A novel symptom assessment tool could be helpful for the management of patients with myasthenia gravis (MG), according to a study recently published in BMC Neurology.

“Focusing on patients’ subjective feelings, representing the most comprehensive content with the fewest entries, with good sensitivity and specificity, and with strong practicality and clinical appropriateness, which can help patients correctly recognize their symptoms, facilitate their self-monitoring of disease progression, and provide a foundation for future research,” the authors wrote.

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This cross-sectional, observational study included a total of 19 items that constituted a symptom cluster scale for patients previously diagnosed with MG. The researchers named this tool MGSC-19.

The study proposed the MGSC-19 scale after a literature review, qualitative interviews, and the Delphi method based on the unpleasant symptom theory. A team of 29 medical professionals, nursing experts, and psychologists created the first draft of the scale. Then, 12 patients with MG underwent cognitive interviews. The validation phase relied on a total of 283 patients with MG from a single center in China.

The MGSC-19 achieved a content validity index of 0.980, with individual items varying from 0.828 to 1.000. A subsequent exploratory factor analysis revealed that almost all (70.187%) of the total variance could be explained by 4 common variables, such as psychiatric problems, general muscular weakness, treatment-related side effects, and ocular muscle weakness.

Moreover, the correlation coefficients among dimensions ranged from 0.324 to 0.510. Conversely, the correlation coefficients of scale dimensions varied between 0.395 and 0.769. Finally, the half reliability, retest reliability, and Cronbach’s alpha were 0.837, 0.845, and 0.932, respectively.

This scale could play a role in the clinical management of patients with MG, guiding tailored symptom control for each patient.

“Due to the low prevalence of MG, as well as the fact that some symptoms, such as diplopia, are very obvious to patients while others, such as lower limb weakness, are not obvious in the early stages, patients frequently attribute this to overwork or lack of exercise and may not believe it is related to the disease,” the authors explained.


Shen F, Hu L, Huang H, Li L. Development and validation of the scale for symptom clusters in patients with myasthenia gravis. BMC Neurol. Published online May 19, 2023. doi:10.1186/s12883-023-03240-4