Cognitive performance in patients with Myasthenia Gravis: an association with glucocorticosteroid use and depression

Abstract

ABSTRACT. 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.

Frequency and Correlates of Mild Cognitive Impairment in Myasthenia Gravis

“…As far as is known, this study is the first that has been purposefully designed to evaluate the frequency of MCI in MG; therefore, comparison with other data is not feasible. However, in a recent Portuguese study, the authors using the Montreal Cognitive Assessment (MoCA)a first-level screening test for MCI-described a frequency of cognitive impairment of 66.7%, which is rather similar to that described in the present study [10].…”

“…Some authors showed that corticosteroids may induce negative effects on memory and executive functioning [40]. Indeed, in a cross-sectional study conducted by Ayres and colleagues, the authors described an association between worse memory performance, depression, and glucocorticoid use [10]. Although no association was found between cognitive impairment and corticosteroid use in the present study, we found a positive correlation between BDI score and prednisone dosage.…”

“…However, several limitations must be considered when interpreting our data. First, the most important limitation of our study is the small sample size, although most previous studies have used smaller MG patient samples than the one assessed in the present study [7,8,10]. Therefore, we could not perform stratified association analyses related to individual cognitive domains vs. putative MG correlates.…”

“…Studies that have assessed the frequency and type of cognitive impairment in patients with MG are still scant and have often reported contradictory results. Some authors have described low cognitive performance on tests evaluating memory, executive functioning, and visuospatial abilities in patients with MG [8][9][10][11]. In contrast, others have not confirmed these findings, suggesting that MG patients' worse performance on cognitive tasks may depend on muscle fatigability, comorbidities, and visual and motor slowness [12,13].…”

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“…However, prednisone does have an effect on CNS function. The use of glucocorticosteroids can alter cognition and mood (30,31). We took the effects of hormones on cognition into account but did not perform the subgroup, correlation, and IRM, immediate recall memory; DRM, delayed recall memory; LL, lower limit; UL, upper limit; CI, confidence interval.…”