Circadian Rhythm Disorders or Sleep-Wake Cycle Disorders: An important cause of irregular sleep pattern in children!

All humans have a sleep-wake cycle which nearly remains the same with minor variations and repeats roughly every 24 hours. This natural, internal process is called the circadian rhythm. The circadian rhythm is controlled by the suprachiasmatic nucleus located in our brains. The sleep-wake cycle is further modulated with the external world factors like light, melatonin, physical activity, body temperature, and meals.

A circadian rhythm sleep disorder occurs when the internal biological clock gets out of sync with the child’s environment. The onset of these disorders are most common in adolescence, with the peak age in the 20s.

What are the common Circadian Rhythm Disorders in Children?
The common circadian rhythm disorders are delayed sleep phase type (sleeps late and wakes late), advanced sleep phase type (sleeps early and wakes early), free-running type, shift work type and jet lag type.

What are the symptoms of circadian sleep wake disorders?
The most common type of circadian sleep wake disorders are delayed sleep wake disorders. In delayed sleep phase disorder the child finds difficulty falling asleep and waking up at socially acceptable times (at least a two-hour delay). The child would have quite late bedtimes (2 am or later) and difficulty awakening on normal times. However, once the child sleeps there are no frequent night-time awakenings. The child usually has no problems with daytime functioning; but occasionally, the child is sleepy in the day, unable to wake for school and experience poor school performance. This usually happens when the child wakes up early in the morning and the duration of sleep is Markedly reduced. However, children would have delayed sleep wake disorders when they sleep for an adequate duration of time especially at weekends, their daytime functioning is absolutely normal.

Circadian Rhythm Disorders or Sleep-Wake Cycle Disorders

Advanced sleep wake disorders are much rarer as compared to delayed sleep wake disorders. Children who have advanced sleep wake disorders tend to sleep very early for example 6:00 PM or 7:00 PM, but wake up quite early at 2:00 AM or 3:00 AM in the night.

How do we diagnose a circadian sleep week disorder?
The diagnosis of a circadian sleep week disorder requires a documentation of sleep and wake times on a sleep diary for two weeks. This usually suffices in children. In situations where the diagnosis is unclear further testing might be required. The most useful investigation for diagnosis of circadian sleep wake disorders is an Actigraphy. Actigraphy is a very simple investigation and is in the form of a smart watch which can be worn by the child for a period of 2 weeks. It measures the child's activity in relation to the 24 hours days cycle and the amount of light in the environment. In some children, if there is suspicion of an underlying obstructive sleep apnea or a restless legs syndrome or periodic limb movement disorder, a sleep study or polysomnography might be warranted.

How do we treat children with circadian sleep wake disorders?
Treatment of. Circadian sleep wake disorders involve aligning the circadian rhythm with desired sleep-wake times. This requires good sleep hygiene, reducing electronics use and using melatonin. In some children, light therapy, also known as chronotherapy, is used. When the child is exposed to bright light in the morning it leads to production of melatonin which maintains wakefulness.

In case your child is having difficulty in the initiation of sleep or finds it difficult to sleep at appropriate times or is extremely sleepy during the day it can be a Circadian Rhythm Sleep Disorder. You need to get in touch with the child sleep specialist for proper evaluation and treatment.

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