Importance of sleep restoration in co-morbid disease: effect of anticonvulsants.

Over the past two to three decades, sleep medicine has emerged as an important discipline as it strives to meet the challenges of some of the most prevalent disorders among humans. Among the 110 disorders listed in the International Classification of Sleep Disorders, two of the most prevalent and treatable have only recently begun to receive significant attention: sleep apnea and restless legs syndrome with sleep-related periodic limb movements disorder. It is becoming clear that the sleep disruption caused by such disorders has ramifications beyond the usually associated daytime sleepiness, and may include: exacerbation of seizures, headaches, short-term memory deficits, and other cognitive problems. Sleep apnea has also been correlated with hypertension and cardiovascular/cerebrovascular disease. Animal studies have taken this one step further by demonstrating that total sleep deprivation is consistently fatal, usually within 1 month, although the precise mechanism remains to be discovered. The most compelling finding in the animal studies is that "rescuing" the animals with sleep, before the irreversible stage, is associated with rebound amounts of deep sleep and rapid eye movement (REM) sleep ("dream sleep"). This same response is seen after initiating treatment of sleep apnea with nasal continuous positive airway pressure (CPAP), and can also occur in patients with other sleep disorders in response to particular medications, such as valproate or gabapentin.