Studies on Myotonia

Abstract

MYOTONIA, the denominating characteristic of three genetically determined diseases of muscle (myotonia congenita, myotonia dystrophica, and paramyotonia), and dystrophy of muscle fibers, a feature of one of these diseases (myotonia dystrophica), remain obscure. Concerning the localization of myotonia, a number of investigators believe it might reside in the muscle cell. Grund¹and later Schaffer²noted the persistence of this phenomenon after complete block of the nerve fibers supplying the muscle; and Gregor and Schilder³and later Lindsley and Curnen⁴observed it during the relaxation phase of contraction, when few nerve impulses were reaching the muscle. Brown and Harvey⁵in a myotonic disease of goats also demonstrated that complete denervation of muscle failed to abolish the myotonia. Landau⁶and Floyd et al⁷have shown that curare has no effect on human myotonia. Denny-Brown and Nevin⁸confirmed this localization but also obtained evidence