Validity, reliability, and sensitivity to change of the myasthenia gravis activities of daily living profile in a sample of Italian myasthenic patients.

Abstract

The purpose of this study is to report on the validity, reliability, and sensitivity of the myasthenia gravis activities of daily living profile (MG-ADL) in a sample of Italian patients. Patients with myasthenia gravis (MG) completed a protocol that included the MG-ADL, the WHO Disability Assessment Schedule (WHODAS 2.0), the Besta Neurological Institute rating scale for myasthenia gravis, and the MG-composite. Cronbach's alpha was used to test reliability, Spearman's correlation and intra-class correlation coefficient (ICC) to test short-term test-retest, Kruskal-Wallis test to assess differences in MG-ADL between patients with different disease severity, and Wilcoxon signed-rank test to assess sensitivity to change. In total, 58 patients were enrolled: 44 were females, mean MG duration 10.5±10.4years, mean MG-ADL 3.98±3.07. The MG-ADL showed good internal consistency (alpha=.774), stability (test-retest correlation=.98, ICC=.97). It was superior to the WHODAS 2.0 in differentiating patients with different MG type and severity (P<.001), it showed higher sensitivity to change (P=.001 for improved and P=.007 for worsened patients) and higher correlation with the MG-composite (RHO=.625). Our analysis shows that the Italian version of the MG-ADL is valid, reliable, stable, and sensitive to change.