[Electromyography and craniomandibular disorders].
Electromyography is a useful tool in the screening of craniomandibular disorders and in the evaluation of the treatment.
Electromyography↗
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.
Electromyography.
Electromyography is a useful extension of the neurological examination. This article reviews the range of methods available to the electromyographer and the types of abnormalities that can be detected.
Acquired Immunodeficiency Syndrome↗
[Anatomy and physiology of the muscles and median frenum of the upper lip. Initial results of selective electromyography].
Usually when reference is made to the Orbicularis oris muscle of the upper lip only the horizontal bands of muscle are mentioned. This muscle also comprises oblique fibres (Orbicularis externus) that are of very great importance in lip movements. The balance of the lip derives from the activity of the two types of muscle fibers. The lip can thus perform, at the same time, a movement of compression of the underlying structures and projection movements whereby these structures are freed. These different modes of action are well demonstrated by selective electromyography. There is also, in the middle of the upper lip, a medial cellulo-fibrous septum forming a prolongation of the septum and penetrating into the median interincisive suture and ending at the frenulum of the upper lip. This medial septum seems to play a very important physiological role in the growth of the premaxilla.
Electromyography↗
Intramuscular pressure and electromyography in the supraspinatus muscle at shoulder abduction.
In ergonomic and biomechanic research, estimations of shoulder muscle load and evaluation of different measuring techniques are important. Intramuscular pressure (IMP), using the microcapillary infusion technique and bipolar intramuscular electromyography (EMG), was recorded from the same part of the supraspinatus muscle. In 12 subjects, IMP and EMG were recorded at shoulder abduction angles of 0 degrees, 30 degrees, 60 degrees, 90 degrees, and 135 degrees with no or a 1- or 2-kg hand load in each position. The shoulder torque was calculated for each test position. A correlation was found for both mean IMP and mean EMG versus shoulder torque if the position with extreme muscle shortening (135 degrees abduction) was excluded. IMP was high (greater than 50 mmHg) in almost all test situations. In seven other subjects, isometric force in abduction was correlated with IMP and EMG. Both methods showed an equally good correlation with external shoulder force, IMP gives as good an estimation of relative muscle force as EMG, but any comparison between EMG and IMP must be done at the same muscle length.
Adult↗
[Electromyography and spinal evoked potentials in cauda equina syndrome of dogs].
In order to investigate usefulness of electrodiagnostic methods in Cauda Equina-Compression, 26 dogs with this disease were subjected to electromyography and spinal evoked potentials. 16 normal dogs served as controls. It was found that--after stimulation of the Nn.tibialis, peronaeus, pudendus and coccygeales and recording at the lumbosacral junction--latencies and nerve-conduction velocities were largely normal. However the amplitudes were decreased and--depending on the severity of the compression--the morphology of the potentials was altered although considerable standard deviations were obtained. Electromyographically, increased spontaneous activity with fibrillations and positive sharp waves were found in the myotomes of the lumbosacral nerves. Their number increased according to the severity of the cauda equina compression and they had a centrifugal distribution pattern. Based on these results it appears indicated to perform an electromyographic exam before applying myelography. The technique of spinal evoked potentials will need more refinement and standardisation before being useful in a clinical situation.
Animals↗
Electromyography of the pharyngeal musculature: technical considerations.
Thirty-one EMG studies of the pharyngeal musculature using three types of electrodes were performed. Electrode characteristics are compared according to criteria developed specifically for the pharynx; techniques for electrode positioning are described in detail; and technical difficulties encountered in performing these studies are discussed. Needle electrodes were best for analyzing individual potentials. For analyzing the timing of myoelectric activity, we preferred the hooked wire electrode (for palatopharyngeus or cricopharyngeus) or bipolar suction electrode (for pharyngeal constrictors). Pharyngeal electromyography is technically feasible and has a role in studying normal and pathologic processes.
Deglutition↗
"Bony sciatica"--the value of thermography, electromyography, and water-soluble myelography.
With an increased interest in sporting activity, particularly among the older population, together with the appreciation of the importance of "bony entrapment" as a cause of sciatica, so the need has arisen to develop a simple, noninvasive, reliable, and reproducible method of determining whether leg pain is of radicular or referred origin. In our experience, liquid crystal thermography has proved unsatisfactory but electromyography appears to be of value in distinguishing root from referred pain in approximately 70 per cent of patients within this group. Our experience with radiculography within this context is also presented and is shown to be currently unsatisfactory.
Athletic Injuries↗
The need for computer-aided electromyography.
