A sleep disorder is a physical and psychological condition or disturbance of sleep and wakefulness caused by abnormalities that occur during sleep or by abnormalities of specific sleep mechanisms. Although the sleep disorder exists during sleep, recognizable symptoms manifest themselves during the day. Accurate diagnosis requires a polysomnogram, widely known as a “sleep test.”
It is estimated that some 40 million Americans suffer from chronic, long-term sleep disorders. Another 20 to 30 million Americans suffer from some kind of sleep disorder on an irregular basis. The annual costs in productivity, health care, and safety have been estimated in the billions of dollars.
Types of Sleep Disorders
InsomniaObstructive Sleep ApneaNarcolepsyCircadian Rhythm Sleep-Wake DisordersRestless Legs Syndrome (RLS)Periodic Limb Movement Disorder (PLMD)
Insomnia is not defined by the number of hours of sleep a person gets or how long it takes to fall asleep. Individuals vary normally in their need for, and their satisfaction with, sleep. Insomnia may cause problems during the day, such as tiredness, a lack of energy, difficulty concentrating, and irritability.
Loud, constant snoring can indicate a potentially life-threatening disorder called obstructive sleep apnea. A person with sleep apnea stops breathing repeatedly while sleeping, anywhere from 10 seconds to 3 minutes.
The main characteristic of narcolepsy is excessive and overwhelming daytime sleepiness, even after adequate nighttime sleep. A person with narcolepsy is likely to become drowsy or to fall asleep, often at inappropriate times and places.
People with circadian rhythm sleep disorders are unable to sleep and wake at the times required for normal work, school, and social needs. They are generally able to get enough sleep if allowed to sleep and wake at the times dictated by their body clocks. Unless they also have another sleep disorder, the quality of their sleep is usually normal.
Restless Legs Syndrome (RLS) is a neurological disorder in which patients experience irrepressible sensations in the legs or arms while sitting or lying still. Terms used to describe RLS may include creepy, crawly, pulling, tingling, itching, or gnawing.
Periodic Limb Movement Disorder (PLMD), formerly known as nocturnal myoclonus, is a condition in which a person’s legs or arms twitch or move involuntarily and periodically during sleep. PLMD is not the same as night muscle spasms, or hypnic jerks, that occasionally occur when a person is falling asleep.
Source: National Sleep Foundation, National Department of Transportation, Centers for Disease Control and Prevention
- National Sleep Foundation
- American Academy of Sleep Medicine
- American Association of Sleep Technologists
- Board of Registered Polysomnographic Technologists
- Drowsy Driving
- NIH information on sleep
- Sleep and Occupational Safety