SLEEP DISORDERS : SYMPTOMS AND TYPES
1. INSOMNIA
2. HYPERINSOMNIA
3. PARASOMNIAS
INSOMNIA
Insomnia is a recurrent or persistent inability to either initiate the onset of sleep, or difficulty maintaining a normal uniform sleep pattern. Insomnia is the most common sleep disorder. Occasional insomnia may affect up to one third of the U.S population. The cause of primary insomnia is unknown but secondary insomnia may be caused by alteration of the circadian cycle (inner clock); medical, neurological or psychological illnesses. There are some transient insomnia that may arise from acute stressful situations of life, jet lag, shift work or side effects of some medications intended for something else.
HYPERINSOMNIA
It is an excessive day time sleepiness in certain conditions such as: narcolepsy and insufficient sleep syndrome. Narcoleptics may have additional problems, such as cataplexy (sudden loss of muscle tone) hypnagogic hallucinations (bizarre hallucinations). Narcoleptics usually present with episodes of sudden, uncontrolled desire to sleep, usually while eating, talking, or while driving. Such condition must be distinguished from other conditions, such as use of drugs, stupor and akinetic seizures (drop attacks).
PARASOMNIAS
To better understand this disorder it is necessary to revise the physiology of the sleep cycle. The normal sleep activity has two major components: REM and NREM phases. REM stands for Rapid Eye.
Movements:
The NREM phase has 4 major stages, known as: NREM-1, NREM-2, NREM-3, and NREM-4.
NREM- 1: is a very superficial drowsiness, very light stage that is a transitional change from wake state. The predominant rhythm is beta rhythm in the EEG trace (4-7 Hz). It may last only a few minutes and the
arousal is easy.
NREM- 2: is a deeper stage and the EEG trace may show Gamma rhythm (12-16 Hz). It may show also “sleep spindles”.
NREM- 3: is a deeper stage that may last from a few minutes up to 2 hours and the arousal is harder
NREM- 4: is the deepest stage and some snoring may appear. The EEG is remarkable for deep, high amplitude, slow rhythm complexes of Delta waves. Most night mares, bed wetting and panic attacks may appear in children. Some sleep walking are common here. The body temperature and blood pressure falls, and the heart slows down.
REM PHASE
It may start around 90 minutes after falling asleep or after NREM-1 or NREM-2. It may fluctuate between certain NREM activities back and forth. Most of the brain activity takes place here. Among the major changes that take place here, are: rapid eye movement, piloerection (goose skin), sweating, tachycardia, penile tumescense. Body temperature and blood pressure rise. Sleep studies may reveal true, physiologic causes of erectile dysfunction, versus psychogenic ones. It is believed that most Parasomnias are due to abnormal swings between REM and NREM phases of sleep.
Some variants of Parasomnias are: Somnambulism (sleep walking), Confusional Arousals, Sleep Terrors, enuresis (bed wetting) and nightmares . Nightmares are unpleasant and frightening dreams that occur during REM phase and most may be considered benign. There usually vivid recollection of such dreams. There are some causes of nightmares that may arise from Post Traumatic Stress Disorders, that may require psychotherapy or SSRI drugs.
Sleep apnea, occurs when the patient stop breathing several times during sleep, only to awake violently gasping for air when the Carbon Dioxide accumulates. It is most frequent in obese people when the cause is external but may appear from alteration of the centers in the brain that control the sleep.