Validity Of Fatigue Severity Scale Research Articles

Psychometric properties of fatigue severity scale in Chinese systemic lupus erythematosus patients

BackgroundFatigue is the most common symptom in Systemic Lupus Erythematosus (SLE) patients. Many fatigue instruments have been used in SLE, with Fatigue Severity Scale (FSS) mostly adopted. However, fatigue instruments haven’t been tested in the Chinese SLE population. The aim of our study was to test the psychometric properties of FSS in Chinese SLE patients.MethodsA cross-sectional study was conducted. 201 patients diagnosed with SLE were enrolled in the study with convenience sampling. Fatigue score, depression score and vitality subscale score of SF-36 were collected. Floor and ceiling effects were tested. Factor analysis was conducted. Reliability and validity of FSS were also tested.ResultsFloor (4.50%) and ceiling (4.00%) effects were minimal. One factor was extracted, explaining 61.80% of total variance. When item1 and item 2 were deleted, one factor explained 69.54% of variance, and Cronbach’s Alpha increased from 0.92 to 0.93. Intraclass correlation coefficient (ICC) was 0.94. Fatigue correlated with both depression (r = 0.52, P < 0.01) and vitality (r = − 0.55, P < 0.01), indicating acceptable construct validity for original FSS. When item 1 and 2 were removed, the correlation coefficient between 7-item FSS and vitality increased (r = − 0.58, P < 0.01), while correlation coefficient between 7-item FSS and depression remained the same (r = 0.52, P < 0.01). Known-groups validity was verified by that patients with depression showed higher fatigue score both for 9-item (Z = -5.56, P < 0.001) and 7-item FSS (Z = -5.70, P < 0.001).Conclusions9-item FSS is a reliable instrument and can be used to assess fatigue problem in Chinese SLE patients, and 7-item FSS also demonstrated good psychometric properties in the same participants.

Test-retest reliability, internal consistency and concurrent validity of Fatigue Severity Scale in measuring post-stroke fatigue.

Post-stroke fatigue (PSF) is a common complaint among stroke survivors and has significant impacts on recovery and quality of life. Limited tools that measure fatigue have been validated in stroke. The purpose of this study was to determine the psychometric properties of Fatigue Severity Scale (FSS) in patients with stroke. Cross-sectional study. Teaching hospital outpatient setting. Fifty healthy controls (mean age 61.1±7.4 years; 22 males) and 50 patients with stroke (mean age 63.6±10.3 years; 34 males). FSS was administered twice approximately a week apart through face-to-face interview. In addition, we measured fatigue with Visual Analogue Scale - Fatigue (VAS-F) and Short-Form Health Survey 36 version 2 vitality scale. We used Cronbach alpha to determine internal consistency of FSS. Reliability and validity of FSS were determined by intraclass correlation coefficient (ICC) and Spearman correlation coefficient (r). FSS showed excellent internal consistency for both stroke and healthy groups (Cronbach's alpha >0.90). FSS had excellent test-retest reliability for stroke patients and healthy controls (ICC=0.93 and ICC=0.90, respectively). The scale demonstrated good concurrent validity with VAS-Fatigue (all r>.60) and a moderate validity with the SF36-vitality scale. Furthermore, FSS was sensitive to distinguish fatigue in stroke from the healthy controls (P<0.01). FSS has excellent internal consistency, test-retest reliability and good concurrent validity with VAS-F for both groups. This study provides evidence that FSS is a reliable and valid tool to measure post-stroke fatigue and is readily to be used in clinical settings.

Psychometric properties of the Fatigue Severity Scale in polio survivors

The objective of this study was to evaluate by means of classical test theory and Rasch analysis the scaling characteristics and psychometric properties of the Fatigue Severity Scale (FSS) in polio survivors. A questionnaire,consisting of five general questions (sex, age, age at time of acute polio, sequelae of polio, and new symptoms), the FSS, and three questions from the Visual Analog Scale questions on fatigue was sent to all 196 polio survivors at the Institute for Rehabilitation in Ljubljana. Responses were assessed in terms of Cronbach's a, item-to-total correlation, factor analysis, and Rasch analysis. Of the128 (65.3%) valid questionnaires returned, those presenting no missing values were used for subsequent analyses (n = 117). The FSS showed good internal consistency: Cronbach's a was greater than 0.95,item-to-total correlation ranged from 0.68 to 0.88. A reduction from seven to three rating categories was necessary to comply with criteria for correct category function. Item difficulty estimates spanned from – 0.91to + 1.09 logits. No item bias was found for sex and age.The internal consistency of FSS was high and its item separation reliability good, indicating a satisfactory replicability of item placement in other samples. In conclusion, Rasch analysis enabled us to confirm the validity of FSS (in its 8-item version, without item 1) as a measure of the severity and impact of physical symptoms of fatigue in polio survivors, so providing a useful starting point for further studies aimed at examining additional psychometric aspects and confirming the appropriateness of the simplification of its rating categories.