Electromyography (Emg) And Nerve Conduction Studies Of

If the clinical decision is difficult if a weakness is caused by a fault on a nerve, a muscle or neuromuscular synapse, these studies can identify the affected nerves and muscles. Electromyography The electromyography is inserted a needle electrode into the muscle and recorded the electrical activity at rest and during contraction of the muscle. Normally, the relaxed muscle is electrically silent; with minimal contraction appear action potentials of single motor units. If the contraction increases, the number of potential increased, an interference pattern is formed. Denervated muscle fibers by increasing puncture activity and pathological spontaneous activity identified (fibrillations, positive waves and fasciculations); during contraction less motor units are recruited, producing a gelichtetes interference pattern. Survivors from axons sprouts to innervate adjacent muscle fibers, thus increasing the motor unit and so produce giant action potentials. For muscle diseases individual muscle fibers are affected with no connection with the motor units; therefore, the amplitude of the potential is reduced but the interference pattern remains sealed. Measurement of the nerve To investigate the nerve conduction a peripheral nerve at various points along its course is stimulated to the muscle with electrical stimuli and the time until the release of a muscle potential response recorded. The time it takes for a pulse to run along a certain measured distance of a nerve, determines the conduction velocity. The time needed to traverse the closest to the muscle segment, the distal latency. Similar measurements can be performed on sensory nerves. Nerve conduction studies to test large myelinated but not thin myelinated or unmyelinated nerves. In a neuropathy line is often slow, and the response potentials can fragmentation of the potential demonstrated by the unequal participation of myelinated axons and nichtmyelinisierter. Neuropathies affect, however, only thin unmyelinated or thinly myelinated fibers (or is based on the weakness of a muscle disease), the results are usually normal. A nerve can be stimulated repeatedly to check the neuromuscular transmission to fatigue, such. B. occurs a progressive decrement in myasthenia.

Health Life Media Team

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