index represents the number of EEG arousals or partial awakenings per hour of sleep.
TABLE 135.1 NORMAL SLEEP ARCHITECTURE
myocardial infarction (MI), and cardiovascular accident in those with moderate to severe OSA (11). OSA syndrome significantly increases the risk of stroke or death from any cause, and the increase is independent of other risk factors, including hypertension (12). OSA is also associated with an increase in insulin resistance and metabolic syndrome (13). This association seems to be dose-related, more severe OSA, as defined by the apnea-hypopnea index (AHI), associated with more severe metabolic syndrome, and it is independent of the body mass index (BMI) (14). Physical characteristics including a BMI > 30, neck circumference greater than 17 inches in men and a BMI > 30,
neck circumference greater than 14½ inches in women, retrognathia, and tonsillar hypertrophy are associated with an increased risk of OSA.
TABLE 135.2 INTERNATIONAL CLASSIFICATION OF SLEEP DISORDERS-2
TABLE 135.3 COMMON CAUSES OF EDS
TABLE 135.4 CLASSIFICATION OF SLEEP APNEA SEVERITY
to subjects who are not sleep deprived or have normal sleep. To put the degree of psychomotor impairment associated with sleep deprivation in perspective, studies that compared the effects of alcohol with sleep deprivation have been conducted. In one study, sleep-deprived subjects scored similarly to those subjects with a blood alcohol level of 0.08% (22).
with narcolepsy, includes EDS, cataplexy, hypnagogic hallucinations, and sleep paralysis. Patients with narcolepsy experience EDS with ESS > 14 and intermittent, uncontrollable episodes of falling asleep during the daytime. Cataplexy, a loss of muscle tone without loss of consciousness elicited by an emotional stimulus, is present in 60% of patients with narcolepsy (33). These sudden sleep attacks may occur during any type of activity at any time of the day. Symptoms generally present in the second decade of life, but the diagnosis of narcolepsy is often delayed by more than 10 years after onset of symptoms (34).
TABLE 135.5 ESSENTIAL DIAGNOSTIC CRITERIA FOR RLS