Sleep-Related Disorders and Their Treatments

Article excerpt

Introduction

The beginning of health is sleep.

--Irish proverb

Sleep is a state of being that every person experiences essentially every day of his or her life. In total, we spend one-third of our lives in this state, yet how little we understand it and how much we may yearn for it to be better than it is now!

Studies on the epidemiology of insomnia show that 10% to 20% of randomly surveyed persons report either severe or constant sleep problems. Among a sample of older persons, the incidence of complaints would be substantially higher, apparently because of age-related changes in brain physiology as well as various pathological problems.

Women of all ages are more likely than men to report sleep difficulties. Among the many who report problems in sleeping, only one-third take their concern to a physician for help. That means the other two-thirds could be provided counsel or their sleep-related problems by a pharmacist who is well informed on the subject, sensitive to signs of a problem, and open to an opportunity to counsel.

"Asleep" is the antonym of "awake"--wakeful or alert. The state of consciousness, i.e., being awake, is interrupted only by physiological sleep or pathological coma. Science has long sought an explanation of sleep, but only a few riddles of sleep physiology have been penetrated, and those successes came with great difficulty.

One recent writer stated that "the function of sleep is one of the remaining great mysteries of science." Currently, there is not even unanimous agreement on the reason or reasons for sleep to be so necessary as it seems.

One scientific viewpoint on the reasons for sleep is presented in Table 1.(Table 1 omitted)W While many other researchers would hold a similar concept of sleep as having necessary restorative functions, these authors place a distinctive added emphasis on thermoregulation. It has been suggested recently that sleep is a period devoted to removing cerebral free radicals, which accumulate to excess during wakefulness because of the high level of oxidative metabolism in brain tissue (E. Reimund, 1994). Thus, sleep is proposed to be a vital antioxidant defense mechanism.

Normal sleep and its deviations

Sleep stages

"Falling asleep" consists of a progression from awake to eyes-closed drowsiness to light sleep (stages 1 and 2) to deep sleep (stages 3 and 4). There are shifts in the electroencephalogram (EEG) corresponding to stages in this progression.

Researchers believe that it is the deep sleep for which the greatest physiological needs exist (see Table 1). This does not deny a lesser benefit from time spent in sleep stages 1 and 2; however, there is less evidence for their value or for any detrimental effect stemming from a deficit in these stages. And such a deficit is unlikely to occur except in total deprivation of sleep.

A phase of sleep that was first recognized only in the mid-twentieth century is known as REM (rapid eye movement) sleep. REM sleep usually follows a sleeper's progression into deep sleep; all other sleep stages (1 through 4) can be lumped as "non-REM sleep."

REM sleep has at times been dubbed "paradoxical sleep." This refers to the fact that the cerebrocortical EEG in REM sleep consists of fast, low-voltage waves like those of the waking state. However, the REM state is easily discriminated in sleep studies by using two other sets of electrodes, which provide: (1) an electro-oculogram (EOG) that records the distinctive rapid motion of the eyeballs, which are controlled by the external ocular muscles, and (2) an electromyogram (EMG) that displays electrical activity from the jaw muscles, which during REM sleep show a flaccidity characteristic of the musculature in general.

Dreaming

Another remarkable feature of REM sleep is the high proportion of all dreaming that occurs in that stage, although a smaller fraction does occur in 'deep sleep," stages 3 and 4. …