Cognitive Performance in Patients with Myasthenia Gravis: an Association with Glucocorticosteroid Use and Depression

We investigated the cognitive performance of patients with Myasthenia Gravis (MG) through a cross-sectional study. A battery of cognitive assessments and self-report questionnaires regarding quality of life (QoL), sleep, and depression were applied. The sample consisted of 39 patients diagnosed with MG. The scores showed a predominance of cognitive impairment in the Montreal Cognitive Assessment screening test (MoCA) (66.7%) and in the immediate (59.0%) and recent memory (56.4%) tests. However, after the Poisson regression analysis with robust variance, it was found that patients diagnosed with depression had a prevalence ratio (PR) of 1,887 (CI 1,166‒3,054) for lower MoCA scores, PR=9,533 (CI 1,600‒56,788) for poorer phonemic verbal fluency scores, and PR=12,426 (CI 2,177‒70,931) for the Semantic Verbal Fluency test. Moreover, concerning a decline in short-term memory retention, patients using glucocorticosteroids (GC) and with Beck Depression Inventory scores indicating depression showed PR=11,227 (CI 1,736‒72,604) and PR=0.35 (CI 0.13‒0.904), respectively. No correlation was found between the QoL questionnaire and performance in cognitive tests. We found worse performance in tasks of memory and executive functions in MG patients. These are not associated with the length and severity of the disease. However, a significant prevalence ratio was found for poorer memory performance in patients diagnosed with depression and in those using GC.