Irregular sleep-wake rhythm
Encyclopedia
Irregular sleep–wake rhythm is a rare form of circadian rhythm sleep disorder
. It is characterized by numerous naps throughout the 24-hour period, no main nighttime sleep episode and irregularity from day to day. Sufferers have no pattern of when they are awake or asleep, may have poor quality sleep, and often may be very sleepy while they are awake. The total time asleep per 24 hours is normal for the person's age. The disorder is serious—an invisible disability
. It can create social, familial, and work problems, making it hard for a person to maintain relationships and responsibilities, and may make a person home-bound and isolated.
There is a possible reciprocal relationship between bipolar disorder
and sleep disorder
s: "Irregular Sleep-Wake Schedule ... is yet another problem that many with Bipolar II experience and [it] in large part results from a lack of lifestyle scheduling."
A sleep diary
should be kept to aid in diagnosis and for chronicling the sleep schedule during treatment. Other ways to monitor the sleep schedule are actigraphy
or use of a Continuous Positive Airway Pressure
(CPAP) machine that can log sleeping times
The following are possible warning signs:
Because of the changes in sleep/wake time, and because this is a rare disorder, initially it can seem like another circadian rhythm sleep disorder such as Non-24-hour sleep-wake disorder or like insomnia.
may ask patients about their medical history; for example: neurological problems, prescription or non-prescription medications taken, alcohol use, family history, and any other sleep problems. A thorough medical and neurological exam is indicated. The patient will be asked to complete a sleep diary, recording natural sleep and wake up times, over several weeks. Sleep rating with the Epworth Sleepiness Scale
may be used.
. It charts brain waves, heart beat, muscle activity, and breathing during sleep. It also records arm and leg movement. It will show if there are other sleep disorders that are causing or increasing the problems with ISWD.
is important, and counseling can be helpful. Melatonin, vitamin B12, sleep aids, wake aids, and other medications may also be used. Light during the daytime, and activities occurring at regular times each day, may help to restore a normal rhythm.
Because there are different systems in the body that help establish regulation, it's helpful to employ a multi-modal approach. A 2008 review states that "...each clock is differentially sensitive to zeitgeber
s. The suprachiasmatic nucleus
(SCN) is very responsive to light, the clock in the liver is very sensitive to food, and clocks in muscle are sensitive to exercise."
The following approaches are recommended by one source:
and Brigham and Women's Hospital
. This research includes programs that are staffed by researchers from various departments at the university, including psychiatry, neurology, chemistry, biology. Other major sleep research centers are in Tel Aviv in Israel, Munich in Germany and in cities in Japan.
A wide variety of sleep disorders are actively being researched. Measuring body temperature or melatonin levels may be used. Some hospitals do blood tests for Melatonin levels. Melatonin saliva tests are now available for online purchase. It can also be tested in urine.
Circadian rhythm sleep disorder
Circadian rhythm sleep disorders are a family of sleep disorders affecting, among other things, the timing of sleep. People with circadian rhythm sleep disorders are unable to sleep and wake at the times required for normal work, school, and social needs. They are generally able to get enough sleep...
. It is characterized by numerous naps throughout the 24-hour period, no main nighttime sleep episode and irregularity from day to day. Sufferers have no pattern of when they are awake or asleep, may have poor quality sleep, and often may be very sleepy while they are awake. The total time asleep per 24 hours is normal for the person's age. The disorder is serious—an invisible disability
Invisible disability
Invisible disabilities are disabilities that are not immediately apparent. Some people with visual or auditory disabilities who do not wear glasses or hearing aids, or discreet hearing aids, may not be obviously disabled. Some people who have vision loss may wear contacts...
. It can create social, familial, and work problems, making it hard for a person to maintain relationships and responsibilities, and may make a person home-bound and isolated.
