neurologic disorders
Insomnia and Excessive Daytime Sleepiness (EDS)
Introduction
Many sleep disorders manifest with insomnia and usually excessive daytime sleepiness (EDS). Insomniais difficulty falling or staying asleep, early awakening, or a sensation of unrefreshing sleep. EDSis the tendency to fall asleep during normal waking hours. (See also Approach to the Patient With a Sleep or Wakefulness Disorder for general information about sleep disorders and about their evaluation and treatment.) Insomnia can be a disorder, even if it exists in the context of other disorders, or can be a symptom of other disorders. EDS is not a disorder but a symptom of various sleep-related disorders. Difficulty falling asleep (sleep-onset insomnia) should be distinguished from difficulty maintaining sleep and early awakening (sleep maintenance insomnia) because the causes differ. Sleep-onset insomnia suggests Circadian rhythm sleep disorder, altered sleep phase types , chronic psychophysiologic insomnia, Sleep disorders may be caused by factors inside the body (intrinsic) or outside the body (extrinsic). 