Multiple sclerosis : clinical and laboratory research
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Comparative Study
Fatigue in multiple sclerosis: a comparison of different rating scales and correlation to clinical parameters.
Fatigue is one of the most common, yet poorly defined, disabling symptoms in patients with multiple sclerosis (MS). To delineate more clearly the frequency and type of fatigue, we first compared four widely used fatigue scales in consecutive MS patients. Secondly, to further clarify the nature of fatigue, we investigated its relation to physical disability, course of the disease, immunotherapy, and depression. ⋯ The association of fatigue and depression suggests that there might be either common underlying mechanisms or interdependence by a cause-and-effect relationship that requires further investigation. The weak correlation within various fatigue scales is best explained by the fact that fatigue is a multidimensional symptom and, therefore, the available tests measure and weight different aspects of fatigue. Our findings underline the necessity for a more exact definition of fatigue and the development of more valid tools if these are to be used to evaluate treatments.