Hypersomnia, or excessive daytime sleepiness (EDS), is a condition in which a person has trouble staying awake during waking hours. People who have hypersomnia can fall asleep at any time; for instance, at work or while they are driving. They may also have other sleep-related problems such as a lack of energy and trouble thinking clearly. People experiencing hypersomnia may get normal amounts of nighttime sleep. However, they often have problems waking up in the morning and staying awake during the day. People with hypersomnia nap frequently, and upon waking from the nap, do not feel refreshed as the brain is not regulating alertness properly.
The following is a brief description of the more common hypersomnia’s.
Primary Hypersomnia is characterized by excessive daytime sleepiness over a long period of time. The symptoms are present all, or nearly all of the time. This may occur in two thirds of sleep apnea patients.
Recurring Hypersomnia involves periods of excessive daytime sleepiness that can last from one to many days, and recur over the course of a year or more. The primary difference between recurring hypersomnia and primary hypersomnia is that persons experiencing recurring hypersomnia will have prolonged periods where they do not exhibit any signs of hypersomnia, whereas persons experiencing primary hypersomnia are affected by it nearly all the time.
Narcolepsy is also a term used to describe persons affected by excessive daytime sleepiness (EDS). This is a complex syndrome that involves dysfunction in the timing of state changes in wake and sleep. Abnormal sleep tendencies include: excessive daytime sleepiness, disturbed nocturnal sleep, and pathological manifestations of REM sleep. People with narcolepsy can fall asleep suddenly and at inappropriate times. These “sleep attacks” can occur while a person is eating, walking or driving, while at home, at work or at school. In other cases, the sleepiness is subtle but dangerous.
Narcoleptics are often temporarily refreshed by short naps, however, after two to three hours, they will feel sleepy again. People with narcolepsy may experience sleep paralysis, which makes them unable to move for a few seconds or minutes as they are falling asleep or waking up from a dream. Some are subjected to hypnagogic hallucinations in which they see things that are not there. Narcoleptics may undergo memory problems as well, having trouble remembering things people tell them because they were not fully awake when being spoken to.
There are two main kinds of narcolepsy, narcolepsy with cataplexy and without cataplexy. Cataplexy is a sudden muscular weakness triggered by an intense emotional experience, usually laughter. Muscle weakness ranges from a barely recognizable relaxing of the facial muscles to the dropping of the jaw or head, weakness at the knees or a total body collapse. Narcoleptics will often experience cataplexy while laughing or when they are surprised.