Arousal Disorders

Arousal Disorders in Children

Arousal disorders are common in children. Arousal does not mean that the child wakes-up. The “arousal” is a partial arousal usually from “deep” sleep also called “slow wave sleep”. Most commonly the child transitions from deep sleep to a mixture of very light sleep and/or partial wakefulness. This stage shift will commonly lead to a confusional state or a “confusional arousal”. During such an episode, the child presents features suggestive of being simultaneously awake and asleep. On one hand, the child may appear to be alert by crying very loudly, moving, or even running. However, the child simultaneously appears to be disoriented, and confused. They can be relatively unresponsive to solicitations from parents as well as from other environmental challenges. There is usually little or no recall of the arousal or any event that may had occurred during the episode the next morning or even 10 to 30 minutes later if the child is to awaken completely.

Various behaviors can occur during sleep ranging from simple to complex activities. Simple behaviors would include mumbling during sleep or sitting up in bed then falling right back asleep. However, more elaborate behaviors are also possible, for example crying loudly in distress, inconsolable and ignoring the reassurance of the parents, seemingly “very far away.” The child may even exhibit aggressive behavior against parents that want to reassure the child and trying to escape an embrace. Finally, very complex behaviors such as sleep walking are possible. The child may quietly walk around the bedroom or rush around in highly agitated state hitting the furniture. The complex behaviors may seems goal oriented or they may be poorly directed. For example, a child may go into a closet looking for the bedroom door, or may go into a closet and urinate before returning to bed.

Usually only one episode occurs during the night and often it is within the first 2 hours of falling asleep However, there are always exceptions to this rule. There may be periods where a child has several episodes during a single night and then go several weeks without a single episode.

Possible triggers for episodes

It seems that a small disruption of sleep due to another cause, such as a health problem or travel, may elicit behaviors associated with confusional arousals. It was shown that fever, abrupt sleep loss, migraine, irregular sleep-wake schedules can be more associated with these events. It was also shown that another sleep disorder such as sleep-disordered-breathing and to a lesser extent restless legs syndrome or nocturnal asthma may be seen in association with the confusional behaviors.

One hypothesis is that the other health problem (fever, sleep-disordered-breathing as an example) already disturbs sleep, particularly when the child is trying to go to deep sleep. The health problem brings the child very abruptly from the deep sleep to a near awakening. It has also been hypothesized that stress or anxiety could be an added trigger. In older teenagers, alcohol intake and sleep deprivation must also be taken into consideration.

Common arousal disorders

The most common confusional behavior syndromes are sleep terrors and sleep walking. When these behaviors are chronic they must be investigated. An epidemiological survey performed on school children in the Tucson (AZ) area found that in this group of children seen outside of a clinic setting, the most common association (though not the only one) with chronic sleepwalking was sleep-disordered-breathing. Other studies have shown that treatment of the associated sleep disorder can positively reduce or eliminate the confusional behaviors. Treating an abnormal sleep-wake schedule and/or reducing stressful conditions has also been associated with the resolution of associated health problems.

The notion that chronic abnormal behavior during sleep has been associated with other sleep disorders, such as sleep-disordered-breathing, is the justification for recommending nocturnal polysomnography when a child presents such a chronic syndrome.

Seizure disorders

A question often raised is: Does my child have a seizure disorder? The presentation of nocturnal seizure with abnormal behavior during sleep is rare: it has been shown that 98% of the time no seizure disorder is present. Most commonly the clinical presentation is different and a clinical interview will allow the physician to dissociate the two problems. In the difficult cases, a polysomnographic evaluation performed with a seizure montage will help confirm the diagnosis.