Fatigue is a common symptom in myasthenia gravis (MG), but both objective and subjective measures of fatigue are poorly studied in the disease. We conducted a pilot study of static fatigue testing (SFT) in a group of MG patients, using an isometric quantified muscle analysis computer system. Results from sustained isometric contraction of 5 muscle groups in 77 patients were correlated to the Quantitative MG Score (QMG) and the Activities of Daily Living Profile (MG-ADL), two commonly used outcome measures. Pearson correlation coefficients for the SFT were highest (0.33) for hand grip for both the QMG and MG-ADL. Correlations were quite poor for the proximal muscle groups and ankle dorsiflexion. More work is needed to develop objective and subjective measures of fatigue in MG.
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