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PubMed2005

Evaluation of conventional subciliary incision used in blepharoplasty: preoperative and postoperative videography and electromyography findings.

BACKGROUND: The purpose of this study was to evaluate the innervation and function of the orbicularis oculi area clinically, with video imaging, and electrically, with electromyography, before and after lower-eyelid blepharoplasty using a conventional subciliary incision. METHODS: Nine patients (18 eyes) were studied before and 4 to 12 weeks after lower-eyelid blepharoplasty. Video imaging documented clinical changes in involuntary (blink) and voluntary (squeeze and squint) eyelid function as well as resting lid position and tone. Electromyography was performed using concentric needle electrodes (25 mm in length, 0.03 mm in diameter) placed in the lateral and medial subciliary orbicularis oculi. A total of 36 sites in nine patients (four sites per patient) were studied. Acute denervation was identified by the presence of fasciculation; fibrillation potentials; insertional activity; sharp waves; and grade based on standard electromyography techniques. All patients underwent lower-eyelid blepharoplasty with a subciliary incision, skin-muscle flap and canthal anchoring with canthopexy or cantholysis, and canthoplasty. RESULTS: Video imaging of the lower eyelid before and after blepharoplasty showed evidence of eyelid malposition or abnormal voluntary or involuntary orbicularis oculi muscle function. There was no evidence of acute denervation in 34 of 36 sites (94 percent). Two patients had abnormal fasciculation in the left lateral position on two of 36 sites (6 percent). Thirty-three weeks postoperatively, one patient was retested and a normal electromyography result was obtained. CONCLUSIONS: This study demonstrated that lower-lid malposition or abnormal function after lower-lid blepharoplasty cannot be explained by denervation of the zygomatic branch of the facial nerve. Any acute or residual denervation seen in the subciliary orbicularis is not clinically significant. The importance of lower-lid support and canthal anchoring cannot be emphasized enough in preventing lower-lid malposition. Blepharoplasty is a challenging procedure that requires careful preoperative planning, intraoperative reassessment, and meticulous surgical technique to optimize facial rejuvenation and patient safety.

Adult↗

PubMed1999

Correlation between surface electromyography and kinematics of the hindlimb of horses at trot on a treadmill.

The purpose of this study was to demonstrate the feasibility of surface electromyography in the horse and to correlate electromyographic activity with kinematic data. Surface electromyography of seven hindlimb muscles was recorded in five horses at trot on a treadmill. Simultaneously, kinematic analysis of the hindlimb was performed using a three-dimensional system and a unidirectional accelerometer was attached to the hoof. Electromyographic activities of the gluteus medius, vastus lateralis and two parts of the biceps femoris started in the late part of the swing phase and ended in the late period of the stance phase or the early period of the next swing phase. The semitendinosus showed two bursts of activity. The tensor fasciae latae acted when the previous muscles were inactive. Activity of the extensor digitorum longus was of low level but lasted during most of the step cycle. Correlation between electromyography, kinematics and anatomy helps us to understand the complex role of biarticular muscles: the tensor fasciae latae flexes the hip joint during the swing phase and extends the stifle joint during the stance phase, whereas the semitendinosus extends the hip joint during the stance phase and flexes the stifle joint during the swing phase. Cranial and caudal regions of the biceps femoris were also found to be bifunctional. Surface electromyography correlated with kinematic analysis gives valuable information about the functions and the timing of activity of the hindlimb muscles.

Animals↗

PubMedDate not supplied

[Use of needle electromyography for diagnosis of radiculopathies].

Radiculopathy is sometimes evaluated with needle electromyography as additional examination to radiographic imaging. The purpose of this study was to determine the optimal needle electromyography protocol and the use of needle electromyography in the diagnosis of radiculopathy. The authors analysed English language writings from years 1981-2000. The selected studies reported a wide range of needle EMG abnormalities--from about 30 to 100% of pathological EMGs. That is caused by wide variety of patient populations and various EMG protocols. EMG of leg muscles in radiculopathy can consist of the assessment of the spontaneous activity only or be completed with the assessment of motor unit potential (MUP). The EMG of paraspinal muscles assesses spontaneous activity only. The number of abnormalities in needle EMG grows with the presence of characteristic radiculopathy symptoms, but positive EMG examinations are of importance only in cases where diagnosis is complicated. The rate of pathological results is higher when needle electromyography is used in the muscles of paraspinal region and extremities at the same time. The assessment of the spontaneous activity in extremity muscles alone minimizes the influence of error- causing factors on the EMG result. Nevertheless lack of assessment of motor units potentials makes electromyographic investigation of chronic radiculopathy impossible. Sensitivity and specificity of the method have to be determined before the clinical use of the assessment of MUP in chronic radiculopathy, especially in patients without motor weakness. Needle EMG abnormalities correlate with radiological findings in limited range as would be expected from the occurrence of radiological findings in asymptomatic patients and overlapping innervations of myotomes.

