An item response analysis of the international restless legs syndrome study group rating scale for restless legs syndrome

Does restless legs syndrome impact cognitive function via sleep quality in adults with Parkinson's disease?

Purpose: Restless legs syndrome (RLS) is a sleep disorder that results in sleep dysfunction. Sleep disruption can have profound negative consequences in adults with Parkinson's disease (PD), potentially including cognitive dysfunction. This study examined the relationships among RLS, cognition, and sleep quality in persons with PD.Materials and methods: Participants (N = 79) with idiopathic PD completed six questionnaires evaluating RLS, sleep quality, daytime sleepiness, global cognitive function, sleep apnea risk, and depression. Participants were further examined for body mass index composition and motor symptom severity (MDS-UPDRS Part III).Results: Persons with RLS (n = 25) had significantly worse cognitive function (p = 0.035, d = -0.56) and sleep quality (p < 0.0001, d = -1.19), and more daytime sleepiness (p = 0.009, d = 0.67) than those without RLS (n = 54). Cognitive function was not significantly correlated with sleep quality (rs = 0.113) or daytime sleepiness (rs = -0.001). The association between RLS and cognition was not attenuated by controlling for sleep quality or daytime sleepiness.Conclusions: This study is unique as it is the first to consider the possibility that RLS in PD may be associated with cognitive deficits through a pathway involving sleep quality. Persons with RLS and PD have greater deficits in both sleep quality and cognitive function than individuals without RLS; however, cognitive dysfunction among those with PD and RLS in this sample is not accounted for by sleep quality.

Impact of Positive Airway Pressure on International Restless Legs Syndrome Score in Sleep Disordered Breathing

Study Objective: Studies have shown increased prevalence of restless legs syndrome (RLS) in sleep disordered breathing (SDB), however limited data have focused on the impact of SDB therapy on RLS. We hypothesize that positive airway pressure (PAP) will improve the International Restless Legs Syndrome (IRLS) score among SDB patients compared to patients without PAP. Methods: Patients with AHI ≥ 5 who responded positively to a RLS qualifier question from January 2010 to May 2015 were included in this retrospective study. IRLS score was used to measure RLS symptom severity. Two-sample t-tests and one-way analysis of variance were used to compare changes in IRLS score and linear regression models were created to examine IRLS change with PAP use and PAP adherence (PAP usage ≥4 h nightly for ≥70% of nights), adjusting for potential confounders. Results: In 434 patients (51.9 ± 13.4years, 50.5% female, 77.6% Caucasian; 325 PAP, 109 control), IRLS scores improved from baseline to follow-up, with the PAP group achieving significant improvement after adjustment for covariates (difference in IRLS: −1.8 (CI −3.6,0.00), p = 0.050). In self-reported PAP adherent patients, IRLS improvement was greater than controls (−5.3 ± 7.4 vs. −2.7 ± 7.6 respectively, p = 0.045), and comparable to non-adherent patients (−5.3 ± 7.4 vs. −3.0 ± 7.0, p = 0.091). Conclusions: Among SDB patients with a positive RLS qualifier, those who used PAP therapy achieved significantly greater improvement in IRLS scores than patients who did not use PAP, with more significant changes in the PAP adherent group. This is the first large clinical study to examine these relationships, providing a basis for future prospective interventional trials and informing clinicians of expected improvement in IRLS score in PAP treated SDB populations.

Genetic and epidemiological characterization of restless legs syndrome in Québec

Currently, a total of 19 genetic loci are associated with the risk for developing RLS. This study aimed to assess these RLS predisposing genetic variants, as well as investigate the epidemiological profile and diagnostic features of individuals with RLS in the Québec population, using an interviewer–administered questionnaire. A total of 18 RLS-associated variants were genotyped in the Québec population-based CARTaGENE cohort. A case–control series consisting of 1,362 RLS cases and 1,379 age-matched unaffected controls was used to conduct a genetic and epidemiological association study that integrated the first four RLS diagnostic features of affected individuals, as well as additional RLS-related questions (e.g. frequency of the symptoms and number of total pregnancies in female). Five RLS-predisposing variants were significantly associated after Bonferroni correction and an additional five variants were nominally associated with RLS (p &lt; 0.05). BTBD9 was the strongest genetic risk factor in our cohort (rs9296249, OR = 1.71, p = 9.57 × 10−10). The patient group that met all four essential diagnostic criteria of RLS provided the most significant genetic findings. These results suggest that employing the questionnaire which included standard diagnostic criteria of RLS could improve the accuracy of the survey-based studies.

