PEOPLE WHO SUFFER FROM SLEEP DISORDERS FIND THEMSELVES UNABLE TO CONCENTRATE ON THEIR WORK DURING THE DAY. OFTEN TIMES, THESE ARE PEOPLE WHO JUST GO THROUGH THE MOTIONS BECAUSE THEY ARE TOO WEAK OR SLEEPY TO MOVE AROUND AND COMMUNICATE. THEY ARE VERY UNPRODUCTIVE BECAUSE ALL THAT RUNS THROUGH THEIR HEADS IS THE DESIRE TO SLEEP; BUT WHEN THEY FINALLY HAVE THE TIME TO GET SOME SHUT-EYE, THEY CAN’T.

Sleep disorders are classified into four main categories specified by the International Classification of Sleep Disorders. These include:
• Dyssomnias,
• Parasomnias,
• Proposed sleep disorders, and
• Medical/psychiatric disorders

Dyssomnias
Dyssomnias are disturbances in the timing, amount, or quality of sleep, which results in excessive daytime sleepiness or insomnia. Dyssomnias are classified into three subcategories:
• Intrinsic sleep disorders originate inside the body and are due to a variety of possible causes. Common intrinsic sleep disorders include: idiopathic insomnia, psychophysiologic insomnia, obstructive sleep apnea, central sleep apnea, narcolepsy, periodic limb movements and restless legs syndrome in sleep.
• Extrinsic sleep disorders originate outside the body and are most commonly due to behavioral or environmental factors. Common extrinsic sleep disorders include environmental sleep disorder, insufficient sleep syndrome, inadequate sleep hygiene, stimulant-dependent sleep disorder, hypnotic-dependent sleep disorder, and alcohol-dependent sleep disorder.
• Circadian rhythm sleep disorders describe the disruption of the sleep cycle in a 24-hour period. Common circadian rhythm sleep disorders include: shift-work sleep disorder, irregular sleep-wake pattern, jet lag, advanced sleep phase syndrome, and delayed sleep phase syndrome.

Parasomnias
Parasomnias are disorders caused by partial arousal, interferences with sleep stage transitions or abnormal events occurring during sleep. Parasomnias are classified into four sub categories:
• Arousal disorders are caused by partial arousal. Common arousal disorders include: sleep terrors, confusional arousals, and sleepwalking.
• Sleep-wake transition disorders are disorders that interfere with sleep stage transitions. Common examples include: sleep talking, rhythmic movement disorder, and nocturnal leg cramps.
• Other parasomnias include common sleep disorders such as sleep enuresis (bedwetting), primary snoring, sleep bruxism (teeth grinding), infant sleep apnea, and sudden infant death syndrome (SIDS).
Parasomnias usually occur during the REM sleep stage. Common examples include: sleep paralysis, nightmares, and REM sleep behavior disorder.

Circadian Rhythm Sleep Disorders
The term circadian originates from Latin words literally meaning “around the day”. The daily cycle of life, which includes sleeping and waking, is called a circadian rhythm, commonly referred to as the biologic clock.
Circadian rhythms are important in determining human sleeping patterns. Shifting to or out of seasonal time changes, travelling across time zones , or working at a job that involves late evening or night-time work, can affect the body’s circadian rhythm.
In a person with a circadian rhythm sleep disorder, the body is unable to maintain its normal rhythm. The natural sleep schedule changes so that the person is out of phase with day and night. This mismatch may lead to insomnia or hypersomnia.
With the help of Sleep Check, circadian rhythm sleep disorder can be easily assessed by determining the so-called Dim Light Melatonin Onset (DLMO) from salivary samples collected at the normal sleep time of the patient.
Circadian rhythm sleep disorders are treated based on the kind of disorder that is present. Therapy usually combines proper sleep hygiene techniques and external stimulus therapy such as bright light therapy or melatonin administration.

Further Information

DL MO
EUCLOCK – Entrainment of the Circadian Clock
Sleep Disorder Guide
National Sleep Foundation – Waking America to the importance of sleep
American Academy of Sleep Medicine