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Single‐fiber EMG with a concentric needle electrode: Validation in myasthenia gravis
Author(s) -
Sarrigiannis Ptolemaios G.,
Kennett Robin P.,
Read Simon,
Farrugia Maria E.
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.20435
Subject(s) - myasthenia gravis , extensor digitorum communis , electromyography , receiver operating characteristic , medicine , orbicularis oculi muscle , concentric , confidence interval , biomedical engineering , surgery , physical medicine and rehabilitation , mathematics , geometry , eyelid
We performed a retrospective study to validate whether a disposable concentric needle electrode (CNE) can be used in place of a single‐fiber (SF) electrode for jitter measurements in myasthenia gravis (MG). Normal values for voluntary contraction of orbicularis oculi (OO) and extensor digitorum communis (EDC) were collected from 20 healthy subjects. The method was validated by a retrospective analysis of 56 consecutive MG patients, the “gold standard” being a positive acetylcholine receptor (AChR) antibody titer at the time of the electrophysiological (electromyography) study and the clinical diagnosis. Receiver operating characteristic (ROC) curves were constructed to define maximal sensitivity and specificity of the technique. The sensitivity was 96.4% (95% confidence interval 87.5%–99.6%), with no false‐positive results, similar to traditional SF EMG and confirming that the disposable CNE is a justifiable alternative. Muscle Nerve, 2005