Fatigue Impact Scale

Despite fatigue being one of the most common symptoms presenting in primary care, clinicians and researchers were constrained by a lack of validated, reliable and fatigue-specific measures. In 1994, a Canadian group frustrated by this limitation developed the Fatigue Impact Scale (FIS) [1]. Since then, it remains one of the most widely used tools, although there now exist modified versions [the modified Fatigue Impact Scale (MFIS), the daily FIS, the unidimentional FIS and the abbreviated MFIS]. The FIS has been translated and validated in 30 languages. It is a detailed and relatively lengthy tool, which takes ∼3 min to complete in a non-fatigued person, but may take much longer in a severely fatigued respondent. The subject completes the tool personally, rather than having an interview and thus, no training is required to deliver it. Scoring is simple and is described briefly below (further details can be found from reference [2]). The score reflects functional limitation due to fatigue experienced within the previous month rather than a measure of the level of fatigue. It may be used in both the clinical and the research setting in people for whom fatigue is a predominant symptom.