Report Viewer

NINDS CDE Notice of Copyright
Fatigue Severity Scale (FSS)
Please visit this website for more information about the instrument: Fatigue Severity Scale
Freely available for non-profit research. For pharmaceutical studies: copyright belongs to Dr. Lauren Krupp, Permission required for use.
Supplemental - Highly Recommended: Mitochondrial Disease (Mito), Myalgic encephalomyelitis/Chronic fatigue syndrome (ME/CFS) as a subjective self-reported measure of fatigue
Recommendations for use: Indicated for studies requiring a measure of fatigue.
Supplemental: Multiple Sclerosis (MS), Parkinson's Disease (PD), Spinal Cord Injury (SCI), and SCI-Pediatric for adolescents at least 16 years of age
Exploratory: Amyotrophic Lateral Sclerosis (ALS)
Short Description of Instrument
Construct measured: Impact of fatigue on patient's daily life
Generic vs. disease-specific: Generic
Means of administration: Interview or paper and pencil
Intended respondent: Patient
# of items: 9
# of subscales and names of sub-scales: N/A
# of items per sub-scale: N/A
Comments/Special Instructions
Background: The FSS was developed and initial validation completed in patients with multiple sclerosis and systemic lupus, but the scale has been used in studies of fatigue in multiple other diseases including SCI. The FSS was recently suggested for both a screening and a rating instrument by an MDS Task Force. There are several more expansive scales that may be appropriate in a given study.
Scoring and Psychometric Properties
Scoring: Each item is a statement on fatigue that the subject rates from 1 (strongly disagree) to 7 (strongly agree). The scoring is done by calculating the average response to the questions (adding up all the answers and dividing by nine). Absolute thresholds for clinical meaningfulness have not been formally defined, although scores greater than 4 to 5 are considered indicative of significant fatigue.
Psychometric Properties: NOTE: Summary of demonstrated properties below includes data from both N. American and European MS studies.
Reliability: Cronbach's alpha .81 to .89; Cronbach's alpha in a Swiss MS cohort = .94. Convergent Validity: correlates with MFIS Spearman r=.68, p<.0001 in a majority RRMS Spanish population; r=.66, p<.0001 in a four-country European study; Kendall's Tau-b = 0.645, Dutch FSS; high correlation with fatigue VAS in a Swiss MS cohort (r=.79). Divergent Validity: Modest correlation with Beck Depression Inventory (r = .48) and EDSS (r= .45, p<.0001; r= 0.33, p<.0001 after adjusting for BDI) in an RRMS predominate Spanish population; correlation with EDSS (r = .34, p<.01) in a Swiss MS cohort. Sensitivity: Dutch FSS not responsive to change (z = -1.417, p= .156) following a four-week rehabilitation program.
Original Validation: It is correlated with single item, vitality visual analogue scale. The FSS measure differentiates fatigue in MS, lupus, ME/CFS and other fatiguing illnesses from healthy controls. It differentiates fatigue in ME/CFS which is higher than in MS and also fatigue in ME/CFS vs. depression. This measure is sensitive to treatment change in ME/CFS. The fatigue link to function is important, also known as fatigability, as similar fatigue levels across patients may be associated with widely divergent levels of impairment. Sensitivity, specificity, positive predictive value, etc., results would require an analysis of FSS scores from with CFS-diagnosed patients, subsyndromal patients, and healthy controls, which has not been done. Also, there is not a gold standard for ME/CFS diagnosis to make such comparisons.
Strengths: Administration only takes a few minutes.
Weaknesses: Limited data on psychometric properties of the FSS in North American MS populations are available.
Strengths: The FSS is brief to administer. It measures not just fatigue but the effect of fatigue on function. This measure has been widely used in ME/CFS.
Weaknesses: The FSS may be susceptible to ceiling effects as many ME/CFS patients scored close to or at the maximum score.
Mitochondrial Disease-Specific:
Strengths: Applied in several systematic observational studies on primary mitochondrial disorders. Easy to administer, low burden, and reproducible. Use of FSS is well documented across groups.
Weaknesses: Not validated in mitochondrial disorders. Scale has ceiling effects.
Key Reference:
Krupp LB, LaRocca NG, Muir-Nash J, Steinberg AD. The fatigue severity scale. Application to patients with multiple sclerosis and systemic lupus erythematosus. Arch Neurol. 1989 Oct;46(10):1121-3.
