Although the importance of sleep and well-being has been known for centuries, only recently has the medical profession begun to focus on sleep disorders and their effects. According to a research, 40 million Americans were chronically ill with various sleep disorders, with an additional 20 to 30 million experiencing intermittent sleep-related problems. Besides excessive daytime sleepiness and loss of productivity, many studies have suggested that sleep disorders cause important cardiovascular morbidity and possibly mortality.
Most patients studied in sleep laboratories for clinical examination do so because of complaints related to excessive daytime sleepiness, nonrefreshing sleep, and chronic fatigue that cannot be ameliorated by sleep. In 80% to 90% of these patients, laboratory examination uncovers breathing disorders during sleep. Sleepiness is the increased likelihood of falling asleep, often during monotonous or sedentary activities, whereas fatigue is difficulty sustaining a high level of performance. There are three commonly available tools to aid in measuring the degree of sleepiness: the Epworth Sleepiness Scale (ESS), the Multiple Sleep Latency Test (MSLT), and the Maintenance Of Wakefulness Test (MWT). The ESS is a self-administered questionnaire that has patients rate on a scale of 0 to 3 their likelihood of falling asleep during eight common situations and provides a simple subjective measure of sleepiness (Table 1). The questionnaire reflects the level of the patient's daytime somnolence; the higher the score, the sleepier the patient. The MSLT and MWT are objective tests of daytime sleepiness, testing length of time to achieving sleep onset and REM sleep during daytime naps. During the MSLT, the subject is instructed to try to sleep, whereas in the MWT the patient is instructed to try to stay awake.
Table 1. Epworth Sleepiness Scale :
Ask patient likelihood of falling asleep or dozing off in the following situations, in contrast to feeling just tired. Have the patient refer to their usually way of life in recent times.
- 0 = Would never doze
- 1 = Slight chance of dozing
- 2 = Moderate chance of dozing
- 3 = High chance of dozing
Situation Score :
- 1) Sitting and reading
- 2) Watching television
- 3) Sitting inactive in a public place (eg,church)
- 4) As a passenger in a car for an hour without a break
- 5) Lying down to rest in the afternoon when circumstances permit
- 6) Sitting and talking to someone
- 7) Sitting quietly after lunch without alcohol
- 8) In a car, while stopped for a few minutes in the traffic
There are three general causes of hypersomnia: Insufficient Sleep, Fragmentation Of Sleep, And Excessive Sleep.
Fragmented sleep, predominantly microfragmentation, result from conditions such as the Sleep-Related Breathing Disorders And Periodic Limb Movement Syndrome
Excessive sleep drive disorders (Primary Hypersonolence) include Narcolepsy And Idiopathic Central Nervous System Hypersomnia, and Can Be Caused By Sedating Medications