Muscle weakness and functional disability in patients with myasthenia gravis.

<bold>Introduction: </bold>Muscle weakness and functional disability have not been evaluated in a population-based study of patients with myasthenia gravis (MG).<bold>Methods: </bold>All patients with MG in a well-defined catchment area were identified in the Danish National Patient Registry. Of the 175 eligible patients, 90 participated and were studied using MG-specific scales, isometric dynamometry, and functional tests. Fifty age- and sex-matched subjects served as controls.<bold>Results: </bold>Muscle strength was reduced by 13%, 21%, and 12% for shoulder abduction, knee extension, and ankle extension, respectively (P < 0.05). Chair stand and 400-meter walking were impaired by 24% and 23%, respectively (P < 0.05). Muscle strength and functional performances were related to MG-specific scales.<bold>Discussion: </bold>MG patients have moderately reduced isometric muscle strength and impaired physical performance. Muscle weakness and functional tests relate closely to MG-specific scales, suggesting that dynamometry and functional tests can be used to monitor MG patients and as efficacy parameters in clinical trials. Muscle Nerve 59:218-223, 2019. [ABSTRACT FROM AUTHOR]