Sleep is a biologic process, which is cyclic, temporary, physiologic loss of consciousness that is readily, promptly and completely reversed by appropriate stimulus. Sleep involves all the neuro-axis, it just does not involve one part of the brain. It is a reversible behavioral state of perceptual disengagement and unresponsiveness to the environment. It is not a passive process since specialized areas in the brain work to maintain sleep.
Sleep follows a predetermined pattern of well-organized sequential stages and cycles. The structured temporal sequence produces a graphic display known as ARCHITECTURE OF SLEEP, also known as SLEEP HYPNOGRAM. Sleep will always cycle with wakefulness. You do not only sleep at one level. You sleep at different levels which also cycle itself hence there are sequential stages and cycle when we go to sleep.
The best way to determine of the patient is asleep or not is with the use of the ELECTROENCEPHALOGRAM (EEG). This is done by putting on an EEG and apply wave, which measures brain activity and you look at the brain activity of the patient. EEG is the most important means to visualize different stages of sleep by studying brain waves.
According to various sleep theories, sleep is essential for body and brain tissue restoration, memory reinforcement & consolidation, restitution for autonomous functions, energy savings, synaptic and cell network integrity and adaptation.
What will happen to your brain if you do not sleep? It has been shown that impaired concentration, psychological imbalance such as increased irritability & hallucinations and subjective well-being impairment are the aftermath of sleep deprivation. With sleep deprivation for 60 to 200 hours, human beings experience increasing sleepiness, fatigue, irritability and difficulty in concentration. Neurologic signs include nystagmus, impaired saccadic eye movements, loss of accomodation, exophoria, slight tremor of the hands, ptosis of the eyelids, expressionless face and thickness of speech with mispronounciation & incorrect choice of words. During recovery from prolonged sleep deprivation, the amount of sleep obtained is never equal to the amount lost.