Electromyography↗

PubMed1976

Needle electromyography: its effect on serum creatine phosphokinase activity.

The effect of needle electromyography on serum creatine phosphokinase (CPK) levels has remained unclear despite the diagnostic implications. Serum CPK was serially assayed for changes before and after electromyography (EMG) in two healthy persons and ten persons having low back pain, while they remained at total bed rest. Mean curves showed a peak at 6 hours post-EMG and a return to baseline 48 hours post-EMG. The mean peak value was 1.5 times the baseline. Only one sample exceeded the normal range and it was from a patient with frank positive waves and fibrillation potentials. Correcting for dilution of CPK released, by body weight and for total trauma, by number of needle insertions did not modify the results. The time course and magnitude of elevation of CPK parallel those reported for post exercise changes but are much less than those reported to follow myocardial infarction. In the differential diagnosis of myopathies, care must be taken to ensure that the combination of needle electromyography, exercise, diurnal variation and active denervation does not lead to a "false-positive" elevation of CPK above the normal range. Needle electromyography by itself should not induce a false-positive CPK level in a normal person and no significant changes in CPK levels are likely to occur within two hours after the study.

Adolescent↗

PubMed1989

Evaluation of the use of surface electromyography in the diagnosis, documentation, and treatment of dental patients.

The use of electromyography as an aid in the differential diagnosis and treatment of dental patients is carefully examined in this literature review. Electromyography has been advocated for the establishment of rest and occlusal positions, and for the detection of muscle hyperactivity and hypoactivity, spasm, fatigue, and muscle imbalance. However, these claims were often based on studies that failed to include a control group when comparing various clinical parameters and EMG activity of the muscles of mastication. When a control group was incorporated, the authors usually failed to match the patients by such variables as age, sex, facial morphology, and history of bruxism. These variables have a significant influence on the level of EMG activity and may account for the high degree of variability observed between groups. Controlled trials evaluating the efficacy of biofeedback using electromyography found significant reductions of diurnal parafunctional activity during treatment, but the low symptom levels were not maintained after cessation of biofeedback. Based upon this extensive literature review, there is no convincing evidence to support the use of electromyography in the diagnosis or treatment of dental patients except in the treatment of parafunction.

Biofeedback, Psychology↗

PubMedDate not supplied

[Comparison of clinical examination, electromyography, myelography, computerized tomography and surgical findings in lumbar disc hernias].

The authors report 152 cases of patients with suspected herniated lumbar disk, operated on by traditional surgical approach. Thirteen of 152 patients underwent exploratory surgery at two vertebral spaces as a result of their neuroradiological examinations. All patients were examined clinically before of instrumental devices. CT-scan was performed on 113 patients, 62 underwent myelography and 36 electromyography. The authors verified reliability of clinical and instrumental devices on the basis of surgical results. Clinical examination was reliable in 83% of cases, electromyography in 78%, myelography in 83% and CT-scan in 87%. The percentage of false positive was 11% for the clinical examination, 9% for CT-scan, 8% for myelography and 11% for electromyography. The percentage of false negative was 6% for the clinical examination, 4% for CT-scan, 9% for myelography, and 11% for electromyography. The authors conclude that the CT-scan is the most reliable method of examination. This is even truer when dealing with extreme lateral disk herniation.

Adolescent↗

PubMed1983

[Electromyography of the larynx].

This paper reports on our experience with electromyography of the larynx in pareses of the recurrent nerve of different causes. Clinical case histories are used to demonstrate the differentiated evaluation of the condition of the damaged recurrent nerve which is possible with the use of electromyography, including reflex electromyography, of the larynx. Knowledge of the type and extent of the lesion of the recurrent nerve only allows limited conclusions to be made about the prognosis of the paresis. For the assessment of the prognosis it is necessary to consider not only the basic disease, but also the actual time at which the electromyography was performed.

Adult↗

PubMed1983

Acute Bell's palsy: prognostic value of evoked electromyography, maximal stimulation, and other electrical tests.

Thirty-seven patients with acute Bell's palsy who had complete unilateral facial paralysis were selected for this study. Evoked electromyography, conduction latency, electromyography, and nerve excitability testing was done by one author while the maximal stimulation test was done by another on each patient. The patients were examined within ten days of onset of facial paralysis and evaluated six months after onset to determine the degree of recovery of facial motor function. The results of the tests were correlated with the degree of recovery of facial motor function in each patient. Evoked electromyography and maximal stimulation tests were the most accurate electrical tests for predicting the course of acute facial paralysis when they were performed serially within the first ten days after onset. When the results of the maximal stimulation test were equal on the involved and uninvolved sides of the face, there was a 92 percent chance of complete recovery of facial function on the involved side. In those patients in whom the response to the maximal stimulation test was markedly reduced or absent, there was an 86 percent chance of incomplete recovery of facial function. When the response to evoked electromyography on the involved side was 30 percent or greater of that on the normal side, 84 percent of the patients had complete recovery of facial function; however, when the response was 25 percent or less of normal, there was an 88 percent chance of incomplete recovery. The results of evoked EMG and the maximal stimulation test agreed in 89 percent of cases in predicting the ultimate outcome of facial paralysis.

