investigated 63 patients with detrusor areflexia by cystometrography, perineal floor electromyography and bethanechol chloride supersensitivity testing. Of the patients 48 had unequivocal evidence of neuropathy, while 15 were neurologically normal and served as controls. The bethanechol chloride supersensitivity test was positive in 98 per cent of the patients and none of the controls, whereas neuropathic changes by electromyography were found in 67 per cent of the patients and 7 per cent of the controls. These findings suggest that the bethanechol chloride supersensitivity test is more sensitive and more specific than perineal floor electromyography in corroborating bladder neuropathy.

Adult↗
PubMed1981

Flow evaluation and simultaneous external sphincter electromyography in clinical urodynamics.

More than 200 patients have undergone combined uroflowmetry and external sphincter electromyography studies in our urodynamic laboratories. Pediatric surface electrocardiographic electrodes placed on the perianal skin were used to monitor skeletal muscle electromyographic activity while the patient voided into a standard load-cell type of uroflowmeter. The findings indicate clearly that 1) flow electromyography is reliable and easy to perform, 2) striated muscle electromyographic activity is reduced during normal voiding, 3) external sphincter dyssynergia is rare in patients without true neurologic disease and 4) many patients, especially women, void by straining, which causes an increase in external sphincter electromyographic activity but, generally, does not impair voiding. Results of this study suggest that sphincter dyssynergia has been overdiagnosed. With the use of the flow electromyography study the behavior of the external striated muscle sphincter during voiding can be demonstrated easily and reliably in most clinical urodynamic evaluations.

Adolescent↗
PubMed2000

Laryngeal electromyography: diagnostic and prognostic applications.

Laryngeal electromyography is a crucial diagnostic test in laryngology. Laryngeal electromyography is important for the diagnosis of vocal fold paresis and cricoarytenoid joint pathology (e.g., arytenoid dislocation). In addition, laryngeal electromyography offers prognostic information regarding potential vocal fold paralysis recovery, which can improve the management strategies for vocal fold paralysis.

Deglutition Disorders↗
PubMedDate not supplied

Effects of tarsal coalition resection on dynamic plantar pressures and electromyography of lower extremity muscles.

The goal of this study was to evaluate kinetic abnormalities in feet after tarsal coalition resection using plantar pressure measurements and electromyography of 4 muscle groups in the lower limb. Eleven subjects (14 feet) with tarsal coalition (3 feet with calcaneocuboid, 6 feet with calcaneonavicular, and 5 feet with talocalcaneal) underwent coalition excision. Patients ranged in age from 9 to 17 years, and mean follow-up was 20 months. Two feet underwent subsequent subtalar fusion and 1 had a triple arthrodesis. Plantar pressure and electromyography measurements were compared with data taken from 68 normal (control) subjects between the ages of 6 to 16 years. Feet with tarsal coalition showed significant differences in the midfoot region, with increases in contact area (40.36 cm2 +/- 14.7 vs 18.02 cm2 +/- 8.0, P < .001), loading (5.63 N/cm2 sec +/- 3.4 vs 1.83 N/cm2 sec +/- 0.9, P < .001) and peak pressure (13.38 N/cm2 +/- 5.8, 6.81 N/cm2 +/- 2.8, P = .01). Tarsal coalition feet also displayed reduced peak pressure and loading at the region of the fifth metatarsal head as compared with uninvolved feet (P < .05). Electromyography measurements were also performed on both the affected and unaffected feet of 9 subjects who had undergone resection of their coalition. These measurements revealed nearly consistent abnormal activity in the peroneal, gastrocnemius, and soleus muscles on both the surgically operated foot and the contralateral side, including either prolonged monophasic activity or biphasic activity. These findings suggest that although resection of coalition may have relieved symptoms of discomfort, it did not restore normal foot alignment or muscular balance.

Adolescent↗
PubMed2002

Motor dysfunction of the upper digestive tract in Pierre Robin sequence as assessed by sucking-swallowing electromyography and esophageal manometry.

