Delayed Sleep Phase Syndrome (DSPS) is one of the circadian rhythm disturbances. This sleep disorder is characterized by a delay in the sleep-wake cycle, where the patient experiences difficulty to falling asleep and awakening at socially accepted times. The person stays up late and sleeps late.
DSPS is often misdiagnosed as psychophysiological insomnia, depression, psychiatric disorders, or some other sleep disorder.
Actigraphy is a measurement of movement during sleep. There are different ways to set up the sensors; one commonly use system is wrist actigraphy. Actigraphy is frequently used to diagnose DSPS. Actigraphy is a procedure in which a small instrument (the actigraph) is worn on the wrist or ankle. The actigraph is worn on the non-dominant limb for at least one week to record the person’s motor activity. The recorded data is later analyzed by computer to assess the sleep-wake cycle. Lately, actigraphy has been replacing the use of full polysomnography in the diagnosis of sleep disorders.
Is wrist actigraphy reliable? It is not a reliable as full-blown polysomnography, but it can provide useful information. A Dept of Veterns Affairs study found wrist actigraphy got about the same results as more full-blown polysomnography when it comes to total sleep time, wake after sleep onset, and sleep efficiency. It is not so good at evaluating sleep-onset latency times.
Treating DSPS patients basically revolves around adjusting the circadian rhythm and sleep pattern to allow them to live normal lives and fulfill the social demands of day to day life - to fall asleep normally, wake up when necessary, feel rested and motivated. Treatment includes bright light therapy, chronotherapy or medication. Patients are also advised to stick to regular daily routines and avoid stimulants including caffeine. Medications prescribed may include Vitamin B12, melatonin and/or sleeping aids. In more severe cases, bright light therapy may be used. The patient is exposed to bright light in the early morning.
Actigraphy is sometimes used in conjuction with logs of sleep patterns to diagnose sleep disorders.
Chronotherapy is a behavioral technique in which bedtime is systematically adjusted. Bright-light therapy is designed to reset a person’s circadian rhythm to the desired pattern. When combined, these therapies might produce significant results in people with DSPS. Patients can also be treated with one medicine that puts them to sleep earlier in the evening and another medicine that helps wake them up in the morning, but this form of treatment is usually used only in extreme cases.
Melatonin can be taken in the evening to advance sleep and circadian phases. But the science on melatonin is unsure and even sleep doctors don't know the right dose or when it should be taken.