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Background The exact genetic causes within each of the known restless legs syndrome ( RLS) loci are still unknown. Recently, it was suggested that an intronic protein tyrosine phosphatase, receptor type δ ( PTPRD) single-nucleotide polymorphism ( SNP) (reference SNP no. rs2381970) is associated with its expression, which may lead to RLS and other related phenotypes. Another study identified 3 nonsynonymous PTPRD variants in familial RLS cases: p.Q447E (a residue change from glutamine to glutamic acid at position 447), p.T781A (a residue change from threonine to alanine at position 781), and p.R995C (a residue change from arginine to cysteine at position 995). Methods Two cohorts of sporadic RLS, a French-Canadian cohort and a cohort from the United States, with a total of 577 patients and 455 controls, and an additional familial RLS cohort with a total of 635 individuals (140 families) were genotyped for these 4 variants (rs2381970, p.Q447E, p.T781A, and p.R995C) by using specific TaqMan probes, and the effects of each variant as well as haplotypes were analyzed. Results None of the 4 PTPRD-specific variants or haplotypes that were tested were associated with RLS in the case-control cohorts or in the familial cohort. The frequencies of the rs2381970 variant in the French-Canadian and US cohorts were 0.07 and 0.04, respectively, and their frequencies in the respective control populations were 0.06 and 0.04, respectively ( P > 0.4 for both). Similar results were obtained for the 3 nonsynonymous variants. Conclusions Although the PTPRD gene is well established as an RLS-associated locus, the rs2381970 SNP and the 3 nonsynonymous PTPRD variants are not likely to cause or affect the risk for developing RLS in the study population. More studies in other populations are needed to determine their potential role in RLS. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Restless legs syndrome/Willis Ekbom disease (RLS/WED) has been recognized as a significant medical disorder since the 17th century. It was studied mostly in the last 50 years in relation to increasing interest in sleep medicine and health-related quality of life. This led to recognition that the disease is not well characterized as restless feelings in the legs. These symptoms are reported in many situations, but the subjective experience of RLS/WED patients differs from that experienced by others. Thus a new name has been introduced that avoids problems of symptom definition of a disease by naming it after those who first characterized it, i.e. 'Willis Ekbom disease'. This article emphasizes the importance of RLS/WED for psychiatry. The disease carries significant increased risk for depression and anxiety disorders. Treatment requires consideration of these co-morbid disorders. RLS/WED can exacerbate or even engender psychiatric disease, so treatment of psychiatric disease should also include consideration of RLS/WED. The need for attention to RLS/WED is particularly significant for depression. Most anti-depressants exacerbate or can even engender RLS/WED. Thus this article seeks to introduce RLS/WED in relation to psychiatric practice. It presents the RLS/WED disease, its overlap with psychiatry and the current treatment options. [ABSTRACT FROM AUTHOR]

Abstract: Background: Restless legs syndrome (RLS) is a medical condition with established neuropathology and genetic associations. Significant questions have, however, recently been raised about its true prevalence, medical significance and the degree to which it is under or over-diagnosed. This study therefore aimed to determine its prevalence, morbidity and adequacy of diagnosis based on physician evaluations of their own patients in primary care practice. Methods: Screening questionnaires were completed by adult patients attending 62 primary care practices across six western European countries within a one-week period. Patients screening positive for significant RLS symptoms were clinically evaluated for RLS by their physician. Physicians also classified the degree RLS affected the patient’s health and well-being. Patients independently completed the SF-36 Quality of Life and Medical Outcomes Study (MOS) sleep questionnaires. Results: Ten thousand five hundred and sixty-four patients completed the screening questionnaire; 804 responded positively to RLS symptoms and 630 of these were subsequently evaluated by their physician. The physicians diagnosed RLS in 365 patients. Ninety-one percent of these had not been previously diagnosed with RLS. In this cohort of adult primary care patients (without or with prorating for missed interviews) the estimated prevalence for diagnosed RLS was 3.5% or 4.4% and for medically-significant RLS 2.1% or 2.7%. A moderate to high degree of RLS negative impact on health related strongly to a lower vitality subscale on the SF-36 and short sleep times (5.2–5.4h) with more sleep disturbance on the MOS sleep scale. Conclusion: RLS in these western European countries is a common, clinically-significant medical condition that, despite all the publicity, remains largely undiagnosed. RLS evaluation is particularly recommended for patients complaining of insomnia. [Copyright &y& Elsevier]