Sleeping for Two: An Open-Pilot Study of Cognitive Behavioral Therapy for Insomnia in Pregnancy

Insomnia and disturbed sleep are common during pregnancy. This study investigated the effectiveness of group cognitive-behavioral therapy for insomnia (CBT-I) delivered in pregnancy. Thirteen pregnant women with insomnia participated in five weekly CBT-I group sessions. All participants completed the study and provided baseline and follow-up data. Significant reductions in insomnia symptoms and increases in subjective sleep quality were observed over the course of the study. Diary and actigraphy assessments of sleep also changed, such that participants reported less time in bed (TIB), shorter sleep onset latency (SOL), increased sleep efficiency (SE), and increased subjective total sleep time (TST). Additionally, symptoms of depression, pregnancy-specific anxiety, and fatigue all decreased over the course of treatment. Effect sizes ranged from medium to large. CBT-I delivered during pregnancy was associated with significant improvements in sleep and mood. The next step in this area of inquiry is to better establish effectiveness via a randomized controlled trial.

Post Hoc Analysis of Data from Two Clinical Trials Evaluating the Minimal Clinically Important Change in International Restless Legs Syndrome Sum Score in Patients with Restless Legs Syndrome (Willis-Ekbom Disease)

STUDY OBJECTIVES

Determine the minimal clinically important change (MCIC), a measure determining the minimum change in scale score perceived as clinically beneficial, for the international restless legs syndrome (IRLS) and restless legs syndrome 6-item questionnaire (RLS-6) in patients with moderate to severe restless legs syndrome (RLS/Willis-Ekbom disease) treated with the rotigotine transdermal system.

METHODS

This post hoc analysis analyzed data from two 6-mo randomized, double-blind, placebo-controlled studies (SP790 [NCT00136045]; SP792 [NCT00135993]) individually and as a pooled analysis in rotigotine-treated patients, with baseline and end of maintenance IRLS and Clinical Global Impressions of change (CGI Item 2) scores available for analysis. An anchor-based approach and receiver operating characteristic (ROC) curves were used to determine the MCIC for the IRLS and RLS-6. We specifically compared "much improved vs minimally improved," "much improved/very much improved vs minimally improved or worse," and "minimally improved or better vs no change or worse" on the CGI-2 using the full analysis set (data as observed).

RESULTS

The MCIC IRLS cut-off scores for SP790 and SP792 were similar. Using the pooled SP790+SP792 analysis, the MCIC total IRLS cut-off score (sensitivity, specificity) for "much improved vs minimally improved" was -9 (0.69, 0.66), for "much improved/very much improved vs minimally improved or worse" was -11 (0.81, 0.84), and for "minimally improved or better vs no change or worse" was -9 (0.79, 0.88). MCIC ROC cut-offs were also calculated for each RLS-6 item.

CONCLUSIONS

In patients with RLS, the MCIC values derived in the current analysis provide a basis for defining meaningful clinical improvement based on changes in the IRLS and RLS-6 following treatment with rotigotine.

Rating of daytime and nighttime symptoms in RLS: validation of the RLS-6 scale of restless legs syndrome/Willis-Ekbom disease

BACKGROUND

The International Restless Legs Scale (IRLS) is the most widely used of the scales rating the severity of restless legs syndrome/Willis-Ekbom disease (RLS/WED). It has been well validated and is the primary end point for most of the therapeutic and nontherapeutic studies of RLS/WED. It has excellent psychometric properties, although it does not capture the severity of RLS under a wide variety of circumstances and times of day. Moreover, the IRLS has a large placebo effect.

