Central sleep apnea
A rare and serious form of apnea (temporary cessation of breathing) caused by problems with how the brain controls breathing. Central sleep apnea usually occurs in people who are seriously ill. The most common causes are diseases affecting the brainstem (the part of the brain that controls breathing), damage to the cervical spine, and congestive heart failure. People who suffer from this type of apnea may also have other symptoms, including difficulty swallowing, weakness, change in voice, or numbness.<
An abnormal pattern of breathing characterized by alternating periods of apnea and deep, rapid breathing. The cycle begins with slow shallow breaths that gradually increase in depth and rate, followed by a period of apnea. The apnea can last 5 to 30 seconds and is followed by a new cycle of increasingly stronger and deeper breaths, as the body attempts to compensate for lack of oxygen. This cycle may repeat every 45 seconds to 3 minutes. Cheyne-Stokes respirations are most commonly seen during sleep in patients with congestive heart failure, stroke, or head injury.
Circadian rhythm disorder
Disruption in the “internal body clock” that controls the daily cycle of biological processes, including hormone production, brain wave activity, and cell regeneration. Circadian rhythms dictate human sleeping patterns, and their disruption reduces the quality and quantity of sleep. Causes of these disorders include pregnancy, jet lag, and changes in medications or daily routine. However, the most common cause of circadian rhythm disorders is shift work.
Conditions characterized by excessive daytime sleepiness and/or prolonged nighttime sleep. Hypersomnolence syndromes may be caused by some other sleep disorder (such as sleep apnea, insomnia, or narcolepsy), or may be idiopathic (having no known cause).
Difficulty sleeping or the inability to sleep. Insomnia can manifest as difficulty falling asleep, difficulty sleeping through the night, or waking too early in the morning. Insomnia can lead to daytime drowsiness, impaired cognitive function, lack of energy, and irritability. There are numerous causes of chronic insomnia, including shift work, anxiety, depression, and restless leg syndrome. Insomnia may also occur as a side effect of diseases that interfere with sleep such as enlarged prostate (men), arthritis and other painful conditions, and COPD.
A sleep disorder characterized by uncontrollable daytime sleepiness and lapses in consciousness that may be associated with automatic behaviors and amnesia. These episodes are usually preceded by a meal, but can occur at any time, including while talking, driving a car, or in virtually any situation. The condition may be associated with sleep paralysis (paralysis of the body upon waking or right before falling asleep), hallucinations in the period just before falling asleep, or brief episodes of severe muscle weakness.
Obstructive sleep apnea
A serious sleep disorder involving episodes of stopped breathing during sleep due to upper airway obstruction. Blockage of the airway usually occurs when the soft tissues in the back of the throat collapse during sleep. This may cause the sleeper to stop breathing repeatedly, resulting in fragmented sleep, excessive daytime sleepiness, morning headaches, and other symptoms. More serious potential consequences include hypertension, stroke, and heart attacks. Excessive daytime sleepiness as a result of fragmented sleep can increase the risk of motor vehicle crashes and job impairment.
Any of a group of undesirable, episodic, physical events that occur during sleep. Parasomnias can occur during different stages of sleep throughout the night, and are usually characterized by partial waking before, during, or after the episode. Most such events are caused or worsened by stress.
Night terrors (sleep terrors)
Sudden arousal from sleep in a terrified state. Night terrors occur during deep sleep, generally in the first half of the night. They differ from nightmares in that nightmares happen during lighter sleep, and when awakened the sleeper is able to function well and usually has some recollection of the bad dream. In night terrors, however, the sleeper often does not fully awaken, or if the sleeper does awaken he or she is confused, difficult to comfort, and has no recollection of the details of the frightening event. Night terrors are most common in children aged 3 to 5, but can occur at any age. In adults this sleep disorder is commonly linked with emotional stress and/or alcohol use.
Periodic limb movement disorder (PLMD)
A condition characterized by repetitive limb movements during sleep. The movements usually involve the lower extremities, and most often consist of extension of the big toe and flexing of the ankle, knee, and hip. Occasionally the upper extremities (arms and fingers) are also involved. Because these movements interfere with the maintenance of sleep, they can result in excessive daytime sleepiness. The exact cause of PLMD is unknown, but some drugs are known to worsen the condition.
Restless legs syndrome (RLS)
A disorder characterized by aching or burning sensations in the lower (and rarely the upper) extremities that occur prior to sleep or awaken the person from sleep. Complying with an irresistible urge to move the affected limbs brings temporary relief. Sleep may become disrupted, resulting in excessive daytime sleepiness.
Talking during sleep that usually happens in the course of brief arousals from deep sleep. The talk that occurs can be brief and involve simple sounds, or it can involve long speeches by the sleeper. Sleep talkers usually have no memory of what they have said. Possible causes include fever, emotional stress, and an underlying sleep disorder.
Sleep walking (somnambulism)
Arising from bed during sleep. Sleep walking tends to occur during the deeper phases of sleep early in the night, but it can also occur during REM sleep (the phase of sleep in which dreams occur) in the early morning. Sleep walkers usually have no memory of their actions. Sleep walking can be dangerous because the sleep walker is unaware of his or her surroundings and can bump into objects or fall down. Although most common among children aged 6 to 12, sleep walking can occur at any age.