Abstract: 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. [Copyright &y& Elsevier]

Abstract: Background: Epidemiological survey studies have suggested that a large fraction of the adult population, from five to more than 10%, have symptoms of Restless Legs Syndrome (RLS). Recently, however, it has become clear that the positive predictive value of many questionnaire screens for RLS may be fairly low and that many individuals who are identified by these screens have other conditions that can “mimic” the features of RLS by satisfying the four diagnostic criteria. We noted the presence of such confounders in a case-control family study and sought to develop methods to differentiate them from true RLS. Methods: Family members from the case-control study were interviewed blindly by an RLS expert using the validated Hopkins telephone diagnostic interview (HTDI). Besides questions on the four key diagnostic features of RLS, the HTDI contains open-ended questions on symptom quality and relief strategies and other questions to probe the character of provocative situations and modes of relief. Based on the entire HDTI, a diagnosis of definite, probable or possible RLS or Not-RLS was made. Results: Out of 1255 family members contacted, we diagnosed 1232: 402 (32.0%) had definite or probable RLS, 42 (3.3%) possible RLS, and 788 (62.8%) Not-RLS. Of the 788 family members who were determined not to have RLS, 126 could satisfy all four diagnostic criteria (16%). This finding indicates that the specificity of the four criteria was only 84%. Those with mimic conditions were found to have atypical presentations whose features could be used to assist in final diagnosis. Conclusion: A variety of conditions, including cramps, positional discomfort, and local leg pathology can satisfy all four diagnostic criteria for RLS and thereby “mimic” RLS by satisfying the four diagnostic criteria. Definitive diagnosis of RLS, therefore, requires exclusion of these other conditions, which may be more common in the population than true RLS. Short of an extended clinical interview and workup, certain features of presentation help differentiate mimics from true RLS. [Copyright &y& Elsevier]

Abstract: Background: Because the diagnosis of restless legs syndrome (RLS) depends on clinical features ascertained by interview, it is important to have structured diagnostic instruments that can guide a diagnostician to an accurate diagnosis. With this aim in mind, the RLS Center at Johns Hopkins has been developing the Hopkins telephone diagnostic interview (HTDI). A previous validation was performed on a patient group. In the current report, we have extended that validation to a non-patient group drawn from on ongoing family study. Methods: Family members from a case-control RLS study were diagnosed by telephone. Once all available family members in a given family had been interviewed, those who lived locally and had responded were asked to come to Johns Hopkins-Bayview Medical center and had dual clinical interviews to ascertain RLS diagnosis. We then compared the results between the two clinical interviews and between the HTDI and the clinical interviews. Results: Diagnostic agreement between two expert clinicians was 93–96% (κ 0.87–0.92). Compared to those subjects on whom the clinicians agreed, the HTDI agreed at least 90% of the time; sensitivity was at least 0.90, specificity 0.91, positive predictive value 0.86, and negative predictive value 0.94. Conclusion: The HTDI managed a high level of diagnostic accuracy, showing only slightly less agreement than the two clinical interviewers. Because of a mean 12-month period between HTDI and clinical interview, this result also indicates that the subjects’ reports of symptoms are consistent and stable. The HTDI should be useful for confirming questionnaire diagnoses or screening subjects to enter basic or therapeutic trials. [Copyright &y& Elsevier]

Abstract: Background and purpose: To evaluate periodic limb movements during sleep (PLMS) in first-degree relatives of both restless legs syndrome (RLS) patients and matched controls without RLS in order to analyze patterns of this motor sign of RLS. Patients and methods: First-degree relatives of a consecutive case series of RLS patients and matched community controls without RLS were evaluated for diagnosis of primary RLS and for PLMS as determined by a leg activity meter. The data were analyzed to determine whether or not PLMS rates are higher than expected for RLS subjects in these families, who have mostly milder disease, and family members of early-onset RLS patients not themselves diagnosed with RLS. Results: PLMS activity in family members was significantly higher for those diagnosed as RLS compared to those diagnosed as not-RLS. This difference was greater for older than younger subjects. In family members older than the median study age (52 years old) who were diagnosed as not-RLS, PLMS were significantly more frequent in those related to an early-onset RLS proband than in those related to either a control or late-onset RLS proband. Conclusions: PLMS are elevated even in those with mild RLS and reveal an age-related worsening of the motor component of RLS. PLMS may represent an incomplete expression of RLS tendencies in families of patients with early-onset RLS, but this needs to be confirmed in future longitudinal studies. The increase in PLMS with age, reported in healthy controls, may in fact occur in part as a partial expression of familial or genetic factors associated with RLS. [Copyright &y& Elsevier]

