Sleep and Activity Disorders of Childhood

Sleep and Activity Disorders of Childhood
Sleep problems are common in childhood. A distinction is made between problems in which polysomnography (PSG) is abnormal (i.e., the parasomnias, sleep apnoea and narcolepsy) and problems that are behavioural in origin and have normal polysomnography.

The parasomnias-sleep terrors, somnambulism and enuresis-appear to be related to central nervous system immaturity and are often outgrown. Obstructive sleep apnoea syndrome (OSAS) is frequently missed in children and can often be cured through surgery.

Behavioural sleep problems may be overcome after parents make interventions.
Physicians and Therapists can be of great assistance to these families by recommending techniques to parents that have been shown to be effective.

The most commonly encountered childhood sleep disorders are:

Nightmares
For most children dreams are pleasant experiences of everyday events. Whilst nightmares are infrequent, often very real, and soon forgotten, for some children they are very disturbing, particularly if frequent or the child dwells on them for several days for example by repetitive acting out of the nightmare with toys; a dread of sleep; struggling to stay awake. So the impact of nightmares should be weighed up with the effect these have on the child's life in general.

Sleep Paralysis
Paralysis can occur in children when they wake up suddenly out of a nightmare and find that they can not move or call out for their parents. The motor inhibition of REM sleep is still active, and may take from seconds to minutes to lift; all the sufferer can do is to breathe, move the eyes and possibly, moan. This is alarming and adds to the child's distress, especially if the dream imagery continues into this wakefulness, as can happen. Younger children may have difficulty in explaining these events and this adds to the parents' concern. Such experiences, which have a neurological basis, usually remit by early adolescence. True familial sleep paralysis is much rarer, and typically happens at sleep onset and/or on awakening, and may well be a symptom of narcolepsy, although, it can occur in isolation. However, narcolepsy seldom appears before adolescence. Both forms of sleep paralysis can often be terminated prematurely by sustained voluntary eye-movement or, if possible, by touch from someone else.

REM Sleep Behaviour Disorder
During REM sleep voluntary muscle are paralysed in order to stop dreams being enacted. In rare circumstances, the paralysis is absent, and if a dream is violent, then harm may come to the sleeper and nearby persons. Although these behaviours are usually correctly diagnosed by patients or their parents, as violent nightmares, they are misunderstood. This disorder has been more frequently reported in adults, but has been found in children. More careful examination usually discloses hindbrain lesions of REM sleep control mechanisms. The most effective treatment is by drugs which suppress REM sleep and psychotherapy such as Hypnosis or Acupuncture.

Sleepwalking
When children are forcibly roused out of stage 2 sleep, a lighter form of non-REM sleep, "thinking" is often reported, which contrasts with the gross visual imagery, unrealism, and more vivid actions of dreaming usually found (but not wholly) in REM sleep. Such thinking is less prevalent in SWS. Sometimes, more disturbing mental events can occur during SWS, with the most notable being sleepwalking (somnambulism) and night terrors (pavor nocturnes), with the latter being quite distinct from the nightmares of dreaming sleep.

These SWS phenomena can be found together. They mainly occur in childhood and tend have some hereditary basis. Sleepwalking peaks in adolescence, but declines rapidly by the late teens. Episodes are often triggered by anxiety; in susceptible children, the worry can be trivial - the loss of a favourite toy, or just a frustrating day. Only in serious cases, when sleepwalking occurs most nights, might there be severe distress and underlying emotional conflict, requiring intervention.

Children are particularly difficult to arouse from SWS, and even very loud sounds of 123 dB can have no effect. It is difficult to wake up a sleepwalking child, and is unwise to do so, as distress or a wild and emotional outburst may set in. It is best to guide or carry them back to bed. As many sleepwalking episodes occur within the first two hours of sleep (when SWS is most prolific), parents are usually still up.

The mind of a sleepwalker is unresponsive to what is going on around and seems steeped in thought. The sleepwalker behaves like an automaton with a limited repertoire of behaviour, but does not walk about with the hands out in front, as is commonly portrayed. There is no memory of the nocturnal activities the next day. Episodes can last up to 30 minutes, but usually average 5-15 minutes.

Sleep EEG recordings of sleep walkers show that they usually remain in SWS whilst sleepwalking, with few signs of arousal. Typically, in a sleepwalking episode the child will sit up quietly, get out of bed and move about in a confused and clumsy manner. Although behaviour becomes more coordinated, the sleepwalker tends to remain in the bedroom, often preoccupied by searching for something in drawers, cupboards or under the bed. It is almost impossible to attract their attention; however, if left alone they normally go back to bed. Navigation is done mostly by memory of the layout of the room and house; the eyes are unseeing and usually it is dark. If the sleepwalker is asked to repeat the act the next day, in wakefulness and blindfolded, then he or she will soon come to grief as recall of the houshold layout is now poor, but somehow heightened during sleep. Difficulties and sometimes injuries occur to sleep-walkers at night if they think they are somewhere else, when walls, doors, staircases and windows are not where they should be.

Night Terrors
These are another phenomenon of deep sleep (SWS) and are sometimes associated with sleep-walking. They are quite distinct from the visually vivid, prolonged nightmare, and are not just bad dreams, but sudden and horrifying sensations accompanying fleeting mental images that shock the sleeper into immediate wakefulness. Night-terrors are also more common in older children than in adults, where, in the latter, the problem is more serious. Typically, the child sits abruptly up in bed, screams and appears to be staring wide-eyed at some imaginary object - maybe "a monster". When this part of the episode passes the child appears to awaken somewhat but is confused and disoriented. They may well remain like this for many minutes until sleep returns, having little or no recollection of the event next morning.

Night terrors can be combined with sleepwalking, particularly in adolescence, when the terrified child may run around the house in an inconsolable and incommunicable state for many minutes; half an hour or more is not uncommon. Again, morning recollection is fragmentary at best.

Toothgrinding
Bruxism is a minor disorder usually found in stages 1 and 2 sleep, and has a tendency to be related to anxiety and/or stressing days. It can occur in children soon after the first dentition has erupted and may lead to tooth damage and misalignment. For this reason a night-time rubber mouthguard is often used. If anxiety is indicated, then relaxation treatments can be successful.

ADHD
More recently there has been an increasing interest in the role of sleep in children diagnosed with Attention Deficit Hyperactivity Disorder (ADHD). Difficulty falling asleep, restless sleep, night waking, and early morning waking are frequently reported in patients with ADHD. Some professionals now regard sub-groups of these patients as having a primary sleep disorder. More than 40% of patients with ADHD report significant sleep disturbance including insomnia and parasomnias. There is also evidence that inadequate sleep can cause ADHD-like symptoms in some children. Sleep loss in children results in symptoms of inattention, irritability, distractibility and impulsiveness - the core features of ADHD. The evaluation of sleep and activity through the use of Actigraphy is now recommended as a part of the diagnostic workup of children with symptoms of inattention and impulsiveness.

The relationship between ADHD and sleep is complex and requires further research. It is precisely for this reason that the Sleep Medicine group of sleep centres is about to embark on a research project to objectively measure sleep parameters in patients with ADHD.