Clinical Sleep Neurology

I am honored to serve as Guest Editor for a third issue of Seminars in Neurology on Sleep Disorders. The aim of this volume is to provide an updated review of key sleep disorders commonly encountered by neurologists. The principal objective of the first issue covering sleep medicine, published in September 2004, was to equip neurologists with the basic framework for recognizing the key sleep disorders, such as sleep apnea, narcolepsy, and parasomnias. The second issue, published in March 2005, focused on sleep disorders in association with other neurologic conditions, including headache, seizures, chronic pain, multiple sclerosis, and stroke.

I have chosen to title this third issue “Clinical Sleep Neurology” to describe the interface of sleep and neurology. Given the 5-year interval since the last review of sleep for Seminars in Neurology, Dr. Roos asked me to prepare an updated issue, given that neurologists continue to be challenged by the overwhelming bidirectionality between untreated sleep and neurologic disorders in their patients. Neurologic disorders often present with symptoms that result from underlying comorbid sleep disorders. Some physicians underappreciate sleep diagnosis, and some view sleep disorders as an enigma to be avoided. Patients with sleep complaints continue to challenge physicians for multiple reasons. Given the high prevalence of sleep disorders in the neurology clinic setting and ever-expanding knowledge about sleep disorders, one would have expected a parallel evolution in teaching about sleep disorders in graduate medical education. Unfortunately, this has not been the case, as a persistent lack of sleep education continues in many medical schools and residency training programs. Despite the abundance of sleep disorders in neurology clinics, many physicians receive little training about the key tools necessary to evaluate and treat patients with sleep complaints. The average teaching time directed to sleep disorders is about 2 to 4 hours during the entire medical school curriculum, which is inadequate to meet the needs of the practicing physician. Furthermore, physicians are not educated about the importance of sleep and fatigue management in their own lives, and they practice in a culture that does not foster adequate sleep hygiene. In this third issue devoted to sleep, I hope to reinvigorate sleep knowledge amongst neurologists. As in the previous two issues on sleep, the intent is not meant to conduct an exhaustive review of sleep disorders, but to provide an easily-read update about practical approaches to sleep disorders in the neurology practice.

The first of the two issues on sleep disorders covers basic aspects of sleep medicine, whereas the second is a more in-depth presentation of specific topics. In this issue, I selected topics that enable the Neurologist, Fellow, and Resident to develop a conceptual framework for approaching sleep disorders.

The following is a brief summary of this issue by topic and author:

“The Neurobiology of Sleep,” lays the foundation for understanding sleep neurophysiology and neurochemistry. In his review, Dr. Jerome M. Siegel from UCLA describes classic lesion experiments associated with sleep pathology, and presents recent data implicating hypocretin neurons in regulation of sleep–wake phenomena.

“Approach to the Patient with Sleep Complaints,” by Drs. Baran (University of Mississippi Medical Center) and Chervin (University of Michigan) provides an elegant approach to patients with sleep complaints, such as snoring, sleepiness, insomnia, and abnormal behaviors during sleep. Their review offers a thorough introduction for physicians unfamiliar with the workup for patients with sleep problems in the clinic.

“The Use of Sleep Studies in Neurologic Practice,” authored by Drs. Bae, Lee, and Foldvary-Schaefer eloquently distills volumes of data on commonly performed sleep tests, their indications, interpretation, and limitations.

“Neurocognitive Consequences of Sleep Deprivation,” by Drs. Goel, Rao, Dinges (University of Pennsylvania) and Dr. Durmer (Fusion Sleep – Sleep Medicine Program), highlights compelling data that describe cognitive functions affected by sleep loss—a timely presentation, given the recent Institute of Medicine (IOM) recommendations on increasing resident physician sleep hours in an effort to decrease medical errors.

“Chronic Insomnia” by Dr. Neubauer (Johns Hopkins University) and Ms. Flaherty (University of the Sciences in Philadelphia) summarizes key updates in recent modifications of the definition and diagnosis of chronic insomnia, and highlight key management strategies. “Primary Hypersomnias of Central Origin” by Drs. Frenette and Kushida (Stanford University), is a comprehensive review of daytime sleepiness, such as narcolepsy, which originates centrally. This area of sleep neurology has seen astonishing new research developments in underlying genetic mechanisms and offers exciting future opportunities in key disease-modifying interventions.

In their review of “Neurologic Aspects of Sleep Apnea: Is OSA a Neurologic Disorder?” Drs. Guilleminault (Stanford University) and Ramar (Mayo Clinic) offer convincing evidence that sleep apnea may be a neurologic disorder. One such example is that the observed pharyngeal muscle collapsibility in sleep apnea is secondary to underlying neurologic lesions. “Parasomnias and Movement Disorders of Sleep,” which I contributed, reviews key complex nocturnal behaviors, providing clinical examples from my sleep clinic, and summarizes other sleep-related motor disturbances of sleep, such as restless legs syndrome and periodic leg movement disorder.

In “Circadian Rhythm Disorders,” Drs. Reid and Zee (Northwestern University) update previous reviews on the clinical presentation, evaluation, and management of these disorders, and emphasize new understanding of the physiologic and genetic bases of circadian rhythm regulation, leading to practical and effective management.

“Sleep and Headache,” by Drs. Brennan and Charles (UCLA) describe shared elements of anatomy and physiology between the two disorders, emphasizing that treatment is, not surprisingly, mutually interdependent.

“Sleep and Epilepsy,” by Drs. Foldvary-Schaefer (Cleveland Clinic Foundation) and Grigg-Damberger (University of New Mexico) emphasizes the crucial links between sleep and epilepsy, and includes excellent examples of how polysomnography can aid in seizure diagnosis during sleep.

“Sleep and Neuromuscular Disease,” by Dr. Nicolle (University of Western Ontario) describes why sleep plays such an important role in management of patients with neuromuscular disorders, and specifically reviews data for improving quality-of-life and increasing survival.

“Sleep and Stroke,” authored by Dr. Culebras (State University of New York, Upstate Medical University), demonstrates yet another reason why neurologists must screen their patients for sleep disorders, demonstrating that successful amelioration of sleep apnea with positive airway pressure lowers stroke risk.

“Sleep and Neurodegenerative Diseases,” by Dr. Chokroverty (JFK, Edison, NJ and Seton Hall University) elegantly summarizes and updates the key sleep disorders and their treatments in patients with neurodegenerative disorders. Given that the population is aging, recognition of sleep disturbances in this cohort is not only useful, but also essential.

I would like to conclude by thanking all of the authors for their exceptional contributions. I have had the pleasure of working with many of them as colleagues and friends in this ever-evolving and exciting field. I would like to thank many of my colleagues at UCLA, in particular, Dr. John Mazziotta, Chair, Department of Neurology, for his exceptional support and Dr. Barbara Giesser, Vice Chair for her mentorship. I appreciate the help of Ms. Beverly Hill, my administrative assistant, Ms. Celia Minott, Manager of the UCLA Neurology Clinic, and the staff of the UCLA Neurology Office of Education. I would also like to thank Linda Hagan for her editorial support. Finally, I would like to give special thanks to Dr. Karen Roos, Editor-in-Chief of Seminars in Neurology, for her efforts to educate clinicians about sleep disorders and sleep and neurologic disorders.