Assessment of cognitive function and fatigue in multiple sclerosis

Address for correspondence: Caio Góes (email: [e-mail]).

Abstract

Multiple sclerosis is an inflammatory, chronic demyelinating disease that affects the central nervous system. Its resulting lesions can incur in progressive fatigue and cognitive function impairment, severely impacting quality of life and the economic burden of disease, regardless of the physical disability. Almost half of the patients defined as NEDA-3 had deterioration in at least 2 cognitive domains in a 2-year follow-up. The study’s aim was to compare the Symbol Digit Modalities Test (SDMT) and the Modified Fatigue Impact Scale (MFIS) results when applied to patients with multiple sclerosis, and to determine if a higher level of fatigue impacted the performance in cognitive function evaluation. The SDMT is a neuropsychological tool to assess sustained attention and information processing speed, two cognitive domains commonly impaired in multiple sclerosis, with a lower score indicating worse performance and more impairment. Conversely, the MFIS is an instrument to measure the subjective experience of fatigue, such that a higher score indicates larger impact, and it was used in place of the 40-item-long Fatigue Impact Scale to avoid unnecessary patient fatigue without skewing the results. Participants with a previous diagnosis of multiple sclerosis were chosen from the general population of the city of São Paulo, Brazil. They were instructed on how to adequately fill the MFIS and, upon finishing, the SDMT was applied by a trained researcher. The results were then compiled in a spreadsheet and compared through the Pearson r of each test result’s z-score. The test results were Pearson r = -0.273 when correlating the SDMT and MFIS z-scores, with p = 0.007, indicating a statistically significant negative correlation between the SDMT and MFIS. The results enable us to infer that, indeed, patients with multiple sclerosis suffering from fatigue perform worse in cognitive demanding tasks.

 

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Publikationsverlauf

Artikel online veröffentlicht:
02. Oktober 2024