Nomenclature
The current formally correct name of the disorder is Circadian Rhythm Sleep Disorder: Irregular Sleep Wake Rhythm Type. This disorder has been referred to by many other terms, including: Irregular Sleep Wake Pattern, irregular sleep wake syndrome, Irregular Sleep Wake Rhythm, Irregular Sleep Wake Cycle, Irregular Sleep Wake Schedule and Irregular Sleep Wake Disorder (ISWD). Sometimes the words sleep and wake are hyphenated (sleep-wake). Sometimes the words are capitalized and sometimes they are not.Causes
ISWD has various causes, including neurological disorders such as dementia (particularly Alzheimer's Disease), brain damage, or mental retardation. It is thought that sufferers have a weak circadian clock. The risk for the disorder increases with age, but only due to increased prevalence of co-morbid medical disorders.There is a possible reciprocal relationship between bipolar disorder
Bipolar disorder
Bipolar disorder or bipolar affective disorder, historically known as manic–depressive disorder, is a psychiatric diagnosis that describes a category of mood disorders defined by the presence of one or more episodes of abnormally elevated energy levels, cognition, and mood with or without one or...
and sleep disorder
Sleep disorder
A sleep disorder, or somnipathy, is a medical disorder of the sleep patterns of a person or animal. Some sleep disorders are serious enough to interfere with normal physical, mental and emotional functioning...
s: "Irregular Sleep-Wake Schedule ... is yet another problem that many with Bipolar II experience and [it] in large part results from a lack of lifestyle scheduling."
Diagnosis
Sleep diary
A sleep diary is a record of an individual's sleeping and waking times with related information, usually over a period of several weeks. It is self-reported or can be recorded by a care-giver....
should be kept to aid in diagnosis and for chronicling the sleep schedule during treatment. Other ways to monitor the sleep schedule are actigraphy
Actigraphy
Actigraphy is a non-invasive method of monitoring human rest/activity cycles. A small actigraph unit, also called an actimetry sensor, is worn by a patient to measure gross motor activity. Motor activity often under test is that of the wrist, measured by an actigraph in a wrist-watch-like package....
or use of a Continuous Positive Airway Pressure
Continuous positive airway pressure
Positive airway pressure is a mode of respiratory ventilation used primarily in the treatment of sleep apnea, for which it was first developed. PAP ventilation is also commonly used for those who are critically ill in hospital with respiratory failure, and in newborn infants...
(CPAP) machine that can log sleeping times
The following are possible warning signs:
- sleeping off and on in a series of naps during the day and at night, with no regular pattern but with normal total sleep time,
- difficulty getting restorative sleep, and
- excessive daytime sleepiness.
Because of the changes in sleep/wake time, and because this is a rare disorder, initially it can seem like another circadian rhythm sleep disorder such as Non-24-hour sleep-wake disorder or like insomnia.
Initial visit with sleep physician
A physician specializing in sleep medicineSleep medicine
Sleep medicine is a medical specialty or subspecialty devoted to the diagnosis and therapy of sleep disturbances and disorders. From the middle of the 20th century, research has provided increasing knowledge and answered many questions about sleep-wake functioning. The rapidly evolving field has...
may ask patients about their medical history; for example: neurological problems, prescription or non-prescription medications taken, alcohol use, family history, and any other sleep problems. A thorough medical and neurological exam is indicated. The patient will be asked to complete a sleep diary, recording natural sleep and wake up times, over several weeks. Sleep rating with the Epworth Sleepiness Scale
Epworth Sleepiness Scale
The Epworth Sleepiness Scale is a scale intended to measure daytime sleepiness that is measured by use of a very short questionnaire. This can be helpful in diagnosing sleep disorders...
may be used.
Medical testing
A neurological condition or another medical problem may be suspected, in which case, blood tests, a CT scan or an MRI may be used. An overnight sleep study is usually not needed to detect this disorder, but may be indicated if other sleep disorders, such as sleep apnea and periodic limb movement disorder, seem likely. The overnight sleep study is called polysomnographyPolysomnography
Polysomnography , also known as a sleep study, is a multi-parametric test used in the study of sleep and as a diagnostic tool in sleep medicine. The test result is called a polysomnogram, also abbreviated PSG...
. It charts brain waves, heart beat, muscle activity, and breathing during sleep. It also records arm and leg movement. It will show if there are other sleep disorders that are causing or increasing the problems with ISWD.
