The reliability, validity and responsiveness of the International Restless Legs Syndrome Study Group rating scale and subscales in a clinical-trial setting

Linda Abetz, Robert Arbuckle, Richard Allen, Diego Garcia-Borreguero, Wayne Hening, Arthur S. Walters, Elena Mavraki, Jeffrey M. Kirsch

Research output: Contribution to journalArticle

Abstract

Patients and methods: To assess the reliability, validity, and responsiveness of the International Restless Legs Syndrome Study Group's rating scale (the International Restless Legs Scale (IRLS)) (V2.0), using pooled data from two matching, placebo-controlled studies of ropinirole for treating Restless Legs Syndrome (RLS). Results: Pooled patient samples comprised 550 patients in the baseline (validation) sample and 439 patients in the week 12 longitudinal (responsiveness) sample. Factor analysis revealed acceptability of the IRLS total score (accounting for 40% of the variance) and that nine of the 10 IRLS items could also be assigned to two distinct subscales, the symptoms or symptoms impact subscales. The IRLS total score, symptoms and symptoms impact subscales had acceptable construct validity, internal consistency reliability (α=0.81, 0.80, and 0.76, respectively), and concurrent validity (r=-0.68, -0.52, -0.70, respectively, with the Restless Legs Syndrome Quality of Life questionnaire (RLSQoL) overall life impact score). IRLS scores differed significantly between different levels of sleep problems and Clinical Global Impression (CGI) of health status (P

Original languageEnglish (US)
Pages (from-to)340-349
Number of pages10
JournalSleep Medicine
Volume7
Issue number4
DOIs
Publication statusPublished - Jun 2006

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Keywords

  • IRLS
  • Psychometric analysis
  • Reliability
  • Responsiveness
  • Restless legs syndrome
  • Validity

ASJC Scopus subject areas

  • Dentistry(all)
  • Ophthalmology
  • Pulmonary and Respiratory Medicine
  • Neurology

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