The limits of quantitative manual electromyography (EMG) are discussed. The role of computers in EMG laboratories is at present to imitate or replace the physician performing the test, extending his memory, to gather valuable information which cannot be obtained in a conventional way or, on the contrary, to delete the redundant information. The difficulties in standardizing the parameters of a single motor unit action potential (MUAP) are mainly related to the complexity of the EMG signal and its variability, particularly in pathological states. A computer-aided quantification of interference pattern is presented. The novel methods of examination applied in computerized EMG laboratories are discussed. The scope and limits of computer-aided EMG should be taken into action potential (MUAP) are mainly related to the complexicity of the EMG be accepted are listed.
Action Potentials↗
[Dependence of the action potential amplitude of motor units on the recruitment threshold: implications for electromyography].
The relationship between the action potential amplitude and the threshold force of recruitment of 275 motor units (MU) recorded from the first dorsal interosseus muscle of 15 healthy subjects was analysed. The number of newly recruited MU decreased exponentially with increasing muscular force. Action potential amplitudes showed a highly significant positive linear correlation with threshold force of recruitment. This relationship is in accordance with the size principle of MU recruitment. Applying the rank correlation method, 88.6 +/- 2.0% (mean +/- standard deviation) of paired comparisons between all MU of one subject followed the normal activation sequence of MU with an increasing action potential amplitude. It is shown that small variations of the distance between the leading-off surface of the electrode and the MU recorded do not affect these findings. These results demonstrate that the force at which a MU is recruited is the most important factor influencing MU action potential amplitude in normal subjects. So far this fact has not been adequately appreciated in clinical electromyography although it is of significance for the assessment of pathological conditions.
Action Potentials↗
Continuous electromyography for monitoring depth of anesthesia.
Utilizing a randomized, controlled study design, the clinical utility of monitoring spontaneous electromyography during methohexital anesthesia was evaluated for short outpatient gynecologic procedures. In the experimental group (n = 20), the anesthesiologist used conventional monitors as well as the Datex ABM device for determining the maintenance anesthetic requirement. The control group (n = 20) was monitored in an identical fashion, but the video monitor screen was turned off during the operation. The methohexital maintenance requirement was nonsignificantly decreased (5.0 +/- 1.2 vs 5.6 +/- 1.8 mg/min) in the experimental group. Adequacy of anesthesia (as determined by cardiorespiratory stability and the absence of purposeful movement during the maintenance period) did not differ between the two study groups. Although the awakening time for the experimental group (2.9 +/- 1.9 minutes) was decreased to a statistically significant degree compared to the control group (4.5 +/- 3.0 minutes), the difference was of no clinical significance. Thus, continuous electromyographic and EEG monitoring with the Datex ABM device did not significantly improve administration of methohexital during brief outpatient procedures.
Adjuvants, Anesthesia↗
[Electromyography in patients with spastic torticollis].
The article describes the results of electromyographic examination of the muscles of the neck in 26 patients with spasmodic torticollis. Electromyography was performed before and after stereotaxic operative interventions on the nucleus of Cajal or in combination with the diencephalic structures. It is shown that electromyographic examination of patients, especially with the use of functional motor and oculomotor tests, widens essentially the possibilities of the diagnosis by facilitating the identification or specification of the predominantly involved group of muscles. The discovery of concurrent oculographic and electromyographic changes in the dominant muscles of the neck during oculomotor tests is evidence of the connection of the system of concurrent movements of the eyes and head with the motor systems participating in the pathology of torticollis. Analysis of the dynamics of electromyographic changes in patients with predominance of the tonic component in the early and late postoperative periods is indicative of gradual increase of positive changes in the motor sphere, which, evidently, is due to the dynamic reorganizations in the previously formed stable pathological system.
Action Potentials↗
Single fiber electromyography in cat extraocular muscles.
Single fiber electromyography (SFEMG) was carried out in the extraocular muscles (EOMs) of 40 adult cats, and the recordings were analyzed. The small fluctuations of the interpotential interval (IPI), so-called "jitter phenomenon", were represented quantitatively as a mean consecutive difference (MCD). The MCD and the IPI recorded from the orbital layer of the rectus muscles were similar among the 4 rectus muscles: the MCD and the mean IPI measured in 58 motor units from the 4 rectus muscles averaged 25.82 microseconds and 0.94 ms, respectively. These values were similar to those recorded from the oblique muscles. The MCD and IPI were 34.12 microseconds and 1.70 ms, respectively, in the retractor bulbi muscles and 45.54 microseconds and 1.23 ms, respectively, in the triceps muscles. The MCDs of the rectus and inferior oblique muscles were considerably smaller than those in the retractor bulbi and the skeletal muscles.
