Whatcha Talkin’ ‘Bout, Willis-Ekbom?
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.