Fatigue Severity Scale

Multiple Sclerosis: (Learmonth et al, 2013; Mean age 49.2 (9); Disease duration (years) mean 11.8 (8.2))

• The SEM for the FSS was 0.7 points (mean = 5.1 points), indicating that a change of less than 0.7 points may be due to measurement error.

Multiple Sclerosis: (Learmonth et al, 2013)

• The MDC provides an indication of clinically important change and is based on the SEM. The FSS had the smallest estimates of clinically important change; however, results indicated that a change in FSS score of 1.9 points (38% of the overall mean score) would be necessary to reflect a clinically important change.
• The CV for the FSS indicated that a change in score of 10.3% or less may be expected over six months and therefore, this level of change or less could be interpreted as no change in fatigue.
• Researchers and clinicians should be aware that a small change in FSS scores might be due to measurement error rather than a clinically relevant change.

Multiple Sclerosis:

(Learmonth et. al., 2013; n=86, mean age=49.2(9), disease duration 11.8 (8.2).

• Moderate: ICC = 0.751 over six months

Convergent Validity:

Multiple Sclerosis:

Learmonth et al, 2013 n=82

• Excellent (r = 0.754) correlation of FSS with MFIS
• Adequate (r = 0.532) correlation of FSS with PDDS
• Adequate (r = 0.350) correlation of FSS with HADS (anxiety)
• Adequate (r = 0.456) correlation of FSS with HADS (depression)
• Adequate (r = 0.466) correlation of FSS with SF-MPQ (sensory)
• Adequate (r = 0.569) correlation of FSS with SF-MPQ (affective)
• Adequate (r = 0. 0.491) correlation of FSS with PSQI
• Excellent (r = 0.628) correlation of FSS with MSWS-12
• Adequate (r = −0.405) correlation of FSS with 6 MW
• Poor (r = −0.263) correlation of FSS with SDMT

(Téllez et al, 2005)—Excellent (r=0.68, p)

Parkinson’s Disease:

(Hagell et al, 2006; n = 118, mean age = 63.9(9.6) years, mean time post PD = 8.4 (5.7) years)

• Mean SD (FSS) score for PD patients; 3.9 (1.6), range 2.6-5.2

(Winward et al; n = 37; H&Y Stages 0 - 4; mean age = 64.1(8.17)

• Mean FSS Score = 4.08 (1.46); FSS Scored 0 - 7

(Fereshtehnejad et al, 2013; n = 90, mean age = 62.0 (10.7) years, mean duration of disease = 6.0 (4.8) years)

• Mean FSS Score = 4.4 (2.0), range 1-7

Parkinson's Disease:

(Valderramas et al, 2012; n = 30, mean age = 62 (11) years, mean time post- PD = 7.6 (6.5) years)

• The evaluation of the FSS-BR (Fatigue Severity Scale-Brazilian-Portuguese version) suggests an excellent Test-retest reliability (ICC = 0.91)

Parkinson’s Disease:

(Hagell et al, 2006)

• Excellent internal consistency (Cronbach’s alpha = 0.94)

(Grace et al, 2006)

• Excellent split half reliability (Cronbach’s alpha = 0.86 and 0.91)
• For 8 out of the 9 items, Adequate-Excellent (0.44-0.78) correlation was observed.
• For item 2, Poor (0.27) correlation was seen.

Convergent Validity:

Parkinson’s Disease:

• Excellent (r = -0.77) negative correlation with Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT-F) scale (Hagell et al, 2006).
• Excellent (r = 0.62) correlation with Nottingham Health Profile (NHP-EN) scale (Hagell et al, 2006).
• Excellent (r = 0.84) correlation with Parkinson’s Fatigue (PFS) scale (Grace et al, 2006).
• Poor-adequate (r = 0.22-0.47) correlation with Parkinson’s Disease Questionnaire-39 (PDQ-39) scale (Herlofson et al, 2003; n = 66, mean age = 70.8 (9.9) years, time since PD = 70.2 (56.1) months).
• Adequate (r = 0.37) correlation with MOS-SF-36 scale (Herlofson et al, 2003).
• Poor (r = 0.19) correlation with Hamilton Depression Rating (HAM-D) scale (Garber CE & Friedman JH, 2003; n = 37)
• Excellent (r = 0.80) correlation with Fatigue rating Scale (Grace et al, 2006)
• Poor-adequate (r = 0.22-0.47) correlation with Parkinson’s Disease Questionnaire-39 (PDQ-39) scale (Herlofson et al, 2003; n = 66, mean age = 70.8 (9.9) years, time since PD = 70.2 (56.1) months)
• Excellent (r = 0.93) correlation of FSS-BR with PDQ-39 (Valderramas et al, 2012)
• Excellent (r = 0.75) correlation of FSS-BR with Beck Depression Inventory (Valderramas et al, 2012)
• Adequate (r = 0.40) correlation of FSS-BR with Hoehn & Yahr scale (Valderramas et al, 2012)
• Adequate (r = 0.45) correlation of the FSS-BR with UPDRS (Valderramas et al, 2012)
• Adequate (r = 0.37) correlation with MOS-SF-36 scale (Herlofson et al, 2003)
• Poor (r = 0.19) correlation with Hamilton Depression Rating (HAM-D) scale (Garber CE & Friedman JH, 2003; n = 37)
• Excellent (r = 0.80) correlation with Fatigue rating Scale (Grace et al, 2006)
• Poor (r = -0.184) correlation of FSS with 6 minute walk test (Garber CE & Friedman JH, 2003)

