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Repetitive nerve stimulation of facial muscles in musk antibody–positive myasthenia gravis
Author(s) -
Oh Shin J.,
Hatanaka Yuki,
Hemmi Shoji,
Young Angela M.,
Scheufele Mia L.,
Nations Sharon P.,
Lu Liang,
Claussen Gwen C.,
Wolfe Gil I.
Publication year - 2006
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.20498
Subject(s) - repetitive nerve stimulation , myasthenia gravis , extensor digitorum communis , facial nerve , orbicularis oculi muscle , medicine , acetylcholine receptor , facial muscles , electromyography , stimulation , electrophysiology , population , endocrinology , pathology , anatomy , receptor , surgery , environmental health , psychiatry , eyelid
Abstract To better define electrophysiological abnormalities in myasthenia gravis (MG) patients with muscle‐specific tyrosine kinase (MuSK) antibodies (Ab), we compared electrophysiological features of 14 MuSK Ab–positive, 73 acetylcholine receptor antibody (AChR Ab)–positive, and 22 MuSK and AChR Ab–negative (seronegative) patients with generalized disease. Repetitive nerve stimulation (RNS) abnormalities were observed in 86% of MuSK Ab–positive and 82% of AChR Ab–positive patients but in only 55% of seronegative patients. RNS decrements in the orbicularis oculi were more common and severe in the MuSK Ab–positive patients than the other two groups. Single‐fiber electromyography (SFEMG) of the extensor digitorum communis was abnormal in 90% of MuSK Ab–positive patients. The high frequency of RNS abnormalities in facial muscles in the MuSK Ab–positive population reflects the propensity for facial muscle involvement in this form of MG and emphasizes the importance of including facial muscles in RNS protocols when evaluating these patients. Muscle Nerve, 2006