[Sleep fragmentation as the cause of daytime sleepiness and reduced performance].

Studies in healthy young adults revealed that periodic arousals during the night result in increasing sleepiness as a function of the interval of time between arousals. When arousals are frequent, deficits similar to those seen after total sleep deprivation have been found. Observed decrements appear to be specifically related to EEG arousals and do not require complete awakening. In patients with fragmenting sleep disorders such as periodic leg movements and central sleep apnea, improved nocturnal sleep is related to increased alertness and daytime performance.