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A circadian rhythm sleep disorder, or CRSD, is a persistent or recurrent pattern of sleep disturbance, due primarily to (1) changes in the body's natural and internal timekeeping system (its circadian rhythm), or (2) a lack of fit between the circadian rhythm and the time of day in the world outside. Thus, a person with CRSD experiences prolonged insomnia, or sleeps fitfully, at socially inappropriate times, because her body behaves as if it were night time when it is really daytime, or vice versa.
CRSDs are most common among pregnant women, people who work night shifts, people who travel frequently by plane between time zones, patients taking medication that keeps them awake, and anybody whose daily routine has changed and must adopt a new schedule for waking up and going to sleep. Just as there are different groups who are vulnerable to CRSD, there are also five different kinds of CRSD that appear to be the results largely of living conditions; disorders caused more by the environment than by genetic abnormalities. The most well-known CRSD is Jet Lag, AKA Rapid Time Zone Change Syndrome, in which people who've traveled long distances in a short time, generally by airplane, cannot fall asleep at night in their new locale and feel excessively sleepy or groggy during the day.
The same tendency to stay awake at night and fall asleep during the day is also common among people who work at night or rotate shifts; they have a CRSD variant known as Shift Work Sleep Disorder.
Then there are the "night owls" who fall asleep very late at night and have trouble waking up in the morning in time for work, school or other social obligations. Their condition is known as Delayed Sleep Phase Syndrome.
"Early Birds" have a condition known as Advanced Sleep Phase Syndrome, which is the opposite of Delayed Sleep Phase Syndrome; they begin feeling tired early in the afternoon, get very sleepy in the evening, and end up going to bed earlier than any one else and waking up before they want to. Finally, the victims of a CRSD known as "Non 24-Hour Sleep Wake Disorder" wake and sleep on a 25-hour rather than a 24-hour cycle. Their bodies think the day is 25 hours long. They experience insomnia every night, but at different times. They may wake up too early one day, too late the next, sometimes behaving like night owls and other times like Early Birds.
Each Circadian rhythm disorder is treated differently, such that the patient's sleep schedule becomes a good fit with her lifestyle. Patients can use sleep hygiene techniques to establish sleeping routines and ease the transitions between sleeping and waking. They can also turn on bright lights to wake themselves up, which helps reset their circadian rhythms, and adjust their bedtime a little every night until they are falling asleep at the hour they want rather than too early or too late.
Bright-light treatment is proving to be useful for just about every circadian rhythm sleep disorder. It is most popular among researchers developing treatments for sleep disorders related to jet lag and shift work. Melatonin is under investigation as a treatment option as well, but it is not as powerful or as effective as bright light treatment.
While circadian rhythm disorders are mild conditions related to the times one wakes up and goes to sleep, REM sleep disorders are problems with the quality of sleep itself during the Rapid Eye Movement phase -- a type of sleep which occurs towards the end of most sleep episodes.
The first of the REM sleep disorders, the cardiac arrhythmia, is purely physiological in nature. It consists of a slowing down or speeding up of the rate at which the heart contracts during sleep, and its main symptom is uneven breathing. People with heart disease, or low levels of blood oxygen due to sleep apnea (or other types of sleep-disordered breathing) are the most likely to have cardiac arrhythmia, and the best treatment available for the condition is CPAP (continuous positive airway pressure), also used for sleep apnea patients.
A far more spectacular and frightening form of REM sleep disorder is the acting out of dreams, also known as REM sleep behavior disorder (RBD). Healthy people do their dreaming during REM sleep. Even if their dreams are packed with drama and action, most dreamers stay still in their sleeping positions as they dream, with their bodies frozen by atonia -- the temporary paralysis of muscles during sleep. People with RBD, on the other hand, do not have atonia. They move their bodies or limbs while dreaming, often violently and unpredictably. Unlike sleepwalkers and children with sleep terrors, RBD patients can wake up easily, and are able to recall their dreams in vivid detail.
RBD is most common among men over 50, but it can also occur in women and in younger people. The most common tools for diagnosing and treating RBD are Polysomnography (sleep tests) and drug treatments. Since RBD patients can injure themselves and the people who sleep near them, the most important form of self-care is to create a safe sleeping environment. The bed can be padded with bedrails. Any objects that could be dangerous need to be removed from the sleeping area, ranging from weapons and knives to objects that could cause sleepers to trip and fall. The floors must be free of any furniture and objects that could injure some one who fell out of bed. To minimize the risk of dangerous falls, it may be a good idea to sleep on a floor mattress, or to surround the bed with cushions, or even to move sleeping quarters to the ground floor where RBD patients would not be able to injure themselves by falling down stairs. The partners of people with RBD might even consider sleeping in another room to avoid being the unwitting victims of the dreamer having an RBD episode.
*This article is based on information provided at WebMD |
