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Multidimensional Fatigue Inventory (MFI)
Availability
Free to use for academic use on the condition that the original publication (Smets et al., 1995) is properly referenced.
Classification
Exploratory: Myalgic encephalomyelitis/Chronic fatigue syndrome (ME/CFS)
Short Description of Instrument
Construct measured: General Fatigue, Physical Fatigue, Mental Fatigue, Reduced Motivation and Reduced Activity
 
Generic vs. disease specific: Generic
 
Means of administration: Paper and pencil
 
Intended respondent: Patient
 
# of items: 20
 
# of subscales and names of sub-scales: 5 - General Fatigue, Physical Fatigue, Mental Fatigue, Reduced Motivation and Reduced Activity
 
# of items per sub-scale: 4
Comments
This measure was developed by Smets et al. (1995). It has been translated to several languages. The original validation had a number of group comparisons including both healthy controls and groups of subjects who at various time points were expected to be fatigued. This included army trainees and doctors undertaking shift work. This means there are normative data available for reference. There is a French-Canadian and French version which is a 15-item, 5-point Likert scale instrument.
Scoring
Each of the 5 subscales contains 4 items rated from 0 (completely true) to 5 (no, not true) for a final subscale score of 4 – 20, lower scores indicate less fatigue. Two of the 4 items are formulated in a positive and 2 in a negative direction. Reeves et al. (2005) used the MFI to measure severe fatigue in CFS, and to do this, they used only two of the five subscales: general fatigue and reduced activity. Using the 2005 Reeves case definition standards, severe fatigue was defined as greater than or equal to 13 on general fatigue or greater than or equal to 10 on reduced activity. Elbers et al. (2012) found that general fatigue and physical fatigue items of MFI were observed to be one factor in a 4-factor modelling. However, the Institute of Medicine (2015) report stated the Reeves definition includes an “overrepresentation of individuals with depression and posttraumatic stress disorder,” making it difficult to know how these thresholds apply to patients with ME/CFS. In contrast, Jason et al. (2011) reported a study by Tiersky et al. (2003) that reported mean MFI general fatigue scores ranged 18.3 to 18.8. Further research is needed.
A floor effect was found for motivational fatigue and ceiling effects for physical fatigue and reduced activity items (Elbers et al., 2012).
Rationale/Justification
Strengths/Weaknesses:
 
Advantages: A significant decrease in MFI score was found to indicate an improvement of >2 cm on a VAS-f over a 1 month period (Friedman et al., 2010;Gentile et al., 2003)
 
Limitations: MFI was not specific and sensitive enough to discriminate fatigue from CFS and from depressed individuals (Jason et al., 2011). MFTQ’s (ME/CFS Fatigue Type Questionnaire) post-exertional fatigue was sensitive (90%) and specific (.93) in identifying true CFS negatives (Jason et al., 2011).
 
Psychometric Properties: Good internal consistency and construct validity in CFS. Cronbach’s alpha = 0.70. Validated in CFS patients in the US (Lin et al., 2009) and many other populations – post polio fatigue (Dencker et al., 2015), cancer-related fatigue (Hagelin et al., 2008). However, as noted above, the Institute of Medicine report noted that definition used in the Lin ME/CFS study included patients with other conditions.
References
Smets EM, Garssen B, Bonke B, De Haes JC. The Multidimensional Fatigue Inventory (MFI) psychometric qualities of an instrument to assess fatigue. J Psychosom Res. 1995;39(3):315–325.
 
Dencker A, Sunnerhagen KS, Taft C, Lundgren-Nilsson Å. Multidimensional fatigue inventory and post-polio syndrome – a Rasch analysis. Health and Quality of Life Outcomes. 2015;13:20.
 
Elbers RG, van Wegen EE, Verhoef J, Kwakkel G. Reliability and Structural Validity of the Multidimensional Fatigue Inventory (MFI) in Patients with Idiopathic Parkinson’s Disease. Parkinsonism Relat Disord. 2012;18(5):532–536.
 
Friedman JH, Alves G, Hagell P, Marinus J, Marsh L, Martinez-Martin P, Goetz CG, Poewe W, Rascol O, Sampaio C, Stebbins G, Schrag A. Fatigue rating scales critique and recommendations by the Movement Disorders Society task force on rating scales for Parkinson's disease. Mov Disord. 2010;25(7):805–822.
 
Gentile S, Delaroziere JC, Favre F, Sambuc R, San Marco JL. Validation of the French ‘multidimensional fatigue inventory’ (MFI 20). Eur J Cancer Care (Engl) 2003;12:58–64.
 
Hagelin CL, Wengström Y, Ahsberg E, Fürst CJ. Fatigue Dimensions in Patients with Advanced Cancer in Relation to Time of Survival and Quality of Life. Palliat Med. 2008;23(2):171–178.
 
Institute of Medicine. Beyond Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: Redefining an Illness. Washington (DC): National Academies Press, 2015.
 
Jason LA, Evans M, Brown M, Porter N, Brown A, Hunnell J, Anderson V, Lerch A. Fatigue Scales and Chronic Fatigue Syndrome: Issues of Sensitivity and Specificity. Disabil Stud Q. 2011 Winter;31(1). pii: 1375.
 
Lin JM, Brimmer DJ, Maloney EM, Nyarko E, Belue R, Reeves WC. Further validation of the Multidimensional Fatigue Inventory in a US adult population sample. Popul Health Metr. 2009;7:18.
 
Reeves WC, Wagner D, Nisenbaum R, Jones JF, Gurbaxani B, Solomon L, Papanicolaou DA, Unger ER, Vernon SD, Heim C. Chronic Fatigue Syndrome – A clinically empirical approach to its definition and study. BMC Medicine. 2005;3:19.
 
Tiersky LA, Matheis RJ, Deluca J, Lange G, Natelson BH. Functional status, neuropsychological functioning, and mood in chronic fatigue syndrome (CFS): relationship to psychiatric disorder. J Nerv Ment Dis. 2003 May;191(5):324–331.
Recommended Instrument for
ME/CFS
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