Sensitivity of repetitive facial-nerve stimulation in patients with myasthenia gravis

• Published in: Muscle & nerve 2006-05, Vol.33 (5), p.694-696
• Main Authors: Zinman, Lorne H., O'Connor, Paul W., Dadson, Keith E., Leung, Rita C. M., Ngo, Mylan, Bril, Vera
• Format: Article
• Language: English
• Subjects: Aged; Biological and medical sciences; Diseases of striated muscles. Neuromuscular diseases; Electric Stimulation - methods; electromyography; Electromyography - methods; Facial Nerve - physiopathology; Facial Nerve - radiation effects; Female; Fundamental and applied biological sciences. Psychology; Humans; Male; Medical sciences; Middle Aged; Motor control and motor pathways. Reflexes. Control centers of vegetative functions. Vestibular system and equilibration; myasthenia gravis; Myasthenia Gravis - diagnosis; Myasthenia Gravis - physiopathology; Neurology; repetitive nerve stimulation; sensitivity; Sensitivity and Specificity; single-fiber electromyography; Vertebrates: nervous system and sense organs
• ISSN: 0148-639X; 1097-4598
• DOI: 10.1002/mus.20511

Repetitive stimulation of the facial nerve is commonly performed in cases of suspected myasthenia gravis (MG) because bulbar weakness is often present, but the most sensitive facial muscle is unknown. We compared the sensitivity of repetitive nerve stimulation (RNS) to the frontalis and nasalis muscles in 244 patients with suspected MG. We found no difference in sensitivity of RNS when recording from these muscles in both ocular and generalized MG. In addition, we confirmed the low sensitivity of RNS for ocular (18%) or generalized (47%) MG. The specificity of facial RNS for both muscles was 100% and, in certain circumstances, may obviate the need for further diagnostic testing. Muscle Nerve, 2006