RESUMO
BACKGROUND: Fatigue is a common symptom in patients with multiple sclerosis and it can lead to activity limitations. Thus, it is important to analyze the relationship between fatigue and activity outcomes, such as walking speed and mobility. OBJECTIVES: To investigate the relationship between fatigue and walking speed and mobility in individuals with multiple sclerosis. METHODS: A cross-sectional study was performed. Adults with multiple sclerosis, without cognitive impairments and who were able to walk were recruited. Fatigue was assessed with the Modified Fatigue Impact Scale (MFIS). Walking speed, usual and fast, was assessed with the 10-meter Walk Test (10MWT), and mobility with the Timed Up and Go Test (TUG). Pearson correlation analysis was performed. A significance level of 5 % was used. RESULTS: Thirty participants were included, most of the relapsing-remitting multiple sclerosis (n = 24, 80 %). A mean age of 41 (11) years and the median Expanded Disability Status Scale (EDSS) score was 2.65 (2.18) points. Mean MFIS score was 41.87 ± 19.42 points, mean usual walking speed was 1.02 ± 0.28 m/s, mean fast walking speed was 1.55 ± 0.48 m/s, and the mean total time in the TUG was 10.07 ± 3.05 s. A significant negative correlation of moderate magnitude was found between fatigue and usual walking speed (r=â0.51, p < 0.05). A significant negative correlation of moderate magnitude was found between fatigue and fast walking speed (r=â0.54, p < 0.05). A significant, positive correlation of moderate magnitude was found between fatigue and mobility (r = 0.54, p < 0.05). CONCLUSION: There was a correlation between fatigue and walking speed and mobility in individuals with multiple sclerosis. These results highlight the need to assess fatigue in individuals with multiple sclerosis, since the presence of fatigue is associated with reduced walking speed and mobility.
RESUMO
BACKGROUND: Fatigue is one of the most common symptoms reported by individuals with multiple sclerosis and it contributes to the reduction of the functionality. Therefore, it is important to assess the impact of fatigue on daily living of individuals with multiple sclerosis. The Modified Fatigue Impact Scale (MFIS) is an instrument to assess the perception of the impact of fatigue. However, there have been no investigations about the measurement properties of this instrument administered over the telephone for individuals with multiple sclerosis. OBJECTIVES: To verify the concurrent validity, the test-retest reliability, the standard error of measurement (SEM) and the minimal detectable change (MDC) of the MFIS applied over the telephone to assess the perception of the impact of fatigue of individuals with multiple sclerosis. METHODS: The MFIS, composed of 21 items covering three domains: physical, cognitive and psychosocial, was applied at three different moments with an interval of 5-7 days. To establish the concurrent criterion validity, the face-to-face application and the first evaluation by telephone were used. The two telephone assessments were used to assess the test-retest reliability The intraclass correlation coefficient (ICC) with 95 % confidence interval (CI) and the Bland-Altman method were used. The standard error of measurement (SEM) and the MDC was calculated according to reliability results. RESULTS: Thirty individuals (40.83 ± 10.61, 60 % female) were included. The median score on the Expanded Disability Status Scale was 2.00 (±4.00). The majority of participants experienced fatigue (n = 17; 56.67 %). A significant and high magnitude correlation (0.70 ≤ ICC ≤ 0.87, p < 0.001) was found in the investigation of concurrent criterion validity. The Bland-Altman method showed a mean difference between 0.70 to 2.17 points between face-to-face and telephone-based application of the MFIS. For test-retest reliability, a significant and very high magnitude correlation (0.91 ≤ ICC ≤ 0.97, p < 0.001) was found. The Bland-Altman method showed a mean difference between -0.03 and -0.77 points between two telephone-based applications. The SEM and the MDC were 0.71 and 1.97 points. CONCLUSION: The telephone-based application of the MFIS to assess the perceived impact of fatigue in individuals with multiple sclerosis demonstrated adequate measurement properties, and may be a valuable tool to assess patients in clinical practice.
