Quality of life in multiple sclerosis: The differential impact of motor and cognitive fatigue

BACKGROUND: Multiple sclerosis is a chronic disease leading to reduced quality of life. OBJECTIVES: To investigate whether motor and cognitive fatigue impact differently on aspects of quality of life among patients with multiple sclerosis, independently from bodily disability. METHODS: 79 patients with multiple sclerosis from Aalborg University Hospital, Denmark were included in an observational, cross-sectional study. Each subject completed two separate questionnaires regarding fatigue (Fatigue Scale for Motor and Cognitive Functions and Modified Fatigue Impact Scale) and one regarding quality of life (Short Form 36). Disability was measured with the Expanded Disability Status Scale (EDSS)-scores obtained from patient records. RESULTS: All fatigue scores were significantly correlated to all areas of quality of life (p < 0,05). This remained significant after adjustment for age, disease duration and EDSS-score. When looking at each type of fatigue separately, cognitive fatigue correlated mainly with mental health aspects of quality of life and motor fatigue with physical health areas of quality of life. CONCLUSION: Increased motor and cognitive fatigue lead to a differential reduction in physical and mental quality of life, independently of bodily disability. This underlines the importance of proper assessment and treatment of fatigue among patients with multiple sclerosis.