Animals↗
Pneumothorax: a complication of needle electromyography of the supraspinatus muscle.
A patient developed sudden, severe pleuritic chest pain during needle electromyography (EMG) of the right supraspinatus muscle. Chest x-rays revealed a 10% right pneumothorax. The patient was treated conservatively and there was complete resolution one week later. A review of the pertinent anatomy indicates that the supraspinatus muscle overlies the pleural cavity. Indications for needle EMG of the supraspinatus muscle are reviewed. A new technique that minimizes the risk of pneumothorax when performing needle EMG of the supraspinatus muscle is presented.
Electrodes↗
The value of automatic analysis for quantitative electromyography.
The value of automatic analysis for quantitative electromyography. Acta Physiol. Pol., 1979, 30 (2): 231--239. The authors describe the automatic analysis of EMG records by means of minicomputer ANOPS-101. Computer works on-line during EMG examination, being directly connected to the output of electromyograph. During slight voluntary muscle contraction 3 histograms could be obtained--namely: distribution of MUAP duration, number of their phases and their amplitudes. During maximum voluntary contraction two more histograms could be obtained--namely: distribution of amplitudes of spikes and distribution of intervals between spikes. These five histograms are displayed on the screen and the mean values are automatically calculated. As a result all quantitative EMG data are obtained which are sufficiently accurate for differentiation between pathological and normal recordings and which help to distinguish the myogenic atrophy from neurogenic one.
Action Potentials↗
Quantified electromyography of lower-limb muscles during level walking.
The electromyography (EMG) of eleven different lower limb muscles of ten healthy subjects was quantified during normal level walking. The surface EMGs obtained were normalized, in percentage, to the activity obtained during an isometric maximum voluntary test contraction of each subject. The mean peak activities of the gluteus maximus, gluteus medius, rectus femoris, vastus medialis, vastus lateralis, biceps femoris and medial hamstring muscles occurred at heel-strike and were between 5 and 15% of max isometric EMG. The magnitudes of tibialis anterior and triceps surae muscular activity were higher than those of the other muscles investigated. Mean peak activity in tibialis anterior was 27%, in gastrocnemius medialis 42%, in gastrocnemius lateralis 19% and in soleus 40%. The important role of the triceps surae during walking was reflected in comparatively high muscular activity at push-off.
Adult↗
Dynamic electromyography analysis of habitual toe-walkers.
The distinction between congenital short tendo calcaneus and mild cerebral palsy may often be difficult to ascertain by standard physical examination. Dynamic electromyography (EMG) was used to study the muscular activity during walking of four children who had a clinical diagnosis of congenital short tendo calcaneus. Two children displayed EMG evidence of cerebral palsy, while two had studies similar to normal children walking on their toes. Dynamic EMG may be a useful diagnostic tool in the evaluation of children with toe-walking.
Achilles Tendon↗
Evoked serial electromyography in the evaluation of the paralyzed face.
Serial evoked electromyography (EEMG) is a reliable, objective, repeatable test of facial nerve function. It is very important in the initial patient evaluation in determining percent degeneration of the facial nerve. A response of 0-20% will usually result in incomplete return of facial function while responses of 60% or better will usually result in normal function. With viral facial paralysis (Bell's palsy, herpes zoster oticus), serial EEMG after several weeks has little value in predicting the final percent recovery of facial function. If there is no EEMG response, the diagnosis of viral facial paralysis is questionable and serial tests should be done until facial function begins to return. If there is no return of facial function or EEMG responses, the diagnosis is probably a tumor and the nerve should be explored. When surgical manipulation of the facial nerve has resulted in partial facial weakness, EEMG helps predict the degree of recovery of facial function. EEMG results of 60% or better will result in normal facial function while EEMG results of 25% or less will result in incomplete return of facial function. Serial testing is not necessary in this group of patients. After transection and repair of the facial nerve, serial EEMG is of value in showing continuity of the repair. Lack of improvement in EEMG over 5-12 months and no return of facial function indicates poor prognosis.
Ear Diseases↗
Endoscopic electromyography and manometry of the human sphincter of Oddi.
The myoelectric and manometric activities of the sphincter of Oddi were recorded in 8 patients using an original probe passed through the papilla of Vater during duodenoscopy. The sphincter of Oddi's myoelectric activity showed rhythmic bursts of action potentials which appeared in correspondence with the ascending phase of the phasic pressure waves. On the basis of these results, we believe that electromyography could in some cases replace manometry for studying sphincter of Oddi motility, since it avoids pressure perfusion of the bilio-pancreatic tract, with its concomitant risks, and provides sufficient information for motor studies.
Ampulla of Vater↗