SLEEP DISORDERS

SLEEP DISORDERS

There are two major phases of sleep: Rapid Eye Movement (REM) phase and the non-rapid eye movement (NREM) phase. The REM phase is also called dream sleep or D-sleep because it is associated with vivid dreams and is also known as paradoxical sleep, because there is a paradoxical deviation of brain and physiological activity during this phase; it is the stage of an ‘awake brain in a paralyzed body’. NREM phase is characterized by diminished physiological functions and a low level of overall activity, and is otherwise known as orthodox sleep, slow wave sleep or S-sleep.

Sleep Deprivation: Even though loss of sleep on an occasional night may not have any deleterious consequences, prolonged sleep deprivation leads to reduced concentration and impairment of intellectual performances, irritability, fatigue and mood disturbances. Misperceptions, hallucinations (mainly visual and tactile) and persecutory delusions also may accompany sleep deprivation.

Sleep Apnoea: This is characterized by temporary cessation of respiration during sleep. It is usually associated with brief periods of profound daytime sleep.

Sleep Disorders

Insomnia: It is difficult to initiate or maintain sleep or its non-restorative nature leading to intense distress and impairment of functioning. Insomnia may be primary or secondary. In primary insomnia there is no discernible cause. Secondary insomnia is caused by any of the several medical conditions that affected sleep.

Hypersomnia: It is excessive sleep. Excess sleep compensating inadequate night time sleep or due to physical exhaustion does not qualify for this diagnosis. Idiopathic Hypersomnia is characterized by difficulty in waking up completely until several hours after getting up. Narcolepsy is characterized by an irresistible desire to sleep and bouts of sleep each lasting for 10 – 30 minutes occurring during the day time. Kleine-Levin Syndrome is characterized by long periods of sleep alternating with voracious eating. Sleep continuous for days and weeks at a stretch with short pauses of arousal limited to eating or voiding. When aroused the patient is irritable and often aggressive.

Rhythm Disorders: Jet lag is a type of rhythm disorder and occurs when there is a mismatch between the circadian rhythm and actual sleep.

Parasomnias: It represents abnormal events occurring during sleep or during sleep-wake transition periods. Insomnia or hyper-somnolence is not complained by these people. Nightmares consist of frightening dreams from which the individual wakes up with fear. Night terrors (or sleep terrors) is characterized by the individual’s abrupt waking up in a frightened manner with screams and symptoms of anxiety (palpitations, panting, sweating, etc.). Somnambulism is a repeated episode of complex motor activities which occur during sleep. The individual gets up and walks about aimlessly avoiding obstacles and self-injury. Somniloquy is sleep talking and consists of words or sentences uttered often in an inarticulate manner. Bruxism is teeth grinding and occurs during light sleep. It may be severe enough to cause damage to the teeth.