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Difference between revisions of "Clinic Electromyography"
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(Created page with "{{main menu}} {{ArtBy|||autore= Cesare Iani}} ===Clinical Electromyography=== Cesare Iani Head of UOC Neurology, San Eugenio Hospital, Rome The electromyographic exam (EMG) consists of three sequential phases: 1) spontaneous activity examination, 2) analysis of individual motor units, 3) interference pattern examination during moderate and maximal effort. ====Definition of Motor Unit (MU)==== The MU is composed of a motor neuron, its axon, and the muscle innervate...") |
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**Clouds Analysis** | **Clouds Analysis** | ||
Stolberg and collaborators developed a computerized T/A analysis system that does not require monitoring contraction force. IP signals are recorded from 6-10 sites in the examined muscle at 3-5 force levels ranging from minimum to maximum for each site. NT and MA values are measured from each of the 20-40 epochs, and a plot of the MA/NT ratio is created for each epoch. An area of this plot called the “Normal Cloud” is defined as the part that contains more than 90% of the points from a reference population. A discrepancy greater than 10% of the analyzed points that fall outside the normal cloud is considered abnormal. Myopathy patients have more points in the lower part of the “normal cloud,” while in neuropathy, the points are located in the upper side of the normal value or outside the normal curve (Fig. 5, 6, 7).<gallery> | Stolberg and collaborators developed a computerized T/A analysis system that does not require monitoring contraction force. IP signals are recorded from 6-10 sites in the examined muscle at 3-5 force levels ranging from minimum to maximum for each site. NT and MA values are measured from each of the 20-40 epochs, and a plot of the MA/NT ratio is created for each epoch. An area of this plot called the “Normal Cloud” is defined as the part that contains more than 90% of the points from a reference population. A discrepancy greater than 10% of the analyzed points that fall outside the normal cloud is considered abnormal. Myopathy patients have more points in the lower part of the “normal cloud,” while in neuropathy, the points are located in the upper side of the normal value or outside the normal curve (Fig. 5, 6, 7).<gallery mode="slideshow"> | ||
File:Figure 5 (Iani).jpg|'''Figure 5:''' Interference pattern EMG trace in a patient with myopathy. Early low-amplitude recruitment is observed. The lower panel shows the plot of the Cloud method (see text). | File:Figure 5 (Iani).jpg|'''Figure 5:''' Interference pattern EMG trace in a patient with myopathy. Early low-amplitude recruitment is observed. The lower panel shows the plot of the Cloud method (see text). | ||
File:Figure 6 (Iani).jpg|'''Figure 6:''' Neurogenic-type EMG trace. Single oscillation motor units of large amplitude and increased duration are observed. The full interference pattern is not achieved with maximal voluntary contraction. | File:Figure 6 (Iani).jpg|'''Figure 6:''' Neurogenic-type EMG trace. Single oscillation motor units of large amplitude and increased duration are observed. The full interference pattern is not achieved with maximal voluntary contraction. | ||
File:Figure 7 (Iani).jpg|'''Figure 7:''' This series of graphs represents the Cloud plots in neurogenic (upper) and myopathic (lower) pathologies. In the first panel, it is observed that in the neurogenic pattern, the plot points fall above the normal cloud, while in the myogenic pattern, they fall below. | File:Figure 7 (Iani).jpg|'''Figure 7:''' This series of graphs represents the Cloud plots in neurogenic (upper) and myopathic (lower) pathologies. In the first panel, it is observed that in the neurogenic pattern, the plot points fall above the normal cloud, while in the myogenic pattern, they fall below. | ||
</gallery><br /> | </gallery><br /> | ||
==Bibliography== | ==Bibliography== | ||
<references /> | <references /> | ||