Format

Send to

Choose Destination
Arch Phys Med Rehabil. 2013 Jul;94(7):1328-34. doi: 10.1016/j.apmr.2012.12.013. Epub 2012 Dec 26.

Construct validity and test-retest reliability of the Fatigue Severity Scale in people with chronic neck pain.

Author information

1
NHMRC Centre of Clinical Research Excellence-Spinal Pain, Injury and Health, Division of Physiotherapy, School of Health and Rehabilitation Science, The University of Queensland, Brisbane, QLD 4072, Australia. h.takasaki@uq.edu.au

Abstract

OBJECTIVE:

To investigate an appropriate scoring system and unidimensionality using Rasch analysis, discriminant validity, and reliability of the Fatigue Severity Scale (FSS) in people with chronic neck pain.

DESIGN:

Cross-sectional.

SETTING:

Tertiary institution.

PARTICIPANTS:

Patients with chronic neck pain (n=100) and asymptomatic controls (n=40).

INTERVENTIONS:

Not applicable.

MAIN OUTCOME MEASURE:

The FSS.

RESULTS:

Twenty-six of the 100 participants with chronic neck pain agreed to complete the FSS again within 1 week after the first administration for the assessment of the test-retest reliability. Two items obviously threatening unidimensionality were eliminated, and the 7-item FSS was developed through Rasch analyses. The 7-item FSS demonstrated the appropriateness of its 7-point scale and adequate internal consistency (Rasch-generated reliability, .83-.91). The 7-item FSS had a negligible floor effect (1%) and ceiling effect (2%). The item-person map demonstrated limited distribution of item difficulty in comparison with the distribution of person ability. The chronic neck pain group demonstrated significantly (P<.001) higher scores in the 7-item FSS than the control group, indicating discriminant validity. The 7-item FSS also demonstrated adequate test-retest reliability with a mean interval of 4.1 days (n=26) for each item (quadratic-weighted κ=.83-.94), and as a whole (intraclass correlation coefficient=.95). A 0-to-100 scale table reflecting Rasch scores was developed, and the minimum detectable change was 9.5 in the 0 to 100 scale.

CONCLUSION:

The 7-item FSS appears unidimensional and reliable, and can be used quickly in clinical practice to gain a basic understanding of fatigue symptoms in people with chronic neck pain. Further, it is possible to modify the 7-item FSS to enhance discriminant ability within people with chronic neck pain by adding additional items, enlarging the distribution of item difficulty.

PMID:
23274223
DOI:
10.1016/j.apmr.2012.12.013
[Indexed for MEDLINE]

Supplemental Content

Full text links

Icon for Elsevier Science
Loading ...
Support Center