Diagnostic utility of stimulated single-fiber electromyography of the orbicularis oculi muscle in patients with suspected ocular myasthenia.
Stimulated single-fiber electromyography (SSFEMG) is a valuable diagnostic tool in cases of myasthenia gravis with limited disease. From 1990 to 2008 SSFEMG in the orbicularis oculi muscle (OO) was performed in a cohort of 456 patients referred with clinical suspicion of myasthenia gravis (MG) and exclusively ocular symptoms. A diagnosis of MG was made on clinical grounds in 103 patients. In this patient cohort, the specificity of SSFEMG for myasthenia was 97%, and the sensitivity was 80%. MG patients with a normal SSFEMG had a benign clinical course. This study confirms a high specificity and sensitivity of SSFEMG when it is performed on patients suspected to have ocular MG. In such patients, a normal SSFEMG of the OO predicts a benign clinical course.
Department of Neurology, Antwerp University Hospital, Wilrijkstraat 10, Antwerp B2650, Belgium. rudy.mercelis@ua.ac.be
Rudy
R
Mercelis
Virginie
V
Merckaert
D004558:Electric Stimulation / Q000379:methods*; D004576:Electromyography / Q000379:methods; D006801:Humans; D018485:Muscle Fibers, Skeletal / Q000502:physiology*; D009157:Myasthenia Gravis / Q000175:diagnosis*; D009801:Oculomotor Muscles / Q000473:pathology / Q000503:physiopathology*