What Are Sleep Disorders?

A sleep disorder is any condition that interrupts normal sleep-wake patterns. All of the sleep disorders described here can be evaluated and effectively treated.

Snoring and Sleep Apnea
Snoring is a common problem. But loud snoring can be a symptom of a serious sleep disorder called sleep apnea. People with this disorder actually stop breathing repeatedly during sleep (as many as several hundred times a night) due to complete or partial blockage of the airway by tissue in the nose or throat. The resulting low levels of oxygen increase blood pressure and may cause the heart rate to slow or stop for a few seconds. The poor sleep quality caused by sleep apnea leads to excessive daytime sleepiness, problems with concentration and memory, and headaches.

Narcolepsy
Narcolepsy is also a common problem that is characterized by excessive, uncontrollable sleep episodes during the day which interfere with activities at work or school. Other symptoms patients may experience are vivid nightmares or hallucinations at the onset of sleep, temporary paralysis of arms and legs when falling asleep, or sudden muscle weakness during moments of intense emotion such as anger or excitement.

Insomnia
People with insomnia have chronic problems with falling asleep or staying asleep. This may be due to a number of causes, the most well-known of which are psychological problems such as stress or depression. However, insomnia may have other causes such as breathing difficulties or involuntary muscle movements.

Periodic Limb Movement Disorder
The notable symptom of this disorder, also referred to as nocturnal myoclonus, is the repetitive kicking, jerking or flexing of arms or legs throughout the night due to involuntary muscle contractions. Patients often experience a crawling sensation or a restless feeling in the legs when first going to bed. It can lead to the inability to fall asleep and remain asleep.

Other Sleep Disorders
Other sleep problems may be the result of:

	Chronic respiratory problems or lung diseases which can worsen during sleep, greatly reducing the oxygen level in the blood.
	Significant changes in your sleep-wake schedule, such as those due to shift work or jet lag.
	Nightmares or night terrors. Nightmares are frightening dreams which can be recalled later. They may occur at any age and, in adults, may be related to psychological factors. Night terrors, on the other hand, cannot be recalled in the morning and are most common in children.