Background: There are relatively few studies on the prevalence of restless legs syndrome (RLS) in the general population, even fewer that used diagnostic questions covering all 4 essential diagnostic criteria defining the RLS symptom complex, and none that have reported on the 2 RLS phenotypes for patients seen by family physicians. Methods: To determine the prevalence of the symptom complex, diagnostic for RLS in a primary care patient population, a prospective population-based single-center study was performed. Every adult patient presenting for care in a small rural primary care practice with mostly white patients was surveyed for a 1-year period using a validated RLS diagnostic questionnaire. Results: A total of 2099 patients completed the questionnaire. Analysis revealed that 24.0% of these patients were positive for all 4 of the essential symptoms used to make the diagnosis of RLS and 15.3% reported these symptoms at least weekly. In addition, the RLS symptom complex was reported significantly more often by women than men and, as a whole, patients reporting the RLS symptoms were significantly older than patients without symptoms. The prevalence of symptoms increased with age until about 60 years and then showed a steady decrease thereafter. Further, early-onset RLS was significantly more common in women than men. Conclusions: A high prevalence of RLS symptoms was observed in this primary care population. This finding supports the need for heightened awareness in both the medical community and general population regarding this disorder, which can often be effectively treated within the primary care practice. [ABSTRACT FROM AUTHOR]

Study Objectives: To develop and validate a telephone diagnostic interview (the Johns Hopkins telephone diagnostic interview for restless legs, abbreviated TDI) for diagnosis of the restless legs syndrome (RLS).Design and Methods: Using the International RLS Study Group diagnostic criteria, specific questions were developed reflecting the diagnostic features of RLS. Seventy-five subjects (37 previously diagnosed RLS patients and 38 controls self-reported to be free of RLS) were interviewed by three expert interviewers blinded to each others' interviews and the patient's clinical status. The interviewers diagnosed each subject based on responses to the TDI.Results: The interviewers overall correctly diagnosed 72 of 75 individuals. Minimum interviewer sensitivity and specificity were 97 and 92%, respectively. The intraclass correlation coefficient (ICC) was used to quantify inter-rater reliability for the three interviewers. The ICC for diagnosis was 0.95. The ICC calculated on other key items in the interview exceeded 0.80 in all cases. The patients were predominantly older individuals with long-standing RLS; 19 of them scored at the highest level of severity on the Johns Hopkins Restless Legs Severity Scale (JHRLSS). The interviewers had more difficulty with assessing the controls accurately, some of whom were probably incorrectly self-categorized as not having RLS.Conclusions: The TDI is a sensitive, specific, and reliable instrument for diagnosing RLS by experienced interviewers in a brief, anonymous telephone encounter. [ABSTRACT FROM AUTHOR]

Background: Restless sleep is a frequent complaint in clinical practice and has been reported in the medical literature since the 1970s. Most often, it has been described in association with specific sleep or medical conditions. However, more recently, publications have emerged that describe a disorder characterized by restless sleep as the core feature. To assess this further, the International Restless Legs Syndrome Study Group (IRLSSG) appointed a task force composed of international sleep experts.Methods: A committee of 10 sleep clinicians developed a set of 16 consensus questions to review, conducted a comprehensive literature search, and extensively discussed potential diagnostic criteria. The committee recommendations were reviewed and endorsed by the IRLSSG Executive Committee.Results: Based on the medical literature and expert clinical experience, the task force found sufficient evidence to formulate diagnostic criteria for a clinical entity designated "restless sleep disorder" (RSD). Eight essential criteria were agreed upon, which include a complaint of restless sleep, observed large body movements during sleep, video-polysomnographic documentation of 5 or more large body movements/hour, occurrence at least three times a week for at least three months, clinically significant impairment, and differentiation from other conditions that might secondarily cause restless sleep. However, the current evidence limits application to ages 6-18 years. Diagnostic coding, addition to existing diagnostic nosologies, and name selection are discussed.Conclusions: Consensus diagnostic criteria for RSD have been developed, which are intended to improve clinical practice and promote further research. [ABSTRACT FROM AUTHOR]