Parkinson’s Disease:

(Hagell et al, 2006)

• The Floor/Ceiling effects were adequate (2.5%) for a sample of PD patients.

Parkinson’s Disease:

Responsiveness to Pharmocological Intervention Mendoca et al, 2007; n = 17 treatment arm, receiving methyphenidate; mean age = 62.2(10), mean H&Y Stage = 2.58(0.5); n = 19 placebo arm, mean age = 66.3(7.6), mean H&Y Stage = 2.38(0.3)

• Those persons in the treatment arm had a significant (p < 0.04) reduction in FSS Score by 6.5 points (from FSS = 43.8 at baseline); Cohen’s d = 0.79
• Smaller reductions in the placebo group did not reach levels of significance Response to Exercise Intervention: Winward et al, 2010; H&Y 0-4. n = 20 exercise group, mean age = 63.4(6.7); n = 19 control group, mean age = 64.9(9.6)
• No significant difference in score reduction between exercise and control group at 12 weeks.

Obesity: (Impellizzeri et al, 2013; n=220, mean age=47 (15)) 

• The agreement as measured using the SEM was 0.43 (0.36 to 0.54) corresponding to 13% (11 to 17%).

Obesity: (Impellizzeri et al, 2013) 

• The MDC was 1.2 points (37%). Cronbach’s alpha was 0.94 and 0.93 at baseline and post-intervention, respectively.

Post-poliomyelitis Syndrome: (Koopman et al, 2014; n = 61, mean age = 59 (10) years, mean time post onset of PPS = 14.2 (11.5) years) 

• The smallest detectable change for FSS (range 1-7) was 1.55 or 28.7%, which represents the percentage of the means of the FSS and CIS20-F. The authors found this SDC to be high and therefore insufficiently sensitive to detect changes beyond measurement error in single individuals. However, much smaller changes can be detected at the group level.

Healthy Population:

(Grace et al, 2006; n = 16, mean age = 69.94 years)

• Mean (SD) FSS scores for healthy individuals; 2.3 (0.7)

Post-poliomyelitis Syndrome: (Koopman et al, 2014; n = 61, mean age = 59 (10) years, mean time post onset of PPS = 14.2 (11.5) years)

• Mean FSS Score = 5.3 (1.3), range 1-7

Epilepsy: (Hernandez-Ronquiloa et al, 2011)

PWE (patients with epilepsy) mean age = 36.5 (16.8) 
PMS (patients with different neurological problems) mean age = 40.2 (10 ) 
HV (healthy volunteers) mean age = 39.6 (11.5)

• Healthy (HV) (n=34), Mean fatigue 2.6 (1.1)
• Epilepsy (PWE) (n=67), Mean fatigue 4.2 (1.5)
• MS (PMS) (n = 30), Mean fatigue 4.8 (1.4)
• Migraine (PMS) (n = 19), Mean fatigue 4.4 (1.9)
• Radiculopathy (PMS) (n = 7), Mean fatigue 4.5 (0.9)

Post-Poliomyelitis Syndrome:

(Koopman et al, 2014; n = 61, mean age = 59 (10) years, mean time post-onset of PPS = 14.2 (11.5) years)

• ICC (95% CI) = 0.80 Excellent

Chronic Hepatitis C:

(Rosa et al, 2014; n = 386, 462, mean age = 48.9(10.36), 44(11.81) years)

• ICC = 0.74, 0.86 Excellent test-retest reliability.

Obesity:

(Impellizzeri et al, 2013; n=220, mean age=47 (15)

• ICC = 0.89 (0.82 to 0.94) Excellent

Epilepsy:

(Hernandez-Ronquilloa et al, 2011)

• The intra-observer reliability for the FSS in PWE (patients with epilepsy) was 0.85

Post-Poliomyelitis Syndrome:

(Koopman et al, 2014) — Acceptable internal consistency (Cronbach’s alpha = 0.90)

Chronic Hepatitis C:

(Rosa et al, 2014)—Excellent internal consistency (Cronbach’s alpha = 0.96, 0.96 across two studies)

Chronic Hepatitis C: (Rosa et al, 2014; PILLAR: n=386, mean age 44.0(11.81); ASPIRE: n=462, mean age 48.9(10.36)) Excellent correlation of concurrent validity (PILLAR: r= -0.63, ASPIRE: -0.66) between the total FSS score and with EQ-5D VAS PILLAR represented treatment-naïve patients while ASPIRE represented treatment-experienced patients with Chronic Hepatitis C infection.

