Sleep Disorder Program

The sleep disorders program in the Department of Neurology conducts research aimed at understanding sleep disorders and improving therapy, as well as providing clinical services to care for patients afflicted by these disorders.

Mayo faculty are involved in many research areas, including:

• The pathophysiology of obstructive sleep apnea and other disorders of sleep
• Periodic limb movement disorders of sleep, and insomnia
• The interactions between the circadian system and diseases such as asthma and cardiovascular disease
• Obstructive sleep apnea, central apnea associated with heart failure, and insomnia
• The relationship of sleep with other disorders, such as hypertension
• Other cardiovascular diseases and cardiovascular biomarkers, seizures and 'nocturnal' asthma
• The effect of aging and gender on sleep disorders
• The influence of sleep deprivation on metabolic function

The major sleep disorders include:

Narcolepsy
Narcolepsy, a disorder in which people experience difficulty staying awake. Narcolepsy can cause a person to suddenly fall asleep during the day. These "sleep attacks" occur even after getting enough sleep at night. The unusual sleep pattern that people with narcolepsy have can affect their schooling, work and social life.

The two main types of sleep are rapid eye movement (REM) sleep and nonrapid eye movement (NREM) sleep. During REM sleep, the eyes move rapidly even though the eyelids stay shut. Dreaming mainly happens during REM sleep, when the body becomes limp because of muscular paralysis. This temporary inability to move prevents an individual from acting out dreams that he/she may be having. Normally, a person who falls asleep first experiences NREM sleep, after which REM sleep occurs. People with narcolepsy have a different sleep pattern. They often fall into REM sleep before NREM sleep. The fine line between being asleep and being awake can be blurred in narcolepsy and its sufferers often find that certain experiences of REM sleep can happen while they are awake, causing them to:

• Suddenly lose muscle tone and control when awake (cataplexy). This can appear to be muscle weakness and sometimes can trigger the body to collapse.
• Be unable to move or speak while falling asleep or waking up (sleep paralysis).
• Have vivid dreams while falling asleep or waking up (hallucinations).

There is no cure for narcolepsy. This lifelong condition can be disabling if left untreated. But medicines and lifestyle changes can improve the symptoms of narcolepsy.

Restless Legs Syndrome (RLS)
RLS is a disorder that causes a strong urge to move one’s legs. This urge to move often occurs with strange and unpleasant feelings in the legs. Moving the legs relieves the urge and the unpleasant feelings. People who have RLS describe the unpleasant feelings as creeping, crawling, pulling, itching, tingling, burning, aching or electric shocks. Sometimes, the feelings also occur in the arms. The urge to move and unpleasant feelings occur when you’re resting and inactive. They tend to be worse in the evening and at night; and are temporarily relieved in the morning.

RLS symptoms often get worse over time. However, some people’s symptoms disappear for weeks to months. If a condition or medicine triggers RLS, it may go away if the trigger is relieved or stopped. For example, RLS that occurs due to pregnancy tends to go away after delivery. Kidney transplants (but not dialysis) relieve RLS linked to kidney failure.

Treatments for RLS include lifestyle changes and medicines. Some simple lifestyle changes often help relieve mild cases of RLS. Medicines usually relieve or prevent the symptoms of more severe RLS. Research is ongoing to better understand the causes of RLS and to find better treatments.

The Mayo Clinic Sleep Disorders Center

The Mayo Sleep Disorders Center is a multidisciplinary team of pulmonologists, neurologists, psychiatrists, a psychologist, nurses and polysomnographic technologists engaged in an array of clinical, educational and research activities.

Comprehensive management of the full spectrum of adult and pediatric sleep disorders characterizes the clinical practice. The most commonly encountered conditions include sleep–disordered breathing syndromes, restless legs syndrome, insomnia, parasomnias and circadian rhythm disturbances.

The Sleep Disorders Center offers:

• 16 beds for polysomnography (sleep studies).
• A "Fast Track" program for uncomplicated obstructive sleep apnea patients.
• Institution of an "Urgent Oximetry" program expedites evaluations (often within 48 hours) for patients whose overnight oximetry suggests severe sleep disordered breathing.

Ongoing research

Michael Silber, M.D., is interested in research in the following areas:

• Epidemiology and pathogenesis of narcolepsy with special reference to the hypocretin system.
• Relationship of REM sleep behavior disorder to neurodegenerative diseases.
• Drug management and predisposing factors for restless legs syndrome.
• Other parasomnias including nocturnal hallucinations.

Bradley Boeve, M.D., is interested in normal aging, neurodegenerative disorders that cause cognitive impairment/dementia, neurogenetics, prion disorders, autoimmune/inflammatory encephalopathies, and the neurologically–based sleep disorders. Specific disorders of interest include REM sleep behavior disorder, narcolepsy, and restless legs syndrome/periodic limb movement disorder.

Suresh Kotagal, M.D.'s areas of research include:

• Restless legs syndrome (RLS), in which he is characterizing the clinical features of childhood–onset RLS. Thus far he has observed that RLS is inherited in about 75% of subjects; mothers are more likely to be the affected parents than fathers; and there is a strong link between childhood RLS and systemic iron deficiency. Studies on the long–term outcome of childhood RLS and clinical treatment trials are being planned.
• Dr. Kotagal is evaluating the effectiveness of sodium oxybate on Narcolepsy–cataplexy in an uncontrolled clinical study. Cataplexy is a component of narcolepsy, which is a disabling disorder that affects both adults and adolescents and leads to severe daytime sleepiness and frequent episodes of muscle weakness in response to emotional triggers.
• Children with epilepsy frequently have disturbed sleep, manifested as difficulty falling and staying asleep. These sleep problems have not been thoroughly investigated. Dr. Kotagal is evaluating the link between sleep complaints and epilepsy on a prospective basis using a questionnaire survey.

Research advances

Drs. Hauri, Silber and Boeve studied the treatment of parasomnias with hypnosis by replicating and extending a 1991 study by Hurwitz et al (1991) on the treatment of certain parasomnias with hypnosis. They studied 36 patients and concluded that one or two sessions of hypnotherapy might be an efficient first–line therapy for patients with certain types of parasomnias. (Journal of Clinical Sleep Medicine 2007 Jun 15;3(4):369–73.)

Drs. Kuzniar and Silber studied multiple skeletal injuries resulting from uncontrolled restless legs syndrome. In this case study, they followed a 73–year–old woman with uncontrolled restless legs syndrome who spent most of the night standing and walking. As a result of her nighttime behaviors, she fell several times and sustained, on several separate occasions, fractures of both forearms, ribs, and nose. Iron replacement therapy and changing of her dopamine–agonist medications resulted in almost complete relief of symptoms. (Journal of Clinical Sleep Medicine 2007 Feb 15;3(1):60–1.)