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Modified Fatigue Impact Scale (MFIS)
Please visit this website for more information about the instrument: Modified Fatigue Impact Scale (MFIS)
Supplemental: Amyotrophic Lateral Sclerosis (ALS), Friedreich's Ataxia (FA), Multiple Sclerosis (MS)
Exploratory: Myalgic encephalomyelitis/Chronic fatigue syndrome (ME/CFS)
Short Description of Instrument
Construct measured: Impact of fatigue on patient's daily life
Generic vs. disease specific: Generic
Means of administration: Self-report or by a trained interviewer for patients with visual or upper extremity impairments
Intended respondent: Patient
# of items: Full-length version - 21; Abbreviated version - 5
# of subscales and names of sub-scales: 3 - Physical, cognitive and psychosocial functioning
# of items per sub-scale: N/A
Administration: Full-length version - 5-10 minutes; Abbreviated version - 2-3 minutes
Comments/Special Instructions
The MFIS is based on the Fatigue Impact Scale (Fisk et al., 1994) which was developed from MS patient interviews. It is part of the Multiple Sclerosis Quality of Life Inventory (MSQLI) battery.
Scoring and Psychometric Properties
The total score is the sum of the scores for the 21 items. Subscale scores are the sum of the scores for items in the subscale. Users should refer to the MSQLI User's Manual for detailed scoring instructions for both the full length 21-item MFIS and abbreviated 5-item version. Each item is scored between 0 (never) and 4 (almost always). Total score varies between 0-84 and are obtained by adding scores for each of the sub-scales. The sub-scales scores are 0-36 (physical), 0-40 (cognitive) and 0-8 (psychosocial).
Psychometric Properties:
MS Psychometric Properties: NOTE: Limited data on psychometric properties in North American MS populations are available. Summary of demonstrated properties below includes data from both N. American and European MS studies.
Reliability: Cronbach's alpha [MSQLI field test population]: Total MFIS = .81, Cognitive subscale = .95, Physical subscale = .91, psychosocial subscale = .81, and abbreviated version = .80; Cronbach's alpha [four-country European study (Kos et al., 2005)]: Total MFIS = .92, Cognitive subscale = .92, Physical subscale = .88, psychosocial subscale = .65; Reproducibility: ICC = .91 (Kos et al., 2005); Convergent Validity: MFIS correlates with the Fatigue Severity Scale: Spearman r =.68, p<.0001 in an RRMS predominate Spanish population (TÉllez et al., 2005); r =.66, p<.0001 in a four-country European study (Kos et al., 2005); Kendall's Tau-b = 0.729, Dutch MFIS. (Kos et al., 2003) Divergent Validity: Does not diverge from Beck Depression Inventory (Spearman r = .7, p<.0001); divergence from EDSS (r = .30, p<.0001; r = 0.15, p =.02 after adjusting for BDI) (TÉllez et al., 2005) Sensitivity: Dutch MFIS sensitive to change (z = -3.401, p =. 001) following a four-week rehabilitation program; no floor or ceiling effect detected.
Strengths/ Weaknesses:
Scale is easy to administer. It has high face validity for patients because it focuses on the effect of fatigue on daily activities. Subscales allow for research on specific areas of function, but they are highly correlated with each other.
Strengths: This scale is free to use. It might be useful for comparison with people with MS. This form is part of a modular instrument MSQLI, which contains a free version of the health status (SF-36), perceived deficits questionnaire (PDQ) and other questionnaires, some of them could be useful in ME/CFS, though others would be very specific to MS. The subscales may be useful to investigators interested in testing hypotheses concerning these different areas of function.
Weaknesses: This scale has not been validated in ME/CFS. It measures the impact and not the severity of fatigue and there are no questions on post-exertional malaise. This scale could be potentially used alongside a scale exploring severity.
Key Reference:
Ritvo PG, Fischer JS, Miller DM, Andrews H, Paty D, LaRocca NG. Multiple Sclerosis Quality of Life Inventory: A User's Manual. New York, NY: National Multiple Sclerosis Society;1997.
Modified Fatigue Impact Scale (MFIS). Retrieved 03Oct2023 from
Additional References:
Fisk JD, Ritvo PG, Ross L, Haase DA, Marrie TJ, Schlech WF. Measuring the functional impact of fatigue: initial validation of the fatigue impact scale. Clin Infect Dis. 1994;18 Suppl 1:S79-S83.
Kos D, Kerckhofs E, Carrea I, Verza R, Ramos M, Jansa J. Evaluation of the Modified Fatigue Impact Scale in four different European countries. Mult Scler. 2005 Feb;11(1):76-80.
Kos D, Kerckhofs E, Nagels G, D'Hooghe BD, Duquet W, Duportail M, Ketelaer P. Assessing fatigue in multiple sclerosis: Dutch modified fatigue impact scale. Acta Neurol Belg. 2003 Dec;103(4):185-91.
Mathiowetz V. Test-retest reliability and convergent validity of the Fatigue Impact Scale for persons with multiple sclerosis. Am J Occup Ther. 2003 Jul-Aug;57(4):389-95.
TÉllez N, Río J, TintorÉ M, Nos C, Galán I, Montalban X. Does the Modified Fatigue Impact Scale offer a more comprehensive assessment of fatigue in MS? Mult Scler. 2005 Apr;11(2):198-202.
Whitehead L. The measurement of fatigue in chronic illness: a systematic review of unidimensional and multidimensional fatigue measures. J Pain Symptom Manage. 2009 Jan;37(1):107-28.
ALS-Specific References:
Fischer JS, Rudick RA, Cutter GR, Reingold SC. The Multiple Sclerosis Functional Composite Measure (MSFC): an integrated approach to MS clinical outcome assessment. National MS Society Clinical Outcomes Assessment Task Force. Mult Scler. 1999 Aug;5(4):244-50.
Fisk JD, Pontefract A, Ritvo PG, Archibald CJ, Murray TJ. The impact of fatigue on patients with multiple sclerosis. Can J Neurol Sci. 1994 Feb;21(1):9-14.
Document last updated October 2023