Background: At high altitude, prevalence of restless legs syndrome has been found to be greater than expected in small population-based studies, which did not use validated tools for identification of RLS. However, it is not known as to whether this increased prevalence is associated with altitude or increased risk factors for RLS in these populations or errors in identification of RLS.Method: This population based, door-to-door study was conducted at low altitude (400 m above sea level) and high altitudes (1900-2000 m and 3200 m above sea level) using random stratified sampling in Himalayan and sub-Himalayan region of India. Subjects between 18 and 84 years were screened for restless-legs-syndrome using the validated Cambridge-Hopkins RLS diagnostic questionnaire. Medical comorbidities were ascertained from their medical records. Their anthropometric measurements were obtained and wake resting oxygen saturation was monitored using finger pulse-oximeter. Physical activity during leisure time was evaluated by using the Goldin leisure time exercise questionnaire.Results: A total of 1689 subjects were included. Average age of the included subjects was 35.2 years; 55.2% were women. RLS was identified in 9.4% subjects with higher prevalence among women (13.6% women vs. 4.1% men; P < 0.001). RLS was significantly more prevalent at higher altitudes (12.2% at 1900-2000 m and 11.8% at 3200 m) compared to low altitude (2.5% at 400 m). The low altitude prevalence matched that reported in prior studies of RLS in India. Subjects with medical disorders sometimes related to RLS (eg, peripheral neuropathy, COPD, varicose veins and anemia) also had higher prevalence of RLS. Binary logistic regression controlling for female gender, number of pregnancies, peripheral neuropathy, varicose veins, anemia showed that high altitude independently significantly increased the likelihood of RLS (OR: 5.4, 95% CI: 2.8, 10.4).Conclusion: RLS is about five times more prevalent at high than low altitudes even when controlling for effects of other medical conditions associated with increased risk of RLS. [ABSTRACT FROM AUTHOR]

Abstract: Objective: There has been recent interest in characterizing potential abnormalities of pain processing in patients with sleep disorders such as Restless Legs Syndrome (RLS). The aim of this study was to evaluate psychophysical responses to noxious heat and pressure stimuli in both treated and untreated RLS patients, compared to matched controls. Methods: This study is a cross-sectional group comparison of RLS patients with matched controls. A total of 31 patients (15 treated, 16 untreated) with a confirmed diagnosis of RLS were compared to 18 controls with no history of RLS or related sleep disorders. Results: RLS patients (both treated and untreated) demonstrated reduced pain thresholds and reported greater clinical pain relative to controls. Moreover, RLS patients demonstrated enhanced temporal summation of heat pain (p <.05), which may reflect aberrant central nervous system facilitation of pain transmission. Both treated and untreated RLS patients reported disrupted sleep relative to controls, and mediation analyses suggested that the reduced pain thresholds in RLS were attributable to sleep disturbance. However, the effect of RLS on the magnitude of temporal summation of heat pain was independent of sleep disturbance. Conclusions: These findings suggest that central nervous system pain processing may be amplified in RLS, perhaps partially as a consequence of sleep disruption. RLS patients, even those whose symptoms are managed pharmacologically, may be at elevated long-term risk for the development or maintenance of persistent pain conditions. Further studies in larger samples could help to improve the prospects for pain management in RLS patients. [Copyright &y& Elsevier]

Objectives: To assess the frequency, impact, and medical response to the restless legs syndrome (RLS) in a large multi-national primary care population. Method: Questionnaire surveys of matched patients and primary care physicians (PCPs) in five modern industrialized western countries. Results: An RLS screening questionnaire was completed by 23,052 patients: 2223 (9.6%) reported weekly RLS symptoms; 1557 of these patients had medical follow-up questionnaires completed both by themselves and by their physician. An RLS sufferer subgroup (n=551) likely warranting treatment was defined as reporting at least twice weekly symptoms with appreciable negative impact on quality of life. A total of 88.4% of RLS sufferers reported at least one sleep-related symptom. Most reported impaired sleep consistent with a diagnosis of insomnia. Out of 551 sufferers, 357 (64.8%) reported consulting a physician about their RLS symptoms, but only 46 of these 357 (12.9%) reported having been given a diagnosis. PCPs reported that 209 (37.9%) RLS sufferers consulted them about RLS symptoms, but only 52 (24.9%) were given an RLS diagnosis. In most countries, sufferers, regardless of diagnosis, were prescribed therapies not known to be effective in RLS. Conclusions: RLS significantly impairs patients' lives, often by severely disrupting sleep. The marked under-diagnosis and inappropriate treatment of RLS indicates that PCPs need better education about this condition. Recognizing how often disrupted sleep results from RLS should improve diagnosis. [ABSTRACT FROM AUTHOR]

