[Alertness disorders and parasomnias of the wakefulness-sleep transition].
Disorders of arousal and parasomnias of sleep-wake transition are revisited. Disorders of arousal are: Sleepwalking (SW), confusional arousals (CA) and sleep terrors (ST). SW, CA and ST are different clinical manifestations of the same disorder being ST the most severe and SW the mildest manifestation. Disorders of arousal are typical parasomnias of NREM sleep, mainly slow wave sleep. Pathophysiological mechanism of these disorders is the state's dissociation of wakefulness and sleep. The conjunction of the constitutional factors (genetic, age, sleep privation, drugs, psychological, etc.), and precipitant factors (light, sound, temperature, touch, apnea, gastroesophageal reflux, seizure, fever, psychological, etc.) permit three possible arousal behavioral response: A full awakening, a shift stage of sleep or a partial arousal. Clinical significance of arousal parasomnias depend on the age. In children are caused by developmental and genetic factors and usually are autolimited. In adults usually are caused by psychopathology. In the elderly are often caused by organic brain syndromes. Parasomnias of sleep-wake transition are: Rhythmic movements of sleep, sleeptalking, starts and the nocturnal cramp. Most of them are mild disorders, almost physiological phenomena that usually don't need any treatment.