Pharmacotherapy in multiple sclerosis-induced cognitive impairment: A systematic review and meta-analysis

Multiple sclerosis (MS) is an inflammatory demyelinating disease of the central nervous system (CNS) commonly complicated by cognitive impairment. Unfortunately, no medical therapy has been proved to improve cognitive problems in these patients. This meta-analysis investigated the effectiveness of different categories of drugs on the minimal assessment of cognitive function in MS (MACFIMS)-related tasks outcome in MS patients. To this end, a systematic evaluation was conducted using PubMed, Google Scholar, and Scopus databases. Among a total of 128 publications, 31 studies met our inclusion criteria, and 22 included in the meta-analysis. We found that symbol digit modalities test (SDMT), paced auditory serial addition test (PASAT), controlled oral word association test (COWAT), and California verbal learning test (CVLT) were the most frequently reported tasks in included studies. The frequently reported drugs were classified into five main groups of acetylcholine esterase inhibitors, CNS stimulants, fampridine, herbal remedies, and miscellaneous. Overall heterogeneity of the studies was modest. The treatments did not affect cognitive function in any of the tasks (p>0.05). However, in subgroup analysis, we found significant improvement in SDMT task outecomes after treatment by fampridine (0.283 SMD, 95%CI, 0.015 to 0.550, p = 0.039, I2=11.7%). Our meta-analysis highlighted that the currently proposed therapeutic agents had no beneficial effects on the alleviation of MS-induced cognitive impairment.