Management
Treatment for irregular sleep-wake rhythm tries to enable the body clock in the brain, such that a normal long sleep period at night can be achieved. Education about sleep hygieneSleep hygiene
Sleep hygiene can be defined as the controlling of "all behavioural and environmental factors that precede sleep and may interfere with sleep." It is the practice of following guidelines in an attempt to ensure more restful, effective sleep which can promote daytime alertness and help treat or...
is important, and counseling can be helpful. Melatonin, vitamin B12, sleep aids, wake aids, and other medications may also be used. Light during the daytime, and activities occurring at regular times each day, may help to restore a normal rhythm.
Because there are different systems in the body that help establish regulation, it's helpful to employ a multi-modal approach. A 2008 review states that "...each clock is differentially sensitive to zeitgeber
Zeitgeber
Zeitgeber is any exogenous cue that synchronizes an organism's endogenous time-keeping system to the earth's 24-hour light/dark cycle. The strongest zeitgeber, for both plants and animals, is light...
s. The suprachiasmatic nucleus
Suprachiasmatic nucleus
The suprachiasmatic nucleus or nuclei, abbreviated SCN, is a tiny region on the brain's midline, situated directly above the optic chiasm. It is responsible for controlling circadian rhythms...
(SCN) is very responsive to light, the clock in the liver is very sensitive to food, and clocks in muscle are sensitive to exercise."
The following approaches are recommended by one source:
- Spend <7–8 hours in bed.
- Add environmental cues such as light and social interactions, regular meal times, and regular sleep-wake times.
- Morning and eve light at 3000 lux for 2 hours have been shown to improve nocturnal sleep in institutionalized patients and reduce agitation in demented patients.
- Melatonin at desired sleep time.
Research
There is currently a great deal of active research on various aspects of circadian rhythm; this often occurs at major universities in conjunction with sleep research clinics at major hospitals. An example is the program with Harvard Medical SchoolHarvard Medical School
Harvard Medical School is the graduate medical school of Harvard University. It is located in the Longwood Medical Area of the Mission Hill neighborhood of Boston, Massachusetts....
and Brigham and Women's Hospital
Brigham and Women's Hospital
Brigham and Women's Hospital is the largest hospital of the Longwood Medical and Academic Area in Boston, Massachusetts. It is directly adjacent to Harvard Medical School of which it is the second largest teaching affiliate with 793 beds...
. This research includes programs that are staffed by researchers from various departments at the university, including psychiatry, neurology, chemistry, biology. Other major sleep research centers are in Tel Aviv in Israel, Munich in Germany and in cities in Japan.
A wide variety of sleep disorders are actively being researched. Measuring body temperature or melatonin levels may be used. Some hospitals do blood tests for Melatonin levels. Melatonin saliva tests are now available for online purchase. It can also be tested in urine.
See also
- Advanced sleep phase syndromeAdvanced sleep phase syndromeAdvanced sleep phase syndrome , also known as the advanced sleep-phase type of circadian rhythm sleep disorder, is a condition in which patients feel very sleepy and go to bed early in the evening and wake up very early in the morning Advanced sleep phase syndrome (ASPS), also known as the...
- ChronobiologyChronobiologyChronobiology is a field of biology that examines periodic phenomena in living organisms and their adaptation to solar- and lunar-related rhythms. These cycles are known as biological rhythms. Chronobiology comes from the ancient Greek χρόνος , and biology, which pertains to the study, or science,...
- Circadian rhythmCircadian rhythmA circadian rhythm, popularly referred to as body clock, is an endogenously driven , roughly 24-hour cycle in biochemical, physiological, or behavioural processes. Circadian rhythms have been widely observed in plants, animals, fungi and cyanobacteria...
- Delayed sleep phase syndromeDelayed sleep phase syndromeDelayed sleep-phase syndrome , also known as delayed sleep-phase disorder or delayed sleep-phase type , is a circadian rhythm sleep disorder, a chronic disorder of the timing of sleep, peak period of alertness, the core body temperature rhythm, hormonal and other daily rhythms, compared to the...
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