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Diagnostic impact of myotonic discharges in myofibrillar myopathies
Author(s) -
Hanisch Frank,
Kraya Torsten,
Kornhuber Malte,
Zierz Stephan
Publication year - 2013
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.23716
Subject(s) - myotonia , myotonic dystrophy , myofibril , electromyography , myopathy , medicine , mononeuropathy , physical medicine and rehabilitation , endocrinology , peripheral neuropathy , diabetes mellitus
: In patients with myofibrillar myopathies (MFM), myotonic discharges have occasionally been detected by needle electromyography (EMG). Nevertheless, this peculiar type of spontaneous repetitive discharge has not attracted special interest in the genetically heterogeneous MFMs. Methods : EMG features were analyzed in 6 patients with genetically confirmed MFM (n = 1 MYOT , n = 1 DES , n = 2 ZASP , n = 2 FLNC ). Results : Fibrillation potentials, positive sharp waves, and myotonic discharges were found in all 6 patients, and complex repetitive discharges were found in 5. Myotonic discharges were detected in approximately 50% of the analyzed muscles independent of the site, including distal (3/6), proximal limb (4/6), and paravertebral muscles (3/6). Clinical myotonia could not be elicited in any patient. Conclusions : Myotonic discharges appear to be part of the electrodiagnostic characteristics of myofibrillar myopathy. Along with other appropriate clinical and histological findings, the presence of myotonic discharges supports the diagnosis of myofibrillar myopathy. Muscle Nerve 47: 845–848, 2013