METHODS

The Restless Legs Syndrome-6 Scale (RLS-6), however, takes another potentially valuable approach. Six items are rated on a 0-10 scale from no symptoms at 0 to very severe at 10. In addition to questions on satisfaction with sleep and sleepiness, the scale rates the severity of RLS for the past week under four separate circumstances: while falling asleep, during the night, during the day while sitting or lying, and during the day when moving around. The purpose of the current study is to report the validation of the RLS-6 under baseline and therapeutic conditions.

RESULTS

The RLS-6 seems to be an acceptable, reliable, precise, valid, and responsive instrument for the assessment of RLS severity in a specific and pragmatic manner.

CONCLUSIONS

At present, we view the RLS-6 not as a replacement for the IRLS but as a supplement, as each scale provides information not captured by the other.

The influence of parathyroidectomy on restless legs syndrome in patients with renal hyperparathyroidism

BACKGROUND

Restless legs syndrome (RLS) is a common and poorly understood movement disorder that leads to unpleasant leg sensations. Although RLS can be idiopathic, secondary etiologies such as iron deficiency and renal failure are common. The aim of this prospective cohort study was to evaluate whether RLS is a common feature in patients undergoing parathyroidectomy for renal hyperparathyroidism (rHPT) and if RLS-related symptoms can be influenced by surgery.

METHODS

After providing written consent, patients who underwent a parathyroidectomy for rHPT between January and November 2011 answered a validated RLS-screening-questionnaire (RLSSQ). If this was suggestive for RLS a confirming questionnaire (IRLS) was also completed on the day before surgery, on the fifth postoperative day, and again during follow-up (minimum 12 months). Perioperative parathyroid hormone and calcium levels, as well as the scores of the questionnaires were analyzed.

RESULTS

Twenty-one patients (14 men, 7 women) with a mean age of 47.8 ± 3.2 years underwent total parathyroidectomy with bilateral cervical thymectomy and parathyroid autotransplantation for rHPT. The mean score of the RLSSQ of all 21 patients prior to operation was 6.1 ± 0.5. In 10 of 21 patients (47.6 %) the results of the RLSSQ were suggestive for RLS with a mean score of 8.0 ± 0.3. The consecutive scores of the IRLS in these latter patients significantly dropped from 26.6 ± 1.4 to 19.0 ± 2.2 between the preoperative and postoperative settings (p < 0.05). After a mean follow-up of 17.3 ± 3.7 months the mean scores of the RLSSQ and the IRLS were 6.1 ± 0.6 and 16.3 ± 1.8.

CONCLUSIONS

rHPT may play a major role in the severity of RLS-associated symptoms in patients with renal failure. Consequently, parathyroidectomy may prove to be a valuable tool to reduce RLS-associated morbidity in affected patients. However, larger prospective trials are required to confirm the possible relation between RLS and rHPT seen in the present study

A pilot study of audio-visual stimulation as a self-care treatment for insomnia in adults with insomnia and chronic pain

This pilot study tested the efficacy of an audio-visual stimulation (AVS) program for the promotion of sleep in individuals with chronic pain. Insomnia and chronic pain are common comorbid conditions and their relationship has been viewed as bidirectional. Recent studies suggest a relatively dominant role of sleep in this dyad. The premise of this pilot study was that AVS enhances low frequency while reducing high frequency brain activity resulting in decreased hyperarousal and improved sleep with potential consequent reduction in pain. We conducted a pilot intervention study of AVS using a pre-post design. Participants self-administered a 30-min AVS program nightly at bedtime for 1 month. Sleep and pain were assessed at baseline and at the conclusion of the 4-week intervention phase. Nine adults (mean age 33 ± 15.8 years; female, 89 %) completed the study. After using the AVS device for 4 weeks, significant improvement was seen in reported insomnia (ISI, p = 0.003), pain severity (BPI, p = 0.005), and pain interference with functioning (BPI, p = 0.001). Large effect sizes (Partial η(2) 0.20-0.94) (Cohen's d 0.44-1.45) were observed. The results of this pilot study suggest that the AVS program may be efficacious in decreasing both insomnia and pain symptoms. In order to better assess the efficacy of AVS for sleep promotion and possible pain reduction, more definitive randomized controlled trials will be needed. These should include appropriate sample sizes, objective measures of sleep and pain, and longitudinal follow-up.