Electric Stimulation↗

PubMed1995

Paraspinal mapping. Quantified needle electromyography of the paraspinal muscles in persons without low back pain.

STUDY DESIGN: This was a case series with intervention performed by masked investigators. OBJECTIVES: To determine values for normal subjects on quantified needle electromyography of the paraspinal muscles compared with a previous sample of patients with clear evidence of radiculopathy. SUMMARY OF BACKGROUND DATA: Diagnosis of radicular back pain is difficult, even with modern imaging studies, partly due to the large percentage of imaging abnormalities in asymptomatic persons. Electromyography has been shown to be as sensitive as imaging studies in diagnosing radicular pain. An electromyographic study of the low back has never been done in normal subjects. We have previously anatomically validated and clinically demonstrated a method of quantitative needle electromyography in the paraspinal muscles called paraspinal mapping. METHODS: Thirty-five subjects free of back pain or polyneuropathy were intermixed with volunteers referred for electromyography of radicular back pain. One electrodiagnostician punctured the skin at five predetermined locations and obtained paraspinal mapping scores in one of these. An electromyographer who was masked to the study's nature then performed a complete paraspinal mapping study. A total "sensitivity" score was compared to scores of previously tested patients who had pain complaints and clear evidence for radiculopathy on either radiologic or traditional electromyographic studies. RESULTS: Mean score in normal subjects was 1.11 (SD 1.49). Mean score for abnormal subjects averaged 12.18 (SD 12.03). Differences between examiners were insignificant. CONCLUSIONS: Normal persons have few, if any electromyographic abnormalities in the paraspinal muscles. This is in contrast to computed tomography, magnetic resonance imaging, or myelographic results in normal subjects. Persons with radiculopathy have significantly different scores. Needle electromyographic examination of the paraspinal muscles is useful in distinguishing false-positive radiologic studies.

Adolescent↗

PubMed1997

Use of electromyography in seven injured wild birds.

Seven wild birds with traumatic injuries affecting the peripheral nervous system were evaluated with the aid of electromyography. Initially, electromyography was performed on these birds because of loss of motor control and muscle atrophy that could not be explained by clinical signs alone. It can be difficult to assess postural reactions and reflexes in these birds. Use of electromyography to provide prognostic information for rehabilitation potential had not been reported. Reviews in the literature indicate that electromyography in human beings helps when assessing prognosis in sports-related injuries. Because wild birds require nearly total function for complete rehabilitation, electromyographic findings of functional motor units or evidence of axonal degeneration can assist in determining their potential for release.

Animals↗

PubMed2002

What do we learn from motor unit action potentials in surface electromyography?

This article gives an overview of what multichannel surface electromyography can teach us about a motor unit. Background information is given about the generation of surface electromyography in general and surface motor unit potentials in particular. Furthermore, we describe how surface motor unit potentials are related to several motor unit characteristics, such as size, location, neuromuscular junction position, fiber length, fiber type, and metabolic fiber properties. In addition, we show how the spatial characteristics of multichannel surface electromyography can be used to obtain single-surface motor unit potentials. The possibilities, challenges, and problems are discussed. Finally, several examples of surface motor unit potential analyses are given.

Action Potentials↗

PubMed1984

Single fiber electromyography in the differential diagnosis of myopathic limb girdle syndromes and chronic spinal muscular atrophy.

Single fiber electromyography ( SFEMG ) of the extensor digitorum communis muscle was performed on 20 patients with either myopathic limb girdle syndromes ( LGS ) or chronic spinal muscular atrophy ( CSMA ) to assess its value in the differential diagnosis of these disorders. Neurologic examinations (muscle biopsies, standard electromyography, or both) were reviewed in 16 patients and resulted in diagnosing LGS in 11 patients and CSMA in 5 patients. In four patients, discordance between EMG and biopsy, or mixed features of myopathy and neuropathy in either test, resulted in an indeterminate diagnosis. Two groups were discerned from SFEMG , one with higher fiber density, jitter, and percentage of abnormal pairs consistent with neuropathy and another with lower values consistent with myopathy. In all 16 patients, SFEMG confirmed the initial diagnosis, and in the four patients with indeterminate diagnoses, SFEMG suggested diagnoses of LGS in two patients and CSMA in two patients. Single fiber electromyography may be a useful diagnostic aid in the differential diagnosis of myopathic LGS and CSMA .

