Reliability and validity of two self-administered questionnaires for screening restless legs syndrome in population-based studies

Dept. of Health Research & Policy, Division of Epidemiology, HRP Redwood Building, Room T209, Stanford University School of Medicine, Stanford, CA 94305-5405, USA.
Sleep Medicine (Impact Factor: 3.15). 02/2010; 11(2):154-60. DOI: 10.1016/j.sleep.2009.01.012
Source: PubMed


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.

5 Reads
  • [Show abstract] [Hide abstract]
    ABSTRACT: In this paper, we present a new learning algorithm, referred to as the logical evolution (LE) method. To learn a Boolean function, the LE method uses not only new information in the given training examples but also old information learned in the past. By using only one network to learn many functions, old information can be re-used for learning new problems efficiently. In this paper, we present the network structure and the learning algorithm of LE and analyse its properties. Its learning capability is also shown by means of two experiments
    Systems, Man, and Cybernetics, 2001 IEEE International Conference on; 02/2001
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The aim of this study was to determine the prevalence and correlates of restless legs syndrome (RLS) in adolescents. A sleep questionnaire aimed at identifying 'definite' RLS criteria (also including the Strengths and Difficulties Questionnaire and the Epworth Sleepiness Scale) was completed by 3304 high school adolescents aged 15 to 18 years (49% male; 51% female) in Gaziantep, Turkey. The diagnosis of RLS was confirmed by face-to-face or phone interviewing. The χ² or Student's t-test and logistic regression tests were used for statistical evaluation. 'Definite' RLS was diagnosed in 3.6% of participants. RLS symptoms were reported to occur on more than one occasion per week (frequent RLS) in 2% of participants and to make it to difficult to fall asleep or stay asleep (RLS with sleeping difficulty) in 1.7%. The prevalence of the combination of frequent symptoms and sleeping difficulty was 0.8%. Logistic regression analysis revealed that RLS was independently associated with nocturnal bed-wetting (4.2% vs 0.8%; p=0.004), sleeping difficulty (47% vs 32%; p=0.011), Epworth Sleepiness Scale score (4.9 vs 3.9; p=0.036), hyperactivity/inattention (25% vs 14%; p=0.049), awakening with discomfort in the legs (51% vs 30%; p<0.001), and parents with RLS-implying symptoms (56% vs 38%; p=0.006). RLS with sleeping difficulty was associated with hyperactivity/inattention (p=0.007); frequent RLS was associated with arm restlessness (p=0.006). 'Definite' RLS is not rare in adolescents; furthermore, it may be accompanied by several comorbid conditions that can impair quality of life in adolescents.
    Developmental Medicine & Child Neurology 01/2011; 53(1):40-7. DOI:10.1111/j.1469-8749.2010.03796.x · 3.51 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: To estimate the prevalence and evaluate the characteristics and severity of restless legs syndrome (RLS) in an urban Brazilian community. A transversal study was conducted over an 18-month period. A neurologist conducted 1155 interviews using the diagnostic criteria of the International Restless Legs Syndrome Study Group (IRLSSG). The lifetime prevalence of RLS was found to be 6.40%. Prevalence during the last year, the last month, and the last week were found to be 5.71%, 5.36%, and 4.15%, respectively. A greater proportion of women met diagnostic criteria for RLS compared to men (OR: 2.63, CI 95%: 1.54-4.51). Furthermore, participants with low monthly family income (<$1575 USD) had a lower prevalence of disease compared to those with a high monthly family income (>$1575 USD) (OR: 2.91, CI 95%: 1.41-5.98). This is the first epidemiologic study of RLS conducted in a Brazilian population. The overall prevalence of disease and the greater proportion of RLS in women found in this study are similar to the findings of other studies conducted in western countries. The association of RLS with high family income is unpublished and should be confirmed in subsequent studies.
    Sleep Medicine 08/2011; 12(8):762-7. DOI:10.1016/j.sleep.2011.01.018 · 3.15 Impact Factor
Show more