Denise Sharon1, Richard P Allen2, Pablo Martinez-Martin3, Arthur S Walters4, Luigi Ferini Strambi5, Birgit Högl6, Lynn Marie Trotti7, Mark Buchfuhrer8, John Swieca9, Richard K Bogan10, Rochelle Zak11, Jennifer G Hensley12, Laurel A Schaefer13, S Marelli14, Marco Zucconi14, Ambra Stefani15, Evi Holzknecht15, Victoria Olvera16, Hailey Meaklim9, Irena Laska9, Philip M Becker17. 1. Tulane University School of Medicine, Clinical Director Advanced Sleep Center Metairie Louisiana, PVMC Sleep Disorders Center, Claremont, CA, USA. Electronic address: denisesharon23@gmail.com. 2. School of Medicine, Johns Hopkins University, Baltimore, MD, USA. 3. National Center for Epidemiology, Carlos III Institute of Health, Madrid, Spain. 4. Division of Sleep Medicine, Vanderbilt University School of Medicine, Nashville, TN, USA. 5. Department of Neurology, OSR-Turro, Department of Neuroscience, Director Sleep Disorders Center, University Vita-Salute San Raffaele, Milan, Italy. 6. Sleep Disorders Center, Department of Neurology, Medical University of Innsbruck, Innsbruck, Austria. 7. Emory University, Atlanta, GA, USA. 8. Stanford University School of Medicine, Palo Alto, CA, USA. 9. Melbourne Sleep Disorders Center, East Melbourne, Australia. 10. University of South Carolina School of Medicine, Columbia, SC, Sleep Med, Inc, USA. 11. University of California San Francisco Sleep Disorders Center, San Francisco, CA, USA. 12. University of Texas Austin, School of Nursing, Austin, TX, USA. 13. Vanderbilt University, Nashville, TN, USA. 14. Department of Neuroscience, Sleep Disorders Center, University Vita-Salute San Raffaele, Milan, Italy. 15. Department of Neurology, Medical University of Innsbruck, Innsbruck, Austria. 16. Emory Healthcare, Atlanta, GA, USA. 17. Southwestern University School of Medicine, Medical Director Sleep Medicine Associates of Texas, Dallas, TX, USA.
Abstract
INTRODUCTION: The International Restless Legs Study Group (IRLSSG) has developed the IRLS (International Restless Legs Syndrome Severity Scale) and validated it as a clinician/researcher administered scale to be used when both patient and examiner are present. The IRLSSG recognized the need for a self-completing scale that can be used economically in clinical practice and in large population-based studies. In this study the validity and the reliability of the IRLS as a self-administered scale (sIRLS) is assessed. METHODS: Established RLS patients were recruited by eight centers in four countries and consented to participate in this study. The validity of the sIRLS was assessed by patients completing the sIRLS before a clinician administered the IRLS. The reliability of the sIRLS was assessed by patients completing the sIRLS again, two weeks after the first one, provided no change had occurred. RESULTS: Overall, 173 patients were recruited and 164 of them were included in the analyses. The sIRLS showed satisfactory scaling assumptions and no relevant floor or ceiling effect. One factor explained 61.3% of the variance. Cronbach's alpha was 0.93 and the item homogeneity index was 0.59. Intraclass correlation coefficient between the sIRLS and the IRLS was 0.94. The sIRLS standard error of measurement was 3.61 (½ SD at baseline = 4.11). The results mostly overlapped those of the IRLS analyzed in parallel. DISCUSSION: The sIRLS is a reliable, valid and precise instrument that showed tight association with the IRLS. These findings support the use of the sIRLS for self-evaluation of RLS severity. The responses obtained on the sIRLS and the IRLS scale varied slightly. Therefore, we recommend that either the sIRLS or the IRLS scale be used as the only scale for serial measures over time.
INTRODUCTION: The International Restless Legs Study Group (IRLSSG) has developed the IRLS (International Restless Legs Syndrome Severity Scale) and validated it as a clinician/researcher administered scale to be used when both patient and examiner are present. The IRLSSG recognized the need for a self-completing scale that can be used economically in clinical practice and in large population-based studies. In this study the validity and the reliability of the IRLS as a self-administered scale (sIRLS) is assessed. METHODS: Established RLS patients were recruited by eight centers in four countries and consented to participate in this study. The validity of the sIRLS was assessed by patients completing the sIRLS before a clinician administered the IRLS. The reliability of the sIRLS was assessed by patients completing the sIRLS again, two weeks after the first one, provided no change had occurred. RESULTS: Overall, 173 patients were recruited and 164 of them were included in the analyses. The sIRLS showed satisfactory scaling assumptions and no relevant floor or ceiling effect. One factor explained 61.3% of the variance. Cronbach's alpha was 0.93 and the item homogeneity index was 0.59. Intraclass correlation coefficient between the sIRLS and the IRLS was 0.94. The sIRLS standard error of measurement was 3.61 (½ SD at baseline = 4.11). The results mostly overlapped those of the IRLS analyzed in parallel. DISCUSSION: The sIRLS is a reliable, valid and precise instrument that showed tight association with the IRLS. These findings support the use of the sIRLS for self-evaluation of RLS severity. The responses obtained on the sIRLS and the IRLS scale varied slightly. Therefore, we recommend that either the sIRLS or the IRLS scale be used as the only scale for serial measures over time.
Authors: Leonard B Weinstock; Arthur S Walters; Jill B Brook; Zahid Kaleem; Lawrence B Afrin; Gerhard J Molderings Journal: J Clin Sleep Med Date: 2020-01-14 Impact factor: 4.062
Authors: Leonard B Weinstock; Jill B Brook; Arthur S Walters; Ashleigh Goris; Lawrence B Afrin; Gerhard J Molderings Journal: J Clin Sleep Med Date: 2022-05-01 Impact factor: 4.324