Fatigue Severity Scale

Fatigue Severity Scale or FFS is a nine-item questionnaire designed in 1989 by Lauren B. Krupp, MD, Nicholas G. LaRocca, PhD, Joanne Muir-Nash, RN, and Alfred D. Steinberg, MD. It was developed to measure fatigue in patients with neurological illnesses, in particular, multiple sclerosis and systemic lupus erythematosus. In 2011, Jason, et al, showed when used with ME/CFS patients it had high reliability. They found that a Fatigue Severity Scale score of >4.95 would select 90% of CFS cases, and 84% of the time would correctly identify negative cases.

Some advantages for its use with ME/CFS patients are that the FSS questionnaire is brief to administer, it measures not just fatigue but the effect of fatigue on function, and has been used in widely in ME/CFS clinically and in research. A limitation is that the FSS may be susceptible to ceiling effects as many ME/CFS patients score close to or at the maximum score, so it is not suitable for severe and very severe ME patients.

The Fatigue Severity Scale copyright belongs to Dr. Lauren Krupp. It is freely available for non-profit research, but for pharmaceutical studies, permission required for use.

Notable studies

 * 2011, Fatigue Scales and Chronic Fatigue Syndrome: Issues of Sensitivity and Specificity (Full Text)

Learn more

 * NINDS CDE Notice of Copyright: Fatigue Severity Scale (FSS)