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PubMedDate not supplied

Electromyography (EMG) and sialometry in the prognosis of Bell's palsy. A methodological study of early investigated, untreated patients.

The degree of remaining motor unit activity at maximal voluntary contraction of the face was examined in three of the facial muscles in 43 untreated patients with Bell's palsy. All the patients were examined within 10 days of the onset of the paresis. In 40 patients the EMG activity was compared with the clinical evaluation of the paresis and in 33 patients with the results from sialometry. EMG revealed remaining motor activity in several patients who had clinically total paresis. It was concluded that EMG can be used as a prognostic indicator at an early stage in Bell's palsy. Sialometry was found to predict the final outcome of the paresis with a slightly better accuracy than EMG.

Adolescent↗
PubMed1984

Electromyography of the paravertebral muscles in idiopathic scoliosis. Measurements of amplitude and spectral changes under load.

The myoelectric activity of the paraspinal muscles was recorded in girls with idiopathic scoliosis and in healthy controls. The muscles of the back were loaded isometrically and the signals recorded at the T8 and L3 levels were analysed as regards amplitude and frequency. A comparatively higher signal amplitude was found on the convex side of the scoliosis curve. This was found to be due to a lower amplitude on the concave side when the scoliosis group was compared to the controls. The amplitude difference was correlated to the degree of scoliosis. A shift in the myoelectric spectrum toward lower frequencies occurred during the loading period. There were no differences in this respect between the sides of the scoliosis, nor were there differences between the scoliosis patients and the controls. Secondary adaptation to the higher load demand by the muscles on the convex side in scoliosis is the most probable explanation for our observations.

Adolescent↗
PubMed1997

Evaluation with evoked and spontaneous electromyography during lumbar instrumentation: a prospective study.

The neuroanatomical structures that approximate the bony pedicles of the lumbar spine allow little room for technical error or compromise of the bone during pedicle screw insertion. Currently available neurophysiological monitoring techniques detect compromised bone and nerve root injury after it occurs. The purpose of this prospective study is to evaluate the reliability and efficacy of a unique neurophysiological monitoring technique. This technique provides immediate evaluation of pedicle cortical bone integrity in patients undergoing lumbar fusion with instrumentation by using electrified surgical instruments throughout the pedicle screw fusion procedure. Spontaneous electromyographic (EMG) activity was also monitored. Intraoperative evoked EMG stimulation was performed using a pedicle probe and feeler as monopolar stimulators during the insertion of 164 pedicle bone screws in 32 patients. The EMG response to subthreshold stimulation intensities indicated cortical bone compromise. Immediate and conclusive feedback via evoked EMG activity using stimulating pedicle probes in appropriate muscle groups was successful in identifying pedicle cortical bone compromise in four patients. One false-negative evoked EMG study was noted but was identified via spontaneous EMG activity. Intraoperative EMG monitoring alerted the surgeon that redirection of the pedicle probe or screw was necessary to avoid nerve root irritation or injury and served as an early warning system. Evoked EMG stimulation proved to be reliable and efficacious, especially when used in combination with spontaneous EMG. This technique may provide an added safeguard during implant placement procedures at centers where intraoperative neurophysiological monitoring is routinely performed.

Adult↗
PubMed1993

Relationship between electromyography and computed tomography in the evaluation of low back pain.

In a group of 109 patients with low back pain, the electromyographic(EMG) findings were compared with computed tomographic (CT) findings. There were 64 (58.7%) patients who had abnormal EMG results combined with abnormal CT findings. 11 (10.1%) cases had abnormal EMG and normal CT findings, another 11 (10.1%) patients had abnormal CT and normal EMG findings. 33 patients underwent operation; nerve root compressions were confirmed in all those with abnormal EMG findings, and 32 of those with abnormal CT findings. Among 33 surgical cases, 24 (72.7%) patients had abnormal EMG findings in both paralumbar and lower extremity muscles. In 9 (27.3%) patients there was evidence of abnormal EMG findings in the paralumbar muscles only. Among 46 who had abnormal EMG findings in paralumbar and lower limb muscles, 44 (95.6%) patients had combined CT abnormalities, and in the remaining 2 patients, nerve root 'compression was confirmed by surgery in 1 case and by myelogram in the other. In 29 cases with abnormal EMG findings in the paralumbar muscles only, 20 (69.0%) patients had combined CT abnormalities. In comparing normal versus abnormal EMG findings of the paralumbar muscles only, a significantly higher percentage of abnormal CT results were found among the abnormal EMG findings. These results indicate that abnormal EMG findings in both the paralumbar and lower limb muscles, strongly suggests the presence of nerve root compression. In cases where there are abnormal EMG findings in the paralumbar muscles only, it is recommended that CT scan must be done for the correct diagnosis of low back pain.

Adolescent↗
PubMed2005

Biomechanical assessment with electromyography of post-stroke ankle plantar flexor spasticity.