Additional References:
Bello-Haas VD, Florence JM, Kloos AD, Scheirbecker J, Lopate G, Hayes SM, Pioro EP, Mitsumoto H. A randomized controlled trial of resistance exercise in individuals with ALS. Neurology. 2007 Jun 5;68(23):2003-7.
Carter GT, Weiss MD, Lou JS, Jensen MP, Abresch RT, Martin TK, Hecht TW, Han JJ, Weydt P, Kraft GH. Modafinil to treat fatigue in amyotrophic lateral sclerosis: an open label pilot study. Am J Hosp Palliat Care. 2005 Jan-Feb;22(1):55-9.
Drory VE, Goltsman E, Reznik JG, Mosek A, Korczyn AD. The value of muscle exercise in patients with amyotrophic lateral sclerosis. J Neurol Sci. 2001 Oct 15;191(1-2):133-7.
Evatt ML, Chaudhuri KR, Chou KL, Cubo E, Hinson V, Kompoliti K, Yang C, Poewe W, Rascol O, Sampaio C, Stebbins GT, Goetz CG. Dysautonomia rating scales in Parkinson's disease: sialorrhea, dysphagia, and constipation - critique and recommendations by movement disorders task force on rating scales for Parkinson's disease. Mov Disord. 2009 Apr 15;24(5):635-46.
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 May 15;25(7):805-22.
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.
Lo Coco D, La Bella V. Fatigue, sleep, and nocturnal complaints in patients with amyotrophic lateral sclerosis. Eur J Neurol. 2012 May;19(5):760-3.
Perez Lloret S, Piran Arce G, Rossi M, Caivano Nemet ML, Salsamendi P, Merello M. Validation of a new scale for the evaluation of sialorrhea in patients with Parkinson's disease. Mov Disord. 2007 Jan;22(1):107-11.
Sanjak M, Bravver E, Bockenek WL, Norton HJ, Brooks BR. Supported treadmill ambulation for amyotrophic lateral sclerosis: a pilot study. Arch Phys Med Rehabil. 2010 Dec;91(12):1920-9.
Tellez N, Rio J, Tintore M, Nos C, Galan 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.
Valko PO, Bassetti CL, Bloch KE, Held U, Baumann CR. Validation of the fatigue severity scale in a Swiss cohort. Sleep. 2008 Nov;31(11):1601-7.
Mitochondrial Disease-Specific References:
LØkken N, Khawajazada T, Storgaard JH, Raaschou-Pedersen D, Christensen ME, Hornsyld TM, Krag T, Ørngreen MC, Vissing J. No effect of resveratrol in patients with mitochondrial myopathy: A cross-over randomized controlled trial. J Inherit Metab Dis. 2021 Sep;44(5):1186-98.
Montano V, Gruosso F, Carelli V, Comi GP, Filosto M, Lamperti C, Mongini T, Musumeci O, Servidei S, Tonin P, Toscano A, Modenese A, Primiano G, Valentino ML, Bortolani S, Marchet S, Meneri M, Tavilla G, Siciliano G, Mancuso M. Primary mitochondrial myopathy: Clinical features and outcome measures in 118 cases from Italy. Neurol Genet. 2020 Oct 20;6(6):e519.
Montano V, Lopriore P, Gruosso F, Carelli V, Comi GP, Filosto M, Lamperti C, Mongini T, Musumeci O, Servidei S, Tonin P, Toscano A, Primiano G, Valentino ML, Bortolani S, Marchet S, Ricci G, Modenese A, Cotti Piccinelli S, Risi B, Meneri M, Arena IG, Siciliano G, Mancuso M. Primary mitochondrial myopathy: 12-month follow-up results of an Italian cohort. J Neurol. 2022 Dec;269(12):6555-65.
Parikh S, Galioto R, Lapin B, Haas R, Hirano M, Koenig MK, Saneto RP, Zolkipli-Cunningham Z, Goldstein A, Karaa A. Fatigue in primary genetic mitochondrial disease: No rest for the weary. Neuromuscul Disord. 2019 Nov;29(11):895-902.
ME/CFS-Specific Reference:
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):1375.
Document last updated March 2024