Vol.99 No.6 contentsPRACTICA OTO-RHINO-LARYNGOLOGICA
Vol. 99 No. 6 June 2006
Overview of Sleep Disorder
Soichiro Miyazaki
(Shiga University of Medical Science Hospital)
The most frequent sleep problems are sleep-related breathing disorders, insomnia, excessive daytime sleepiness, and circadian rhythm disorder. In 2004, we treated 468 sleep disorder patients, at the Sleep Disorder Center, Shiga University of Medical Science Hospital. Forty-nine percent of the subjects were diagnosed as having sleep related breathing disorders, 22％ as insomnia, 10％ as rhythm disorders and 5％ as having excessive daytime sleepiness. Insomnia is a common sleep-wake-related complaint, and sleeping pills are among the most commonly prescribed drugs in clinical practice. However, insomnia is a symptom that can be caused by various disorder's, many of which require specific therapies. One specific cause of insomnia in older adults is restless legs syndrome. This condition, characterized by an urge to move the legs, which is usually accompanied by sensations of discomfort and aggravations of symptoms by rest. Daytime sleepiness is a common complaint. Snoring, the use of hypnotic agents, sleep difficulties, irregular sleep-wake schedule and sleep deprivation are related to daytime sleepiness. Circadian rhythm sleep disorders have intrinsic and extrinsic subtypes: delayed sleep phase syndrome, advanced sleep phase syndrome and non-24-h sleep-wake syndrome. The underlying problem of circadian rhythm sleep disorders is that the patient cannot sleep when sleep is desired. Waking episodes may occur at inappropriate times; therefore, the patient may complain of insomnia or excessive sleepiness.
Key words : insomnia, sleep disorder, circadian rhythm disorder