Excessive Daytime Sleepiness (EDS)
EDS is usually the first and most severe symptom of narcolepsy; it is defined as an irresistible urge to sleep, called “sleep attacks” or ‘Microsleep events’, which are split seconds to several minutes of sleep during the awake stage, and can occur about 3 – 5 times per day. Upon awakening from these episodes, patients may be unaware that they were asleep and continue whatever activity they were doing before the sleep attack; this phenomenon is referred to as “automatic behaviour”. These episodes tend to occur at unusual and inopportune times such as in the middle of a meal, listening to a lecture, during conversations, while driving a car, etc. Daytime sleepiness occurs daily, recurring typically every 2 h, although this can vary widely. Sleepiness is exacerbated when the patient is physically inactive. Daytime sleepiness occurs daily, recurring typically every 2 h, although this can vary widely. These sleep episodes have several characteristics:
(1) they are often irresistible, despite the individual making desperate efforts to fight the urge to sleep;
(2) they are usually short, although their length can vary with environmental factors (eg, the duration can increase with passive activities such as watching television)
(3) they are frequently associated with dreaming; and
(4) they typically restore normal wakefulness for up to several hours.
Learning impairment is often associated with narcolepsy, however psychophysiological testing is generally normal. In most cases, EDS and sleep attacks last throughout the patient’s lifetime, although symptoms often improve after retirement (possibly due to improved management of activities), daytime napping, and adjustment of nighttime sleep.
Since narcolepsy is a disorder of excessive sleepiness, it may seem surprising that patients with narcolepsy often have difficulty in maintaining sleep at night. The reason for this may be explained by the dysfunction of central sleep regulation, which results in frequent and inappropriate transitions between sleep and wakefulness. Narcolepsy results in sleep and wake episodes that occur throughout a 24-hour cycle. As a result, most patients with narcolepsy have difficulty maintaining sleep or full alertness for extended periods; in addition, they report frequent nocturnal awakenings and occasionally indicate that they do not sleep for long periods during the night.
(1) they are often irresistible, despite the individual making desperate efforts to fight the urge to sleep;
(2) they are usually short, although their length can vary with environmental factors (eg, the duration can increase with passive activities such as watching television)
(3) they are frequently associated with dreaming; and
(4) they typically restore normal wakefulness for up to several hours.
Learning impairment is often associated with narcolepsy, however psychophysiological testing is generally normal. In most cases, EDS and sleep attacks last throughout the patient’s lifetime, although symptoms often improve after retirement (possibly due to improved management of activities), daytime napping, and adjustment of nighttime sleep.
Since narcolepsy is a disorder of excessive sleepiness, it may seem surprising that patients with narcolepsy often have difficulty in maintaining sleep at night. The reason for this may be explained by the dysfunction of central sleep regulation, which results in frequent and inappropriate transitions between sleep and wakefulness. Narcolepsy results in sleep and wake episodes that occur throughout a 24-hour cycle. As a result, most patients with narcolepsy have difficulty maintaining sleep or full alertness for extended periods; in addition, they report frequent nocturnal awakenings and occasionally indicate that they do not sleep for long periods during the night.
References
Ahmed I, Thorpy M. Clinical features, diagnosis and treatment of narcolepsy. Clin Chest Med 2010; 31: 371 – 381
Nishino S. Clinical and neurobiological aspects of narcolepsy. Sleep Medicine 2007; 2: 373 – 399
Images:
http://bouldersleeptherapy.com/disorders/narcolepsy.php/
autoimmunediseasesa2z.com
www3.unil.ch
Nishino S. Clinical and neurobiological aspects of narcolepsy. Sleep Medicine 2007; 2: 373 – 399
Images:
http://bouldersleeptherapy.com/disorders/narcolepsy.php/
autoimmunediseasesa2z.com
www3.unil.ch