Fatigue in multiple sclerosis: a comparison of different rating scales and correlation to clinical parameters

Abstract

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.