MFI-20 comprises 20 statements to assess fatigue, which are
measured on a five-point scale (14). Five different dimensions of fatigue
(four items each) are calculated from these statements: 1) general fatigue,
2) physical fatigue, 3) reduced activity, 4) reduced motivation, and 5)
mental fatigue. Scores vary from 0–20; a high score indicates greater
fatigue. Age-related Dutch reference values were derived from the study
by Smets et al.