Review of Severity Rating Scales for Restless Legs Syndrome: Critique and Recommendations

Over the last decade, research in restless legs syndrome (RLS; also known as Willis-Ekbom disease) has increased dramatically. The International Parkinson and Movement Disorder Society commissioned a task force to formally evaluate the available evidence on severity rating scales in RLS. A literature search retrieved instruments specific to RLS. Each scale was evaluated by three criteria: (1) use in RLS; (2) use by research or clinical groups other than the group that developed the scale; and (3) formal validation and adequate clinimetric properties. Scales were then qualified as "recommended" when all three criteria were met, "suggested" when used for RLS but only one of the other criteria was met, and "listed" when only used in RLS. Details regarding the development, use, and psychometric properties of each instrument and the recommendations of the committee are summarized. The scale of the International Restless Legs Syndrome Study Group for rating the severity of RLS (International Restless Legs Scale or IRLS) and the Augmentation Severity Rating Scale fulfilled criteria for "recommended" instruments to assess severity. Future endeavors should include a validation of the Pediatric RLS Severity Scale, the only available instrument for evaluation of the severity of pediatric RLS, and a validation of a patient version of the IRLS that will not require the interface of a live interviewer.

Restless legs syndrome as a cause of sleep disturbances in cancer patients receiving chemotherapy

CONTEXT

Sleep disturbances are frequent in cancer patients during chemotherapy; the contributory role of restless legs syndrome (RLS) in this setting has never been assessed.

OBJECTIVES

This study investigated the role of RLS in causing sleep disturbances and altering the quality of life in cancer patients during chemotherapy.

METHODS

Evaluation tools included the Pittsburgh Sleep Quality Index (PSQI), the RLS questionnaires, the Functional Assessment of Cancer Therapy-General, and the Hospital Anxiety and Depression Scale for quality of life and anxiety/depression assessment. The study population was 173 cancer patients. The questionnaires were administered during the third chemotherapy cycle. Patients positive for RLS were reassessed six months after the end of chemotherapy.

RESULTS

In all, 58.8% of patients reported experiencing sleep disturbances (PSQI≥5) and 20% screened positive for RLS. Neither sleep disturbances nor RLS was associated with anemia, neurotoxic cytotoxic drugs, or benzamide treatment. A direct relationship was found between the PSQI and RLS (P=0.007); both PSQI and RLS scores were significantly associated with poor quality of life (P=0.008 and 0.01, respectively) and anxiety (P=0.0001 and 0.01, respectively). PSQI score also was associated with depression (P=0.0001). RLS persisted in four of the 25 RLS-positive patients reassessed at six months after chemotherapy. RLS recovery was associated with a significant reduction in sleep disturbances and improvement in quality of life.

CONCLUSION

RLS can be a contributory factor in sleep disturbances in cancer patients undergoing chemotherapy. Screening for RLS could aid in tailoring a potentially more efficacious treatment of such disturbances.

Rotigotine in the Long-Term Treatment of Severe RLS with Augmentation: A Series of 28 Cases

This structured clinical observation includes 28 patients with severe RLS, severe augmentation, and previously frustrating changes of dopaminergic treatment. All were switched from their current dopaminergic regimen to an individually adjusted rotigotine monotherapy; dosages were kept stable for 12 months. Follow-up exams were performed after 1, 3, 6, and 12 months. Severity of RLS symptoms (IRLS), augmentation (ASRS), depressive symptoms (BDI), and daytime sleepiness (ESS) were assessed at all visits. Median rotigotine dose was 4 mg. 27 of the 28 patients showed a major to complete reduction of RLS symptoms. IRLS and BDI scores (both P < .001), but not ESS scores, were significantly reduced. IRLS and BDI amelioration remained stable over the 12-month follow-up period. Augmentation occurred in only one patient. 71.4% suffered at least one mostly mild side effect; most common were increased appetite with compulsive eating (42.9%), application site reaction (28.6%), and nausea (14.3%). In the clinical setting, rotigotine seems to be valuable for the long-term treatment of patients with severe RLS and augmentation.

