Single-fiber electromyography in limb and facial muscles in muscle-specific kinase antibody and acetylcholine receptor antibody myasthenia gravis

• Published in: Muscle & nerve Vol. 33; no. 4; pp. 568 - 570
• Main Authors: Farrugia, Maria Elena, Kennett, Robin P., Newsom-Davis, John, Hilton-Jones, David, Vincent, Angela
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc., A Wiley Company 01.04.2006; Wiley
• Subjects: Acetylcholinesterase - metabolism; Antibodies - analysis; Biological and medical sciences; Disability Evaluation; Diseases of striated muscles. Neuromuscular diseases; Electromyography; Electrophysiology; Extremities - innervation; Facial Muscles - innervation; Facial Muscles - physiology; Fundamental and applied biological sciences. Psychology; Humans; Medical sciences; Muscle Fibers, Skeletal - physiology; Muscle, Skeletal - innervation; Muscle, Skeletal - physiology; MuSK antibody; myasthenia gravis; Myasthenia Gravis - immunology; Myasthenia Gravis - metabolism; Neurologic Examination; Neurology; Receptor Protein-Tyrosine Kinases - metabolism; Receptors, Cholinergic - immunology; Receptors, Cholinergic - metabolism; seronegative myasthenia gravis; single-fiber electromyography; Striated muscle. Tendons; Vertebrates: osteoarticular system, musculoskeletal system; Human; Neuromuscular diseases; Nervous system diseases; Extensor digitorum communis muscle; Jitter; single-fiber electromyography; Orbicularis oculi muscle; seronegative myasthenia gravis; Neurophysiology; Cholinergic receptor; Myasthenia gravis; Single fiber electromyography; MuSK antibody
• ISSN: 0148-639X; 1097-4598
• DOI: 10.1002/mus.20491

We examined the findings from single‐fiber electromyography in extensor digitorum communis (EDC) and orbicularis oculi (OOc) in 13 myasthenia gravis (MG) patients with muscle‐specific kinase antibodies (MuSK‐MG) and 12 MG patients with acetylcholine receptor antibodies (AChR‐MG) with similar clinical scores. More than 70% of AChR‐MG patients had abnormal jitter in both EDC and OOc, but the majority of MuSK‐MG patients had normal jitter in EDC despite abnormal jitter in OOc. These findings demonstrate clear differences between the neurophysiology of MuSK‐MG and AChR‐MG. Muscle Nerve, 2005