Characteristics of Repetitive Nerve Stimulation (Rns) and Correlation with Severity and Quality of Life of Myasthenia Gravis Patients

Abstract

Background: Myasthenia gravis is a rare autoimmune disease due to neuromuscular junction (NMJ) disorders. The diagnosis of myasthenia gravis is based on cardinal clinical symptoms, including fluctuating weakness, worsening with activity, and improving with rest. In addition to clinical signs and antibody tests, other tests that are also crucial for diagnosis are electrodiagnostic examination (EDX) such as repetitive nerve stimulation (RNS) and single fibre electromyography (SFEMG). Recent studies have focused on assessing patients' severity and quality of life, essential for determining the prognosis and subsequent treatment plans. Objective: To evaluate the characteristic of RNS and its correlation with rigor and quality of life of myasthenia gravis patients. Methods: Inclusion criteria: patients diagnosed with myasthenia gravis, aged 18-65 years, willing to participate in the study. Exclusion criteria include a history of neuropathy, motor neuron disease, or myopathy and dropping out of the study. Patient demographic data were collected. The results of the RNS examination were divided into two categories, normal and abnormal. MG severity was assessed by the Myasthenia gravis foundation of America (MGFA) classification, and the patient's quality of life was assessed by Myasthenia Gravis Quality of Life 15 (MG-QOL 15). Results: Of the 24 samples, 69.1% of RNS were positive. The most sensitive muscle for assessing RNS is the anconeus muscle, followed by the trapezius and nasal. There was no significant relationship between RNS features and severity and the quality of life of myasthenic Gravis patients. Conclusion: Onconeus muscle is the best location for assessing RNS. Although the number of patients with normal RNS had lower severity and better quality of life, there was no statistically significant relationship. Further studies with larger samples and longer follow-ups are needed.