Adolescent↗

PubMed1988

AAEE minimonograph #29: automatic quantitative electromyography.

The present status of different computerized methods of automatic quantitative electromyography are reviewed. Interference pattern methods-turns analysis, spectral analysis-are efficient, but the results usually cannot be directly related to the physiological properties of the motor units. Integration analysis does not currently have a major role in diagnostic electromyography. Traditional measurement of single motor unit action potentials during weak contraction can be facilitated and made more objective with computer assistance, but only the lowest-threshold motor units in the muscle are amenable to study. A new class of methodologies under development permit the decomposition of interference patterns into their constituent motor unit action potentials for measurement of configurational and behavioral properties. Patient data from these various methods can be statistically compared with normative data bases available on-line in computerized electromyographs. Both quantitative and quantitative electromyography have applications in the neuromuscular electrodiagnostic examination.

Electromyography↗

PubMed1990

A comparison of thermography and electromyography in the diagnosis of cervical radiculopathy.

We studied 20 asymptomatic control subjects and 14 patients with clinically unequivocal cervical radiculopathy to compare the diagnostic value of thermography with that of electromyography. We measured the average skin temperature of designated regions over the neck, shoulder, and upper extremities. We then compared the temperature between corresponding regions of the two limbs, and between fingers innervated by different roots in the same hand. Thermography was abnormal in 6 patients (43%), whereas electromyography was abnormal in 10 (71%). Thermographic abnormalities were seen only in the hands and fingers, and the pattern did not follow the dermatome of the clinically involved cervical root. When compared to electromyography, thermography provided no additional diagnostic information. Thus, thermography does not have an established role in the evaluation of patients with cervical radiculopathy.

Arm↗

PubMed1993

Needle electromyography of the diaphragm: a new technique.

Electrodiagnostic evaluation of diaphragmatic function has consisted of phrenic nerve stimulation and surface or esophageal recordings of the electrical activity of the diaphragm. Needle electromyography of the diaphragm has rarely been reported because of the perceived danger of this procedure. We describe a new technique for needle electromyography of the diaphragm. An EMG electrode is placed in the costal insertion of the diaphragm under the 8th, 9th, or 10th rib cartilage, distant from the major vessels, pleura, lungs, and abdominal viscera. Diaphragmatic denervation was found in 42 of 81 patients using this method. There were no complications related to the procedure. Needle electromyography of the diaphragm provides important information in the diagnosis and management of respiratory dysfunction.

Adult↗

PubMed1989

Laryngeal electromyography.

Over the last 40 years sporadic reports have appeared in the otolaryngological and neurological literature describing techniques and applications of laryngeal electromyography. Despite considerable refinements in methodology and instrumentation over that time laryngeal electromyography has not been widely adopted in routine clinical practice. This paper describes a simple, reliable and reproducible technique which has been employed by the author over a 15-year period. The indications for laryngeal electromyography are reviewed and the technique currently used is briefly described with reference to alternative techniques. The usefulness of the information obtained by this examination is discussed.

Electromyography↗

PubMed1991

Is paradoxical sphincter reaction provoked by needle electrode electromyography?

In 10 patients with emptying disturbances, the anal sphincter reaction was investigated clinically and by electromyography with needle and wire electrodes to elucidate whether pain during the investigation could provoke the paradoxical sphincter reaction. In eight of the patients, the paradoxical reaction was easily felt at digital examination. Two patients complained of pain during the needle electrode recording; none complained during the wire electrode investigation. Nevertheless, all 10 patients had paradoxical sphincter reaction independent of the electrode used at electromyography. With careful clinical investigation, most cases of paradoxical sphincter reaction can be diagnosed. When this is inconclusive, the diagnosis should be confirmed by electromyography, preferably by the wire technique.

Adult↗

PubMed2005

Single-fiber electromyography correlates more closely with incontinence scores than pudendal nerve terminal motor latency.

BACKGROUND: The investigation of fecal incontinence is important in deciding the most appropriate treatment. The presence of neuropathy has been shown to affect surgical outcomes adversely. Latency studies are of dubious value in assessing neuropathy; needle electromyography is the gold standard test. The relationship between these two tests and the symptoms of fecal incontinence has not been studied. METHOD: A cohort of 57 patients underwent neurologic and symptom assessment using latency studies, concentric and single-fiber electromyography, and symptom assessment using the Cleveland Clinic Scoring System. RESULTS: There was a significant correlation between left mean fiber density and Cleveland Clinic Scoring (correlation: 0.32, P = 0.02) but not between right or left latency studies. CONCLUSION: Single-fiber electromyography gave relevant results that could be obtained easily on modern equipment. Latency values were not reliable.

Adult↗