The relationship with iron and health outcomes in persons with restless legs syndrome

BACKGROUND

Restless Legs Syndrome (RLS) is a sleep disorder cause by inadequate iron metabolism. However, no studies have identified the impact of iron in RLS patients on sleep, depression, fatigue, or quality of life (QoL).

OBJECTIVE

The aims of this secondary data analysis was to determine relationships (a) between serum iron with RLS symptom severity, sleep quality, daytime sleepiness, depression, fatigue, and quality of life (QoL); and (b) based on demographics, specifically age and ethnicity.

METHOD

Data were collected on iron and ferritin concentrations in 48 persons with RLS.

RESULTS

Low serum iron levels were measured in 32% of the participants with only 1 person (4%) treated with iron supplementation. General linear models identified age and race as covariants: (a) being White (p = .047) and higher iron levels (p = .019) were independent predictors of higher social functioning; (b) being White (p = .047) and higher iron levels (p = .004) were independent predictors of less sleepiness; (c) younger age (p = .001) and lower iron levels (p = .025) were independent predictors of depression; and (d) younger age (p = .006) and lower iron levels (p = .005) were independent predictors of fatigue.

DISCUSSION

Findings from this study show that iron supplementation for persons with RLS not only improves motor and sensory symptoms but might also improve sleep, sleepiness, depression, fatigue, and QoL and should be considered by health care providers for treatment of RLS.

Development and validation of patient-reported outcome measures for sleep disturbance and sleep-related impairments

STUDY OBJECTIVES

To develop an archive of self-report questions assessing sleep disturbance and sleep-related impairments (SRI), to develop item banks from this archive, and to validate and calibrate the item banks using classic validation techniques and item response theory analyses in a sample of clinical and community participants.

DESIGN

Cross-sectional self-report study.

SETTING

Academic medical center and participant homes.

PARTICIPANTS

One thousand nine hundred ninety-three adults recruited from an Internet polling sample and 259 adults recruited from medical, psychiatric, and sleep clinics.

INTERVENTIONS

None.

MEASUREMENTS AND RESULTS

This study was part of PROMIS (Patient-Reported Outcomes Information System), a National Institutes of Health Roadmap initiative. Self-report item banks were developed through an iterative process of literature searches, collecting and sorting items, expert content review, qualitative patient research, and pilot testing. Internal consistency, convergent validity, and exploratory and confirmatory factor analysis were examined in the resulting item banks. Factor analyses identified 2 preliminary item banks, sleep disturbance and SRI. Item response theory analyses and expert content review narrowed the item banks to 27 and 16 items, respectively. Validity of the item banks was supported by moderate to high correlations with existing scales and by significant differences in sleep disturbance and SRI scores between participants with and without sleep disorders.

CONCLUSIONS

The PROMIS sleep disturbance and SRI item banks have excellent measurement properties and may prove to be useful for assessing general aspects of sleep and SRI with various groups of patients and interventions.

Development of a Japanese version of the Epworth Sleepiness Scale (JESS) based on item response theory

BACKGROUND

Various Japanese versions of the Epworth Sleepiness Scale (ESS) have been used, but none was developed via standard procedures. Here we report on the construction and testing of the developer-authorized Japanese version of the ESS (JESS).

METHODS

Developing the JESS involved translations, back translations, a pilot study, and psychometric testing. We identified questions in the ESS that were difficult to answer or were inappropriate in Japan, proposed possible replacements for those questions, and tested them with analyses based on item response theory (IRT) and classical test theory. The subjects were healthy people and patients with narcolepsy, idiopathic hypersomnia, or obstructive sleep apnea syndrome.

RESULTS

We identified two of our proposed questions as appropriate replacements for two problematic questions in the ESS. The JESS had very few missing data. Internal consistency reliability and test-retest reliability were high. The patients had significantly higher JESS scores than did the healthy people, and higher JESS scores were associated with worse daytime function, as measured with the Pittsburgh Sleep Quality Index.