Spasticity has been defined as a motor disorder characterized by a velocity-dependent increase in tonic stretch reflex (muscle tone). Muscle tone consists of mechanical-elastic characteristics, reflex muscle contraction and other elements. The aims of this study were to determine whether to assess spasticity quantitatively, and to characterize biomechanical and electromyographic spasticity assessment parameters. These assessment parameters were described by investigating the correlation between clinical measures and the response to passive sinusoidal movement with consecutive velocity increments. Twenty post-stroke hemiplegic patients and twenty normal healthy volunteers were included in the study. Five consecutive sinusoidal passive movements of the ankle were performed at specific velocities (60, 120, 180, and 240 degrees/ sec). We recorded the peak torque, work, and threshold angle using a computerized isokinetic dynamometer, and simultaneously measured the rectified integrated electromyographic activity. We compared these parameters both between groups and between different velocities. The peak torque, threshold angle, work, and rectified integrated electromyographic activity were significantly higher in the post-stroke spastic group at all angular velocities than in the normal control group. The threshold angle and integrated electromyographic activity increased significantly and linearly as angular velocity increased, but the peak torque and work were not increased in the post-stroke spastic group. Peak torque, work, and threshold angle were significantly correlated to the Modified Ashworth scale, but the integrated electromyographic activity was not. The biomechanical and electromyographic approach may be useful to quantitatively assess spasticity. However, it may also be very important to consider the different characteristics of each biomechanical parameter.

Adult↗
PubMed1985

Acute and latent effect of poliomyelitis on the motor unit as revealed by electromyography.

When polio virus attacks the motor neuron it may be completely destroyed, damaged, or unaffected. Muscle fibers of a destroyed motor neuron are orphaned or reinnervated. Nearby functioning motor units will then send terminal axon sprouts to reinnervate the orphaned muscle fibers. If there are too many orphaned muscle fibers and not enough surviving motor units to reinnervate them, the orphaned muscle fibers will continue to fibrillate until they atrophy and die. The resultant effect of poliomyelitis upon the affected muscle is an overall loss of motor units with the remaining units innervating many more muscle fibers than they originally did. There appears to be a late effect of polio upon these larger reinnervated motor units. After approximately 20 to 30 years, impulse transmission to the muscle fibers of the large reinnervated motor unit begins to fail. These transmission difficulties increase with age and time from recovery. These late onset transmission abnormalities may be factors in patient complaints of fatigue and progressive weakness.

Aged↗
PubMed1995

Electromyography and biomechanics of a dynamic knee brace for anterior cruciate ligament deficiency.

Twelve anterior cruciate ligament (ACL)-deficient subjects performed concentric isokinetic knee extensions at maximum effort both with and without the Bledsoe Pro Shifter knee brace. Electromyogram signals from the quadriceps, hamstrings, knee angle, and the extension force were recorded and evaluated to determine the effects of such dynamic bracing on muscle activity and joint stability. High activity, or asymptomatic, subjects (n = 5) experienced no change in muscle activity, but displayed a decrease in extension force throughout the active range of the brace. Low activity, or symptomatic, subjects (n = 7) exhibited increased quadriceps activity and decreased hamstrings activity, and displayed a minor increase in force in the mid-range (80 degrees to 40 degrees flexion). These results indicate that dynamic bracing prevents quadriceps inhibition in symptomatic subjects by exerting a posteriorly directed force to the superior tibia; thus, the brace compensates externally for the absence of the ACL.

Adult↗
PubMed1998

Electromyography of the shoulder: an analysis of passive modes of exercise.

Passive shoulder motion is standard early rehabilitation in patients undergoing rotator cuff repair. A number of rehabilitation protocols exist to obtain this goal. This article evaluated different rehabilitation protocols using electromyographic analysis of the rotator cuff muscles to determine if the different protocols promote passive motion. Ten healthy volunteers underwent EMG to investigate the relative activity of the rotator cuff muscles during various exercises used postoperatively following shoulder surgery. The exercises tested were continuous passive motion machine (CPM), pulley, pendulum, self-assisted bar raise using the contralateral arm for power, self-assisted internal and external rotation, therapist-assisted elevation in plane of the scapula, and therapist-assisted internal and external rotation. The relative activity of the supraspinatus, infraspinatus, anterior deltoid, and trapezius muscles were measured and expressed as a percentage of maximal activity. For all muscle groups tested, the pulley exercise showed significantly more activity than the CPM machine. In the supraspinatus muscle, the pulley exercise averaged 17.6% of maximal activity and 8.7% for the self-assisted bar raise using contralateral arm power compared with 5.0% for the CPM machine. In general, therapist-assisted exercises and Codman's pendulum exercises showed activity that was not significantly different from the CPM machine. These results indicate that CPM and therapist-assisted passive range of motion, by being more passive, may increase the safety margin for obtaining early passive range of motion without disrupting the rotator cuff repair.

Adolescent↗