Validity and reliability of the Traditional Chinese version of the Multidimensional Fatigue Inventory in general population

<div><p>Background</p><p>Fatigue is a common symptom in the general population and has a substantial effect on individuals’ quality of life. The Multidimensional Fatigue Inventory (MFI) has been widely used to quantify the impact of fatigue, but no Traditional Chinese translation has yet been validated. The goal of this study was to translate the MFI from English into Traditional Chinese (‘the MFI-TC’) and subsequently to examine its validity and reliability.</p><p>Methods</p><p>The study recruited a convenience sample of 123 people from various age groups in Taiwan. The MFI was examined using a two-step process: (1) translation and back-translation of the instrument; and (2) examination of construct validity, convergent validity, internal consistency, test-retest reliability, and measurement error. The validity and reliability of the MFI-TC were assessed by factor analysis, Spearman rho correlation coefficient, Cronbach’s alpha coefficient, intraclass correlation coefficient (ICC), minimal detectable change (MDC), and Bland-Altman analysis. All participants completed the Short-Form-36 Health Survey Taiwan Form (SF-36-T) and the Chinese version of the Pittsburgh Sleep Quality Index (PSQI) concurrently to test the convergent validity of the MFI-TC. Test-retest reliability was assessed by readministration of the MFI-TC after a 1-week interval.</p><p>Results</p><p>Factor analysis confirmed the four dimensions of fatigue: general/physical fatigue, reduced activity, reduced motivation, and mental fatigue. A four-factor model was extracted, combining general fatigue and physical fatigue as one factor. The results demonstrated moderate convergent validity when correlating fatigue (MFI-TC) with quality of life (SF-36-T) and sleep disturbances (PSQI) (Spearman's rho = 0.68 and 0.47, respectively). Cronbach’s alpha for the MFI-TC total scale and subscales ranged from 0.73 (mental fatigue subscale) to 0.92 (MFI-TC total scale). ICCs ranged from 0.85 (reduced motivation) to 0.94 (MFI-TC total scale), and the MDC ranged from 2.33 points (mental fatigue) to 9.5 points (MFI-TC total scale). The Bland-Altman analyses showed no significant systematic bias between the repeated assessments.</p><p>Conclusions</p><p>The results support the use of the Traditional Chinese version of the MFI as a comprehensive instrument for measuring specific aspects of fatigue. Clinicians and researchers should consider interpreting general fatigue and physical fatigue as one subscale when measuring fatigue in Traditional Chinese-speaking populations.</p></div

Reliability (internal consistency, test-retest, and measurement error) of the total score and four subscales of the MFI-TC in healthy adults (<i>n</i> = 123).

<p>Reliability (internal consistency, test-retest, and measurement error) of the total score and four subscales of the MFI-TC in healthy adults (<i>n</i> = 123).</p

Factor analysis of the MFI-TC.

<p>Factor analysis of the MFI-TC.</p

Correlations between fatigue, quality of life, and quality of sleep.

<p>Correlations between fatigue, quality of life, and quality of sleep.</p

Correlations between subscales and the total score of the MFI-TC.

<p>Correlations between subscales and the total score of the MFI-TC.</p

Characteristics of the participants (<i>n =</i> 123).

<p>Characteristics of the participants (<i>n =</i> 123).</p

Bland-Altman plot of the total fatigue score of the MFI-TC.

<p>The plot illustrates the agreement between time 1 and time 2 and identifies possible outliers. Each subject is represented on the graph by conveying the mean value of the 2 assessments (x-axis) and the difference between the 2 assessments (y-axis). The mean difference was the estimated bias, and the standard deviation (SD) of the differences measured the fluctuations around this mean (outliers being above 1.96 SD_diff). The reference lines show the mean difference between time 1 and time 2 (solid line), and the 95% limits of agreement for the mean difference (broken lines).</p

Examples of visual stimuli and illustrations of the filling-the-gap hypothesis.

<p>A–C. Single barber pole with aspect ratios (height: width) of (A) 1:1 (1.19°/1.19°), (B) 1:1.41 (1°/1.41°), and (C) 1.41:1 (1.41°/1°), and a fixed aperture area of 1.41 (°)². D–I. To test whether the perceived direction of the dual barber poles is mediated through the filling-the-gap hypothesis, we presented a series of completed barber poles (as shown in G, H, and I) constructed by filling the grating into the inter-component space of the dual barber poles in D, E, and F, respectively.</p

The perceived directions of dual barber poles in which the phase of the two component barber poles differed.

<p>A. Three example dual barber poles in which the phase difference between the bilateral component barber poles was 0 (upper panel), 1/4 (middle panel), or 1/2 (lower panel) cycles. B–C. The probability of perceiving a global motion observed in an example subject (B) and in the mean across subjects (C). D–E. The perceptual bias observed in an example subject (D) and in the mean across subjects (E). *: <i>p</i> < 0.05 across conditions.</p

The perceived directions of single and dual barber poles and the predictions of the perceived directions of the dual barber poles based on the filling-the-gap and simple concatenation hypotheses.

<p>A. The mean perceptual bias toward the horizontal direction as a function of the aspect ratio induced by single barber poles illustrated in Figure 1A–C. The three barber poles with aspect ratios (height/width) of 1:1.41 (1°/1.41°), 1:1 (1.19°/1.19°), and 1.41:1 (1.41°/1°) are illustrated in the upper panel. The error bars indicate standard error of mean. B The mean perceptual bias toward the horizontal direction induced by the dual barber poles as a function of inter-component distance. Examples of the dual barber poles with inter-component distances of 0.03°, 0.41°, and 1.66° are illustrated in the upper panel. The perceptual bias to dual barber poles (circle trace) peaked when the inter-component distance was zero (yielding a single horizontal barber pole) and, as the inter-component distance increased, gradually decreased to approach the perceived direction of the single component barber pole. The dashed line indicates the perceptual bias induced by the single component barber pole (with an aspect ratio of 1.41:1) shown in (A). C–D. The perceptual bias to the dual barber poles at various inter-component distances (circle trace), the predictions made by the filling-the-gap (star trace) and simple concatenation hypotheses (dotted line), and the perceptual bias induced by the single component barber pole (dashed line), observed in an example subject (C) and in the mean across subjects (D) (* symbols indicate significant difference between the dual barber pole and completed barber pole, <i>p</i> < 0.05 using repeated-measures ANOVA).</p