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Twitch response in a myopathy with impaired relaxation but no myotonia
Author(s) -
Quinlan John G.,
Iaizzo Paul A.,
Gronert Gerald A.,
Lambert Edward H.
Publication year - 1990
Publication title -
muscle and nerve
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.025
H-Index - 145
eISSN - 1097-4598
pISSN - 0148-639X
DOI - 10.1002/mus.880130408
Subject(s) - myotonia , myopathy , medicine , ankle , stimulation , relaxation (psychology) , muscle relaxation , motor unit , nerve stimulation , anesthesia , electromyography , physical medicine and rehabilitation , anatomy , myotonic dystrophy
A patient with slow muscle relaxation but without accompanying motor unit or myotonic electrical activity had a unique staircase twitch response to repeated nerve stimulation. During 1‐Hz stimulation, twitches recorded by measurement of the ankle dorsiflexor group displayed progressively increasing relaxation times with successive stimuli (37% increase) unlike the progressively decreasing relaxation time of the normal response (12–37% decrease). The response may be diagnostic of this unusual myopathy; the test methods are noninvasive and easily tolerated.