OBJECTIVES: To evaluate motor dysfunction in infants with Pierre Robin sequence (PRS) who manifest upper airway obstruction and congenital dysphagia. STUDY DESIGN: Term infants (n = 28) with nonsyndromic PRS were studied between days 15 and 45. Sucking-swallowing electromyography was used to evaluate suction and coordination between the oral and pharyngeal phases of swallowing. Esophageal manometry was used to study the lower esophageal sphincter, esophageal body, and upper esophageal sphincter functions. Manometry results were compared with those of 16 infants with gastroesophageal reflux disease (GERD). RESULTS: Electromyography showed incoordination of sucking and swallowing in 24 of 28 patients. The disorder was mild in 6, moderate in 6, and severe in 12 patients. All patients showed manometry disturbances: incomplete or asynchronous lower sphincter relaxation (15), multipeaked esophageal body waves (17), very high amplitude waves (14), and asynchronous upper sphincter relaxation (19). The frequency of disturbances and mean resting pressures of both lower and upper sphincters were significantly higher than GERD patients. CONCLUSION: In Pierre Robin sequence, sucking-swallowing electromyography and esophageal manometry reveal dysfunction in the motor organization of the tongue, the pharynx, and the esophagus.

Electromyography↗
PubMed1993

Electromyography: some methodological problems and issues.

The purpose of this review is to discuss electromyography (EMG) and some of the problems and issues that are encountered during the recording and interpretation of EMG data. Recordings of electrical activity of muscles can be contaminated by interference from the electrical supply, mechanical artifacts, stimulus artifacts, and activity of other muscles. The advantages and disadvantages of surface electromyography and intramuscular EMG are compared and contrasted, and precautions to be taken when recording and interpreting these data are described. Surface electromyography is usually more susceptible to artifacts than is intramuscular EMG. It is possible, however, to make useful recordings with the surface electrodes from large superficial muscles if appropriate precautions are observed. Intramuscular electrodes, on the other hand, may be preferred for recording the activity from small peripheral muscles or muscles located deep within the body.

Artifacts↗
PubMedDate not supplied

Paraspinal electromyography in high lumbar and thoracic lesions.

OBJECTIVE: To use needle electromyography in the paraspinal muscles to localize the root level of a radiculopathy. DESIGN: We collected nine cases of clinically proven, isolated high lumbar or thoracic disk herniations of patients who underwent MiniPM. Four were from a prospective study of 114 persons with low back pain (MiniPM had 100% sensitivity to magnetic resonance imaging-documented high disks). RESULTS: In the most medial "S" column, mean MiniPM scores were 0.7 for the level above the radiologically documented lesion; 3.1 at the lesion; and 1.6, 1.6, and 1.1 at the three spinous processes below the lesion. Similar numbers were obtained in the "M" column (slightly lateral), with no significant differences between S and M. Differences were significant between and at the level of the lesion for S (P < 0.06) and M (P < 0.01), and between the lesion level and three levels below for the M column (P < 0.01). CONCLUSIONS: These findings suggest that paraspinal electromyography has a higher than previously reported sensitivity for high lumbar lesions. Electromyography using MiniPM can localize some radiculopathies. The individual cases suggest that, consistent with the anatomy of the caudi equina, thoracic lesions and lateral lumbar lesions denervate only at one level, but more central lumbar lesions also denervate distally innervated paraspinal muscles.

Adult↗
PubMed2002

Laryngeal electromyography in the management of vocal cord mobility problems in children.

OBJECTIVES: To evaluate the efficacy and clinical usefulness of laryngeal electromyography (EMG) in the evaluation and management of vocal cord mobility problems in children; and to determine the ability of laryngeal EMG to differentiate vocal fold fixation versus paralysis. STUDY DESIGN: Case-series review of 8 children with vocal cord immobility who underwent laryngeal EMG. METHODS: Eight children with bilateral vocal fold immobility underwent microlaryngoscopy and electromyography. Bipolar concentric needle electrodes were used and implanted separately into both posterior cricoarytenoid (PCA) and both thyroarytenoid (TA) muscles. EMG activity was recorded during spontaneous ventilation under a light plane of anesthesia with propofol. EMG activity was correlated with the phases of the respiratory cycle. RESULTS: Three patients had evidence of normal EMG activity with PCA activity peaking during early inspiration. Maximal TA activity occurred expiration. These patients were assumed to have vocal fold fixation. Two of these 3 patients underwent laryngotracheoplasty (LTP) with posterior glottic expansion with costal cartilage. One is being considered for LTP in the future. Five patients had abnormal EMG activity and remain tracheotomy-dependent. Four patients exhibited synkinetic activity with peak PCA activity during expiration and peak TA activity during expiration. Two patients had both fixation and unilateral vocal cord paralysis. One was successfully decannulated after posterior graft LTP and the other is planned for the future. CONCLUSIONS: Electromyography, which differentiates paralysis from fixation, is a useful diagnostic tool in the evaluation of children with vocal cord immobility.

Child, Preschool↗
PubMed1995

Evaluation of intrapedicular screw position using intraoperative evoked electromyography.

