Reliability and validity of two self-administered questionnaires for screening restless legs syndrome in population-based studies (original) (raw)
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Prevalence and Correlates of Restless Legs Syndrome
Chest, 2006
The purpose of this analysis was to investigate the prevalence and correlates of restless legs syndrome (RLS) symptoms in the 2005 National Sleep Foundation (NSF) Sleep in America 2005 Poll. The NSF poll is an annual telephone interview of a random, representative sample of US adults. Methods: The NSF 2005 poll included 1,506 adults. Their mean age was 49 years, and 775 were women. Results: Symptoms of RLS that included unpleasant feelings in the legs for at least a few nights a week, which were worse at night, were reported by 9.7% of individuals in this poll, including 8% of men and 11% of women. Those from the northeast United States were much less likely to be at risk than those from other regions of the country (p < 0.05). Those who were unemployed (p < 0.05) or smoked daily (p < 0.5) were more likely to be at risk for RLS, as were those with hypertension, arthritis, gastroesophageal reflux disease, depression, anxiety, and diabetes (p < 0.05 for all). Adults who were at risk for RLS appeared to also be at increased risk for sleep apnea and insomnia (p < 0.05), and were more likely to stay up longer than they planned, to take longer than 30 min to fall asleep, to drive when drowsy, and to report daytime fatigue than those who were not at risk (p < 0.05 for all). They were also more likely to report being late to work, missing work, making errors at work, and missing social events because of sleepiness than other respondents in the poll (p < 0.05 for all). Conclusions: RLS is significantly associated with medical and psychiatric conditions, other sleep disorders, unfavorable lifestyle behaviors, and adverse effects on daytime function. Chest physicians who practice sleep medicine need to be able to identify and manage RLS, which is prevalent and is associated with considerable morbidity.
Correlation between putative indicators of primary restless legs syndrome severity
2007
Background and purpose: Several methods of assessing disease severity in restless legs syndrome (RLS) have been suggested. The purpose of this study was to examine the relationship between the suggested immobilization test (SIT), the International RLS Study Group rating scale (IRLS), sleep efficiency, and periodic leg movements of sleep index (PLMI). Patients and methods: Forty primary RLS patients with periodic leg movements of sleep were included in this prospective study. Study procedures were all performed during the same night, beginning with IRLS administration and following with SIT and polysomnography (PSG) evaluations, in that order. SIT was composed of two parameters: SIT mean discomfort score (SIT-MDS) and SIT periodic leg movements of wakefulness index (SIT-PLMW). PSG target measures were PLMI and sleep efficiency. Pearson's correlation was used for analysis at a P < 0.01 significance level.
Restless Legs Syndrome Prevalence and Impact
Archives of Internal Medicine, 2005
Background: Restless legs syndrome (RLS), a common sensorimotor disorder, has a wide range of severity from merely annoying to affecting sleep and quality of life severely enough to warrant medical treatment. Previous epidemiological studies, however, have failed to determine the prevalence of those with clinically significant RLS symptoms and to examine the life effects and medical experiences of this group. Methods: A total of 16 202 adults (aged Ն18 years) were interviewed using validated diagnostic questions to determine the presence, frequency, and severity of RLS symptoms; respondents reporting RLS symptoms were asked about medical diagnoses and the impact of the disorder and completed the Short Form-36 Health Survey (SF-36). Criteria determined by RLS experts for medically significant RLS (frequency at least twice a week, distress at least moderate) defined "RLS sufferers" as a group most likely to warrant medical treatment. Results: In all, 15 391 fully completed questionnaires were obtained; in the past year, RLS symptoms of any frequency were reported by 1114 (7.2%). Symptoms occurred at least weekly for 773 respondents (5.0%); they occurred at least 2 times per week and were reported as moderately or severely distressing by 416 (2.7%). Of those 416 (termed RLS sufferers), 337 (81.0%) reported discussing their symptoms with a primary care physician, and only 21 (6.2%) were given a diagnosis of RLS. The SF-36 scores for RLS sufferers were significantly below population norms, matching those of patients with other chronic medical conditions. Conclusion: Clinically significant RLS is common (prevalence, 2.7%), is underdiagnosed, and significantly affects sleep and quality of life.
Sleep Medicine, 2006
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 (aZ0.81, 0.80, and 0.76, respectively), and concurrent validity (rZK0.68, K0.52, K0.70, 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!0.0001), indicating known groups and clinical validity, respectively. Changes in scores differed significantly among CGI 'global improvement' levels (P!0.0001), providing evidence of responsiveness. Conclusions: The IRLS total score, symptoms, and symptoms impact subscales are reliable, valid, and responsive in a clinical trial setting.
European Journal of Neurology, 2007
The purposes of this study were to validate the use of a single standard question for the rapid screening of restless legs syndrome (RLS) and to analyze the eventual effects of the presence of RLS on self-assessed daytime sleepiness, global clinical severity and cognitive functioning. We evaluated a group of 521 consecutive patients who accessed our neurology clinic for different reasons. Beside the answer to the single question and age, sex, and clinical diagnosis, the following items were collected from all patients and normal controls: the four criteria for RLS, the Epworth Sleepiness Scale (ESS), the Clinical Global Impression of Severity (CGI-S), and the Mini-Mental State evaluation. RLS was found in 112 patients (70 idiopathic). The single question had 100% sensitivity and 96.8% specificity for the diagnosis of RLS. ESS and CGI-S were significantly higher in both RLS patient groups than in normal controls. RLS severity was significantly higher in idiopathic than in associated/symptomatic RLS patients. RLS can be screened with high sensitivity and good reliability in large patient groups by means of the single question; however, the final diagnosis should always be confirmed by the diagnostic features of RLS and accompanied by a careful search for comorbid conditions.
