Self-report instruments for fatigue assessment: a systematic review.

This systematic review analyzed 18 self-reported fatigue instruments for adults. Five databases were searched combining fatigue with instrument, questionnaire, inventory, scale, or assessment. Eighteen fatigue instruments and six definitions of fatigue were found. Six instruments apply to physical or psychiatric disease; five are cancer-specific. Nine were unidimensional; others included intensity (n = 10), mental (n = 7), and physical (n = 7) dimensions. Eleven instruments had 15 or fewer items; the longest had 40 items. Four instruments were discriminative; 14 were evaluative. Fifteen assessed reliability using Cronbach's alpha, which was greater than or equal to .90 seven times. Validity tests were convergent or divergent (n = 11), discriminant (n = 10), and factor analysis (n = 9). Because fatigue is a highly prevalent limiting symptom, this review is important for improving fatigue assessment.