Leg movements during wakefulness in restless legs syndrome: Time structure and relationships with periodic leg movements during sleep

ArticleinSleep Medicine 13(5):529-35 · February 2012with17 Reads
DOI: 10.1016/j.sleep.2011.08.007 · Source: PubMed
Approximately one third of patients with restless legs syndrome (RLS) also show periodic leg movements (PLM) during relaxed wake fulness (PLMW). In contrast with the large amount of data published on periodic leg movements during sleep (PLMS), PLMW have received less attention from the scientific community. The objective of this study was to evaluate the correlations/differences of time-structure and response to a dopamine-agonist between PLMW and PLMS in patients with RLS. Ninety idiopathic RLS patients and 28 controls were recruited. Subjects underwent clinical and neurophysiological evaluation, hematological screening, and one or two consecutive full-night polysomnographic studies. A subset of patients received 0.25mg of pramipexole or placebo before the second recording. Polysomnographic recordings were scored and LM activity was analyzed during sleep and during the epochs of wakefulness occurring during the first recording hour. RLS patients had higher LM activity during wakefulness than controls, but with a similar periodicity. Even if correlated, the ability of the PLMW index to predict the PLMS index decreased with increasing LM activity. Intermovement intervals during wakefulness showed one peak only at approximately 4s, gradually decreasing with increasing interval in both patients and controls. The effect of pramipexole was very limited and involved the small periodic portion of LM activity during wakefulness. PLMW index and PLMS index were correlated; however, the magnitude of this correlation was not sufficient to suggest that PLMW can be good predictors of PLMS. Short-interval LM activity during wakefulness and sleep might be linked to the severity of sleep disruption in RLS patients and the differences between their features obtained during wakefulness or sleep might be relevant for the diagnosis of sleep disturbances in RLS.
    • "PLMW of RLS/WED patients during the sleep period have mostly short inter-movement intervals (<10 s). The PLMS of RLS/WED patients, in contrast, have mostly long inter-movement intervals (10–90 s) [103]. Contrary to initial expectations, PLMS are not directly related to the primary RLS/WED morbidity of sleep disturbance [69], rather they may reflect some RLS/WED biology partially independent of that. "
    [Show abstract] [Hide abstract] ABSTRACT: 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.
    Article · Aug 2014
  • [Show abstract] [Hide abstract] ABSTRACT: This paper evaluates, in both the theoretical and practical frameworks, the value of the application of the current criteria for the scoring of leg movement activity during sleep, recorded in clinical and research settings, for the study of restless legs syndrome (RLS) and other conditions. Recently, new parameters have been introduced to better describe the time structure of leg movement activity during sleep. The periodicity index, the distribution of inter-movement intervals, and the hourly distribution of periodic leg movements during sleep have emerged as valuable descriptors. Therefore, the additional value provided by the new methods is discussed with a glance at the rationale behind these new approaches. It is concluded that these new methods have proven to be able to provide new insights into the phenomenon of leg movement activity during sleep. In particular, the classical periodic leg movements during sleep (PLMS) index does not seem to be sufficiently specific for the diagnosis and clinical significance of RLS. The specificity of PLMS for the diagnosis of RLS can be significantly increased by considering these additional parameters. The same parameters also allow a more detailed analysis of several aspects of RLS and PLMS that were impossible to perform before on the basis of the simple PLMS index alone.
    Full-text · Article · Apr 2012
  • [Show abstract] [Hide abstract] ABSTRACT: Introduction Nocturnal sleep disturbances, excessive daytime sleepiness, sleep-related breathing disorders, and sleep-related movement disorders are major non-motor key features of many movement disorders. Most research has focussed on Parkinson’s disease, but there is also a substantial knowledge that has been generated for other movement disorders such as atypical Parkinson syndromes, dystonias, heredoataxias, and choreatic disorders. In addition to providing an understanding of the sleep disturbances associated with these disorders, there is increasing evidence that studies of sleep may provide a unique early window into neurodegenerative disorders. For example, research over the last decade demonstrated that REM sleep behavior disorder (RBD) – a complex parasomnia characterized by dream enactment and loss of physiological REM atonia – is often the first non-motor symptom of a neurodegenerative disease. Up to 80 percent of patients initially diagnosed as idiopathic RBD will develop parkinsonism within a twenty-year observational period. In this chapter we will provide an overview of specifically sleep-related movement disorders and start with movement disorders during sleep over motor phenomena in parasomnias to restless legs syndrome (RLS) which presents as a circadian sensorimotor movement disorder.
    Article · Jan 2012 · Journal of clinical sleep medicine: JCSM: official publication of the American Academy of Sleep Medicine
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