Sleep Medicine, 2009
Background and purpose: Epidemiological studies of restless legs syndrome (RLS) have been limited by lack of a well validated patient-completed diagnostic questionnaire that has a high enough specificity to provide a reasonable positive predictive value. Most of the currently used patient completed diagnostic questionnaires have neither been validated nor included items facilitating the differential diagnosis of RLS from conditions producing similar symptoms. The Cambridge-Hopkins diagnostic questionnaire for RLS (CH-RLSq) was developed with several iterations to include items covering the basic diagnostic features of RLS and to provide some basic differential diagnosis. This validation study sought to determine the sensitivity and specificity of the RLS diagnosis based on this questionnaire. Patients and methods: The CH-RLSq was completed by 2005 blood donors who were asked to consent to being contacted for a telephone diagnostic interview. A scoring criterion was established for ascertainment of RLS based on the clinical definition of the disorder and the exclusion of ''mimic" conditions. A weighted sample (N = 185) of all completed questionnaires was selected for expert clinical diagnosis of RLS using the validated Hopkins Telephone Diagnostic Interview (HDTI). The telephone interviewers were blinded to all questionnaire responses. Results: A telephone diagnosis was obtained on 183 of the sample's 185 questionnaires. The questionnaire's normalized sensitivity and specificity were 87.2% and 94.4%, respectively, for RLS compared to not RLS. The positive predictive values in this sample were 85.5%. Conclusions: The Cambridge-Hopkins RLS questionnaire provides a reasonable level of sensitivity and specificity for ascertainment of RLS in population-based studies.
Sleep Medicine, 2005
Background and purpose: Restless legs syndrome (RLS) is a common central nervous system disorder; however, there is currently a lack of well-validated and easily-administered measures of RLS severity available. The International Restless Legs Syndrome Study Group has recently developed a 10-item scale to meet this need. The International Restless Legs Severity Scale (IRLS) has been shown to have a high degree of reliability, validity, and internal consistency. In order to further demonstrate the validity of the IRLS, the present study examined the relationship between scores on individual IRLS items and overall RLS severity. Patients and methods: The 10-item IRLS was administered to 196 RLS patients. Option characteristic curves (the probability of scoring different options for a given item as a function of overall IRLS score) were generated in order to illustrate the scoring patterns for each item across the range of total RLS severity. Item characteristic curves (the expected score on an item as a function of overall IRLS score) were also generated to illustrate the relationship between scores on the individual items and total RLS severity. Results: The IRLS items demonstrated excellent item response properties, with option and item characteristic curves closely approximating those of an ideal item. Item 3 (relief of arm or leg discomfort from moving around) was the most problematic item in that a 'floor' effect was evident; however, the item response characteristics for this item were still acceptable. Conclusions: Each IRLS item showed a good relationship between responses on that item and overall RLS severity, providing further evidence for the validity of the IRLS as a measure of RLS severity in RLS patients.
BMC Neurology, 2011
Background: Because of the subjective nature of Restless Legs Syndrome (RLS) symptoms and the impact of these symptoms on sleep, patient-reported outcomes (PROs) play a prominent role as study endpoints in clinical trials investigating RLS treatments. The objective of this study was to validate a new measure, the Post Sleep Questionnaire (PSQ), to assess sleep dysfunction in subjects with moderate-to-severe RLS symptoms. Methods: Pooled data were analyzed from two 12-week, randomized, placebo-controlled trials of gabapentin enacarbil (N = 540). At baseline and Week 12, subjects completed the PSQ and other validated health surveys: IRLS Rating Scale, Clinical Global Impression of Improvement (CGI-I), Profile of Mood States (POMS), Medical Outcomes Study Scale-Sleep (MOS-Sleep), and RLS-Quality of Life (RLSQoL). Pooled data were used post hoc to examine the convergent, divergent, known-group validity and the responsiveness of the PSQ. Results: Convergent validity was demonstrated by significant correlations between baseline PSQ items and total scores of IRLS, POMS, RLSQoL, and the MOS-Sleep Scale (p ≤ 0.007 each). Divergent validity was demonstrated through the lack of significant correlations between PSQ items and demographic characteristics. Correlations (p < 0.0001) between RLS severity groups and PSQ items demonstrated known-group validity. Mean changes in investigator-and subject-rated CGI-I scores for each PSQ item (p < 0.0001) demonstrated the PSQ's responsiveness to patient change as reported by their care provider. Conclusions: Although these analyses were potentially limited by the use of clinical trial data and not prospective data from a study conducted solely for validation purposes, the PSQ demonstrated robust psychometric properties and is a valid instrument for assessing sleep and sleep improvements in subjects with moderate-to-severe RLS symptoms.