Electromyography

FeldmanRG. 1970. Facial nerve latency studies in man. Effects of trichloroethylene exposure. Electromyography 10 93-100. 

Reflex action can be objectively examined. Measurement of the so-called electrical conduction velocity of motor nerves gives an indication of whether peripheral nerves have been damaged. Electromyography, or examination of the electrical activity of the muscle, and electroencephalography (EEG) can also be used to detect the presence of neurologic abnormalities. And, at least in animal tests, detailed pathological examination of neural tissue can be performed on animals that are killed. 

A 45-year-old man in otherwise good health complains of muscle weakness early in the morning but says it is less of a problem as the day goes on. The neurologist performs electromyography and notes no alteration in nerve conduction velocity but does observe facilitation in the compound action potential with repetitive 50-Hz stimulation. This indicates a defect at the prejunctional side of the neuromuscular junction. Which of the following is a possible cause ... 

Brown, W.E. (1994). Development of a method to investigate differences in chewing behaviour in humans. I. Use of electromyography in measuring chewing. J. Texture Studies 25, 1-16. 

An 87-year-old man developed progressive proximal limb weakness 1 year after starting leuprolide therapy for prostate cancer (60). Electromyography showed a moderately severe non-inflammatory myopathy without evidence of fiber necrosis or associated biochemical changes. Within 6 months after stopping leuprolide he was able to resume his usual activities. 

Rodrequez, A.A., Agre, J.C., et al.(1993) Acoustic myography compared to electromyography during isometric fatigue and recovery. Muscle and Nerve 16 188-192... 

Electromyography and saccadic velocity studies demonstrated that the mechanical restriction of the eye is caused by interstitial edema and fibrosis of the muscles rather than by myopathy. However, in the acute phases of Graves orbitopathy saccadic velocity testing demonstrates a neuropathic state, which resolves on fibrosis. 

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