Although the precise purpose of sleep remains obscure, there is no question that adequate sleep is essential to normal function. Sleep disorders are among the most common human maladies, they commonly compromise daytime activity, and in some cases they may be completely disabling. By and large, they are treatable. Nevertheless, patients seldom volunteer that they are having trouble sleeping, and health care personal seldom ask.
In this chapter, we will begin with a review of normal sleep and the neurological mechanisms underlying sleep. We will then discuss the potential impact of sleep deprivation on waking function, describe the most common sleep disorders, consider their mechanisms, and review treatment.
Sleep, far from constituting a simple shutting down of the brain, is actually more complicated than wakefulness. Sleep studies employing a combination of behavioral observation, subjectinquiry, electroencephalographic (EEG) monitoring, and measurement of muscle tone define five different stages of sleep. In the eyes openawake state, the EEG is dominated by unsynchronized low voltage, high frequency activity (Fig. 1). With stage I sleep, slower, more synchronized rhythms appear.
Sleep and Sleep Disorders