Convergent Validity:

(Ghajarzadeh et al, 2012)

Excellent (r=0.69, p

Obesity:

(Impellizzeri et al, 2013; n=220, mean age=47 (15)—At baseline:

• Adequate (r = 0.58; 95% CI 0.48 to 0.66) correlations were found between FSS and POMS Fatigue score
• Adequate (r = −0.53; 0.43 to 0.62) FSS and POMS Vigor was significantly negative and moderate large
• Adequate (r = 0.41, 0.29 to 0.51) The correlation between the change scores in FSS and POMS-Fatigue was positive and moderate
• Poor (r = −0.26, 0.13 to 0.38) POMS-Vigor the correlation was negative and small.
• Adequate (r = 0.52, 0.42 to 0.61) Moderate-large correlations were also found between FSS and ORWELL97
• Poor (r = 0.29, 0.16 to 0.41).small moderate correlation was found between change scores of the two questionnaires.
• Poor (r = 0.15, 0.02 to 0.28) The correlation between FSS and BMI was significant but small, however, when adjusted for age the correlation increased to r = 0.25 (0.12 )

Post-poliomyelinits Syndrome:

(Koopman et al, 2014)—Both questionnaires had adequate floor and ceiling effects, with less than 15% of the post-polio patients demonstrating highest and lowest possible scores.

Chronic Hepatitis C:

(Rosa et al, 2014)—Floor / Ceiling effects were adequate (Floor: 4.9% (PILLAR) and 8% (ASPIRE); Ceiling 1.2% (PILLAR) and 2.7% (ASPIRE).

Obesity:

(Impellizzeri et al, 2013; n=220, mean age=47 (15)—Taking into account the MDC, the floor and ceiling effects post-intervention were 5%. The floor and ceiling effects were lower than the 15% cut-off value considered acceptable.

Chronic Hepatitis C:

(Rosa et al, 2014)—The FSS showed responsiveness, however, neither PILLAR nor ASPIRE achieved statistical significance (p

Obesity:

(Impellizzeri et al, 2013; n=220, mean age=47 (15)—Significant moderate changes were found for all the instruments and BMI after the three-week intervention. The internal responsiveness of FSS was comparable to the ORWELL97.

Congenital Myopathy:

(Werlauff et al, 2013, n=71, mean age 34.2 (14.4)

• Adequate test-retest reliability (0.72)

Congenital Myopathy:

(Werlauff et al, 2013)—Excellent internal consistency (Cronbach’s alpha = 0.89), IRC ranged from 0.80 to 0.30, item 1 has weakest correlation

Chronic Neck Pain:

(Takasaki & Treleaven, 2013; n = 26, mean age = 35.4 (12.1) years, mean symptom duration = 36.6 (26.4).

• Test-retest reliability was examined using quadratic-weighted kappa (>0.4) and was considered adequate.

Chronic Neck Pain:

(Takasaki & Treleaven, 2013)—Good internal consistency (Cronbach’s alpha = 0.81 ≤ α ≤ 0.89)

Convergent Validity:

Chronic Neck Pain:

(Takasaki & Treleaven, 2013)—Excellent (0.63 ≤ r ≤ 0.78) correlation of FSS-7 with the Fatigue Impact Scale, Adequate (r = 0.42) correlation of FSS-7 with the Visual Analog Fatigue Scale.

Stroke: (Lerdal & Kottorp, 2011) Cronbach’s alpha for the FSS-9 was 0.86 (adequate) at baseline while the alpha in the FSS-7 varied between 0.87 and 0.93 at four measurement times, supporting item reliability in the FSS-7. At baseline (n=119): 0.87; adequate 6 months (n=106): 0.92; excellent 12 months (n=104): 0.93; excellent 18 months (n=99): 0.92; excellent “Analyses of the concurrent validity of the FSS-7 showed a moderate to high relationship with SF-36-vitality and a moderate relationship with the one-item perceived energy item” (p. 1263).

Spinal Muscular Atrophy Type II:

(Werlauff et al, 2013)—Excellent internal consistency (Cronbach’s alpha = 0.92)

• IRC weak in item 1 (0.49) and item 2 (0.69)
• Excellent internal consistency amongst three factors
• Cronbach’s alpha = 0.84 for physical status questions
• Cronbach’s alpha = 0.94 for cognitive status questions
• Cronbach’s alpha = 0.80 for psychosocial function status questions

Multiple Sclerosis and Systemic Lupus Erthymatosus:

(Krupp et al, 1989; n = 74, mean age = 40.2 years)

• The cut-off score is 36 where a score > 36 may indicate severe fatigue or need for further evaluation.