Background and Purpose: A Matrix Laboratory (MATLAB) script (MATPLM1) was developed to rigorously apply World Associations of Sleep Medicine (WASM) scoring criteria for periodic limb movements in sleep (PLMS) from bilateral electromyographic (EMG) leg recordings. This study compares MATPLM1 with both standard technician and expert detailed visual PLMS scoring.Methods and Subjects: Validation was based on a 'macro' level by agreement for PLMS/h during a night recording and on a 'micro' level by agreement for the detection of each PLMS from a stratified random sample for each subject. Data available for these analyses were from 15 restless leg syndrome (RLS) (age: 61.5 ± 8.5, 60% female) and nine control subjects (age: 61.4 ± 7.1, 67% female) participating in another study.Results: In the 'micro' analysis, MATPLM1 and the visual detection of PLMS events agreed 87.7% for technician scoring and 94.4% for expert scoring. The technician and MATPLM1 scoring disagreements were checked for 36 randomly selected events, 97% involved clear technician-scoring error. In the 'macro' analysis, MATPLM1 rates of PMLS/h correlated highly with visual scoring by the technician (r(2) = 0.97) and the expert scorer (r(2) = 0.99), but the technician scoring was consistently less than MATPLM1: median (quartiles) difference: 10 (5, 23). There was little disagreement with expert scorer [median (quartile) difference: -0.3 (-2.4, 0.3)].Conclusions: The MATPLM1 produces reliable scoring of PLMS that matches expert scoring. The standard visual scoring without careful measuring of events tends to significantly underscore PLMS. These preliminary results support the use of MATPLM1 as a preferred method of scoring PLMS for EMG recordings that are of a good quality and without significant sleep-disordered breathing events. [ABSTRACT FROM AUTHOR]

Background The complaint of pain has largely been ignored in the diagnostic criteria for restless legs syndrome (RLS). The purpose of this study was to investigate the prevalence of painful symptoms in RLS, and to compare sleep-related characteristics between the patients who experienced the painful symptoms and those who did not. Methods The patients with RLS were retrospectively screened from July 2011 to December 2013 at a tertiary-care sleep center. For classifying those with pain and those without pain, more than three specialists separately observed the patients' reports and complaints of symptoms, and the final decision was made through consensus. The demographics and clinical characteristics, including sleep, psychiatric-related scales, and polysomnographic data were reviewed for the study. Results One hundred and sixty patients with RLS were selected, and 23.8% of them reported painful symptoms of RLS. Patients with RLS who experienced painful sensations were found to have lower ferritin levels, more severe RLS symptoms, anxiety and depressive symptoms, and a lower quality of life. The polysomnography data found that patients with RLS who experienced painful sensations had a longer latency to sleep onset and a lower periodic limb movement index (PLMI) ( p  <   0.05). Conclusions Patients who experienced painful sensations had more severe RLS symptoms and a trend toward lower PLMI during sleep. According to these results, an inference can be made that painful sensations may be one important point in determining the severity of RLS. [ABSTRACT FROM AUTHOR]

