Reliability and validity of two self-administered questionnaires for screening restless legs syndrome in population-based studies
ABSTRACT A reliable and valid questionnaire for screening restless legs syndrome (RLS) is essential for determining accurate estimates of disease frequency. In a 2002 NIH-sponsored workshop, experts suggested three mandatory questions for identifying RLS in epidemiologic studies. We evaluated the reliability and validity of this RLS-NIH questionnaire in a community-based sample and concurrently developed and evaluated the utility of an expanded screening questionnaire, the RLS-EXP.
The study was conducted at Kaiser Permanente of Northern California and the Stanford University Sleep Clinic. We evaluated test-retest reliability in a random sample of subjects with prior physician-assigned RLS (n=87), subjects with conditions frequently misclassified as RLS (n=31), and healthy subjects (n=9). Validity of both instruments was evaluated in a random sample of 32 subjects, and in-person examination by two RLS specialists was used as the gold standard.
For the first three RLS-NIH questions, the kappa statistic for test-retest reliability ranged from 0.5 to 1.0, and sensitivity and specificity was 86% and 45%, respectively. For the subset of five questions on RLS-EXP that encompassed cardinal features for diagnosing RLS, kappas were 0.4-0.8, and sensitivity and specificity were 81% and 73%, respectively.
Sensitivity of RLS-NIH is good; however, the specificity of the instrument is poor when examined in a sample that over-represents subjects with conditions that are commonly misclassified as RLS. Specificity can be improved by including separate questions on cardinal features, as used in the RLS-EXP, and by including a few questions that identify RLS mimics, thereby reducing false positives.
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ABSTRACT: Background In 2003, following a workshop at the National Institutes of Health, the International Restless Legs Syndrome Study Group (IRLSSG) developed updated diagnostic criteria for restless legs syndrome/Willis–Ekbom disease (RLS/WED). These criteria were integral to major advances in research, notably in epidemiology, biology, and treatment of RLS/WED. However, extensive review of accumulating literature based on the 2003 NIH/IRLSSG criteria led to efforts to improve the diagnostic criteria further. Methods The Clinical Standards Workshop, sponsored by the WED Foundation and IRLSSG in 2008, started a four-year process for updating the diagnostic criteria. That process included a rigorous review of research advances and input from clinical experts across multiple disciplines. After broad consensus was attained, the criteria were formally approved by the IRLSSG executive committee and membership. Results Major changes are: (i) addition of a fifth essential criterion, differential diagnosis, to improve specificity by requiring that RLS/WED symptoms not be confused with similar symptoms from other conditions; (ii) addition of a specifier to delineate clinically significant RLS/WED; (iii) addition of course specifiers to classify RLS/WED as chronic–persistent or intermittent; and (iv) merging of the pediatric with the adult diagnostic criteria. Also discussed are supportive features and clinical aspects that are important in the diagnostic evaluation. Conclusions The IRLSSG consensus criteria for RLS/WED represent an international, interdisciplinary, and collaborative effort intended to improve clinical practice and promote further research.Sleep Medicine 08/2014; 15(8). DOI:10.1016/j.sleep.2014.03.025 · 3.10 Impact Factor
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ABSTRACT: Background Specific diagnostic criteria for pediatric restless legs syndrome (RLS) were published in 2003 following a workshop at the National Institutes of Health. Due to substantial new research and revision of the adult RLS diagnostic criteria, a task force was chosen by the International Restless Legs Syndrome Study Group (IRLSSG) to consider updates to the pediatric diagnostic criteria. Methods A committee of seven pediatric RLS experts developed a set of 15 consensus questions to review, conducted a comprehensive literature search, and extensively discussed potential revisions. The committee recommendations were approved by the IRLSSG executive committee and reviewed by the IRLSSG membership. Results The pediatric RLS diagnostic criteria were simplified and integrated with the newly revised adult RLS criteria. Specific recommendations were developed for pediatric application of the criteria, including consideration of typical words used by children to describe their symptoms. Pediatric aspects of differential diagnosis, comorbidity, and clinical significance were then defined. In addition, the research criteria for probable and possible pediatric RLS were updated and criteria for a related condition, periodic limb movement disorder (PLMD), were clarified. Conclusions Revised diagnostic criteria for pediatric RLS have been developed, which are intended to improve clinical practice and promote further research.Sleep Medicine 12/2013; 14(12):1253–1259. DOI:10.1016/j.sleep.2013.08.778 · 3.10 Impact Factor
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ABSTRACT: Objective: To estimate the prevalence of Willis-Ekbom disease (WED) in a racially homogeneous population of adults Amerindians living in rural coastal Ecuador, and to assess the reliability of the International Restless Legs Syndrome Study Group (IRLSSG) questionnaire when used in population-based studies. Methods: Two-phase, door-to-door, population-based survey. During Phase I, rural doctors screened all Atahualpa residents aged years with the IRLSSG questionnaire. In Phase II, neurologists evaluated suspected WED cases and a matched sample of negative individuals. Results: The census identified 665 persons aged >= 40 years. An affirmative response to the questionnaire was obtained in 94 persons. Medical history and neurological examination confirmed the diagnosis of WED in >= 40 of them. The evaluation of 188 non-suspected individuals revealed no further cases. The questionnaire had a sensitivity of 100% (95% CI, 89% to 100%), a specificity of 78% (95% CI, 72% to 83%), a positive predictive value of 0.43 (95% CI, 0.33 to 053), and a negative predictive value of 1 (95% CI, 0.98 to I). The prevalence of WED in Atahualpa residents aged >= 40 years was 6%. Conclusion: The prevalence of WED in this adult Ecuadorian population is higher than that reported from most studies conducted in tropical countries, but similar to that found in Brazil. Specificity and positive predictive value of the IRLSSG questionnaire are poor, which reinforces the need for a second phase that should include an expert interview.Journal of the Neurological Sciences 06/2014; 344(1-2). DOI:10.1016/j.jns.2014.06.043 · 2.26 Impact Factor