The MRC scale is traditionally used for assessment of the severity of movement disorders. The patients' effort is graded on a scale of 0-5. The use of this scale is limited by subjective biases and inadequate assessment of some functions. The quantitative scale for assessment of the severity of clinical symptoms of myasthenia (QMGS) allows to evaluate pathological muscle fatigability, the main syndrome of this disease, which is important for evaluating the severity of symptoms before and after the pathogenetic treatment or when probes with the introduction of acetylcholinesterase preparations are used.