Ecological Momentary Assessment of the association between fatigue and daily physical activity in patients with Multiple Sclerosis

Abstract

Background: Fatigue is a major symptom in Multiple Sclerosis (MS) and contributes to impaired daily activity. While, it is unclear if fatigue and daily physical activity are associated in Patients with MS (PwMS). Objective: To investigate the longitudinal association between feelings of fatigue and level of physical daily activity in PwMS over a period of 1 week. And thereby, determine potential confounders that distort the relationship between feelings of fatigue and level of daily physical activity in PwMS. Methods: 17 ambulatory PwMS aged between 18-65 years old scored the level of fatigue 7 times a day for 7 days and wore an accelerometer on the wrist to measure the mean active minutes continuously. The one-minute daily physical activity counts were categorized in mean counts of: I) one hour before the measurement of fatigue, II) on the exact moment of fatigue and III) one hour after measurement of fatigue. Multilevel modelling was used for analysis. Results: An association between fatigue and daily physical activity was found. An increase of fatigue is followed by a decrease of daily physical activity on the exact moment (ß -.059, p=0.05) and an hour after fatigue measurement (ß -.107, p<.000). No potential confounders were found that distort this association. Conclusion: To the best of our knowledge this was the first Dutch study to investigate the association between fatigue and daily physical activity with a 7 day Ecological Momentary Assessment design. These results suggest that an increase of fatigue is followed by a decrease of daily physical activity in both the exact moment and one hour after fatigue measurement. These findings suggest an adaptation of the current health care in managing fatigue by planning daily activity.