Bovine myoclonus: Model of human hyperekplexia (Startle disease)

Health-related quality of life and economic burden in patients with restless legs syndrome

Restless legs syndrome (RLS) is characterized by a distressing, irresistible need or urge to move the legs. It often co-exists with an uncomfortable, though not usually painful, sensation in the legs. Although clear diagnostic criteria and effective treatment options exist, RLS is generally underdiagnosed and under-treated. RLS patients often suffer from sleep disturbances that may severely disrupt normal life functioning. Furthermore, it is one of the most common neurological disorders. In this communication, we provide a systematic review of the literature on health-related quality of life (HRQoL) and health economic issues in patients suffering from RLS. RLS has a considerable impact on the HRQoL of patients, which is comparable to other neurological and chronic diseases. The most important factors contributing to the impairment of HRQoL are the severity of RLS symptoms and the associated sleep disturbances. Although little work has been published on cost-of-illness of RLS, available studies suggest that a considerable economic burden is caused by RLS. Because of the large number of patients requiring treatment and the considerable increase in the number of treatment studies performed in recent years, as well as approval of several drugs for this indication, we assume a considerable increase in treatment frequency. Very few of the RLS treatment options, however, have been evaluated for their cost-effectiveness, and further research is needed on both quality-of-life issues and the economic impact of RLS.

Rotigotine transdermal system for the treatment of restless legs syndrome

Rotigotine is a nonergot D3, D2 and D1 dopamine agonist that is currently approved for use in Parkinson’s disease and is awaiting approval for restless legs syndrome (RLS) in Europe. In the USA, it is currently approved for the treatment of early-stage Parkinson’s disease, but not for RLS patients. Oral dopaminergic agents are considered first-line for the treatment of RLS, but may not benefit all patients. Transdermally administered rotigotine delivers medication continuously, which may benefit patients with more severe RLS symptoms that persist or fluctuate throughout the day. It may also benefit patients with gastrointestinal problems or difficulty swallowing. Future research may further define the benefits of minimizing pulsatile stimulation of dopamine receptors. Several studies support the efficacy and tolerability of rotigotine in RLS patients. After treatment with rotigotine, patients had improved International RLS scores compared with placebo. Side effects reported were generally not serious and included application site reaction, nausea, somnolence, dizziness, headache, vomiting and insomnia. The well-known effectiveness and tolerability of dopaminergics, combined with a new pharmaceutical form, represents a promising treatment option for patients with RLS.

Clinical trials in restless legs syndrome--recommendations of the European RLS Study Group (EURLSSG)

The European Restless Legs Syndrome (RLS) Study Group (EURLSSG) is an association of European RLS experts who are actively involved in RLS research. A major aim of the Study Group is the development and continuous improvement of standards for diagnosis and treatment of RLS. Several members developed study designs and evaluation methods in investigator-initiated trials early in the 1990s, and all members have since contributed to many pivotal and nonpivotal drug trials for the treatment of RLS. The recommendations on clinical investigations of pharmacological treatment of RLS patients summarize the group's expertise and knowledge acquired through clinical trials. The recommendations primarily address how to plan and conduct confirmatory, randomized clinical studies in patients with idiopathic RLS. Advice is presented for the diagnosis of RLS and clinical and polysomnographic inclusion and exclusion criteria. Primary and secondary endpoints for an evaluation of efficacy are based on a critical description of validated methods for both short- and long-term trials, also in special populations (children, pregnant women, elderly patients). The recommendations include the assessment of augmentation. Finally, general issues including the evaluation of safety and tolerability, as well as specific neurological and cardiovascular risks and sleep attacks/daytime somnolence, are discussed. The aim of these recommendations is to support research groups or pharmaceutical companies in the design of optimized study protocols.

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.

Cabergoline compared to levodopa in the treatment of patients with severe restless legs syndrome: Results from a multi-center, randomized, active controlled trial

We report the first large-scale double-blind, randomly assigned study to compare two active dopaminergic therapies for Restless Legs Syndrome (RLS), the dopamine agonist cabergoline (CAB) and levodopa/benserazide (levodopa). Patients with idiopathic RLS were treated with fixed daily doses of 2 or 3 mg CAB or 200 or 300 mg levodopa for 30 weeks. Efficacy was assessed by changes in the IRLS (International RLS Severity Scale) and by time to discontinuation of treatment due to loss of efficacy or augmentation. 361 of 418 screened patients (age 58 +/- 12 years, 71% females) were randomly assigned and treated (CAB: n = 178; levodopa: n = 183) in 51 centers of four European countries. Baseline IRLS total score was 25.7 +/- 6.8. The baseline-adjusted mean change from baseline to week 6 in IRLS sum score was d = -16.1 in the CAB group and d = -9.5 in the levodopa group (d = -6.6, P < 0.0001). More patients in the levodopa group (24.0%) than in the CAB group (11.9%, P = 0.0029, log-rank test) discontinued because of loss of efficacy (14.2% vs. 7.9%, P = 0.0290) or augmentation (9.8% vs. 4.0%, P = 0.0412). Adverse events (AEs) occurred in 83.1% of the CAB group and in 77.6% of the levodopa group. In both groups, most frequent AEs were gastrointestinal symptoms (CAB: 55.6%, levodopa: 30.6%, P < 0.0001). This first large-scale active controlled study in RLS showed superior efficacy of cabergoline versus levodopa after a 30-week long-term therapy. Tolerability was found more favorable with levodopa than with cabergoline.

Molecular structure and function of the glycine receptor chloride channel

The glycine receptor chloride channel (GlyR) is a member of the nicotinic acetylcholine receptor family of ligand-gated ion channels. Functional receptors of this family comprise five subunits and are important targets for neuroactive drugs. The GlyR is best known for mediating inhibitory neurotransmission in the spinal cord and brain stem, although recent evidence suggests it may also have other physiological roles, including excitatory neurotransmission in embryonic neurons. To date, four alpha-subunits (alpha1 to alpha4) and one beta-subunit have been identified. The differential expression of subunits underlies a diversity in GlyR pharmacology. A developmental switch from alpha2 to alpha1beta is completed by around postnatal day 20 in the rat. The beta-subunit is responsible for anchoring GlyRs to the subsynaptic cytoskeleton via the cytoplasmic protein gephyrin. The last few years have seen a surge in interest in these receptors. Consequently, a wealth of information has recently emerged concerning GlyR molecular structure and function. Most of the information has been obtained from homomeric alpha1 GlyRs, with the roles of the other subunits receiving relatively little attention. Heritable mutations to human GlyR genes give rise to a rare neurological disorder, hyperekplexia (or startle disease). Similar syndromes also occur in other species. A rapidly growing list of compounds has been shown to exert potent modulatory effects on this receptor. Since GlyRs are involved in motor reflex circuits of the spinal cord and provide inhibitory synapses onto pain sensory neurons, these agents may provide lead compounds for the development of muscle relaxant and peripheral analgesic drugs.