Does fatigue occur in MS patients without disability?

Background: Motor dysfunction and fatigue are the most common impairments that are associated with multiple sclerosis (MS). Walk tests and scales demonstrate the presence of fatigue in patients with MS with different levels of disability. Objective: To evaluate objective and subjective fatigue in MS patients without disability. Methods: Were selected MS patients with relapsing remitting clinical course, from 18 to 55 years old and EDSS 0 to 1.5; controls were paired for age, gender, body mass index, and physical activity level. Fatigue caused by pulmonary diseases, anemia, diabetes, thyroid disease, psychiatry diseases (except depression), and orthopedic and rheumatologic diseases are excluded. All participants performed the 6-minute walk test (6MWT), the MS Functional Composite (MSFC), and completed the Modified Fatigue Impact Scale (MFIS) and the Beck Depression Inventory. A multivariate model was applied to identify the variables associated with fatigue. Results: 54 individuals were selected (31 patients; 23 controls). In the MSFC and 6MWT, no significant difference was observed between the groups. A MFIS total score indicated fatigue in 35% of the patients, 42% in the physical domain, 25.8% in the cognitive domain, and 29% in the psychosocial domain, which differed from the controls in all comparisons. Fatigue was associated with MS, low-physical activity, and mood disorders. Conclusions: Fatigue occurs in patients with MS in the absence of motor dysfunction and is associated with the disease itself, the sedentary lifestyle, and mood disorders. The 6MWT is not useful to demonstrate motor fatigue in subjects without neurological disability.