Definition: Defining the Meaning of Sleep Disorder
A sleep disorder, or somnipathy, is a medical disorder of the sleep patterns of a person or animal. Some sleep disorders are serious enough to interfere with normal physical, mental, social and emotional functioning. Polysomnography and actigraphy are tests commonly ordered for some sleep disorders.
Is it hard for you to fall asleep or stay asleep though the night? Do you wake up feeling tired or feel very sleepy during the day, even if you have had enough sleep? You might have a sleep disorder. According to the National Institute of Neurological Disorders and Stroke, about 40 million people in the United States suffer from chronic long-term sleep disorders each year and an additional 20 million people suffer occasional sleep problems.
In fact there are more than 70 different sleep disorders that are generally classified into one of three categories:
- Excessive sleep (e.g. narcolepsy)
- Disturbed sleep (e.g. obstructive sleep apnea)
- Lack of sleep (e.g. insomnia)
Sleep disorders are a medical disorder of the sleep patterns of a person. Some sleep disorders are serious enough to interfere with normal physical, mental and emotional functioning. A test commonly ordered for some sleep disorders is the polysomnogram.
Nightmares, night terrors, sleepwalking, sleep talking, head banging, wetting the bed and grinding your teeth are kinds of sleep problems called parasomnias.
Dyssomnias are a broad category of sleep disorders characterized by either hypersomnolence or insomnia. The three major subcategories include intrinsic (i.e., arising from within the body), extrinsic (secondary to environmental conditions or various pathologic conditions), and disturbances of circadian rhythm.
Insomnia is the most common sleep disorder and it occurs more often in women and in the elderly. Medications and somatic treatments may provide the most rapid symptomatic relief from some sleep disturbances. Some disorders, such as narcolepsy, are best treated pharmacologically. Others, such as chronic and primary insomnia, may be more amenable to behavioral interventions, with more durable results.
The amount of sleep that a person needs to function normally depends on several factors (e.g., age). Infants sleep most of the day (about 16 hours); teenagers usually need about 9 hours a day; and adults need an average of 7 to 8 hours a day.
The most common sleep disorders include:
- Bruxism: Involuntarily grinding or clenching of the teeth while sleeping
- Delayed sleep phase syndrome (DSPS): inability to awaken and fall asleep at socially acceptable times but no problem with sleep maintenance, a disorder of circadian rhythms. Other such disorders are advanced sleep phase syndrome (ASPS) and Non-24-hour sleep-wake syndrome (Non-24), both much less common than DSPS.
- Restless legs syndrome (RLS): An irresistible urge to move legs. RLS sufferers often also have PLMD.
- Situational circadian rhythm sleep disorders: shift work sleep disorder (SWSD) and jet lag
- Hypopnea syndrome: Abnormally shallow breathing or slow respiratory rate while sleeping
- Narcolepsy: Excessive daytime sleepiness, often culminating in falling asleep spontaneously and unwillingly at inappropriate times. Cataplexy, a sudden weakness in the motor muscles that could result in collapse to the floor is also common.
- Night terrors: Pavor nocturnus, sleep terror disorder: abrupt awakening from sleep with behavior consistent with terror
- Obstructive sleep apnea: Obstruction of the airway during sleep, causing lack of sufficient deep sleep; often accompanied by snoring. Central sleep apnea is less common.
- Sleep paralysis: Characterized by temporary paralysis of the body shortly before or after sleep. Sleep paralysis may be accompanied by visual, auditory or tactile hallucinations. Not a disorder unless severe. Often seen as part of Narcolepsy.
- Sleepwalking or somnambulism: Engaging in activities that are normally associated with wakefulness (such as eating or dressing), which may include walking, without the conscious knowledge of the subject
- Parasomnias: Disruptive sleep-related events involving inappropriate actions during sleep stages - sleep walking and night-terrors are examples.
- Periodic limb movement disorder (PLMD): Sudden involuntary movement of arms and/or legs during sleep, for example kicking the legs. Also known as nocturnal myoclonus. See also Hypnic jerk, which is not a disorder.
- Rapid eye movement behavior disorder (RBD): Acting out violent or dramatic dreams while in REM sleep.
FIU study reveals sleep-deprived teens at greater risk for health and behavioral problems:
Adolescents who get six hours of sleep or less may face health and behavior issues, particularly those who get five hours of sleep per night on a regular basis.
- Teenagers who say they get an average of five hours of sleep per night are 37% more likely to report engaging in fighting than those who get an average of eight or more hours of sleep. That percentage jumps to 137% for those who get less than five hours of sleep on average.
- Teenagers who get five hours of sleep per night are 40% more likely to be obese than those who get eight or more hours of sleep, and that percentage jumps to 83% for those who get less than five hours of sleep.
Transition Point of Falling Asleep
How can we tell when someone has fallen asleep
Understanding the process of falling asleep is an important problem in neuroscience and sleep medicine. Researchers have replaced a standard measure, the behavioral response task, which uses sounds that can disturb sleep, with a new task centered on a subject's focused natural breathing - an act which may even promote sleep. They modeled the physiological and behavioral changes occurring during sleep onset as a continuum that can develop gradually over time. The identification of some subjects who continued to perform the task even though current clinical measures would say they were asleep suggests a natural variation in the way cortical and thalamic networks interact in these people. Ultimately, such methods could greatly improve clinicians ability to diagnose sleep disorders and to more precisely measure the effects of sleep drugs and other medications.
Future work will look to improve the understanding of the mechanisms underlying neural dynamics during sleep, as well as the development of more sophisticated diagnostic and monitoring tools.
Sleep Disorder Awareness
The Sleep Disorders Awareness Ribbon color is black, and the month of May is U.S. National Sleep Disorder Awareness month.
Quick Facts: Good Sleep Habit
The promotion of good sleep habits and regular sleep is known as sleep hygiene. The following sleep hygiene tips can be used to improve sleep.
- Avoid nicotine.
- Avoid large meals before bedtime.
- Avoid caffeine and alcohol close to bedtime.
- Go to bed at the same time each night and rise at the same time each morning.
Statistics: Sleep Disorder
- Restless Leg Syndrome affects as many as 10% of Americans.
- Over half of those over the age of 65 experience disturbed sleep.
- Women are twice as likely as men to have difficulty falling and staying asleep.
- In 2009, only 31% of high school students reported getting at least 8 hours of sleep on an average school night.
- Over 18 million Americans suffer from sleep apnea and an estimated 10 million Americans remain undiagnosed.
- Over 70 million Americans suffer from disorders of sleep and wakefulness - Of those, 60% have a chronic disorder.
- 20 - 40% of all adults have insomnia in the course of any year - 1 out of 3 people have insomnia at some point in their lives.
- Narcolepsy affects as many as 200,000 Americans - Fewer than 50,000 are diagnosed - 8 to 12% have a close relative with the disease.
- Adults who reported sleeping less than the recommended 7 to 9 hours per night were more likely to have difficulty performing many daily tasks.
- According to data from the National Health Interview Survey, nearly 30% of adults reported an average of 6 hours of sleep per day in 2005-2007.