Fatigue in patients with spinal muscular atrophy type II and congenital myopathies: evaluation of the fatigue severity scale
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The aim of this study was to evaluate whether the fatigue severity scale (FSS) is an appropriate instrument to assess fatigue in patients with spinal muscular atrophy type II (SMA II) and congenital myopathies (CM).
FSS and visual analog scale (VAS) were administered to 33 SMA II- and 72 CM patients. The psychometric properties of the FSS were evaluated by means of classical test theories for each of the disease groups. If abnormal fatigue was present in the disease group, the construct of fatigue was evaluated by means of focus group interviews.
Fatigue was rare in SMA II patients, but very frequent in patients with CM. The cut-off score designating abnormal fatigue (FSS score ≥ 4) was exceeded by 10 % of the SMA II patients in contrast to 76 % of the CM patients, of whom 52 % suffered from severe fatigue (FSS score ≥ 5). Focus group interviews demonstrated that fatigue had an adverse effect on motor function, level of energy, social relations, and identity, four themes that could be captured by the FSS. The FSS and VAS were strongly correlated in SMA II patients, but only moderately in CM patients. The psychometric properties indicated that the original FSS with nine items measures more than one construct of fatigue, eliminating the first two items improved scale properties.
This study demonstrates that fatigue is characteristic in patients with CM, but not in patients with SMA II, in whom fatigue does not seem to impact daily life. While fatigue in CM and SMA II can be captured by FSS, omitting the first two items of the scale will improve its properties and content validity, along with comprehension of the scale itself.
KeywordsNeuromuscular diseases Fatigue Focus groups Qualitative research Reliability Validity
We thank all the patients in the studies for participating and sharing their knowledge.
- 2.World Health organization. (2001). International classification of functioning, disability and health: ICF. Geneva: WHO.Google Scholar
- 8.ENMC. (2011). http://www.enmc.org/workshop/?id=110&mid=88.
- 10.Kalkmann, J. S., Schillings, M. L., van der Werf, S. P., Padberg, G. W., Zwarts, M. J., van Engelen, B. G., et al. (2005). Experienced fatigue in facioscapulohumeral dystrophy, myotonic dystrophy, and HMSN-I. Journal of Neurology, Neurosurgery and Psychiatry, 76(10), 1406–1409.CrossRefGoogle Scholar
- 24.Takasaki, H., & Treleaven, J. (2012). Construct validity and test–retest reliability of the Fatigue Severity Scale in people with chronic neck pain. Archives of Physical Medicine and Rehabilitation, 94(7), 1328–1334.Google Scholar
- 25.Rothmann, M., Burke, L., Erickson, P., Leidy, N. K., Patrick, D. L., & Petrie, C. D. (2009). Use of existing patient-reported outcome (PRO) instruments and their modification: The ISPOR good research practice for evaluating and documenting content validity for the use of existing instruments and their modification PRO task report. Value in Health, 12(8), 1075–1083.CrossRefGoogle Scholar
- 26.Patrick, D. L., Burke, L., Erickson, P., Gwaltney, C. J., Leidy, N. K., Martin, M. L., et al. (2011). Content validity—Establishing and reporting the evidence in newly developed patient-reported outcome (PRO) instruments for medical product evaluation: ISPOR PRO good research practices task force report: Part I—Eliciting concepts for a new PRO instrument. Value in Health, 14(8), 967–977.PubMedCrossRefGoogle Scholar
- 27.Patrick, D. L., Burke, L., Gwaltney, C. J., Leidy, N. K., Martin, M. L., Molsen, E., et al. (2011). Content validity—Establishing and reporting the evidence in newly developed patient-reported outcome (PRO) instruments for medical product evaluation: ISPOR PRO good research practices task force report: Part 2—Assessing respondent understanding. Value in Health, 14(8), 978–988.PubMedCrossRefGoogle Scholar
- 28.Tashakkori, A., & Teddlie, C. (1998). Mixed methodology. Combining quantitative and qualitative approaches. Thousand Oaks, CA: Sage.Google Scholar
- 29.Morgan, D. L. (1997). Focus groups as qualitative research (2nd ed.). London: Sage.Google Scholar
- 31.Fayers, P. M., & Machin, D. (2009). Quality of life. The assessment analysis and interpretation of patient-reported outcomes. New York: Wiley.Google Scholar
- 33.Krueger, R. A. (1998). Moderating focus groups. Thousand Oaks, CA: Sage.Google Scholar
- 35.Coffey, A., & Atkinson, P. (1996). Making sense of qualitative data. Complemtary research strategies. London: Sage.Google Scholar