STUDY DESIGN: This study analyzed the parameters needed for electrical stimulation of vertebral pedicle drill bits and screws. OBJECTIVES: The feasibility of using electrically evoked electromyography was studied. SUMMARY OF BACKGROUND DATA: Considerable potential for damage of adjacent nerve roots with incorrectly placed bits and screws exists with pedicular fixation of the lumbar spine. METHODS: Ninety-five drill bits, one hundred forty-four screws, and thirty-four exposed nerve roots were electrically stimulated in thirty-six patients. Simultaneous evoked electromyographic activity was recorded from four muscle groups in each lower extremity during partial neuromuscular blockade. RESULTS: A constant current threshold of 6 mA or less correlated with misplaced drill bits and screws that broached the cortex. Evoked electromyography was 93% sensitive whereas radiography was only 63% sensitive to detecting bits and screws that had broached the cortex. CONCLUSIONS: Evoked electromyography is a valuable sensitive adjunct to radiographic examination of pedicle drill bit and screw placement.

Adult↗
PubMed2001

Prognostic value of electromyography in acute peripheral facial nerve palsy.

OBJECTIVE: To analyze the value of electromyography in predicting recovery from acute idiopathic facial nerve paralysis. STUDY DESIGN: Retrospective case-series review. SETTING: University-based hospital department of otorhinolaryngology/head neck surgery. PATIENTS: Three hundred fifty-five patients with sudden facial paralysis of unknown cause (Bell's palsy). INTERVENTION: Treatment consisted uniformly of high-dose prednisolone, dextran, and pentoxifylline. Prognostication was based on electromyography performed not earlier than 10 to 14 days after the onset of palsy. The findings were classified according to Seddon into neurapraxia and axonotmesis/ neurotmesis. There is an inherent statement on prognosis in this classification because neurapraxia is presumed to recover completely within 8 to 12 weeks, whereas axonotmesis is most likely to be followed by sequelae. MAIN OUTCOME MEASURES: Facial nerve function after 6 months. RESULTS: Complete recovery was predicted correctly in 92.4% of cases. For the relatively rare and therefore principally more difficult predictable event defective recovery prognosis was still accurate in 80.8%. CONCLUSION: The detection of spontaneous fibrillation in needle electromyography is a reliable sign predicting unfavorable outcome. An accuracy of 80.8% for predicting unfavorable outcome may be sufficient to advise patients what to expect in the course of their facial nerve disorder. However, it seems dubious to build a decision about surgical intervention on such a test, because in the process, unnecessary surgery would be accepted for as much as one fifth of the patient population.

Acute Disease↗
PubMed2002

Video-based system for intraoperative facial nerve monitoring: comparison with electromyography.

OBJECTIVE: To validate a recently developed intraoperative facial nerve monitoring system that is based on video control of facial movements. STUDY DESIGN: In a single-subject design study, involving 15 otoneurosurgical patients, the relationship between intensity of neural stimulation, facial movements, and electrophysiologic voltage were measured. The analysis was performed by measuring the ipsilateral oral commissure displacement in relation to different levels of current administered to the nerve during surgical procedures. SETTING: Electromyography and video system intraoperative facial nerve monitoring. PATIENTS: 15 patients (9 men, 6 women; mean age, 61 yr) undergoing a translabyrinthine approach for removal of acoustic neuroma. RESULTS: Electromyography showed slightly greater sensitivity. With regard to the stimulation-response ratio, facial movement and electromyographic amplitude showed very similar responses. CONCLUSIONS: The video system was considered useful in terms of validity and reliability. Furthermore, the authors' surgical experience showed some limitations of electromyography, especially in terms of electrical artifact during cauterization, totally masking the electrophysiologic monitoring.

Electric Stimulation↗
PubMed2003

Large-array surface electromyography in low back pain: a pilot study.

STUDY DESIGN: A large-array surface electromyography device was used to collect data from healthy pain-free persons and from those with acute or chronic low back pain. Images of regional muscle electromyographic activity were assessed visually, and maximum root mean square values were compared statistically. OBJECTIVE: To determine whether data differs by patient type. SUMMARY OF BACKGROUND DATA: Whereas there is a good understanding of the anatomy and psychosocial aspects of low back pain, there is a need to understand better the physiology of low back pain. METHODS: Large-array surface electromyography data were collected from the low back muscles of 201 participants over a 3-month period using a 63-electrode fixed array and a standardized protocol. Color images representing the voltage root mean square difference of each electrode pair were created. Three images from each of three positions (standing upright, standing in 20 degrees of trunk flexion, standing holding weights) were collected from each participant. Serial studies were performed on the acute population over a 6-week follow-up period. RESULTS: Images of regional muscle activity from 92.7% of normal controls (n = 163) showed symmetrical activity. Patients with acute (n = 13) or chronic (n = 25) low back pain had multifocal and/or asymmetrical patterns. Symmetrical patterns returned in the three patients whose acute pain resolved during the study. Maximum root mean square values were higher among patients with acute (P = 0.03) and chronic (P = 0.04) pain than among control subjects. CONCLUSIONS: Large-array surface electromyography produced data from patients with back pain that differed from data on subjects without back pain. This method may be useful in evaluating patients with low back pain.

