ABSTRACT
Regardless of etiology, sleep arousals generally do not result in shortened sleep but rather in sleep fragmentation. It is this fragmentation that is believed to be an important factor affecting impaired daytime wakefulness. Studies have suggested a strong association between sleep fragmentation and daytime sleepiness (55). Treatment studies also demonstrate a close link between sleep fragmentation and excessive daytime sleepiness. Reduced frequency of arousals from sleep with resultant reduction in the level of sleepiness is commonly seen in patients who are successfully treated for sleep apnea, whereas those who do not subjectively benefit from treatment show no decrease in arousals or sleepiness, despite improved sleeping oxygenation. It must, however, be stressed that lack of fragmented sleep does not exempt one from feeling sleepy. Partial sleep deprivation may occasionally be seen in patients who are unable to sustain sleep from repeated sleep disruption. This is commonly seen in patients with anxiety predispositions or superimposed insomnia.
