[Pubmed] Enhancing diagnostic sensitivity in Myasthenia Gravis: The combined role of CMAP area and amplitude decrements

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Clin Neurophysiol. 2025 Apr 20;174:169-172. doi: 10.1016/j.clinph.2025.04.004. Online ahead of print.

ABSTRACT

OBJECTIVE: To evaluate the diagnostic utility of using CMAP area decrement, in addition to CMAP amplitude decrement, in RNS testing for patients with suspected MG.

METHODS: This retrospective study analyzed EMG data from January 2019 to December 2023 on patients with suspected MG. CMAP area and amplitude decrements of ≥10 % were considered abnormal, and MG diagnosis was based on clinical presentation, antibody testing, or response to treatment.

RESULTS: A total of 204 patients were included in the final analysis. MG was diagnosed in 71 patients (29.8%). The sensitivity of the amplitude decrement was 29.6%, while the sensitivity of the area decrement was 38%, with specificities of 99.2% and 96.12%, respectively. Combining both criteria yielded a sensitivity of 43.7%, representing a 14.1% improvement over amplitude decrement alone.

CONCLUSION: Incorporating CMAP area decrement into RNS testing significantly enhances diagnostic sensitivity for MG, particularly in ocular forms, without compromising specificity. This combined approach presents a promising improvement over existing diagnostic tools for MG, especially in cases where traditional methods have limitations. Future research is needed to validate these findings.

SIGNIFICANCE: This study introduces a practical and easy to adopt enhancement to repetitive nerve stimulation, significantly improving diagnostic sensitivity for Myasthenia Gravis.

PMID:40279946 | DOI:10.1016/j.clinph.2025.04.004


Source: https://pubmed.ncbi.nlm.nih.gov/4027994 ... t9+e462414