I am very thankful to Guest Editor Dr Erik K. St. Louis for assembling a remarkable group of renowned sleep experts to guide us in the care of our many patients with disordered sleep, whether in the context of a primary sleep disorder or in the setting of another neurologic disorder.
In 2013, the Restless Legs Syndrome Foundation changed its name to the Willis-Ekbom Disease Foundation1 based on the recommendation of an advisory group that suggested a name change for the condition.2 The recommendation and decision were based on a number of factors, including recognition that the disorder is not always restricted to the legs, a response to a concern about trivialization of the disorder, an acknowledgement of its first known description by Sir Thomas Willis in 1672 and the detailed description in a case series by Karl Ekbom in 1945, and for ease of cross-cultural communication.1 By 2015, based on “feedback from members, health care providers, and scientists” and recognition that the name restless legs syndrome continued to be used, the foundation reverted to the Restless Legs Syndrome Foundation.3 The result is that restless legs syndrome, which had become restless legs syndrome/Willis-Ekbom disease in the literature, is now typically initially referred to as “restless legs syndrome (also known as Willis-Ekbom disease),” with the parenthetical mention for clarification and recognition of its (arguably ephemeral) recent alternative name. So, in this issue we aren’t “talking about” Willis-Ekbom, aside from a parenthetical initial mention of the eponym.
The sleep literature has at least one other set of alternative terms for the same entity, that being hypocretin and orexin for the neurotransmitter whose deficiency is integral in the pathogenesis of narcolepsy type 1. In this case, the use of two terms for the same molecule is based on its near-simultaneous discovery by two groups: one that coined the term hypocretin because it is produced in the hypothalamus and resembles the hormone secretin,4 and another that coined the term orexin while performing research related to obesity.5 These two synonymous terms remain in ongoing use,6 often occurring next to each other separated by a slash (hypocretin/orexin). In Continuum, we have tended to continue that usage, although we admit to some variation (using either term or both terms with the slash mark) between articles and even within articles, according to the article authors’ original usage. Note that terminology issues are not restricted to any particular subspecialty, as in the “fibular nerve/peroneal nerve” nomenclature in the next issue of Continuum.
Back to this issue, I am very thankful to Guest Editor Dr Erik K. St. Louis for assembling a remarkable group of renowned sleep experts to guide us in the care of our many patients with disordered sleep, whether in the context of a primary sleep disorder or in the setting of another neurologic disorder. After reading this remarkable issue, which was so carefully crafted by Dr St. Louis and his team, I suspect that many readers will agree with me—on the subject of language—that the intersection of sleep (a neurologic process), sleep disorders (themselves neurologic disorders), and other neurologic disorders makes the term neurology in the Sleep Neurology title of the issue reiterative.
The issue begins with an overview by Drs Richard L. Horner and John H. Peever of the fundamental anatomy and physiology controlling normal sleep and wakefulness, providing the background of how dysfunction in these circuits underlie many of the disorders described in the subsequent articles. Next, Dr Michael H. Silber provides a thorough introduction and overview of the indications for, and reasoning underlying, the diagnostic approaches and investigation of the many sleep disorders we encounter.
The issue then moves on to specific sleep disorder syndromes, starting with the article by Drs Yves Dauvilliers and Lucie Barateau, who review the current concepts of pathophysiology and diagnosis and management of narcolepsy and other central hypersomnias. Dr Lynn Marie Trotti next reviews the pathophysiology, diagnosis, and current management recommendations for restless legs syndrome and other sleep-related movement disorders.
The issue proceeds to discussions of the rapid eye movement (REM) sleep and non-REM sleep parasomnias, beginning with the article by Drs Birgit Högl and Alex Iranzo, who review the diagnosis and management of REM sleep behavior disorder (and its prognosis as a frequent harbinger of an underlying synucleinopathy) and other REM sleep parasomnias. Drs Muna Irfan, Carlos H. Schenck, and Michael J. Howell discuss the diagnosis, differential diagnosis, evaluation, and management of the non-REM sleep parasomnias and overlap parasomnias.
Dr Milena Pavlova then discusses the physiology of endogenous circadian rhythms and the pathophysiology, diagnosis, and management of the circadian rhythm sleep-wake disorders. Drs Alon Y. Avidan and David N. Neubauer next review the diagnostic evaluation and management of our patients with the various causes of chronic insomnia disorder.
Drs Nancy R. Foldvary-Schaefer and Tina E. Waters next summarize the diagnostic criteria, evaluation, and management of the various causes of sleep-disordered breathing. Drs Yo-El S. Ju, Aleksandar Videnovic, and Bradley V. Vaughn then review the sleep disturbances that are comorbid with a number of other neurologic disorders, emphasizing that management of the sleep disturbance may improve the symptoms of the neurologic disease. In the final review article of the issue, Dr Suresh Kotagal reviews the diagnosis and management of the spectrum of sleep-wake disorders that occur in childhood.
In the Ethical and Medicolegal Issues section, Dr Michael Rubin discusses shared medical decision making between physician and patient using a case in which the use of opioid therapy is considered in a patient with restless legs syndrome. In the Practice Issues article, Drs Jon Tippin and Mark Eric Dyken review the issues we need to be aware of regarding driving safety and fitness to drive in sleep disorders. In the Coding article, Dr Waleed Hamed El-Feky and Mr David A. Evans update us on sleep medicine coding and coverage guidelines.
As with every issue of Continuum, several opportunities exist for CME. After reading the issue and taking the Postreading Self-Assessment and CME Test written by Drs Ronnie Bergen and James W. M. Owens Jr, you may earn up to 12 AMA PRA Category 1 Credits™ toward self-assessment and CME. The Patient Management Problem, written by Dr St. Louis, describes the case of a 62-year-old woman presenting with daytime tiredness. By following her case and answering 12 multiple-choice questions corresponding to diagnostic and management decision points along the course of her disorder, you will have the opportunity to earn up to 2 AMA PRA Category 1 CME Credits. Canadian participants can now claim a maximum of 14 hours toward the Self-Assessment Program (Section 3) as defined by the Maintenance of Certification Program of the Royal College of Physicians and Surgeons of Canada and approved by the Office of Continuing Medical Education and Professional Development, University of Calgary, for completing the Postreading Self-Assessment and CME Test and the Patient Management Problem.
My sincere gratitude to Dr St Louis for his expert leadership as well as his attentiveness and responsiveness in the creation of this issue (and his devotion as a member of the Continuum Editorial Board, as well). I would like to extend a similar thank you to the expert authors who have so thoughtfully and carefully lent their substantial knowledge to “talk us” through our care of the many patients presenting primarily because of disordered sleep or whose neurologic disorders impact, or are impacted by, the quality of their sleep.
—Steven L. Lewis, MD, FAAN