CONCLUSIONS

In Japan, the JESS provides reliable and valid information on daytime sleepiness. Researchers who use the ESS with other populations should combine their knowledge of local conditions with the results of psychometric tests.

Possible association between G-protein β3 subunit C825T polymorphism and antipsychotic-induced restless legs syndrome in schizophrenia

OBJECTIVE

The incidence of restless legs syndrome (RLS) is presumed to be higher among people with schizophrenia who take antipsychotic medication, most of which blocks the dopamine D2 receptor. The purpose of this study was to determine whether the G-protein β3 subunit (GNB3) C825T polymorphism is associated with antipsychotic-induced RLS in schizophrenia.

METHODS

We examined 178 Korean patients with schizophrenia. All of the subjects were evaluated using the diagnostic criteria of the International Restless Legs Syndrome Study Group and the International Restless Legs Scale. Genotyping was performed for the C825T polymorphism in the GNB3 gene.

RESULTS

The genotype distribution did not differ significantly between antipsychotic-induced RLS patients and patients who had no-RLS symptoms (χ 2 = 4.30, p = 0.116). The genotypes of the C825T single-nucleotide polymorphism (SNP) were classified into two groups: C+ (CC and CT genotypes) and C- (TT genotype). The presence of the C allele (C+) was associated with an increased likelihood of RLS (χ 2 = 4.14, p = 0.042; odds ratio = 2.56, 95% confidence interval = 1.02-6.47).

CONCLUSIONS

These results suggest that the GNB3 C825T SNP is associated with RLS in schizophrenia. However, confirming this association requires future larger scale studies in which the effects of medication are strictly controlled.

Symptoms of Restless Legs Syndrome in Older Adults: Outcomes on Sleep Quality, Sleepiness, Fatigue, Depression, and Quality of Life

OBJECTIVES

To compare differences in sleep quality, sleepiness, fatigue, depression, and quality of life according to severity of symptoms of restless legs syndrome (RLS) in older adults.

DESIGN

Descriptive, comparative study; cross-sectional design.

SETTING

Penn Sleep Center at the University of Pennsylvania and RLS support groups in Philadelphia.

PARTICIPANTS

Thirty-nine adults, aged 65 and older, diagnosed with RLS with symptoms at least 3 nights per week. Participants were stratified according to symptom severity based on scores from the RLS Symptom Severity Scale. Exclusion criteria were dementia, cognitive impairments, and sleep disorders other than RLS.

MEASUREMENTS

Sleep quality, measured using the Pittsburgh Sleep Quality Index (PSQI), was the primary outcome. Secondary outcomes were sleepiness, fatigue, depression, and quality of life measured using the Epworth Sleepiness Scale (ESS), Fatigue Severity Scale (FSS), Center for Epidemiological Studies--Depression Scale (CES-D), and RLS Quality of Life Instrument (RLS-QLI), respectively.

RESULTS

Significant differences were found in subjective sleep quality (P=.007) and sleep duration (P=.04), as well as in PSQI global score (P=.007). RLS-QLI sleep quality (beta=-0.12, 95% confidence interval (CI)=-0.18 to -0.06, P<.001) and sleepiness (beta=0.35, 95% CI=0.09-0.61, P=.01) were significantly related to PSQI global score. Subjects with severe symptoms were five times as likely to use medication to treat RLS (OR=5.3, 95% CI=1.2-22.2).

CONCLUSION

The severity of RLS symptoms in older adults affects not only sleep quality but also many aspects of quality of life, including social functioning, daily functioning, and emotional well-being.

Challenging issues: Sleep–wake, augmentation and quality of life

RLS is a common disorder which has an important impact on the health and quality of life of patients, with the main consequences being sleep-related. Special attention needs to be paid to patients with depression. The diagnosis of RLS is based on medical history and clinical examination. The most important laboratory examination is measurement of serum ferritin which should be >40 microg/L. The presence of all four essential diagnostic criteria confirms the RLS diagnosis. To detect secondary forms, a clinical examination and laboratory investigations, especially measuring serum ferritin are required. Augmentation is a problem for some patients, especially those being treated with levodopa. However, augmentation can be controlled by using the lowest possible doses of nonergoline dopamine agonists or by using opioids, gabapentin or anti-epileptics.

