Association between myasthenia gravis and cognitive function: A systematic review and meta-analysis

The course of myasthenia gravis (MG) is complicated by increased reports of cognitive defects in both human and animal models, which suggests potential central nervous system (CNS) damage. We conducted a systematic review of the relationships between MG and cognitive function. This systematic review followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Major databases were searched to examine the neuropsychological studies of adults with MG. Weighted effect sizes were pooled by cognitive domain. Eight studies representing 300 subjects were included. Eight cognitive domain categories were identified: (i) Mini-Mental State Examination (MMSE), (ii) language, (iii) processing speed, (iv) verbal learning and memory, (v) visual learning and memory, (vi) attention span, (vii) response fluency, and (viii) motor performance. Nine (cognitive domain categories, MMSE, language, processing speed, verbal learning and memory (except for delayed recall memory), and motor performance) of 16 cognitive tasks revealed significant moderate effect sizes. Verbal logical-delayed memory, finger tapping with the preferred hand, and the Symbol Digit Modalities Test showed a greater magnitude relationship to cognitive function than did other specific cognitive domains. Verbal learning and memory seems to be the most significant affected according to cognitive domain categories. For MG, the ability of attention, response fluency, visual learning, and memory seems to be reserved. The MG patients seem to perform significantly worse than the non-MG controls in a range of cognitive domains. Our findings should be interpreted with caution because of the clinical and methodological heterogeneity of included studies.