Background: The prevalence of restless legs syndrome (RLS) in patients with peripheral neuropathy has been reported to be higher than that of the general population in some studies, which suggests an association between neuropathy and RLS, but not all studies show increased RLS with neuropathy. These differences may reflect adequacy of the diagnosis, effects of chronic pain complicating the diagnosis, or population differences. Moreover, if there is increased risk for RLS with neuropathy, it may reflect consequences of the chronic pain rather than other aspects of diabetes mellitus (DM). Therefore, we investigated the effects of diagnosis rigor on the estimated prevalence of RLS in patients with diabetic peripheral neuropathy (DPN) and those with chronic leg pain from osteoarthritis (OA), and then we compared the RLS prevalence in these two populations with each other and with population prevalence for Korea. Methods: Our study is a prospective case-control study of 199 patients with DPN and 220 patients with OA. After evaluating the presence of RLS in these subjects using the diagnostic criteria of the International RLS Study Group, we confirmed the diagnosis of RLS through face-to-face interviews using the 18-item Hopkins Diagnostic Questionnaire, which removes RLS mimics; and through independent examinations by two neurologists. Results: Of the 199 subjects with DPN, 44 (22%) appeared to have RLS from their answers on the 4-item RLS diagnostic questionnaire compared to 8 (3.6%) of 220 subjects with OA. However, the prevalence of RLS in the DPN group dropped to 16 (8%) subjects but stayed at 8 (3.6%) OA subjects when using the Hopkins Telephone Diagnostic Interview (HTDI) adapted for clinical interview. The RLS prevalence determined by HTDI remained significantly higher (P =.042) in the DPN group compared to the OA group and was twice that reported for the general Korean population (8% vs 3.9%). Among subjects with DPN, those with RLS were older (68.06±8.43years vs 62.46±11.05years; P =.049) and had higher pain scores (visual analog scale [VAS], 4.69±2.52 vs 2.72±2.12; P =.002). The quality of sleep (MOS [Medical Outcomes Study] sleep scale) and health-related quality of life (QoL) (total score on the 36-Item Short-Form Health Survey [SF-36]) showed no significant difference between the two groups. Conclusions: The prevalence of RLS in patients with DPN cannot be accurately assessed with only the four diagnostic criteria interview, but the prevalence was higher than expected for Koreans from the general population prevalence and also was higher than occurred with OA patients with chronic leg pains when accurately assessed with a structured interview. Chronic leg pain from OA does not significantly complicate RLS diagnosis, and chronic pain itself does not explain the increased RLS prevalence in diabetic neuropathy. [ABSTRACT FROM AUTHOR]

Abstract: Background: Augmentation is the main complication during long-term dopaminergic treatment of restless legs syndrome (RLS) and reflects an overall increase in RLS severity. Its severity varies considerably from a minor problem to a devastating exacerbation of disease. Despite its clinical relevance, systematic evaluations have rarely been undertaken and there has been no development of methods to assess the severity of augmentation. To fill this gap, the European RLS Study Group (EURLSSG) has developed the Augmentation Severity Rating Scale (ASRS), using three items that assess the degree of change in three specific dimensions of augmentation. The changes in each dimension are summed to give an ASRS total score. Methods: The ASRS was developed to cover the basic dimensions defining RLS augmentation. The items were developed by an interactive process involving professional and patient input. The ASRS that was evaluated included four major items and two alternative forms of one item. The validation was conducted using 63 (85%) mostly untreated RLS patients from six centers, who were treated for six months with levodopa (l-Dopa) (up to 500mg/day, as clinically needed). Two consecutive assessments before and at baseline measured test–retest reliability. Consecutive ASRS ratings by two independent raters on a subsample of patients evaluated inter-rater reliability. Comparison with clinical severity ratings of two independent experts provided external validation of the ASRS. Comparison of patients with and without augmentation with regard to the items and the total score of the ASRS added discriminant validity. Results: Sixty patients (63% females, mean age: 53years, baseline International RLS Severity Rating (IRLS) score 24.7±5.2) were treated with a median daily dose of 300mg l-Dopa (range: 50–500mg). Thirty-six patients (60%) experienced augmentation. Item analyses indicated that one item could be removed as it did not contribute significantly to the test score and only one form of the duplicated item needed to be used. The final ASRS then included three items. Test–retest reliability for the total score was ρ =0.72, and inter-rater reliability was rcc=0.94. Cronbach’s α was 0.62. Validity as assessed by the correlation between the worst ASRS total score during the trial and the expert rating was ρ =0.72. ASRS total score differed between patients without versus with augmentation (mean: 7.4 (standard deviation (SD)=4.0) vs. 2.0 (2.7) (P <0.0001). Conclusions: The ASRS is a reliable and valid scale to measure the severity of augmentation. Due to the need to systematically quantify augmentation for both long-term efficacy and tolerability, the ASRS may become a useful tool to monitor augmentation in future clinical trials. [Copyright &y& Elsevier]