Characteristics and clinical correlates of restless legs syndrome in schizophrenia

OBJECTIVE

The cause of restless legs syndrome (RLS) has not yet been ascertained, but one of the most promising theories involves dopaminergic deficiency. In accordance with this theory, we assumed that the prevalence of RLS would be higher among schizophrenics treated with antipsychotics than in the normal population. The purpose of this study was to establish the prevalence, characteristics, and clinical correlates of RLS in schizophrenic patients undergoing treatment with antipsychotics.

METHODS

A total of 182 hospitalized schizophrenic patients and 108 age- and sex-matched normal controls were enrolled. The presence of RLS and its severity were assessed using the International Restless Legs Syndrome Study Group (IRLSSG) diagnostic criteria and the IRLSSG rating scale, respectively. The Athens Insomnia Scale (AIS), Brief Psychiatric Rating Scale (BPRS), and Barnes Akathisia Rating Scale (BARS) were used to evaluate insomnia, global psychiatric symptoms, and akathisia, respectively, in schizophrenic patients.

RESULTS

Of the 182 schizophrenic patients, 39 (21.4%) were found to have RLS and 87 (47.8%) met at least one of the RLS diagnostic criteria. The prevalence of RLS was significantly higher in the schizophrenia group than in the control group (p=0.009), as were the RLS scores (p<0.001). The BPRS (p=0.001) and the AIS (p<0.001) scores were higher in the RLS group than in the group with no RLS symptoms.

CONCLUSION

We conclude that it is important to consider the diagnosis of RLS when schizophrenic patients complain of insomnia, and that RLS symptoms could be associated with more severe psychiatric symptoms and insomnia.

Assessment of restless legs syndrome—Methodological approaches for use in practice and clinical trials

The Restless Legs Syndrome (RLS) is a sensorimotor disorder that has only recently been extensively investigated by validated methods. Following the first presentation of diagnostic criteria by the International RLS Study Group in 1995, several methods were specifically developed for clinical trials in RLS or adapted from other areas of medicine and health sciences. We present a critical overview on validated methods to assess (1) severity of RLS symptoms [International RLS Rating Scale (IRLS), John Hopkins RLS Severity Scale (JHRLSSS), the RLS-6 scales, and the investigator-based Clincial Global Impressions (CGI)]; (2) quality of life [RLS Quality of Life Instrument (RLS-QLI), Hopkins RLS Quality of Life Questionnaire (RLSQoL), and the RLS Quality of Life Questionnaire (QoL-RLS)]; (3) sleep disturbances and sudden onset of sleep; (4) sleep laboratory methods (polysomnography, limb activity monitoring by actigraphy) to evaluate sleep and periodic leg movements (including the "suggested immobilization test"); and (5) severity of augmentation (Augmentation Severity Rating Scale, ASRS). It is concluded that several validated methods are available to investigate the main features of RLS in practice and in clinical trials; however, further developments are needed to address new questions like the consequences of RLS on life functioning in areas such as ability to travel, days missed at work or impaired work performance.

Correlation between putative indicators of primary restless legs syndrome severity

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.

RESULTS

PSG-PLMI correlated with IRLS (r=0.462; P=0.003) and with SIT-PLMW (r=0.681; P=0.0004). A correlation was also found between IRLS and SIT-MDS (r=0.447; P=0.004), even though SIT-PLMW and IRLS did not correlate with each other (P=0.286). A negative correlation was found between PSG-PLMI and sleep efficiency (r=-0.435; P=0.005). Neither SIT nor IRLS correlated with sleep efficiency. Only SIT discomfort scores from the second half of SIT correlated with SIT-PLMW (r=0.457, P=0.004), and they had a stronger correlation with IRLS (P=0.003).

CONCLUSIONS

This study attempted a much needed comprehensive evaluation of the relationship between various RLS severity indicators. Our findings support a strong role of motor dysfunction on sleep quality in RLS, as well as the potential use of SIT-PLMW as a sensitive indicator of RLS severity.