Acute Disease↗
PubMed2005

Paraspinal electromyography: age-correlated normative values in asymptomatic subjects.

STUDY DESIGN: Cross-sectional study. OBJECTIVES: To determine if the amount of lumbar paraspinal denervation increases with age and present normative data on the amount of denervation present in asymptomatic subjects. SUMMARY OF BACKGROUND DATA: To our knowledge, there are no data on the relationship of paraspinal denervation with age or normative data on the amount of denervation expected in asymptomatic older adults. METHODS: We combined the data from our current study of asymptomatic adults, age 55-79 years, and a previous study of asymptomatic adults, age 18-58 years, who underwent lumbar paraspinal muscle needle electromyography using a validated needle electromyography (MiniPM) technique. We then compared the results of the age group 55-79 to that of the age group 18-54. RESULTS: The older group scored significantly higher than the younger group by 1.7 (P = 0.008, 95% confidence interval 0.5-3.0). Linear regression showed that age was a significant predictor of the MiniPM score (beta = 0.04, and P = 0.04). For subjects 55 years and older, mean MiniPM score on one side was 2.3 (standard deviation 3.6). The upper range of the 95th percentile was 10. CONCLUSIONS: The amount of lumbar paraspinal muscle denervation does increase with age. Understanding the range of findings in asymptomatic subjects will help us interpret lumbar paraspinal needle electromyography findings in patients with spinal disorders.

Adult↗
PubMed2003

Paraspinal electromyography that compares concentric with monopolar needles: a blinded study.

OBJECTIVE: To establish interrater reliability for paraspinal muscle needle electromyography study with both monopolar and concentric needles in symptomatic and asymptomatic persons and to further establish normative data for paraspinal needle study. DESIGN: At a university spine center, participants with and without radiating low back pain were evaluated with the mini-paraspinal mapping paraspinal needle technique by an unblinded and a blinded electromyographer. RESULTS: In the symptomatic group, the intraclass correlation coefficient between concentric and monopolar needles was 0.793; between monopolar needles, it was 0.876; and between concentric needles, it was 0.966. In the asymptomatic group, the mean total score was 0.25. CONCLUSIONS: The good interrater reliability with the same needle type helps support the validity of the needle electromyography study of the paraspinal muscles. The good correlation between the concentric and monopolar needles shows the data published using monopolar needle data also apply to studies using paraspinal needle electromyography with concentric needles. The low score with the asymptomatic group reaffirms that using a cutoff score of >2 as abnormal has a false-positive rate of <5%.

Adolescent↗
PubMed1995

Differential effects of vecuronium on the thumb and great toe as measured by accelography and electromyography.

We evaluated possible differential effects of vecuronium on the thumb and great toe using two types of neuromuscular transmission monitor. Train-of-four stimuli were simultaneously applied to the ulnar nerve and tibial nerves using cutaneous electrodes. The responses were quantified with accelographs (thumb and left great toe) and an electromyograph (right great toe). Twenty ASA 1 or 2 patients received, by random allocation, one of two types of anaesthesia: neuroleptanaesthesia or sevoflurane-based anaesthesia. With both techniques, the shortest time to maximum block after vecuronium 0.1 mg.kg-1 occurred in the thumb as measured by accelography. The average (SD) values with neuroleptanaesthesia were: 173(23) s for thumb using accelography; 220(16) s for great toe using accelography; 205(44) s for great toe using electromyography. The average (SD) value(s) with sevoflurane-based anaesthesia were: 137(15) for thumb using accelography; 179(21) for great toe using accelography; 153(23) for great toe using electromyography. The differences between the thumb and great toe were statistically significant during both types of anaesthesia when measured with the accelograph (p < 0.01). The time from completion of maximal block to 25% recovery of twitch height in the thumb was significantly longer than that of the great toe as measured by accelography during both types of anaesthesia (p < 0.05). In contrast, there were no statistically significant differences between time to maximum block and 25% recovery of twitch height of the thumb as measured by accelography compared to the values measured for the great toe using electromyography during either anaesthetic technique.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